JP2012030452A - Inkjet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent ink ejected during a flushing operation from being splashed onto a printing head.SOLUTION: In a platen 45, a plurality of suction holes 60 are formed in accordance with to printing areas of the printing head H, and flushing holes 61 are also formed in accordance with the flushing areas of the printing head H. The printing head H is controlled by a head control section 203 so as to perform a flushing operation for ejecting a predetermined amount of ink toward the flushing holes 61. The head control section 203 changes the moving speed of the printing head H in a main scanning direction X according to an amount of ink used for the flushing operation, and causes the printing head H to perform the flushing operation while causing the printing head H to move in the main scanning direction X at the changed moving speed.

Description

  The present invention relates to an inkjet printer.

  2. Description of the Related Art Conventionally, inkjet printers are known as means for recording characters and images (hereinafter collectively referred to simply as “images”) (see, for example, Patent Documents 1 and 2). In this ink jet printer, an image is printed on a recording sheet by ejecting ink while scanning in the main scanning direction orthogonal to the recording sheet conveying direction toward the recording sheet intermittently conveyed along the conveying path. Is printing.

  Here, if the state in which ink is not ejected continues for a while, the ink at the tip of the ink ejection nozzle (hereinafter simply referred to as “nozzle”) of the print head thickens. As a result, the discharge capability is reduced, and in severe cases, there is a risk of nozzle clogging.

  In order to prevent such a problem, in an ink jet printer, a flushing hole is formed at a location outside the print area scanned by the print head, the print head is stopped above the flushing hole, and “flushing” or “ A print head nozzle discharge capacity recovery process called “empty discharge” is performed. That is, in the flushing region where the ink absorbing material or the like is disposed, the thickened ink is forcibly discharged from the nozzles of the print head.

  In the ink jet printers of Patent Documents 1 and 2, a slope portion is provided immediately below the flushing hole, and ink ejected from the print head adheres to the slope portion. When a certain amount of ink adheres to the slope portion, the ink drops into an ink absorbing material and is absorbed.

JP 2000-168105 A JP 2000-280488 A

  However, since the conventional inkjet printer has a configuration in which a slope portion is provided between the flushing hole and the ink absorbing material, there is a problem that the printer becomes larger or the cost increases due to an increase in the number of parts. There is.

  Therefore, it is considered preferable to adopt a form in which the ink absorbing material is accommodated in the flushing hole. However, in this form, when the amount of ink used for the flushing operation is large, the ejected ink rebounds on the surface of the ink absorbing material. As a result, the print head becomes dirty.

  Specifically, when the flushing operation is performed in a state where the print head is stopped, the ink continuously ejected toward the flushing hole is landed on the same position of the ink absorbing material. Therefore, there is a problem in that the next ink is ejected before the ink is absorbed by the ink absorbing material, the ink rebounds on the surface of the ink absorbing material, and adheres to the surface of the print head. As described above, when the ink adhering to the surface of the print head is thickened, the nozzles are clogged and nozzle missing occurs.

  The present invention has been made in view of such a point, and an object thereof is to prevent ink ejected during a flushing operation from splashing back to the print head.

  The present invention discharges ink while scanning a print head in a main scanning direction orthogonal to the recording sheet conveyance direction toward the recording sheet intermittently conveyed along the conveyance path when the conveyance is stopped. The following solution was taken for an inkjet printer that prints an image on paper.

That is, the first invention is provided below the print head, and a suction portion formed with a plurality of suction holes corresponding to the print area of the print head;
A flushing portion provided at a position deviating from the print area in the main scanning direction and having a flushing hole formed corresponding to the flushing area of the print head;
A head control unit that controls the operation of the print head so as to perform a flushing operation for discharging a predetermined amount of ink toward the flushing hole;
The head controller changes the moving speed of the print head in the main scanning direction according to the amount of ink used for the flushing operation, and moves the print head in the main scanning direction at the changed moving speed. However, the flushing operation is performed.

  In the first invention, an adsorption portion and a flushing portion are provided below the print head. A plurality of suction holes are formed in the suction portion corresponding to the print area of the print head. A flushing hole is formed in the flushing portion corresponding to the flushing region at a position deviating from the print region in the main scanning direction. The print head is controlled by the head controller so as to perform a flushing operation for ejecting a predetermined amount of ink toward the flushing hole. In the head controller, the moving speed of the print head in the main scanning direction is changed according to the amount of ink used for the flushing operation. Further, the flushing operation is performed while the print head is moved in the main scanning direction at the changed moving speed.

  With such a configuration, by performing the flushing operation while moving the print head at a predetermined moving speed from one end to the other end in the width direction of the flushing hole, the ink ejected from the print head a plurality of times can be obtained. All can be landed at different positions. Thereby, even if the next ink is ejected before the ink is absorbed by the ink absorbing material accommodated in the flushing hole, the ink landing position is different, so that the ink rebounds on the surface of the ink absorbing material. This prevents the ink from adhering to the surface of the print head.

  Here, the predetermined moving speed is a speed at which all the ink used for the flushing operation can be consumed while the print head is moving. Specifically, when the amount of ink used for the flushing operation is large, the movement speed is changed to be slow, while when the ink amount is small, the movement speed is changed to be high. In this way, by performing the flushing operation while the print head is moving, time loss can be reduced by the amount of time the print head is moved after the flushing is completed, compared to the case where the flushing operation is performed with the print head stopped. Can do.

According to a second invention, in the first invention,
The head controller is configured to change the flushing start position of the print head according to the amount of ink used for the flushing operation.

  In the second invention, the head controller changes the flushing start position of the print head according to the amount of ink used for the flushing operation.

  With such a configuration, when the amount of ink used for the flushing operation is relatively small, the flushing start position is changed to, for example, the center position in the width direction of the flushing hole, so that the entire area from the center position to the other end is uniform. Ink can be ejected.

  According to the present invention, by performing the flushing operation while moving the print head from one end to the other end in the width direction of the flushing hole at a moving speed changed according to the amount of ink used for the flushing operation, All of the ink ejected from the print head a plurality of times can be landed at different positions. Thereby, even if the next ink is ejected before the ink is absorbed by the ink absorbing material accommodated in the flushing hole, the ink landing position is different, so that the ink rebounds on the surface of the ink absorbing material. This prevents the ink from adhering to the surface of the print head.

FIG. 2 is a perspective view illustrating an appearance of the printer according to the embodiment of the present invention, viewed from an oblique right side on the front side of printing. It is the schematic seen from the printer right side which shows the internal structure of a printer. It is the figure seen from the printer left side which shows the structure of a printing part and a cap part. It is a top view which shows the structure of the platen of a printing part. It is a front sectional view showing a configuration of a recording paper holding unit. FIG. 2 is a block diagram illustrating a configuration of a printer control system. It is the schematic which shows the landing position of the ink at the time of flushing operation | movement. It is the schematic which shows the landing position of the ink when changing the flushing start position.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the following description of the preferred embodiment is merely illustrative in nature and is not intended to limit the present invention, its application, or its use.

  FIG. 1 is a perspective view showing a partially omitted configuration of an ink jet printer A according to an embodiment of the present invention. The printer A is used in a photo print system. For example, the printer A obtains image data and order information and performs necessary correction processing from a reception block 200 (see FIG. 6) via a communication cable. The transmitted image data is configured to be printed on the recording paper P based on the order information.

-Overall configuration-
FIG. 2 is a schematic diagram illustrating the configuration of the printer A. As shown in FIG. 2, the printer A has a recording paper storage unit 1 provided in the lower part of the printer for storing a roll-shaped recording paper P, and a recording paper P drawn from the recording paper storage unit 1. And a printing unit 2 provided on the upper part of the printer so as to perform recording printing of the image data.

  In the upper part of the printer A, on the downstream side of the conveyance of the printing unit 2, a cutter unit 4 for cutting the printed recording paper P into a predetermined print size, and the printed recording paper P by switching back the cut printing paper P A switchback unit 5 for changing the orientation, a back surface printing unit 6 for printing a serial number or the like on the back surface of the recording paper P, a drying unit 7 for drying the printing surface of the recording paper P, and a roll wound recording A decurling unit 8 for removing the curl of the paper P and discharging it, and a conveyor device 150 for distributing the discharged recording paper P to one side of the printer in the left-right direction of the printer (direction perpendicular to the paper surface of FIG. 2). The large-size tray 104 (see FIG. 1) for receiving the distributed large-size recording paper P such as B5 size or A4 size, and the photographic-size recording paper P such as the L plate are ordered. It is arranged an integrated device 210 for integrating the. The printer A is covered with the casing 3 except for the large-size tray 104 and the stacking apparatus 210, and a moving caster 3 a is attached to the lower surface of the casing 3.

  The recording paper storage unit 1 is positioned almost directly below the printing unit 2 and can store two magazines M1 and M2 for storing the recording paper P. The magazines M1 and M2 are arranged side by side in the vertical direction, and a roll-shaped recording sheet P is accommodated in the magazines M1 and M2 while being held by the winding core R.

  In the present embodiment, the printer A includes the manual feed unit 9, which enables printing on the sheet-like recording paper P supplied from the manual feed unit 9.

  The printing unit 2 ejects ink onto the recording paper P, thereby forming a print head H that forms an image composed of a large number of ink dots, and the recording paper P provided below the printing head H is sucked to the printing position. And a recording paper holding unit D for holding the recording paper.

  The print head H is configured to be movable along a guide rail 10 (see FIG. 3) extending in the main scanning direction X. Specifically, the rotational force of the drive motor 11 is transmitted to the drive belt 12 via the pulley 46, and the print head H moves in the main scanning direction X according to the rotation amount of the drive belt 12.

  Further, the print head H has two head units 13 and 13 arranged in the sub-scanning direction, and ejects ink from an ink ejection nozzle 15 (see FIG. 5) provided in the head unit 13. A predetermined image, characters, etc. can be printed on the recording paper P.

  Four ink cartridges (not shown) in which inks having different hues are sealed are detachably accommodated in the lower portions on both the left and right sides of the inkjet printer A, respectively. Accordingly, by attaching or detaching these ink cartridges from the case, it is possible to exchange used or used ones with new ones.

  These ink cartridges contain yellow (Y), magenta (M), cyan (C), and black (K) inks, respectively.

-Recording paper transport mechanism-
As shown in FIG. 2, the printer A is provided with a recording paper storage unit 1 for storing a long recording paper P wound in a roll shape at the bottom of the printer, while the recording paper P from the recording paper storage unit 1 is provided. A transport mechanism accommodating portion 20 is provided in the upper part of the printer.

  In the present embodiment, in addition to supplying the recording paper P from the recording paper storage unit 1, a manual feed unit 9 configured to supply a predetermined size of recording paper from the manual feed tray 102 via the manual feed roller pair 27. However, the case where the recording paper P is supplied mainly from the recording paper storage unit 1 will be described below.

  In the following description, the side on which the manual feed tray 102 is provided is defined as the front side of the printer, and the opposite side is defined as the rear side of the printer. Further, the left side when viewed from the front side of the printer is defined as the left side of the printer, and the right side is defined as the right side of the printer.

  Two magazines M 1 and M 2 are accommodated in the recording paper accommodating portion 1, and one of the recording papers P accommodated in the magazines M 1 and M 2 is pulled out from the leading end and guided by the guide roller 21. While being done, it is fed out of the magazine by the magazine roller pair 22.

  Here, the recording paper P sent out from the magazine M1 passes through a branching portion 23b on the rear side of the printer of the guide portion 23 that branches into two on the upstream side, and is supplied to the supply roller 24 and the supply roller 24 that form the recording paper transport mechanism. It is sandwiched between a pair of pressure-bonding rollers 24a and 24b arranged to face each other. On the other hand, the recording paper P sent out from the magazine M2 passes through the branch portion 23a on the printer front side of the guide portion 23 and is sandwiched between the supply roller 24 and the pair of pressure-bonding rollers 24a and 24b. Note that only one of the pair of pressure rollers 24a and 24b may be provided.

  The recording paper P conveyed by the rotation of the supply roller 24 is supplied to the printing unit 2 on the downstream side of the conveyance, and an image is printed on the recording paper P by the print head H.

  The printed recording paper P is sent to the cutter unit 4 by the post-printing conveyance roller pair 25 and cut into a predetermined print size. The cut recording paper P is delivered to the switchback unit 5 by the three post-cutting conveyance roller pairs 26. These three post-cutting conveying roller pairs 26 are prepared for receiving the recording paper P that is transported next after the recording paper P is delivered to the switchback unit 5 and then simultaneously released from pressure bonding.

  In the switchback unit 5, the cut recording paper P is received from the leading end side and drawn by the switchback roller pair 73, and then the conveyance direction is changed from the horizontal direction to the vertical direction (the horizontal direction in FIG. 2 to the vertical direction). Change and discharge from the rear end.

  The recording paper P discharged from the switchback unit 5 is sent to the back surface printing unit 6 by the supply roller pair 75 and printed with a serial number on the back surface of the recording paper P and then conveyed to the drying unit 7. .

  In the drying unit 7, the printing surface P is dried while being transported by the transport roller pair 28. The recording paper P that has been dried is sent to the decurling unit 8 by the conveying roller pair 29.

  In the decurling unit 8, in order to remove the curling of the recording paper P wound in a roll shape, the decurling roller 82 is moved between the driving conveying roller 81 while the recording conveying P is sandwiched and conveyed by the driving conveying roller 81 and the decurling roller 82. It moves to the clockwise direction of FIG. 2 along an outer peripheral surface. As a result, the recording paper P is decurled while being bent in a direction opposite to the curling direction, and is discharged from the discharge port 90 onto the conveying belt 151 of the conveyor device 150.

-Details of each component-
Hereinafter, each component of the printer A will be described in detail. The recording paper storage unit 1 is provided with slide tables 30 and 30 for mounting magazines M1 and M2, respectively. The slide table 30 is configured to be slidable in the front-rear direction of the printer by linear guides (not shown) provided on the left and right sides in the housing 3 and extending in the front-rear direction of the printer. Thus, the magazines M1 and M2 can be taken in and out of the housing 3 by sliding the slide table 30. The front surface of the slide table 30 is covered with a door member 31 that forms a part of the housing 3 and can be opened and closed. By opening the door member 31, the recording paper P can be replaced. It has become.

  In the following description, the left side of FIG. 2 is defined as the magazine front side, and the right side is defined as the magazine rear side. Further, a direction perpendicular to the paper surface of FIG. 2 is defined as a magazine length direction (a direction matching the printer left-right direction).

  The magazines M1 and M2 are substantially hermetically sealed box-type containers configured to be portable. An opening 111 for pulling out the recording paper P stored in the magazines M1 and M2 to the outside of the magazines M1 and M2 is formed at the front end of the magazines M1 and M2. The opening 111 has a substantially rectangular shape extending in the magazine length direction.

  The magazine roller pair 22 provided in the recording paper storage chambers S1 and S2 inside the magazines M1 and M2 is composed of a pressure-bonding roller pair including a magazine driving roller 32 and a magazine driven roller 33.

  The supply roller 24 is driven by a motor (not shown), rotates in the forward direction to pull out the recording paper P from the recording paper storage unit 1 and transport it to the printing unit 2 side, and the recording paper P in the recording paper storage unit 1. The rotation in the reverse direction to return to can be switched. Thus, after the printed portion of the recording paper P is cut into a predetermined size by the cutter unit 4 on the downstream side of the supply roller 24, the long recording paper P is returned to the upstream side and the head of the recording paper P is started. When printing or when the recording paper P is supplied from the manual feed unit 9 instead of the long recording paper P, the long recording paper P can be returned into the recording paper storage unit 1. Yes.

  As shown in FIG. 3, the printing unit 2 includes two guide rails 10 that guide the print head H in the main scanning direction X (a direction perpendicular to the conveyance direction (sub-scanning direction Y) of the recording paper P); A drive belt 12 that is wound around two pulleys 46 (only one is shown in FIG. 3) and reciprocates the print head H along the guide rail 10, a drive motor 11 that rotationally drives the pulley 46, a print A recording paper holding portion D (see FIG. 2) that sucks and holds at a position where printing can be performed by the head H, and a pressure-bonding post-printing conveyance roller pair 25 disposed on the downstream side of the recording paper holding portion D. And. Here, the main scanning direction X corresponds to the left-right direction of the printer (also the width direction of the recording paper P), and the sub-scanning direction Y corresponds to the front-rear direction of the printer (also the longitudinal direction of the recording paper P).

  Two head units 13 are provided on the bottom surface of the print head H (a surface facing a recording paper holding portion D described later) at an interval in the sub-scanning direction Y (recording paper transport direction).

  Each of the head units 13 has the same configuration, and each head unit 13 includes a plurality of nozzle arrays 14 (see FIG. 5) that are arranged in the main scanning direction X and discharge each ink. In each nozzle array 14, ink discharge nozzles 15 are arranged in a row in the sub-scanning direction Y. A total of eight rows of the ink discharge nozzles 15 are provided at intervals in the main scanning direction X. Accordingly, each head unit 13 is configured to be able to form a color image by itself.

  Here, the configuration of each head unit 13 is not particularly limited, but each head unit 13 in the present embodiment is provided for each ink ejection nozzle 15 and has a volume of a pressure chamber filled with ink. Is changed by a piezoelectric element (piezo element), and is a general piezo system that ejects ink. Further, the number of head units 13 is not limited to two, and may be one or three or more, for example.

  The recording paper P on the recording paper holding section D is intermittently (stepped) in the sub-scanning direction Y by a supply unit 24 provided on the upstream side of the recording paper holding section D with a constant unit conveyance amount. At each stop of the recording paper P during the intermittent conveyance, the print head H is scanned once in the main scanning direction (one-way operation or one-time operation), and at this scanning, at each position in the main scanning direction, Ink is ejected from the ink ejection nozzle 15 of each head unit 13. That is, after one scan of the print head H, the recording paper P is transported by the unit transport amount, and then the print head H is scanned once again, and this operation is repeated to print a desired image on the recording paper P. Will be.

  Further, a standby position for the print head H to wait when printing is not being performed is set at a position outside the print area in the main scanning direction X of the print head H. A part 51 is provided.

  The cap 51 is in close contact with the head unit 13 of the print head H in order to prevent ink thickening when the print head H is not used. Suction caps 52 arranged in a row are provided. The cap unit 51 is configured to move up and down between a position that is in close contact with the bottom surface of the print head H and a position that is away from the bottom surface of the print head H.

  A bearing holder portion 56 having a guide hole 55 is formed at the rear end portion of the print head H, and a plate-like guide plate 57 extending in the main scanning direction is formed at the front end portion of the printer. Yes. The print head H is supported by placing the guide plate 57 on the guide rail 10 on the front side of the printer with the guide rail 10 on the rear side of the printer fitted in the guide hole 55 of the bearing holder portion 56. Yes. With such a configuration, when a paper jam or the like occurs, the jammed paper can be easily removed by rotating the print head H upward with the guide rail 10 on the rear side of the printer as a fulcrum. .

  On the other hand, at the standby position of the print head H, there is provided a mechanism for preventing the print head H from floating when the cap portion 51 is in close contact with the lower surface of the print head H. This mechanism includes a pressing roller 54 rotatably supported by a fixing member 53, and the front side of the printer of the print head H is sandwiched between the pressing roller 54 and the guide rail 10. The movement of the end of the upper and lower sides is restricted. Accordingly, it is possible to prevent the print head H from being lifted when the cap portion 51 is in close contact with the print head H, and to reliably prevent the ink from being thickened.

  As shown in FIGS. 4 and 5, the recording paper holding portion D has a plurality of suction holes 60 opened on the surface (upper surface) corresponding to the print area of the print head H, and corresponds to the flushing area. A platen 45 (suction part, flushing part) in which a flushing hole 61 is formed, a suction chamber 62 provided below the print area of the print head H in the platen 45 and communicating with the suction hole 60, and flushing of the print head H in the platen 45 A flushing chamber 63 provided below the region and communicated with the flushing hole 61, and air in the suction chamber 62 is sucked and exhausted to generate a negative pressure on the surface of the platen 45 through the suction hole 60, so that the recording paper P is placed on the platen. And a suction fan (not shown) for suction-holding on the surface of 45. In the present embodiment, the suction hole 60 and the flushing hole 61 are formed in one platen 45, but the suction hole 45 and the flushing hole 61 may be formed in separate members.

  On the support surface 45a of the platen 45, a recess 45b extending in the sub-scanning direction Y is formed. An ink absorbing material 72 is accommodated in the recess 45b. The ink absorbing material 72 allows the width of the recording paper P on the support surface 45a to be partially discharged from the print head H (head unit 13) when performing borderless printing for printing an image on the entire recording paper P. This is provided in order to prevent the support surface 45a of the platen 45 from being soiled by the ink that has come off from the outer edge of the direction. For this reason, the concave portion 45b extends along the edge at a position corresponding to the edge in the width direction of the recording paper P on the support surface 45a on the support surface 45a and a position corresponding to the print head H in the sub-scanning direction Y. (That is, extending in the sub-scanning direction Y).

  The flushing hole 61 is for receiving a small amount of ink ejected from the ink ejection nozzle 15 of the print head H at the start of printing in order to prevent the ink from thickening. An ink absorbing material 64 is accommodated in the flushing chamber 63. The waste ink discharged to the flushing hole 61 is absorbed by the ink absorber 64 and stored in a waste liquid tank (not shown) through the waste pipe 65.

  The cutter unit 4 is disposed on the lower side of the conveyance path of the recording paper P and the fixed blade 4a on the upper side of the conveyance path of the recording paper P, and is vertically moved with respect to the fixed blade 4a by a motor (not shown). The movable blade 4b moves to the lower side of the recording paper P, and the recording paper P is cut. Chips resulting from this cutting fall and are stored in a waste box (not shown) disposed in the lower part of the housing 3.

  The switchback unit 5 switches back the recording paper P and discharges the recording paper P from the rear end side of the recording paper P to the transport path so that the printing surface of the recording paper P faces the upper surface on the transport belt 151 of the conveyor device 150. It is something to be made.

  As shown in FIG. 2, the switchback unit 5 includes a pressure-bonding switchback roller pair 73 including a lower drive roller 73a and an upper driven roller 73b, and an upstream side of the switchback roller pair 73. A pair of first guide members 74 that are provided so as to sandwich the conveyance path and guide the recording paper P conveyed from the conveyance roller pair 26 after cutting to the switchback roller pair 73, and the back surface of the recording paper P that has been switched back will be described later. A pair of pressure-feed type supply rollers 75 to be supplied to the printing unit 6, a switchback roller pair 73, and a supply roller pair 75 are provided so as to sandwich the conveyance path, and the switched back recording paper P is supplied to the supply roller pair 75. A pair of second guide members 76 for guiding are provided.

  The driving roller 73a of the switchback roller pair 73 is driven forward by a motor (not shown) to sandwich the recording paper P and transport it to the front of the printer, and reversely rotated to sandwich the recording paper P and transport it to the rear of the printer. And is configured to be possible.

  The switchback roller pair 73 and the first guide member 74 can be moved integrally around the rotation axis of the drive roller 73a of the switchback roller pair 73 by a motor (not shown). The relative position of the driven roller 73b with respect to the driving roller 73a of the roller pair 73 is located almost directly above the driving roller 73a, and is a first position for conveying the recording paper P to the rear side of the printer (shown by a solid line in FIG. 2). And a second position for supplying the switched back recording paper P from the rear end side to the back surface printing unit 6 (shown in phantom lines in FIG. 2). And can be switched to.

  A recording paper collection box 83 that opens upward is provided below the switchback unit 5. The recording paper collection box 83 is for collecting the recording paper P remaining in the transport path when an error (for example, a paper jam error) occurs. When an error occurs, the recording paper P remaining on the transport path is transported to the switchback unit 5 by the recording paper transport mechanism. The switchback unit 5 receives the recording paper P and discharges it to the recording paper collection box 83. As a result, when an error occurs, the recording paper P remaining in the transport path can be easily removed without opening a necessary portion of the printer cover (housing 3).

  The back surface printing unit 6 is composed of a dot impact type thermal printer, and is disposed on the back surface side of the recording paper P (on the rear side of the printer with respect to the transport path).

  On the downstream side of the conveyance of the back surface printing unit 6, a conveyance roller pair 28 for feeding the recording paper P after the back surface printing is disposed. Then, the recording paper P is transported to the drying unit 7 on the downstream side by the rotation of the transport roller pair 28.

  The drying unit 7 records a suction fan 154 for taking air into the drying device 153, a heater 155 for heating the air taken in by the suction fan 154, and the air heated by the heater 155 as dry air. The exhaust nozzle unit 156 sprays on the printing surface of the paper P.

  The decurling unit 8 includes a driving conveyance roller 81 and a decurling roller 82 configured to be movable around the driving conveyance roller 81. The decurling unit 8 switches the position of the decurling roller 82 between the transport position and the decurling position according to the type of the recording paper P (roll paper or sheet paper).

  The conveyance position is defined as a position where the decurling roller 82 is located directly above the driving conveyance roller 81. At this transport position, the recording paper P is transported without being decurled by both rollers 81 and 82.

  The decurling position is defined as a position where the decurling roller 82 is rotated in the clockwise direction around the driving conveying roller 81 from the conveying position. At this decurling position, the recording paper P is conveyed while being decurled by both rollers 81 and 82.

  The decurling unit 8 controls the decurling roller 82 to be positioned at the conveying position when the recording sheet P conveyed from the drying unit 7 is the sheet-shaped recording sheet P supplied from the manual feeding unit. On the other hand, when the recording sheet P is a roll-shaped recording sheet P drawn from the magazines M1 and M2, the decurling roller 82 is controlled to be positioned at the decurling position. Accordingly, the recording paper P drawn from the magazines M1 and M2 can be surely decurled without unnecessarily curling the recording paper P supplied from the manual supply unit.

  The accumulating device 210 is for accumulating the recording paper P conveyed from the conveyor device 150, and is disposed at the upper and lower ends of the accumulating main body 211, and a box-shaped accumulating main body 211 having an opening on the front side of the printer. An endless stacking belt 213 wound around the pair of rollers (not shown) with an appropriate tension, and a stacking plate 212 provided on the outer peripheral surface of the stacking belt 213 at substantially equal intervals. Yes. The roller pair is connected to a drive motor (not shown) for rotating the accumulation belt 213 to move the accumulation plate 212 in the transport direction.

  Of the plurality of stacking plates 212, the stacking plate 212 exposed to the outside of the stacking main body 211 moves downward following the rotation of the stacking belt 213, and is accommodated inside the stacking main body 211. The collecting plate 212 is configured to move upward following the rotation of the collecting belt 213. That is, the accumulation plate 212 is configured to be able to rotate continuously around the roller pair together with the accumulation belt 213.

  The stacking plate 212 waits at the delivery position of the recording paper P on the downstream side of the conveyance belt 151 so that the plate surface is horizontal and substantially flush with the belt surface of the conveyance belt 151. After the number of sheets corresponding to 1 is accumulated, the recording paper P of the next order is conveyed downward by the accumulation belt 213 before being conveyed.

-Control system configuration-
As shown in FIG. 6, the inkjet printer A according to this embodiment includes a microprocessor 201 (hereinafter referred to as a CPU), a conveyance control unit 202 connected to the CPU 201 via a data bus, and head control. Section 203, print control section 204, semiconductor memory RAM / ROM 205, and communication interface 206.

  The conveyance control unit 202 controls the operation of the recording paper conveyance mechanism. The head control unit 203 controls the print head H by driving a drive belt 12 for reciprocating the print head H in the main scanning direction and supplying a voltage having a predetermined waveform to each piezoelectric element. . The communication interface 206 is for transmitting and receiving information to and from the reception block 200. The print control unit 204 performs control for realizing printing of image data on the recording paper P based on the image data received from the reception block 200 via the communication interface 206. Here, the order information includes print channel information for specifying the size of the recording paper P to be printed, and print form information for specifying the number of printed sheets.

-Control of flushing operation-
Hereinafter, control of the flushing operation for forcibly discharging the thickened ink from the ink discharge nozzles 15 of the print head H at the start of printing will be described. In the example shown below, it is assumed that ink is ejected four times from one ink ejection nozzle 15 during the flushing operation.

  FIG. 7A is a schematic diagram showing the landing position of ink during the flushing operation. As shown in FIG. 7A, the head control unit 203 moves the print head H above the flushing hole 61 to discharge ink. Specifically, of the eight ink discharge nozzles 15 arranged at intervals in the main scanning direction X, the rightmost ink discharge nozzle 15 is moved so as to face the left end of the ink absorbing material 64 in the flushing hole 61.

  7B, the head controller 203 performs the flushing operation while moving the print head H from the left end to the right end of the ink absorbing material 64 in the flushing hole 61 at a predetermined moving speed. Make it.

  Here, the predetermined moving speed is changed in accordance with the amount of ink used for the flushing operation. Specifically, the print head H is moved from the left end to the right end of the ink absorbent 64. The speed is such that all of the ink used for the flushing operation can be consumed during the period.

  For example, when the period during which the print head H has been stopped is long, it is considered that the thickening of the ink has progressed, and thus it is necessary to increase the amount of ink used for the flushing operation. In this case, the moving speed of the print head H is changed so as to be slow.

  On the other hand, when the period during which the print head H has been stopped is short, it is considered that the thickening of the ink has not progressed so much, so that the amount of ink used for the flushing operation can be small. In this case, the moving speed of the print head H is changed so as to increase.

  Next, as shown in FIG. 7C, the head control unit 203 positions the second ink discharge nozzle 15 from the right end of the print head H so as to face the left end of the ink absorbing material 64, and discharges ink. . In the example shown in FIG. 7C, when the rightmost ink discharge nozzle 15 is positioned at the right end of the ink absorbing material 64, the second ink discharge nozzle 15 is already opposed to the left end of the ink absorbing material 64. Therefore, ink is ejected at that position.

  7D, the head controller 203 performs the flushing operation while moving the print head H from the left end to the right end of the ink absorbent 64 in the flushing hole 61 at a predetermined moving speed. Make it. Hereinafter, such a flushing operation is similarly performed for the remaining ink discharge nozzles 15.

  With such a configuration, the moving speed of the print head H is changed according to the amount of ink used for the flushing operation, and the print head H is moved from the left end to the right end of the ink absorbing material 64 in the flushing hole 61. By performing the flushing operation, the ink ejected from the print head H a plurality of times can be landed at different positions. As a result, even if the next ink is ejected before the ink is absorbed by the ink absorbing material 64, the ink landing position is different, so that the ink does not splash on the surface of the ink absorbing material 64, and the printing is performed. Ink can be prevented from adhering to the surface of the head H.

  In the present embodiment, the case where ink is ejected four times from one ink ejection nozzle 15 during the flushing operation has been described. However, the number of times this ink is ejected is the number of times illustrated to facilitate understanding of the flushing operation. In the actual flushing operation, ink is ejected more frequently.

<< Modification of Embodiment >>
In the above-described embodiment, the flushing operation is performed while moving the print head H from the left end to the right end of the ink absorbing material 64 in the flushing hole 61. However, the present invention is not limited to this mode. Hereinafter, modifications of the present embodiment will be described. In this modification, ink is ejected twice from one ink ejection nozzle 15 during the flushing operation.

  FIG. 8A is a schematic diagram showing the landing position of the ink when the flushing start position is changed. As shown in FIG. 8A, the head control unit 203 moves the print head H above the flushing hole 61 to discharge ink. Specifically, of the eight ink discharge nozzles 15 arranged at intervals in the main scanning direction X, the rightmost ink discharge nozzle 15 is moved so as to face the position on the right side of the center in the width direction of the ink absorber 64. .

  Then, as shown in FIG. 8B, the head control unit 203 causes the print head H to perform a flushing operation while moving the print head H from the position on the right side of the center of the ink absorbing material 64 toward the right end at a predetermined moving speed. That is, in this modification, only the flushing start position is changed while the moving speed of the print head H is set to the same speed as when ink is ejected four times.

  Next, as shown in FIG. 8C, the head control unit 203 positions the second ink discharge nozzle 15 from the right end of the print head H so as to face the left end of the ink absorbing material 64, and discharges ink. . In the example shown in FIG. 8C, when the rightmost ink discharge nozzle 15 is positioned at the right end of the ink absorber 64, the second ink discharge nozzle 15 is already opposed to the left end of the ink absorber 64. Therefore, ink is ejected at that position.

  Then, as shown in FIG. 8D, the head control unit 203 causes the print head H to perform a flushing operation while moving the print head H from the left end of the ink absorbing material 64 to a position closer to the center left side at a predetermined moving speed.

  Next, as shown in FIG. 8E, the head control unit 203 positions the third ink ejection nozzle 15 from the right end of the print head H so as to face the position on the right side of the center of the ink absorbing material 64, and the ink. To discharge.

  Then, as shown in FIG. 8F, the head control unit 203 causes the print head H to perform a flushing operation while moving the print head H from the position on the right side of the center of the ink absorbing material 64 to the right end at a predetermined moving speed. Hereinafter, such a flushing operation is similarly performed for the remaining ink discharge nozzles 15.

  With such a configuration, when the amount of ink used for the flushing operation is relatively small, the flushing start position is changed to the central position of the ink absorbing material 64 in the flushing hole 61, so that the central position extends to the right end. Ink can be discharged evenly.

  As described above, the present invention is extremely useful and industrially applicable because it has a highly practical effect that ink ejected during the flushing operation can be prevented from splashing back to the print head. The nature is high.

A Inkjet printer P Recording paper X Main scanning direction H Print head 45 Platen (Suction part, flushing part)
60 Suction hole 61 Flushing hole 203 Head controller

Claims (2)

By ejecting ink while scanning the print head in the main scanning direction orthogonal to the recording paper conveyance direction toward the recording paper intermittently conveyed along the conveyance path, the image is printed on the recording paper. An inkjet printer for printing,
An adsorbing portion provided below the print head and having a plurality of adsorbing holes formed corresponding to the print area of the print head;
A flushing portion provided at a position deviating from the print area in the main scanning direction and having a flushing hole formed corresponding to the flushing area of the print head;
A head control unit that controls the operation of the print head so as to perform a flushing operation for discharging a predetermined amount of ink toward the flushing hole;
The head controller changes the moving speed of the print head in the main scanning direction according to the amount of ink used for the flushing operation, and moves the print head in the main scanning direction at the changed moving speed. An ink jet printer configured to perform the flushing operation. In claim 1,
The ink jet printer, wherein the head control unit is configured to change a flushing start position of the print head in accordance with an ink amount used for the flushing operation.

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