JP6545578B2 - Media transport apparatus and media transport method - Google Patents

Description

  The present invention relates to a media transport apparatus and a media transport method.

  2. Description of the Related Art Conventionally, as an image forming apparatus, for example, an ink jet printer is known which performs printing by discharging ink on a medium such as a recording sheet which is a print target by an ink jet method.

In the present specification, “media” refers to various recording media such as plain paper and the like, as well as various resin materials such as PCV and polyester, and various materials such as aluminum, iron and wood. Materials shall be included.

  In such an image forming apparatus such as an inkjet printer, for example, as disclosed in Japanese Patent No. 5471205 disclosed as Patent Document 1 and Japanese Patent Laid-Open No. 2008-137196 disclosed as Patent Document 2, media are stabilized. A medium provided with suction means for providing a plurality of holes on the surface of the platen on which the medium is placed and for sucking air from the lower side of the platen to suck the medium onto the platen in order to transport the medium on the platen. A transport device is used.

In the media conveyance device having such suction means, the medium is sucked onto the platen by suctioning air by the suction means to generate negative pressure in the space below the medium, and the medium floats from the platen during printing. In addition, it is possible to prevent printing failure due to a change in the position of the medium in the height direction during conveyance.

  By the way, since the media is sequentially transported on the platen during printing by the image forming apparatus, the number of holes blocked by the media varies depending on which portion of the media is positioned on the platen. .

  That is, at the start of printing on the medium, only a part of the holes are blocked by the medium, but when the conveyance of the medium progresses as the printing progresses, the area of the medium located on the platen gradually increases, The number of holes blocked by the media also increases. Further, as conveyance proceeds and printing on the media is completed, the area where the media is located on the platen decreases, and the number of holes blocked by the media decreases as the area of the media located on the platen decreases. .

Here, as described above, the suction means sucks the media onto the platen, and the suction force of the media onto the platen is negative between the media and the platen because the media blocks the hole. Although it depends on the area of the area where pressure is generated (hereinafter referred to as "negative pressure area"), in the conventional media transport apparatus, the suction force of the suction means is constant, so that the medium is blocked. The larger the number of holes that are ejected, that is, the larger the negative pressure area, the more the media will be attracted by the platen.

  That is, in the process of conveying the above-described series of media at the time of printing, the suction force by the suction means is constant despite the change in the number of holes blocked by the medium during conveyance. Depending on the position of the media, the negative pressure generated by the suction unit is too large, and the adsorption force of the media on the platen becomes high, making it difficult to transport, or the negative pressure is too small, the adsorption force of the media on the platen is low. As a result, the media can not be held, and the amount of transport of the media per unit time fluctuates, and the media can not be stably positioned on the platen.

  For this reason, there has been a demand for a method that can suppress the fluctuation of the transport amount of the media per unit time and can stably position the media on the platen.

  In addition, if the negative pressure is too weak when printing on the edge of the media, it is difficult to hold the media, and printing on the edge is not performed correctly, and so-called borderless printing to the center of the media is performed. There is a problem that a difference occurs in finishing between printing and printing on the end.

  For this reason, there has been a demand for a method that enables good borderless printing.

Patent No. 5471205 gazette JP 2008-137196 A

  The present invention has been made in view of the above-described various problems of the prior art, and the object of the present invention is to suppress the fluctuation of the transport amount of the media per unit time, and It is an object of the present invention to provide a media transport apparatus and a media transport method capable of stably positioning media on

  Another object of the present invention is to provide a media transport apparatus and media transport method that can enable good borderless printing.

In order to achieve the above object, the present invention controls the suction force of suction means for suctioning the medium onto the platen based on the area of negative pressure area formed on the platen closed by the medium located on the platen It is intended to

That is, according to the present invention, there is provided a platen which is provided below the ink head and which has a plurality of holes arranged in a row and which is provided with the media on the upper surface, and which is disposed under the platen. And a suction means for suctioning the medium with a predetermined suction force via the medium, wherein the medium suction device sucks the medium through the hole and sucks the medium onto the platen while conveying the medium. Acquisition means for acquiring an area of negative pressure area which is an area of an area where a negative pressure is generated between the medium and the platen by closing the hole by the medium located on the platen; Control means for controlling the suction means to achieve a suction force suitable for the negative pressure area obtained by the means, the control means increasing the negative pressure area Reducing the suction force of the suction means, and when the negative pressure region area decreases to increase the suction force of the suction means.

Further, according to the present invention, in the above-described invention, when the end located on the front side in the transport direction of the medium is located below the ink head, the end located on the rear side in the transport direction of the medium Is positioned below the ink head, the suction means is controlled so as to maximize the suction force.

  Further, according to the present invention, there is provided a platen which is provided on the lower side of the ink head and which has a plurality of holes arranged in an array and which is provided on the upper surface and a lower side of the platen. And a suction means for suctioning the medium with a predetermined suction force via the medium, wherein the medium suction device sucks the medium through the hole and sucks the medium onto the platen while conveying the medium. An acquisition step of acquiring a negative pressure area which is an area of a region where a negative pressure is generated between the medium and the platen by the medium located on the platen closing the hole. And a control step of controlling the suction unit so as to obtain a suction force suitable for the negative pressure area obtained in the acquisition step; When the negative pressure region area increases to reduce the suction force of the suction means, and to increase the suction force of the suction means when said negative pressure region area decreases.

  Further, according to the present invention, in the above-described invention, the end located on the front side in the transport direction of the medium is located below the ink head, and the end located on the rear side in the transport direction of the medium is When positioned below the ink head, the suction means is controlled to maximize the suction force.

  Since the present invention is configured as described above, it is possible to suppress the fluctuation of the transport amount of the media per unit time, and to provide the media transport device and the media transport capable of stably positioning the media on the platen. The excellent effect of being able to obtain the method is achieved.

  Further, since the present invention is configured as described above, it is possible to obtain an excellent effect of being able to obtain a media transport apparatus and a media transport method capable of excellent borderless printing.

FIG. 1 is a schematic cross-sectional explanatory view of an inkjet printer provided with a media conveyance device according to the present invention. FIGS. 2 (a) (b) (c) (d) are conceptual explanatory diagrams showing the media conveyance method according to the present invention. FIGS. 3A, 3B, 3C, and 3D are conceptual explanatory diagrams showing a media conveyance method according to the present invention.

  Hereinafter, with reference to the accompanying drawings, an example of an embodiment of a media conveyance device and a media conveyance method according to the present invention will be described in detail.

  FIG. 1 is a schematic cross-sectional explanatory view of an inkjet printer provided with a media conveyance device according to the present invention.

  In the ink jet printer 10, for example, a plate-like body having a predetermined flexibility such as a styrene board or a plastic cardboard can be used as a medium to be printed.

  The media is not limited to a plate-like body, and may be a roll-like or film-like media.

Further, although a flatbed type inkjet printer is used in the present embodiment, the inkjet printer is not limited to the flatbed type, and may be a type that performs printing on media such as a roll.

  An ink jet printer 10 equipped with the media conveyance device shown in FIG. 1 is a flat bed type ink jet printer.

  The ink jet printer 10 controls the whole of the ink jet printer 10 and the position of the medium M on the platen 20, and controls the suction force of the suction means to be described later. And a microcomputer 10a.

  In the ink jet printer 10, the media M is inserted from the media inlet 12a located on the rear side in the sub scanning direction, which is the transport direction, and printing is started, and the media M after printing is located on the front side in the sub scanning direction It is discharged from the media outlet 12b.

  More specifically, the medium transport device 14 is disposed in the main body 12 so as to be rotatable in parallel in the sub scanning direction, and supports the medium M from below to front the medium M in the sub scanning direction. A rear roller 18 is disposed to convey the sheet to the side.

  A platen 20 described later is disposed on the front side of the rear roller 18 in the sub scanning direction.

  On the front side in the sub-scanning direction of the platen 20, the main body 12 is rotatably disposed in parallel along the sub-scanning direction in the inside of the main body 12 to support the medium M from below and front the medium M in the sub-scanning direction A front roller 22 is disposed to convey the sheet to the side.

  Above the platen 20, an ink head 26 is disposed which ejects ink from a plurality of ink nozzles (not shown) to the medium M while moving in a main scanning direction orthogonal to the sub scanning direction.

Reference numeral 24 denotes a rear side media bar which is rotatably disposed at a position facing the upper side of the rear roller 18 and urges the medium M from the upper side of the medium M to be conveyed. It is a front side media bar which is rotatably disposed at a position opposite to the upper side of the front roller 22, and urges the medium M from above the medium M to be conveyed.

Here, when the medium M is positioned on the rear side in the sub scanning direction, the medium M is sandwiched and conveyed by the rear roller 18 and the rear side media bar 24, and the medium M is conveyed to the front side in the sub scanning direction. Then, the pressure contact of the medium M by the rear roller 18 and the rear side media bar 24 is released, and the medium M is nipped and conveyed by the front roller 22 and the front side media bar 28.

  The platen 20 is a plate-like member having a predetermined length in the sub scanning direction and extending in the main scanning direction, and both ends in the main scanning direction are locked in the main body 12.

  As a position of the platen 20 in the height direction, the upper surface of the platen 20 is disposed lower than a horizontal surface in contact with the upper end edge of the front roller 22 and the upper end edge of the rear roller 18.

  The platen 20 may be disposed so that the upper surface of the platen 20 is at the same height as a horizontal surface in contact with the upper end edge of the front roller 22 and the upper end edge of the rear roller 18.

  A plurality of holes 20aa are bored in the platen 20 along the main scanning direction. In addition, it is preferable that the opening area of each hole of several holes 20aa is the same.

  Further, the plurality of holes 20aa are arranged in a plurality of rows in the sub-scanning direction.

  In the present embodiment, it is assumed that, for example, 20 holes 20aa are bored in the main scanning direction, and six rows are arranged in the sub-scanning direction.

The medium M inserted from the medium inlet 12 a on the platen 20 is conveyed, and the ink is ejected onto the medium M by the ink head 26 on the platen 20 to perform printing.

  Next, the area under the platen 20 will be described. The intake area 20a and the suction fan 20b are disposed immediately below the platen 20.

  The intake area 20a is a box-like body having an open upper portion having a space therein, and the platen 20 is disposed on the upper surface thereof.

  In addition, the suction fan 20b is disposed on the lower side of the suction area 20a so as to be connected to the suction area 20a, and can suction air in the suction area 20a.

By driving the suction fan 20b, a negative pressure is generated in the suction area 20a, and the suction fan 20b is placed on the platen 20 through the hole 20aa formed in the platen 20 located above the suction area 20a. The medium M can be adsorbed onto the platen 20.

In addition, about the other structure of the inkjet printer 10, since it is possible to use a conventionally well-known technique, it abbreviate | omits about the detailed description.

  A method of transporting the medium M in the ink jet printer 10 having the media transport device 14 in the above configuration will be described.

  First, the full length of the medium M, that is, the dimension in the sub scanning direction is registered in the ink jet printer 10. Here, the full length of the medium M is registered in the ink jet printer 10 by the user using input means (not shown) and stored in the microcomputer 10a.

In this case, the total length of the medium M may be input, or the size defined by a predetermined standard may be input.

  Next, the medium M is placed on the platen 20 so that the front end of the medium M is located at the reference position provided on the platen 20.

  Here, the reference position is a reference provided to calculate the transport amount of the medium M on the platen 20, and is the start position of the transport of the medium M (hereinafter, the reference position We call it "." The start position of the transfer is stored in advance in the microcomputer 10a.

  The user inserts the media M from the media inlet 12a, and places the end of the media M at the start position of transportation.

  The microcomputer 10 a of the ink jet printer 10 stores the arrangement of the holes 20 aa formed in the platen 20, the total length or size of the medium M, the conveyance speed of the medium M, and the start position of the conveyance of the medium M As the medium M is transported, the number of holes 20 aa blocked by the medium M located on the platen 20 and the negative pressure area area are acquired.

Then, based on the negative pressure area according to the number of holes 20 aa blocked by the media M located on the platen 20, the microcomputer 10 a sucks so as to have an adsorption force suitable for the media M on the platen 20. The suction force of the fan 20b is adjusted to control the transport of the medium M.

Here, when transporting the medium M, immediately after the start of printing and just before the end of printing, the number of the holes 20aa blocked by the medium M is the smallest in the series of printing, and the negative pressure area is reduced. Then, the medium M is held by being suctioned by the suction fan 20 b through a part of the holes 20 aa blocked by the medium M. In order to stably place the medium M on the platen 20 for conveyance and printing via only such a portion of the holes 20aa, the suction force of the suction fan 20b is greater than when the negative pressure area is large. You need to raise it.

  When printing is started and the medium M is transported, the area of the medium M located on the platen 20 gradually increases, the number of holes 20aa blocked by the medium M increases, and the negative pressure area increases. . In such a case, the suction power of the suction fan 20b is lowered along with the increase in the number of the holes 20aa blocked by the medium M, and the suction power of the suction fan 20b does not become the suction power that hinders conveyance. Adjust the

  When the area of the medium M located on the platen 20 gradually decreases and the number of the holes 20aa blocked by the medium M decreases as printing is completed, the negative pressure area decreases. In such a case, the suction power of the suction fan 20b is increased as the number of the holes 20aa blocked by the medium M decreases.

In addition, while the number of the holes closed by the medium M is the same number, it is preferable to maintain the same suction force and to carry.

  The media M in the ink jet printer 10 according to the present embodiment will be described by taking the cases shown in FIGS. 2A, 2B, 2C, 2D and 3A, 3B, 3C, 3D as an example below. The method of transporting the

  FIG. 2A shows a state in which a part of the medium M including the front end is located on the platen 20 after the medium M is inserted from the medium inlet 12 a.

  When the medium M is in the position shown in FIG. 2A, among the six lines of holes 20aa formed in the platen 20, the three lines of holes 20aa arranged on the rear side are blocked by the medium M. ing.

In the present embodiment, as shown in FIG. 2A, the suction fan 20b for stably holding the medium M on the platen 20 in a state where the medium M blocks the holes 20aa on the rear side three rows. The suction power of is 100%.

  Next, in the ink jet printer 10, when printing on the medium M at the position shown in FIG. 2A is completed, the medium M is sequentially transported to the front side in the sub scanning direction to print on the next area of the medium M. For example, the medium M is transported to the position shown in FIG. In this case, among the plurality of holes 20aa formed in the platen 20, the holes 20aa in the rear four rows in the sub-scanning direction are blocked by the medium M.

In FIG. 2B, as compared with the case shown in FIG. 2A, the number of holes 20aa blocked by the medium M increases, and the negative pressure area increases. Therefore, the medium M can be stabilized by operating the suction fan 20b with a suction force of 80%, which is smaller than the case shown in FIG. 2A.

  Next, when the medium M is conveyed to the position shown in FIG. 2C, of the plurality of holes 20aa formed in the platen 20, the holes 20aa on the rear side five rows in the sub scanning direction are blocked by the medium M Be

In FIG. 2C, as compared with the case shown in FIG. 2B, the number of holes 20aa blocked by the medium M increases, and the negative pressure area increases. Therefore, the medium M can be stabilized by operating the suction fan 20b with a suction force of 60%, which is smaller than the case shown in FIG. 2B.

  Furthermore, when the medium M is conveyed to the position shown in FIG. 2D, all of the plurality of holes 20aa formed in the platen 20 are blocked by the medium M.

In FIG. 2D, compared to the case shown in FIG. 2C, the number of holes 20aa blocked by the medium M increases, and the negative pressure area increases. Therefore, the medium M can be stabilized by operating the suction fan 20b with a suction force of 40% smaller than the case shown in FIG. 2C.

The suction force of the suction fan 20b is advanced until the conveyance of the medium M proceeds and the rear end of the medium M approaches the row of holes 20aa located in the last row on the platen 20, as shown in FIG. 3A. Maintain at 40%.

When the conveyance of the medium M proceeds and the medium M is conveyed to the position shown in FIG. 3B, the holes 20aa in the rearmost row in the sub-scanning direction are opened. In FIG. 3B, the number of the holes 20aa blocked by the medium M is reduced compared to the case shown in FIG. 3A, and the negative pressure area area is reduced. Therefore, the medium M can be stabilized by operating the suction fan 20b with a suction force of 60%, which is larger than the case shown in FIG. 3A.

Next, when the medium M is conveyed to the position shown in FIG. 3C, the two rows of holes 20aa on the rear side in the sub-scanning direction are opened. In FIG. 3C, the number of the holes 20aa blocked by the medium M is reduced compared to the case shown in FIG. 3B, and the negative pressure area is reduced. Therefore, the medium M can be stabilized by operating the suction fan 20b with a suction force of 80%, which is larger than the case shown in FIG. 3B.

Furthermore, when the medium M is conveyed to the position shown in FIG. 3D, only a part of the medium M is positioned on the platen 20, and only the front three rows of holes 20aa are blocked by the medium M. Be In FIG. 3D, the number of the holes 20aa blocked by the medium M is reduced compared to the case shown in FIG. 3C, and the negative pressure area area is reduced. Therefore, the medium M can be stabilized by operating the suction fan 20b with a suction force of 100% larger than that shown in FIG. 3C.

That is, in the ink jet printer 10 provided with the media conveyance device 14, the suction force of the suction fan 20b is reduced as the negative pressure area increases due to the increase in the number of holes blocked as the medium M is conveyed. Control the suction fan 20b so that the number of the holes 20aa blocked by the medium M decreases and the negative pressure area decreases, and accordingly the suction fan 20b is controlled to increase the suction force of the suction fan 20b. It is

Then, according to the present embodiment, the end on the front side in the transport direction of the medium M corresponding to a state where so-called borderless printing is performed is located below the ink head (FIG. 2A) The media M is stably held even when the end on the rear side in the transport direction of the media M is located below the ink head (see FIG. 3D). It is possible to print on the edge of the medium M.

As described above, according to the media conveyance device and medium conveyance method of the present invention, the suction fan 20b is controlled to increase or decrease the suction force of the suction fan 20b from the print start to the print end according to the negative pressure area. It was made to do.

  As a result, it is possible to suppress the fluctuation of the transport amount of the media per unit time and stably position the media on the platen.

In addition, even when so-called borderless printing is performed, good borderless printing is possible.

  The above-described embodiment can be modified as shown in the following (1) to (3).

  (1) In the embodiment described above, the suction power is increased or decreased by 10% by the suction fan to change the suction power in stages, but of course the present invention is not limited to this. The suction force by the fan may be changed gradually.

  (2) In the embodiment described above, in the microcomputer 10a, the arrangement of the holes 20aa formed in the platen 20, the total length or size of the medium M, the conveyance speed of the medium M, and the conveyance of the medium M Although the start position is stored and the number of holes 20aa blocked by the medium M located on the platen 20 and the negative pressure area area are acquired as the medium M is transported, the invention is not limited thereto. Of course not.

  As a method of acquiring the negative pressure area, for example, the relationship between the conveyance amount of the medium M and the negative pressure area is measured in advance, and the negative pressure is determined based on the conveyance amount of the medium M measured along with printing. There is a method of acquiring the area area, and a method of measuring the number of the holes 20aa blocked by the medium M and acquiring the negative pressure area based on the number.

  The method of acquiring the negative pressure area is not limited to the method described above, and any other method may be used as long as the area of the area where negative pressure is generated between the medium M and the platen 20 can be acquired.

  (3) The above-described embodiment and the modifications shown in the above (1) to (2) may be combined appropriately.

  The present invention can be used for an image forming apparatus that performs printing on media.

  Reference Signs List 10 inkjet printer 12 main body 12a media inlet 12b media outlet 14 media transport device 18 rear roller 20 platen 22 front roller 24 rear media bar 26 ink head 28 front media bar M media

Claims (4)

A platen provided with a plurality of holes arranged on the lower side of the ink head and arranged in a plurality of holes and positioning the media on the upper surface;
A suction unit disposed below the platen and suctioning the medium with a predetermined suction force through the hole;
A media conveyance device that conveys the medium while suctioning the medium via the hole and suctioning the medium to the platen by the suction unit.
Storage means for storing the arrangement of the holes formed in the platen, the entire length of the medium, the transport speed of the media, and the start position of transport of the media on the platen;
Based on the arrangement of the holes in the platen stored in the storage means, the total length of the media, the transport speed of the media, and the start position of transport of the media on the platen, The area of the area where negative pressure is generated between the medium and the platen by closing the hole by the medium located on the platen, and the area of negative pressure area changing as the medium is transported Acquisition means,
Control means for controlling the suction means so as to have a suction force suitable for the negative pressure area obtained by the obtaining means;
A medium transport apparatus, wherein the control means decreases the suction force of the suction means when the negative pressure area increases, and increases the suction force of the suction means when the negative pressure area decreases. In the media conveyance device according to claim 1,
When the end located on the front side in the transport direction of the medium is located below the ink head, and when the end located on the rear side in the transport direction of the medium is located below the ink head And a control unit configured to control the suction unit such that the suction force is maximized. A platen provided with a plurality of holes arranged on the lower side of the ink head and arranged in a plurality of holes and positioning the media on the upper surface;
A suction unit disposed below the platen and suctioning the medium with a predetermined suction force through the hole;
A medium conveyance method in a medium conveyance device, wherein the medium is conveyed by suctioning the medium via the hole by the suction unit and causing the medium to be attracted to the platen.
A storage step of storing the arrangement of the holes formed in the platen, the entire length of the medium, the transport speed of the media, and the start position of transport of the media on the platen;
Based on the arrangement of the holes in the platen stored in the storage step, the total length of the media, the transport speed of the media, and the start position of transport of the media on the platen, The area of the area where negative pressure is generated between the medium and the platen by closing the hole by the medium located on the platen, and the area of negative pressure area changing as the medium is transported Acquisition process,
And a control step of controlling the suction unit so as to obtain a suction force suitable for the negative pressure area obtained in the acquisition step.
In the control step, the suction force of the suction means is decreased when the negative pressure area is increased, and the suction force of the suction means is increased when the negative pressure area is decreased. In the media conveyance method according to claim 3,
When the end located on the front side in the transport direction of the medium is located below the ink head, and when the end located on the rear side in the transport direction of the medium is located below the ink head And controlling the suction unit so that the suction force is maximized.

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