JP2012218406A - Ink jet recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recording apparatus capable of optimizing suction power of a suction area of a platen in any sheet width.SOLUTION: The ink jet recording apparatus includes a contact part 2 contactable with a sheet 36 to be conveyed and changeable in its position so as to receive the conveyance of the sheet by the contact with the sheet 36. In accordance with a change in the position of the contact part 2, a sucking condition of suction holes 8 in an area associated with the contact part 2 out of a plurality of suction holes 8 is changed selectively.

Description

  The present invention relates to an ink jet recording apparatus.

  As an ink jet recording apparatus, an apparatus including a carriage on which a recording head is mounted and a platen provided to face the recording head is known. For example, the ink jet recording apparatus disclosed in Patent Document 1 includes a suction area in which a plurality of suction holes are formed on the sheet conveying surface of a platen, and a suction force is generated in the suction area by a suction fan or the like to perform recording. Adsorb a sheet as a medium.

JP 2010-269456 A

  Incidentally, in an ink jet recording apparatus that sucks a sheet onto a platen with the suction force of a suction fan, the suction area that is not covered by the sheet increases as the width of the sheet decreases. Since air flows in from the opened suction holes that are not covered by the sheet, the suction pressure decreases. More leaks occur. For this reason, in order to ensure a sufficient suction force, it has been necessary to drive the suction fan at a higher speed, or to increase the size of the suction fan.

  The present invention has been made in view of the above problems, and it is an object of the present invention to provide an ink jet recording apparatus capable of optimizing the suction force of the suction area of the platen in any sheet.

  An ink jet recording apparatus according to the present invention is provided on a back surface of a sheet that faces a recording head that ejects ink and is provided along a main scanning direction of the recording head and that is conveyed in a predetermined conveying direction that intersects the main scanning direction. An ink jet recording apparatus comprising: a platen formed with a plurality of suction holes formed on a sheet conveying surface that supports a plurality of suction holes; a duct communicating with the plurality of suction holes; and suction means for decompressing the inside of the ducts. A contact portion provided so as to be capable of contacting the conveyed sheet and capable of changing a posture so as to receive the conveyance of the sheet by contact with the sheet, and the plurality of the plurality of contact portions according to a change in the posture of the contact portion. It has the mechanism which selectively changes the suction state of the suction hole of the area | region matched with the said contact part among these suction holes.

  According to the present invention, since the suction state of the suction hole in the area corresponding to the contact portion that is in contact with the conveyed sheet can be changed, the suction force can be optimized for any width sheet. .

1 is a perspective view of an example of an ink jet recording apparatus to which the present invention is applied. FIG. 2 is a perspective view illustrating a configuration of an image forming unit of the recording apparatus in FIG. 1. Sectional drawing of a suction area | region. Sectional drawing of a borderless processing part. The figure which shows the state of the suction hole before printing. The figure which shows the state of the suction hole during small size sheet printing. The figure which shows the state of the suction hole during large size sheet printing. The opening / closing flow diagram of a suction hole. Sectional drawing of the duct wall opening part of the inkjet recording device which concerns on the 2nd Embodiment of this invention. The figure which shows the state of the suction hole in printing on the small sized sheet | seat by opening and closing of a duct wall opening part. The figure which shows the state of the suction hole in printing on the large sized sheet | seat by opening and closing of a duct wall opening part.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows an example of an ink jet recording apparatus to which the present invention is applied. This recording apparatus includes a roll paper 32, a LF roller 30 and a pinch roller 31 that convey the roll paper to the image forming unit, a carriage 33 that includes a recording head that includes a plurality of nozzles that eject ink droplets onto the sheet, and a carriage 33. It has a rail 35 to support and a cutter 34 for cutting the roll paper. On the opposite side of the carriage 33 having the recording head, a suction platen 7 for adsorbing and supporting the sheet is disposed at a position separated from the recording head by a predetermined gap. The roll paper 32 is adsorbed by the suction platen 7, the carriage 33 reciprocates in the main scanning direction along the rail 35 while ejecting ink droplets from the recording head, and the LF roller 30 and the pinch roller 31 move in the direction of the carriage 33. According to the switching timing, the roll paper is fed out by a predetermined amount in the paper discharge direction (conveyance direction) orthogonal to (intersects with) the main scanning direction to achieve image formation.

  FIG. 2 is a perspective view of the image forming unit of the ink jet recording apparatus. The sheet 36 fed from the roll paper 32 is held between the LF roller 30 and the pinch roller 31 and is ready for printing. The suction platen 7 is connected to a fan 10 through a duct 4, and the inside of the duct 4 is divided into a plurality of chambers by a duct wall 5 having an opening 6.

  The sheet conveying surface 9 of the suction platen 7 has a plurality of suction holes 8. The suction platen 7 sucks and supports the back surface of the sheet 36 by the suction force generated in the suction hole 8 when the inside of the duct 4 is depressurized by driving the fan 10. When the fan 10 is viewed as the most upstream part of the airflow F, the suction platen 7 is the most downstream part. The plurality of suction holes 8 arranged in the region W1 of the suction platen 7 communicate with the fan 10 via the upstream compartment of the duct 4, and the plurality of suction holes 8 arranged in the region W2 are upstream of the duct 4 It communicates with the fan 10 via the compartment and the downstream compartment. On the sheet conveyance surface 9 of the suction platen 7, suction areas (sheet suction areas) 25 and 26 for the sheet 36 are formed, respectively. Further, on the sheet conveying surface 9, an edgeless process for quickly dropping ink droplets that have not landed on the sheet and landed on the both sides of the suction areas 25 and 26 in the sheet width direction x into the duct 4. Portions 11, 12, and 13 are formed. In the processing portions 11, 12, and 13, suction holes 8 for ink processing are respectively formed.

(First embodiment)
A plurality of contact members 20 to 24 are arranged along the width direction x of the sheet 36 with respect to the sheet conveying surface 9. Each contact member 20-24 has the contact part 2 which can contact the sheet | seat 36, respectively. The contact members 20, 21, and 22 are provided to open and close the suction holes formed in the edgeless processing units 11, 12, and 13, respectively, and the contact members 23 and 24 are respectively associated with them. It is provided to open and close the suction holes of the suction areas 25 and 26.

[Contact member in suction area]
Here, FIG. 3 shows the structure of the contact members 23 and 24 for opening and closing the suction holes 8 in the suction regions 25 and 26. FIG. 3 is a cross-sectional view taken along the line GG in FIG. 5 described later. The following description will be limited to the suction region 25. The suction regions 25 and 26 have the same configuration, and the mechanisms for opening and closing the suction regions 25 and 26 have the same configuration. As shown in FIG. 3, the contact member 23 is rotatably supported by a support shaft p fixed in the duct 4, and a rear end portion 2 </ b> B extending on the opposite side of the contact portion 2 with respect to the support shaft p is a free end. It has become. An opening / closing member 27 is rotatably supported on a support shaft q fixed in the duct 4 so as to be respectively engageable with the rear end portion 2B of the contact member 23. The opening / closing member 27 includes an engaging portion 3 </ b> B that can engage with the shielding portion 3 that opens and closes the suction hole 8 and the rear end portion 2 </ b> B of the contact member 23. The opening / closing member 27 is always urged by the spring 14 in the direction in which the shield 3 </ b> A closes the suction hole 8. Thereby, in a state where nothing is in contact with the contact portion 2, as shown by a broken line in FIG. 3, the opening / closing member 27 is in a state where the shielding portion 3A closes the suction hole 8, and the contact member 23 is in contact with the contact member 23. The portion 2 is inclined so as to protrude upward from the sheet conveying surface 9.

  If the sheet 36 is fed by the LF roller 30 while the fan 10 is driven to decompress the inside of the duct 4, the leading end of the sheet 36 comes into contact with the contact portion 2 of the contact member 23, and the contact member 23 is From the state of the broken line in FIG. 3, it is turned around the support shaft p and pushed down to be in a state indicated by a solid line. In other words, the contact member 23 is provided so that its posture can be changed so as to receive the conveyance of the sheet 36 by contact with the sheet 36. By the rotation of the contact member 23, the shielding portion 3A of the opening / closing member 27 that has closed the suction hole 8 from the duct 4 side is separated from the suction hole 8 to open the suction hole 8, and the fan 10 and the suction hole 8 are ducted. 4, the suction force is applied to the back surface of the sheet 36. Thereby, the suction state of the suction hole 8 is changed.

[Contact members in borderless processing section]
FIG. 4 shows the structure of the contact members 20, 21, 22 for opening and closing the suction holes 8 of the edgeless processing parts 11, 12, 13. 4 is a cross-sectional view taken along the line HH in FIG. The following description will be limited to the borderless processing unit 12. However, the borderless processing units 11, 12, and 13 have the same configuration, and the mechanisms for opening and closing the borderless processing units 11, 12, and 13 have the same configuration. It is.

  The contact member 21 is double-supported so as to be rotatable about the support shaft p, which is fixed in the duct 4. The contact member 21 has a rear end portion 2C extending to the opposite side of the contact portion 2 with respect to the support shaft p, and a shielding portion 3C fixed to the rear end portion 2C and capable of opening and closing the suction hole 8. In a state where the leading end of the sheet 36 and the contact surface 2 of the contact member 21 do not contact each other, the contact member 21 is in a posture in which the contact portion 2 protrudes upward from the sheet conveying surface 9 due to its own weight, as indicated by a broken line. When the sheet 36 is fed by the LF roller 30 while the fan 10 is driven and the inside of the duct 4 is decompressed, the leading end of the sheet 36 contacts the contact surface 2 and the contact member 21 is indicated by a broken line. From the state shown, it is turned around the support shaft p and pushed down, resulting in a state indicated by a solid line. By the rotation of the contact member 21, the shielding portion 3 that has opened the suction hole 8 approaches the suction hole 8 and closes the suction hole 8. As a result, the communication between the fan 10 and the suction hole is blocked, and the suction force is not applied to the end portion in the width direction of the sheet 36 on the edgeless processing unit 12.

  In an ink jet recording apparatus in which a plurality of contact members are applied to the suction area and borderless processing section formed on the platen described above, the suction holes in the sheet width area that fit within the sheet width are opened, and the non-sheet width that does not fit within the sheet width The suction hole in the region is configured to be closed. With this configuration of the present embodiment, the image of the end region in the width direction of the sheet is not deteriorated by the suction of the suction platen, and the suction force is not reduced due to the inflow of air into the suction holes of the non-sheet region. It is possible to achieve both sheet suction.

[Overall description of suction platen]
5, 6, and 7 are top views of the image forming unit viewed from the V direction in FIG. 2, FIG. 5 shows the opening / closing state of the suction holes before printing, and FIG. 6 shows the suction during printing of a small size sheet. FIG. 7 shows the opening / closing state of the suction holes during printing of the large size sheet. As shown in FIG. 5, the leading end of the sheet 36 before printing is sandwiched between an LF roller 30 and a pinch roller 31 (not shown), and stands by in front of the sheet conveying surface 9 of the suction platen. That is, the sheet 36 and the contact member are in a non-contact state.

  In the standby state, the plurality of suction holes 8 formed in the sheet conveying surface 9 are closed in the suction regions 25 and 26 as shown in FIG. Both suction holes 8 are open.

  Here, the transition from the state shown in FIG. 5 to the opening / closing state of the suction hole during the printing operation will be described with reference to FIG. FIG. 8 shows the opening and closing states of the suction holes on the suction platen in chronological order with respect to the sheet leading edge position (y), and shows each operation from standby to start of printing step by step.

  Step 1 is the state of FIG. 5, and shows the open / close state of each suction hole 8 when the leading edge of the sheet 36 is sandwiched between the LF roller 30 and the pinch roller 31 and stands by before the platen suction area.

  In step 2, the front end of the sheet 36 in FIG. 5 is fed to the print start position SS, and as shown in FIG. 6, the contact members 20, 21, 23 in which the front end of the sheet 36 is disposed in the sheet width region W1. The open / close state of each suction hole 8 when it comes into contact with is shown.

  Step 3 shows a state in which the printing operation is started from the state shown in FIG. Since the suction holes 8 in the suction region 26 which is a non-sheet width region are closed, it is possible to prevent a decrease in the suction force of the sheet. Further, since the suction hole 8 in the suction region 25 which is the region immediately below the sheet 36 where the suction force of the sheet 36 is desired to be generated is opened, the sheet 36 can be continuously sucked.

[Small size sheet]
When the fan 10 is driven to perform printing and the small size sheet 36 having the sheet width W1 is conveyed to the sheet conveying surface 9 to the image forming unit, the suction hole 8 is in the open / closed state shown in FIG. The front end portion of the sheet 36 pushes down the contact members 20, 21, and 23, but the contact members 22 and 24 do not come into contact with the front end portion of the sheet 36, so that they are not pushed down and remain protruding from the sheet conveyance surface 9. As a result, the suction holes 8 in the suction region 25 immediately below the sheet width W1 are opened, and the suction holes in the suction region 26 outside the sheet W1 region are closed, and air is sucked from the suction holes 8 in the non-sheet width region. Does not flow in, and the sheet 36 can be reliably adsorbed to the sheet conveying surface 9. Further, since the suction holes 8 of the edgeless processing portions 11 and 12 that are both ends of the sheet 36 are closed, it is possible to prevent the image from flowing near the end of the sheet.

[Large size sheet]
When the fan 10 is driven and the large size sheet 36 having the sheet width W1 + W2 is conveyed to the sheet conveying surface 9 to the image forming unit, the suction hole 8 is in the open / closed state shown in FIG. At this time, the tip of the sheet 36 pushes down all of the contact members 20, 21, 22, 23, 24. All the suction holes 8 in the suction area 25 and the suction area 26 immediately below the sheet width W1 + W2 are opened, and the entire area of the sheet 36 can be adsorbed to the sheet conveyance surface 9. Since the suction holes 8 of the edgeless processing portions 11 and 13 which are both ends of the sheet 36 are closed, it is possible to suppress deterioration in image quality in the end region in the width direction of the sheet 36 as in the case of the small size sheet. .

  According to the present embodiment, since the suction holes 8 in the non-sheet width region are closed even when the small-size sheet 36 is printed, the suction force equivalent to that of the large-size sheet 36 is reduced. It is also possible to act on. In addition, since the suction holes 8 of the edgeless processing unit located at both ends in the width direction of the sheet 36 are closed during printing, it is possible to suppress deterioration in image quality at the end in the width direction of the sheet 46.

(Second Embodiment)
[Contact member at the opening of the duct wall]
9 to 11 are views showing a second embodiment of the present invention. In FIG. 9, the difference from the first embodiment is the structure of the contact member. FIG. 9 is a cross-sectional view taken along the line II of FIG. 10 and FIG. 9 to 11, the same reference numerals are used for the same components as those in the first embodiment.

  The contact member 24B shown in FIG. 9 is supported by the support shaft p and can contact the sheet 36. The contact member 24B extends to the opposite side of the contact portion 2 with respect to the support shaft p, and the opening 6 of the duct wall 5. And a shielding part 3D for opening and closing. In a state where the leading end portion of the sheet 36 and the contact member 24B do not come into contact with each other, the posture is indicated by a broken line in FIG.

  In a state where the fan 10 is driven and the inside of the duct 4 is depressurized, when the sheet 36 is fed by the LF roller 30, the front end of the sheet 36 contacts the contact portion 2, and the contact portion 2 of the contact member 24 is a broken line. From the state shown, it is pushed down as shown by the solid line, and the contact member 24 rotates about the support shaft P. By the rotation of the contact member 24, the shield 3 </ b> D that has closed the opening 6 of the duct wall 5 opens the opening 6. As a result, the fan 10 and the compartment on the downstream side of the duct 4 can communicate with each other, and a suction force can be applied to the entire area of the sheet 36 on the sheet conveying surface 9.

[Large size sheet]
When the fan 10 is driven and a large sheet 36 having a sheet width W1 + W2 is conveyed to the sheet conveying surface 9 to the image forming unit, the suction hole 8 is opened and closed as shown in FIG. Pushes down all of the contact members 20, 21, 22, 24. As a result, the shielding part 3D of the contact member 24B opens the opening 6 as shown in FIG. 9 so that the two compartments of the duct 4 communicate with each other. As a result, the suction holes 8 in the suction regions 25 and 26 immediately below the sheet width W1 + W2 are communicated with the fan 10 so that the entire area of the sheet 36 can be adsorbed to the sheet conveying surface 9. Since the suction holes 8 of the edgeless processing portions 11 and 13 which are both ends of the sheet 36 are closed, it is possible to suppress image quality deterioration at the end portions in the width direction of the sheet 36.

[Small size sheet feed]
In order to perform printing, when the fan 10 is driven and the small sheet 36 having the sheet width W1 is conveyed to the sheet conveying surface 9 to the image forming unit, the suction hole 8 is opened and closed as shown in FIG. The front end portion of the sheet 36 pushes down the contact members 20 and 21, but the contact members 22 and 24 </ b> B do not come into contact with the front end portion of the sheet 36, so that they are not pushed down and protrude above the sheet conveying surface 9. Since the shielding part 3D of the contact member 24B closes the opening 6 of the duct wall 5, the suction force of the suction hole 8 of the suction area 26 that becomes the non-sheet width area does not decrease, and the suction area 25 that becomes the sheet width W1 area. The sheet 36 can be adsorbed by generating a suction force only in the suction holes 8. Since the suction holes 8 of the edgeless processing portions 11 and 12 that are both ends of the sheet 36 are closed, it is possible to suppress image quality deterioration at the end portions in the width direction of the sheet 36.

  In the present embodiment, even for a small-sized sheet, by closing the opening 6 with the shielding part 3D of the contact member 24B, it is possible to prevent a reduction in suction force and obtain a suction force equivalent to that of a large-size sheet. Therefore, the sheet can be efficiently sucked regardless of the sheet width.

  In the above embodiment, the case where a plurality of contact members are provided has been described, but the contact member may be single. In this case, the suction holes in some areas of the plurality of suction holes can be selectively opened and closed by contact between the sheet and the contact member. Further, a suction hole opening / closing mechanism may be provided only in the sheet suction region, or a suction hole opening / closing mechanism may be provided only in the edgeless processing portion.

2 Contact part 3A, 3C, 3D Shield part 4 Duct 5 Duct wall 6 Opening part 7 Suction platen 8 Suction hole 9 Sheet conveying surface 10 Fans 11, 12, 13 Borderless processing parts 20-24 Contact members 25, 26 Suction area 36 Sheet

Claims (10)

Formed on a sheet conveyance surface that faces the recording head that ejects ink and is provided along the main scanning direction of the recording head and supports the back surface of the sheet that is conveyed in a predetermined conveyance direction that intersects the main scanning direction. An ink jet recording apparatus comprising: a platen having a plurality of suction holes formed therein; a duct communicating with the plurality of suction holes; and suction means for decompressing the inside of the duct,
A contact portion that is capable of contacting the conveyed sheet and is capable of changing a posture so as to receive the conveyance of the sheet by contact with the sheet, and according to a change in the posture of the contact portion, An ink jet recording apparatus comprising: a mechanism for selectively changing a suction state of a suction hole in a region of the suction hole associated with the contact portion.   The said mechanism further has a shielding part which opens and closes a suction hole of a field corresponding to said contact part among said a plurality of suction holes according to change of a posture of said contact part. 2. An ink jet recording apparatus according to 1.   The mechanism includes a plurality of the contact portions, and the plurality of contact portions are provided along the main scanning direction, and the posture of the plurality of contact portions is changed in contact with a conveyed sheet. The inkjet recording apparatus according to claim 2, wherein the suction hole of the sheet suction region corresponding to the contact portion is opened and closed by the shielding portion.   In the state where the sheet is not in contact with the plurality of contact portions, the mechanism closes the suction holes of the sheet suction region corresponding to each of the plurality of contact portions by the shielding portion, and 4. The ink jet recording apparatus according to claim 3, wherein the suction hole of the corresponding sheet suction area is opened when the posture is changed by contacting at least one of the sheets being conveyed. The plurality of suction holes include a suction hole for sucking and supporting the back surface of the sheet, and an ink processing for processing ink droplets that protrude from the sheet without landing on the sheet at the end in the width direction of the sheet. Including suction holes,
The mechanism opens the ink processing suction holes in a state where the sheet is not in contact with the plurality of contact portions, and contacts corresponding to the ink processing suction holes among the plurality of contact portions. The ink jet recording apparatus according to claim 2, wherein the suction hole for ink processing is closed when the posture is changed by contact with the sheet being conveyed. The mechanism includes a contact member in which the contact portion is formed and an opening / closing member in which the shielding portion is formed,
The contact member and the opening / closing member are supported so as to be able to engage with each other and to rotate about a predetermined support shaft,
The opening / closing member opens the suction hole when the contact member is in contact with the sheet, and the opening / closing member closes the suction hole when the contact member is not in contact with the sheet. An ink jet recording apparatus according to any one of claims 2 to 5. The mechanism has a contact member on which the contact portion and the shielding portion are formed,
The contact member is rotatably supported around a predetermined support shaft,
The contact member closes the suction hole when the contact member is in contact with the sheet, and the contact member opens the suction hole when the contact member is not in contact with the sheet. An ink jet recording apparatus according to any one of claims 2 to 5. The duct is divided into a plurality of chambers by a duct wall in the main scanning direction,
The duct wall has an opening communicating with adjacent chambers,
The inkjet recording apparatus according to claim 1, wherein the mechanism further includes a shielding portion that opens and closes the opening according to a change in the posture of the contact portion.   The mechanism opens the opening so that a suction force is generated in a suction hole in a sheet suction region corresponding to the contact portion whose posture has been changed in contact with a conveyed sheet. Item 9. The ink jet recording apparatus according to Item 8. The mechanism has a contact member on which the contact portion and the shielding portion are formed,
The contact member is rotatably supported around a predetermined support shaft,
When the contact member is in contact with the sheet, the contact member opens the opening, and when the contact member is not in contact with the sheet, the contact member closes the opening. An ink jet recording apparatus according to claim 8 or 9.

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