JP2017047589A - Media transport device and media transport method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a media transport device and a media transport method in which fluctuation of transport amount of media per unit time is prevented and the media can stably be positioned on a platen, and thereby good edgeless print is made possible.SOLUTION: A media transport device is provided with: a platen including holes disposed to the lower side of an ink head and arranged and bored in multiple numbers, and having the media positioned in the upper surface; and suction means disposed in the lower side of the platen, and sucking the media, and transports the media while suctioning the media in the platen. The media transport device is provided with acquisition means for acquiring a negative pressure region area as the area of the holes blocked up by the media, and control means for controlling the suction means to become the suction power suitable for a negative pressure region area. The control means is configured such that the suction power of the suction means is reduced when the negative pressure region area is increased, and the suction power of the suction means is increased when the negative pressure region area is decreased.SELECTED DRAWING: Figure 2

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 that performs printing by ejecting ink onto a medium such as recording paper that is a printing target by an ink jet method is known.

In this specification, the term “media” refers to various recording media such as plain paper, various resin media such as PCV and polyester, and various materials such as aluminum, iron, and wood. Material shall be included.

  In such an image forming apparatus such as an ink jet printer, for example, as disclosed in Japanese Patent No. 5471205 presented as Patent Document 1 and Japanese Patent Application Laid-Open No. 2008-137196 presented as Patent Document 2, the media is stabilized. A plurality of holes on the surface of the platen on which the medium is placed, and a medium having suction means for sucking air from the lower side of the platen and adsorbing the medium on the platen A transport device is used.

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

  By the way, during printing by the image forming apparatus, since the media is sequentially conveyed on the platen, the number of holes blocked by the media differs depending on which part of the media is located on the platen. .

  In other words, at the start of printing on the media, only a part of the holes are blocked by the media, but as the media advances as the printing progresses, the area of the media located on the platen gradually increases, The number of holes blocked by the media also increases. As the conveyance further progresses and printing on the media is finished, the area where the media is located on the platen decreases, and the number of holes that the media closes decreases as the area of the media located on the platen decreases. .

Here, as described above, the medium is adsorbed on the platen by the suction means, and the adsorbing force of the medium on the platen is negative between the medium and the platen because the medium closes 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 the medium is blocked. The larger the number of open holes, that is, the larger the negative pressure area, the more the media will be adsorbed on the platen.

  That is, in the process of transporting the series of media during printing, the suction force by the suction means is constant despite the change in the number of holes blocked by the media during transport. Depending on the position of the media, the negative pressure generated by the suction means is too high and the suction force of the media on the platen becomes high, making it difficult to transport, or the negative pressure is too low and the suction force of the media on the platen is low. As a result, there is a problem that the medium cannot be held, the amount of transport of the medium per unit time varies, and the medium cannot be stably positioned on the platen.

  For this reason, there has been a demand for a proposal of a method capable of suppressing the fluctuation of the transport amount of the medium per unit time and stably positioning the medium on the platen.

  Also, if the negative pressure is too weak when printing on the edge of the media, it will be difficult to hold the media, and printing on the edge will not be performed accurately, so when performing so-called borderless printing, There is a problem in that there is a difference in the finish between printing and printing on the edges.

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

Japanese Patent No. 5471205 JP 2008-137196 A

  The present invention has been made in view of the above-described various problems of the prior art. The object of the present invention is to suppress fluctuations in the transport amount of 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.

  The present invention is also intended to provide a media transport apparatus and a media transport method capable of enabling good borderless printing.

In order to achieve the above object, the present invention controls the suction force of suction means for adsorbing media on the platen based on the negative pressure area formed on the platen that is blocked by the media located on the platen. It is what you do.

That is, the present invention includes a platen that is disposed below the ink head and includes a plurality of holes that are arranged and perforated, and a medium is positioned on the upper surface, and the hole that is disposed on the lower side of the platen. A medium transporting device that transports the medium while sucking the medium through the hole by the suction means and attracting the medium to the platen. An acquisition means for acquiring a negative pressure area which is an area of an area in which a negative pressure is generated between the medium and the platen when the medium located on the platen blocks the hole, and the acquisition Control means for controlling the suction means so as to obtain a suction force suitable for the negative pressure area obtained by the means, and the control means increases 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, the present invention is the above-described invention, wherein the end portion positioned on the front side in the transport direction of the medium is positioned below the ink head and the end portion positioned on the rear side in the transport direction of the medium. The suction means is controlled so that the suction force is maximized when is located below the ink head.

  The present invention also includes a platen that is disposed below the ink head and includes a plurality of holes that are arranged and perforated, and a medium is positioned on the upper surface, and the holes that are disposed below the platen and that are disposed below the platen. A medium transporting device that transports the medium while sucking the medium through the hole by the suction means and attracting the medium to the platen. A method of acquiring a negative pressure region, which is an area of a region in which a negative pressure is generated between the medium and the platen when the medium located on the platen blocks the hole. And a control step for controlling the suction means so as to have a suction force suitable for the negative pressure region area obtained from the acquisition step, in the control 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, when the end portion positioned on the front side in the medium transport direction is positioned below the ink head, and the end portion positioned on the rear side in the medium transport direction is The suction means is controlled so that the suction force is maximized when positioned below the ink head.

  Since the present invention is configured as described above, it is possible to suppress a variation in the transport amount of the medium per unit time and to stably position the medium on the platen and the media transport. There is an excellent effect that a method can be obtained.

  In addition, since the present invention is configured as described above, there is an excellent effect that a media transport apparatus and a media transport method capable of good borderless printing can be obtained.

FIG. 1 is a schematic cross-sectional explanatory diagram of an ink jet printer provided with a media transport device according to the present invention. 2A, 2B, 2C, and 2D are conceptual explanatory views showing a media transport method according to the present invention. FIGS. 3A, 3B, 3C, and 3D are conceptual explanatory views showing a media conveying method according to the present invention.

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

  FIG. 1 is a schematic cross-sectional explanatory diagram of an ink jet printer provided with a media transport device according to the present invention.

  In the inkjet printer 10, a plate-like body having a predetermined flexibility, such as a styrene board or a plastic cardboard, can be used as a medium that is a printing target.

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

In this embodiment, a flat bed type ink jet printer is used. However, the ink jet printer is not limited to the flat bed type, and may be a type that performs printing on media such as a roll.

  An ink jet printer 10 including the media conveying device shown in FIG. 1 is a flat bed type ink jet printer.

  The ink jet printer 10 performs control of the main body 12 incorporating the media transport device 14 according to the present invention, the entire ink jet printer 10, the position of the medium M on the platen 20, and control of the suction force of the suction means described later. And a microcomputer 10a to be executed.

  In the inkjet printer 10, the medium M is inserted from the medium inlet 12a located on the rear side in the sub-scanning direction, which is the transport direction, and printing is started. The medium M that has finished printing is located on the front side in the sub-scanning direction. It is discharged from the media outlet 12b.

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

  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 of the platen 20 in the sub-scanning direction, the platen 20 is disposed in the main body 12 so as to be parallel and rotatable along the sub-scanning direction. A front roller 22 for conveying to the side is disposed.

  An ink head 26 that ejects ink from a plurality of ink nozzles (not shown) to the medium M while moving in the main scanning direction orthogonal to the sub-scanning direction is disposed above the platen 20.

Reference numeral 24 denotes a rear media bar that is rotatably disposed at an opposing position on the upper side of the rear roller 18 and that facilitates conveyance while suppressing the media M from above the media M. It is a front media bar that is rotatably disposed at an opposing position on the upper side of the front roller 22 and promotes conveyance while suppressing the media M from above the media M.

Here, when the medium M is located 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 press contact of the media M by the rear roller 18 and the rear media bar 24 is released, and the media M is sandwiched between the front roller 22 and the front media bar 28 and conveyed.

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

  As the position in the height direction of the platen 20, the upper surface of the platen 20 is arranged below the horizontal plane 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 arranged so that the upper surface of the platen 20 is at the same height as the horizontal plane that is in contact with the upper edge of the front roller 22 and the upper edge of the rear roller 18.

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

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

  In the present embodiment, for example, 20 holes 20aa are formed in the main scanning direction, and six rows are arranged in the sub-scanning direction.

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

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

  The intake area 20a is a box-shaped body having an open top with a space inside, and the platen 20 is disposed on the upper surface thereof.

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

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

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

  A method for transporting the medium M in the inkjet printer 10 having the medium transport device 14 having 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 inkjet printer 10. Here, the entire length of the medium M is registered in the inkjet printer 10 by an input means (not shown) by the user and stored in the microcomputer 10a.

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

  Next, the medium M is arranged on the platen 20 such that the front end of the medium M is positioned at a reference position provided on the platen 20.

  Here, the reference position is a reference provided for calculating the transport amount of the medium M on the platen 20 and is a start position of transport of the medium M (hereinafter, the reference position is referred to as “transport start position”). As appropriate.). The starting position of this conveyance is stored in advance in the microcomputer 10a.

  The user inserts the medium M from the medium inlet 12a and arranges the end of the medium M at the transport start position.

  The microcomputer 10a of the inkjet printer 10 stores 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 start position of conveyance of the medium M. As the medium M is conveyed, the number of holes 20aa and the negative pressure area that are blocked by the medium M located on the platen 20 are acquired.

Then, the microcomputer 10a performs suction so as to obtain an adsorbing force suitable for the medium M on the platen 20, based on the negative pressure area corresponding to the number of holes 20aa closed by the medium M located on the platen 20. The conveyance force of the medium M is controlled by adjusting the suction force of the fan 20b.

Here, when the medium M is transported, immediately after the start of printing and just before the end of printing, the number of 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 sucked by the suction fan 20b through a part of the holes 20aa blocked by the medium M. In order to stably transport and print the medium M on the platen 20 through only some of these holes 20aa, the suction force of the suction fan 20b is larger than that when the negative pressure area is large. Need to be high.

  When printing is started and the medium M is conveyed, the area of the medium M located on the platen 20 gradually increases, and the number of holes 20aa blocked by the medium M increases and the negative pressure area increases. . In such a case, the suction force of the suction fan 20b is decreased as the number of holes 20aa blocked by the medium M increases, and the suction force of the suction fan 20b is prevented from becoming a suction force that hinders conveyance. Adjust.

  Further, as the printing is finished, the area of the medium M located on the platen 20 is gradually reduced, and the number of holes 20aa closed by the medium M is reduced, so that the negative pressure area is reduced. In such a case, as the number of holes 20aa blocked by the medium M decreases, the suction force of the suction fan 20b is increased.

It should be noted that as long as the number of holes blocked by the medium M is the same, it is preferable that the same suction force be maintained for conveyance.

  The media M in the inkjet printer 10 according to the present embodiment will be described below using the cases shown in FIGS. 2A, 2B, C, and D and FIGS. 3A, 3B, 3C, and 3D as examples. Will be described.

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

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

In the present embodiment, as shown in FIG. 2 (a), the suction fan 20b for stably holding the medium M on the platen 20 in a state where the medium M blocks the three rows 20aa of the rear side. Is set to 100%.

  Next, in the inkjet printer 10, when printing on the medium M at the position shown in FIG. 2A is completed, the medium M is sequentially conveyed forward in the sub-scanning direction in order to perform printing on the next area of the medium M. For example, the medium M is conveyed to the position shown in FIG. In this case, among the plurality of holes 20aa drilled in the platen 20, the four rows of holes 20aa in the sub-scanning direction are closed by the medium M.

In FIG. 2B, compared to 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% smaller than that shown in FIG.

  Next, when the medium M is transported to the position shown in FIG. 2C, among the plurality of holes 20aa drilled in the platen 20, the holes 20aa in the rear five rows in the sub-scanning direction are blocked by the medium M. It is.

In FIG. 2C, compared to 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% smaller than that shown in FIG.

  Further, when the medium M is transported to the position shown in FIG. 2D, all of the plurality of holes 20aa drilled 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.

The suction force of the suction fan 20b is continued until the conveyance of the medium M progresses and the end of the rear side of the medium M reaches the row of holes 20aa located in the last row on the platen 20 as shown in FIG. Is maintained at 40%.

When the conveyance of the medium M advances 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 holes 20aa closed by the medium M is reduced as compared with the case shown in FIG. 3A, and the negative pressure region area is reduced. Therefore, the medium M can be stabilized by operating the suction fan 20b with a suction force of 60% larger than the case shown in FIG.

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 holes 20aa blocked by the medium M is reduced as compared with 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% larger than that shown in FIG.

Further, 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 three rows of holes 20aa on the front side are blocked by the medium M. It is. In FIG. 3D, the number of holes 20aa closed by the medium M is reduced as compared with the case shown in FIG. 3C, and the negative pressure area is reduced. Therefore, the medium M can be stabilized by operating the suction fan 20b with a suction force 100% larger than that shown in FIG.

That is, in the ink jet printer 10 provided with the media transport device 14, when the number of holes to be blocked increases as the media M is transported and the negative pressure area increases, the suction force of the suction fan 20 b decreases accordingly. When the number of holes 20aa blocked by the medium M decreases and the negative pressure area decreases, the suction fan 20b is controlled so as to increase the suction force of the suction fan 20b. To do.

Then, according to the present embodiment, a case where the front end in the transport direction of the medium M corresponding to a so-called borderless printing state is located below the ink head (FIG. 2A). In the case where the end on the rear side in the transport direction of the medium M is positioned below the ink head (see FIG. 3D), the medium M is stably held. Printing can be performed on the edge of the medium M.

As described above, according to the media transport apparatus and the media transport method of the present invention, the suction fan 20b is controlled so as to increase or decrease the suction force of the suction fan 20b from the start of printing to the end of printing according to the negative pressure area. I tried to do it.

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

Even when so-called borderless printing is performed, good borderless printing is possible.

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

  (1) In the above-described embodiment, the suction force is increased or decreased by 10% by the suction fan, and the suction force is changed step by step. However, the present invention is not limited to this. The suction force by the fan may be gradually changed.

  (2) In the above-described embodiment, 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 The start position is stored, and the number of holes 20aa and the negative pressure area that are blocked by the medium M located on the platen 20 as the medium M is conveyed is acquired. However, the present invention is not limited to this. Of course not.

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

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

  (3) You may make it combine the above-mentioned embodiment and the modification shown in above-mentioned (1) thru | or (2) suitably.

  The present invention can be used in an image forming apparatus that performs printing on a medium.

  DESCRIPTION OF SYMBOLS 10 Inkjet printer, 12 Main-body part, 12a Media inlet, 12b Media outlet, 14 Media conveying apparatus, 18 Rear roller, 20 Platen, 22 Front roller, 24 Back side media bar, 26 Ink head, 28 Front side media bar, M media

Claims (4)

A platen disposed on the lower side of the ink head, and provided with a plurality of holes formed in an array, and for positioning the medium on the upper surface;
A suction means disposed on the lower side of the platen and sucking the medium with a predetermined suction force through the hole;
A media transport device that transports the media while sucking the media through the holes by the suction means and attracting the media to the platen,
An acquisition means for acquiring a negative pressure region area that 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;
Control means for controlling the suction means so as to have a suction force suitable for the negative pressure area obtained by the acquisition means,
The media transport device according to claim 1, 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 apparatus of Claim 1,
When an end portion located on the front side in the transport direction of the media is located below the ink head, and an end portion located on the rear side in the transport direction of the media is located below the ink head The media transport device is characterized in that the suction means is controlled so that the suction force is maximized. A platen disposed on the lower side of the ink head, and provided with a plurality of holes formed in an array, and for positioning the medium on the upper surface;
A suction means disposed on the lower side of the platen and sucking the medium with a predetermined suction force through the hole;
A media transport method in a media transport apparatus that transports the media while sucking the media through the holes by the suction means and adsorbing the media to the platen,
An acquisition step of acquiring a negative pressure region area that 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;
A control step of controlling the suction means so as to have a suction force suitable for the negative pressure region area obtained from the acquisition step,
In the control step, when the negative pressure area increases, the suction force of the suction means is decreased, and when the negative pressure area decreases, the suction force of the suction means is increased. In the media conveyance method of Claim 3,
When an end portion located on the front side in the transport direction of the media is located below the ink head, and an end portion located on the rear side in the transport direction of the media is located below the ink head The method of transporting media is characterized in that the suction means is controlled so that the suction force is maximized.

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