JP4710686B2 - Inkjet printer - Google Patents

Description

  The present invention relates to a drum type ink jet printer provided with means for bringing a recording head into contact with a maintenance unit at a maintenance position.

  Conventionally, recovery processing (maintenance) of a recording head surface in a drum-type ink jet printer is performed by relatively moving a recovery processing device (hereinafter referred to as “maintenance unit”) and the recording head so that the maintenance unit touches the head surface. It is done by touching.

  In this case, in the conventional drum type ink jet printer, the platen surface for conveying the recording medium is formed in a curved shape, for example, and each of the plurality of heads is substantially perpendicular to the curved platen and has a center of curvature. Were arranged radially.

  For example, in Patent Document 1, a plurality of recording heads are arranged radially with a predetermined gap on the outer periphery of the drum, and a maintenance unit is arranged inside the drum so as to face the plurality of recording heads. The drum is provided with an openable / closable shutter. When the recording medium is continuous paper during maintenance, the shutter is opened after the recording medium is retracted from the paper conveyance path. The maintenance unit is moved so that the maintenance unit is brought into contact with a plurality of recording heads to clean the recording head surface.

In Patent Document 2, a plurality of recording heads are arranged radially with a predetermined gap on the outer periphery of the drum, and a maintenance unit is arranged in the vicinity of the drum. At the time of maintenance, the recording head is retracted from the drum as much as the maintenance unit enters between the recording head and the drum surface. Further, the maintenance unit is moved between the drum and the recording head, and the maintenance unit is brought into contact with the direction perpendicular to the nozzle surface of each recording head to perform the maintenance operation.
JP-A-5-330030 (page 4-5, FIG. 4) Japanese Patent Laid-Open No. 10-138504 (page 11, FIG. 2)

  However, in Patent Document 1, since the maintenance unit is disposed in the drum, it is necessary to remove the sheet from the sheet conveyance path in order to perform maintenance. In this case, if the paper is a cut paper, the removal of the paper is not so difficult. However, if the paper is a continuous paper such as a roll paper, it is a difficult work. In addition, a plurality of recording heads are arranged radially according to the curved surface of the drum, and it is necessary to incline or incline the maintenance unit according to the inclination of the plurality of recording heads during maintenance.

  As described above, when the maintenance unit is tilted radially in accordance with the tilt of the recording head, the pitch between the maintenance units becomes smaller as the distance from the center of the drum becomes closer, so that the size of the maintenance unit is limited. For this reason, it is necessary to consider the moving distance to the recording head and the size of the maintenance unit.

  Further, in Patent Document 2, the moving direction of the maintenance unit with respect to a plurality of recording heads is not a direction perpendicular to the nozzle surface of the recording head. For this reason, it does not approach from the state where both of them face each other during maintenance, but deviates from the perpendicular to the nozzle surface and approaches from an oblique direction. For this reason, in Patent Document 2, it is difficult to accurately arrange the maintenance unit at the maintenance position.

  The present invention has been made to solve such a problem, and an object of the present invention is to perform maintenance accurately without removing the recording medium even if the recording heads are arranged radially. It is to provide an ink jet printer.

In order to achieve the above object, the invention according to claim 1 is directed to a circumference of the cylindrical medium support surface at an image recording position for recording an image on a medium supported on the cylindrical medium support surface. A plurality of recording heads arranged along a direction;
A maintenance unit for performing maintenance on each of the plurality of recording heads at a maintenance position provided at a position different from the image recording position;
In the inkjet printer having the plurality of recording heads, a head moving unit that moves between the image recording position and the maintenance position.
Head support means for rotatably supporting the plurality of recording heads;
At the image recording position, an image recording angle that makes the ink ejection directions of the plurality of recording heads different from each other, and at the maintenance position, at a maintenance angle that makes the ink ejection directions of the plurality of recording heads parallel to each other, Angle adjusting means for adjusting the angles of the plurality of recording heads.

The invention according to claim 2 is the inkjet printer according to claim 1,
The angle adjusting means includes
Image recording angle adjusting means for adjusting to the image recording angle;
Maintenance angle adjusting means for adjusting to the maintenance angle.

The invention according to claim 3 is the ink jet printer according to claim 2,
The image recording angle adjusting means includes:
An angle adjuster provided in each recording head;
An angle adjusting plate disposed on a moving path of the plurality of recording heads and in contact with the angle adjusting unit;
In the process of moving the plurality of recording heads to the image recording position by the head moving means, the angle adjusting unit of the recording head is brought into contact with the angle adjusting plate.

The invention according to claim 4 is the inkjet printer according to claim 3,
The angle adjusting plate is configured to be shared with the angle adjusting units of the plurality of recording heads.

The invention according to claim 5 is the ink jet printer according to claim 2,
The image recording angle adjusting means includes:
It is a motor for rotating each recording head provided in each recording head.

The invention according to claim 6 is the inkjet printer according to claim 2,
The image recording angle adjusting means includes:
It is arranged on the back side of each recording head at the image recording position, and has a head pressing means for pressing the recording head from the back side,
The head pressing means presses the recording head from both sides toward the medium support surface across the rotation center of the recording head in the circumferential direction on the back surface of the recording head.

The invention according to claim 7 is the inkjet printer according to claim 2,
The image recording angle adjusting means includes:
A stopper for restricting rotation of the recording head;
And an elastic member that urges the recording head toward the stopper.

The invention according to claim 8 is the ink jet printer according to claim 2,
The maintenance angle adjusting means includes:
An angle adjuster provided in each recording head;
An angle adjustment plate disposed at the maintenance position,
In the process of moving the plurality of recording heads to the maintenance position by the head moving means, the angle adjusting portion of the recording head is brought into contact with the angle adjusting plate.

  According to the present invention, even if the recording heads are arranged radially, maintenance of the recording head can be performed accurately without removing the recording medium.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is an overall perspective view of the ink jet printer according to the present embodiment, and FIG. 2 is an external perspective view of a printing unit.

  In FIG. 1, an inkjet printer 1 surrounded by a casing includes a printing unit 2 that prints (images record) on a recording medium 3 that is conveyed from the upstream side, and maintenance that is disposed on the downstream side in the conveyance direction of the recording medium 3. And a unit 19. The printing unit 2 includes a drum 4 as a cylindrical medium support surface that conveys the recording medium 3, and a plurality of (four colors of yellow, magenta, cyan, and black) recording heads 5 that eject ink onto the recording medium 3. Is provided.

  The recording head 5 has an elongated rectangular shape extending in the longitudinal direction of the drum 4. The plurality of recording heads 5 are arranged substantially concentrically at regular intervals along the circumferential direction of the drum 4. In the present embodiment, roll-shaped continuous paper is assumed as the recording medium 3, but cut paper or the like may be used, for example.

  As shown in FIG. 2, the recording head 5 is supported at its both ends in the longitudinal direction by a pair of guide plates 7 and 7 arranged to face each other via a bearing 6 as a head support means. The bearing 6 has a V-groove 6a formed on the outer periphery (see FIG. 12).

  The guide plate 7 has an arc portion 7a formed along the circumferential direction of the drum 4 and a horizontal portion 7b connected to the rear portion of the arc portion 7a in the medium conveying direction substantially horizontally. Further, a guide groove 7c is continuously formed in the arc portion 7a and the horizontal portion 7b. The bearing 6 can move along the guide groove 7c.

  A link mechanism 8 serving as a head moving means for connecting the plurality of recording heads 5 is provided on one end side in the longitudinal direction of the recording head 5 (left side as viewed from the front). Sensors 9a and 9b are provided on the upstream side and the downstream side of the guide plate 7 in the medium conveyance direction, respectively. In the present embodiment, contact type sensors are used as the sensors 9a and 9b. However, the present invention is not limited to this, and a non-contact sensor such as a photoelectric sensor may be used.

  Further, a belt mechanism 10 as a head moving means is disposed on one side (left side as viewed from the front) along the guide plate 7. The belt mechanism 10 includes a belt 11 wound between a driving pulley 13 and a driven pulley 14. The driving pulley 13 is fixed to the output shaft of the motor 12.

  As shown in FIGS. 3 and 4, the belt 11 is stretched with a predetermined tension while its direction is regulated by the tension rollers 15 and 52. Thus, the belt 11 is disposed on the side of the guide plate 7 along the guide groove 7c. Note that three tension rollers 52 are provided in the present embodiment, but this is for the purpose of smoothly stretching the belt 11 along the guide groove 7c, and is not limited to three. .

  As shown in FIG. 5, the link mechanism 8 is provided with a belt holding portion 16 having a protrusion 16 a that protrudes toward the belt mechanism 10. The link mechanism 8 is integrally connected to the belt 11 by the belt holding portion 16 and the fixing plate 17. The dimension of the fixing plate 17 in the width direction (belt width direction) is narrower than the width of the groove 18 (see FIG. 2) formed in the tension roller 15. This is to allow the fixing plate 17 to pass without interfering with the groove 18 when the belt 11 moves.

  Further, as shown in FIG. 6, a notch 53 is formed on the lower surface of the belt holding portion 16. The width dimension of the notch 53 is formed wider than the width dimension of the tension roller 52. This is to allow the belt holding portion 16 to pass without interfering with the tension roller 52 when the belt 11 moves.

  As shown in FIGS. 7 to 9, an angle adjusting plate 50 as an image recording angle adjusting means is provided on the outer peripheral side of the drum 4 at a predetermined interval from the recording head 5. The angle adjusting plate 50 is formed on a curved surface portion 50 a as an angle adjusting plate whose surface facing the recording head 5 is curved substantially concentrically with the drum 4.

The curvature radius of the curved portion (angle adjusting portion) 5a and the angle adjusting plate 5 0 of the curved surface portion 50a of the recording head 5 and is formed in substantially the same. Thereby, in the process of moving the recording head 5 from the maintenance position to the printing position, the curved surface portion 5a of the recording head 5 is closely engaged with the curved surface portion 50a inside the angle adjusting plate 50.

  In this case, the curved surface portion 50a of the angle adjusting plate 50 is shared and brought into close contact with the curved surface portions 5a of the plurality of recording heads 5. In this way, the plurality of recording heads 5 are automatically adjusted so that all nozzle surfaces thereof face the center of the drum 4 (that is, at an image recording angle that makes the ink ejection directions different from each other).

  Next, as shown in FIGS. 10 to 12, at the maintenance position of the recording head 5, the recording head 5 has moved to the end side of the horizontal portion 7 c of the guide plate 7. On the other hand, both end portions in the longitudinal direction of the recording head 5 slightly protrude in the direction opposite to the center side of the drum 4, and the upper end surface thereof is formed in a curved surface portion 5a as an angle adjusting portion. Further, an intermediate portion excluding both ends in the longitudinal direction of the recording head 5 is formed in a horizontal portion 5b as an angle adjusting portion.

  On the other hand, a maintenance unit 19 is disposed below the horizontal portion 7 b of the guide plate 7. An angle adjusting plate 51 as a maintenance angle adjusting means is attached above the maintenance unit 19. During maintenance, the angle adjusting plate 51 comes into contact with the horizontal portion 5b of the recording head 5 described above. Thereby, the ink ejection directions of the recording head 5 are made parallel to each other.

  Further, as shown in FIG. 13, the maintenance unit 19 includes a plurality of elongated rectangular cleaner members 19 a extending in the same direction as the longitudinal direction of the recording head 5, and the cleaner members 19 a at both left and right ends in the longitudinal direction. And a support plate 19b to be supported. The same number of cleaner members 19 a as the recording heads 5 are provided, and the arrangement interval thereof is adjusted to be approximately equal to the arrangement interval of the recording heads 5.

  Further, a total of four lifting guides 20 are disposed on the upstream and downstream sides of the maintenance unit 19 in the medium conveyance direction. A rack 21 is fixed to one side of the left and right support plates 19b, and an elevating motor 22 having a pinion 22a meshing with the rack 21 fixed to the shaft is disposed.

  Further, the cleaner member 19a is provided with the same number of cleaning heads 70 as the nozzles on the side facing the recording head 5. The cleaning head 70 has a vacuum suction portion (not shown) and a wipe rubber.

Next, the operation of the present embodiment will be described.
In FIG. 2, when the recording medium 3 is transported and supplied along the outer peripheral surface of the drum 4, ink is printed by the recording heads 5 of four colors (yellow, magenta, cyan, and black) arranged on the circumference of the drum 4. Are ejected and printed on the recording medium 3. Eventually, when maintenance of the recording head 5 becomes necessary due to use for a certain period (or periodically), the operator drives the motor 12 on the side of the guide plate 7 to rotate the belt 11.

  Then, the link mechanism 8 fixed to the belt 11 via the belt holding part 16 starts moving. Further, the recording head 5 fastened to the link mechanism 8 is also directed to the maintenance unit 19 on the downstream side in the conveyance direction of the recording medium 3 in the guide groove 7c of the guide plate 7 together with the bearings 6 provided at both ends in the longitudinal direction. Move.

  At this time, the recording head 5 that has started moving in the guide groove 7c moves in the circumferential direction on the circular arc portion 7a of the guide plate 7 on the circumference of the drum 4, and moves in the horizontal direction when it reaches the horizontal portion 7b. When the recording head 5 starts to move in the horizontal direction along the horizontal portion 7b, the horizontal portion 5b (see FIGS. 10 to 12) of the recording head 5 advances while contacting the lower surface of the angle adjusting plate 51. As a result, the plurality of recording heads 5 move in a substantially horizontal state.

  The fixing plate 17 that fastens the belt 11 and the link mechanism 8 is formed to be narrower than the groove 18 provided in the tension roller 15 when passing through the tension roller 15 and therefore does not interfere. . Further, since a wide notch 53 is formed on the lower surface of the belt holding portion 16, it does not interfere with the tension roller 52.

  Thus, when the recording head 5 reaches the maintenance position, one end of the link mechanism 8 comes into contact with the sensor 9b, the drive of the motor 12 is stopped, and the movement of the recording head 5 is stopped. Next, the lifting / lowering motor 22 is actuated, and the maintenance unit 19 is guided by the lifting / lowering guide 20 by the rack 21 and the pinion 22a to be raised.

  Next, when the maintenance unit 19 comes into contact with the recording head 5, the movement of the maintenance unit 19 is stopped by a sensor (not shown), and the maintenance operation is started. In this maintenance operation, for example, the ink ejection part of the recording head 5 is vacuum-sucked by a vacuum suction part (not shown) or wiped with a wiper rubber (not shown).

  When this maintenance operation is completed, the motor 12 is driven again, and the recording head 5 moves along the guide plate 7 in the direction opposite to the previous time, that is, in the direction of the drum 4. Then, while the recording head 5 is moving to the arc portion 7 a of the guide plate 7, the curved surface portion 50 a inside the angle adjusting plate 50 and the curved surface portion 5 a of the recording head 5 are engaged so as to be in close contact. Thus, each of the plurality of recording heads 5 is accurately directed to the center of the drum 4.

  Thereby, the plurality of recording heads 5 are respectively adjusted to the printing angle, and when reaching a predetermined printing position, the end of the link mechanism 8 comes into contact with the sensor 9a. Then, the drive of the motor 12 is stopped and the recording head 5 is stopped. Thereafter, normal printing can be performed at the printing position by the plurality of recording heads 5.

  According to the present embodiment, a plurality of recording heads 5 are maintained from an inclined state (each of which faces the center of the drum 4) in order to print the recording heads 5 on the recording medium 3 at the printing position. For this reason, the ink discharge surface of the recording head 5 can be directly applied to the maintenance unit 19 at the time of maintenance.

  In this case, if the recording head 5 is inclined and brought into contact with the maintenance unit 19, the interval between the adjacent recording heads 5 is narrow and it is difficult to dispose the maintenance unit 19 near the center of the drum 4. There is a risk of becoming.

  However, when the plurality of recording heads 5 are arranged substantially horizontally during maintenance and the maintenance unit 19 is arranged so as to be movable in a direction substantially perpendicular thereto, as in the present embodiment, even when the interval between the recording heads 5 is narrow. The maintenance unit 19 having a size corresponding to the size can be manufactured.

When performing maintenance with the recording head 5 tilted, if the maintenance unit 19 is not in close contact with the ink ejection surface of the recording head 5, ink may leak from the gap and adhere to the recording medium 3. In this embodiment, such a fear does not occur.
(Modification 1)
FIG. 14 shows a first modification of the first embodiment.

  In the first modification, a chain mechanism 27 is arranged instead of the belt mechanism 10 as the head moving means described above. The chain mechanism 27 includes a chain 26, a large sprocket 23, a medium sprocket 24, and a small sprocket 25. A midway portion in the longitudinal direction of the connected chain 26 is fastened to the link mechanism 8 installed at the end of the recording head 5.

  The chain 26 has a protrusion 29 formed in the middle in the longitudinal direction. Then, photoelectric sensors 28 a and 28 b are arranged at the movement start end and movement end of the chain 26 so as to face the protrusion 29. Other configurations are the same as those of the first embodiment.

Next, the operation of the first modification will be described.
During maintenance, the motor 12 rotates, so that the medium sprocket 24 fixed to the output shaft rotates. When the medium sprocket 24 rotates, the chain 26 meshing with it moves, and the large sprocket 23 rotates. Then, the link mechanism 8 integrally fastened to the chain 26 moves, and the plurality of recording heads 5 fastened to the link mechanism 8 move.

  A small sprocket 25 that restricts the moving direction of the chain 26 is disposed in the middle of the chain 26 in the longitudinal direction. Thus, the plurality of recording heads 5 move along the guide plate 7. At this time, the sensor 28 a detects the protrusion 29 formed on the chain 26 at the printing position of the recording head 5 and moves the recording head 5. Stop. The sensor 28b senses the protrusion 29 at the maintenance position of the recording head 5, and stops the movement of the recording head 5.

According to the first modification, the chain mechanism 27 causes the recording head 5 to be in a horizontal state for maintenance from an inclined state in which the recording head 5 is printed on the recording medium 3 (a state in which the recording head 5 faces the center of the drum 4). Thus, the ink discharge surface of the recording head 5 can be directly applied to the maintenance unit 19 during maintenance.
(Modification 2)
FIG. 15 shows a second modification of the first embodiment.

  In the second modification, a cylinder mechanism 33 is arranged instead of the belt mechanism 10 as the head moving means described above. The cylinder mechanism 33 includes an air cylinder 30, a floating joint 31, and a floating joint 32. A floating joint 31 is fastened to the tip of the rod 35 of the air cylinder 30.

  The floating joint 31 is fastened to the link mechanism 8. A floating joint 32 is fastened to the rear end of the air cylinder 30. The air cylinder 30 is provided with a sensor 34 a and a sensor 34 b that detect the movement start end and movement end of the rod 35. Other configurations are the same as those of the first embodiment.

Next, the operation of the second modification will be described.
During maintenance, when the plurality of recording heads 5 at the printing position move to the maintenance position, the rod 35 of the air cylinder 30 is pulled into the cylinder in the movement direction. At the same time, the link mechanism 8 starts to move through the floating joint 31, and the plurality of recording heads 5 fastened to the link mechanism 8 also move along the guide grooves 7 c of the guide plate 7. When the plurality of recording heads 5 reach the maintenance position, the sensor 34b detects the end of movement of the rod 35 and stops moving.

  Further, when the recording head 5 moves from the maintenance position to the printing position, the rod 35 is fed out from the air cylinder 30, and the recording head 5 starts moving accordingly. When the recording head 5 reaches the printing position, the sensor 34a detects the movement start end of the rod 35, and the movement of the recording head 5 is stopped.

According to the second modification example, the cylinder mechanism 33 causes the plurality of recording heads 5 to be printed on the recording medium 3 from a tilted state (each of which faces the center of the drum 4) to a horizontal state for maintenance. By doing so, the ink ejection surfaces of the plurality of recording heads 5 can be directly applied to the maintenance unit 19 during maintenance.
(Second Embodiment)
16 to 19 are diagrams illustrating a second embodiment.

  In this embodiment, as shown in FIGS. 16 and 17, a pulse motor 36 as an image recording angle adjusting means corresponding to each recording head 5 is connected to the link mechanism 8 provided in the plurality of recording heads 5. Is attached. The guide plate 7 is provided with one origin sensor 61 and a plurality of sensors 62 for detecting the position of the recording head 5 in the rotational direction with respect to the drum center.

  The shaft 5 c extending from the recording head 5 toward the pulse motor 36 is supported by a bearing 6 attached to the guide plate 7 and a bearing 63 attached to the link mechanism 8. Thus, the recording head 5 and the pulse motor 36 are coupled to each other via the coupling 64.

As a method for moving the recording head 5 in this embodiment, any method such as the above-described embodiment may be used. Other configurations are the same as those of the first embodiment.
Next, the operation of the present embodiment will be described.

  During printing or maintenance, when it is detected by a sensor (not shown) that the plurality of recording heads 5 have reached a predetermined printing position or maintenance position, the movement of the plurality of recording heads 5 is stopped. For example, at the printing position, the position in the rotation direction of each recording head 5 with respect to the center of the drum 4 is detected by the origin sensor 61 and the sensor 62.

Next, a positioning method of the recording head 5 at the printing position or maintenance position will be described with reference to FIG. 19 based on the flowchart of FIG.
In S1, when both the origin sensor 61 and the sensor 62 are OFF, a signal pulse is output from a control device (not shown) in S2, and the pulse motor 36 is rotated counterclockwise (the arrow direction in FIG. 19). The origin sensor 61 is rotated until the recording head 5 is detected. This is because the recording head 5 is not in contact with either the origin sensor 61 or the sensor 62, and therefore it is impossible to determine what tilt position the recording head 5 is at. It is rotated until the sensor 61 detects it.

  Next, in S3, the pulse motor 36 is driven counterclockwise until the origin sensor 61 is turned on. Further, in S4, after the origin sensor 61 is turned on, a signal indicating the amount of movement from the origin is output from the control device to the pulse motor 36, and the recording head 5 is rotated clockwise by a predetermined amount. Thereby, for example, in the case of positioning at the printing position, the angle of the recording head 5 with respect to the drum center is set to an appropriate position.

  In S5, for example, when the origin sensor 61 is OFF and the sensor 62 is ON, it can be seen that the recording head 5 is rotated clockwise. Therefore, in this case, the process proceeds to S2, and the control device rotates the pulse motor 36 in the counterclockwise direction until the origin sensor 61 detects the recording head 5.

  Further, in S3 and S4 described above, the amount of movement from the origin (a point where the origin sensor 61 is ON) is signaled from the control device to the pulse motor 36 so that the angle of the recording head 5 becomes an appropriate maintenance position or printing position. And the recording head 5 is rotated clockwise by a predetermined amount.

  Further, in S6, for example, when the origin sensor 61 is ON and the sensor 62 is OFF, it can be seen that the recording head 5 is rotated counterclockwise. Therefore, in this case, in S7 and S8, the control device rotates the pulse motor 36 in the clockwise direction until the origin sensor 61 is OFF and the sensor 62 is ON. Hereinafter, the control is performed in the above-described steps S2 to S4.

  In this way, when the recording head 5 is at the printing position, the pulse motor 36 is rotated so that the plurality of recording heads 5 face the center of the drum 4. When the recording head 5 is at the maintenance position, the pulse motor 36 is rotated so that the plurality of recording heads 5 face the maintenance unit 19.

According to the present embodiment, even when the recording head 5 is at the printing position or at the maintenance position, the accurate angle adjustment of the recording head 5 is performed according to each position. Can do.
(Third embodiment)
FIG. 20 is a diagram illustrating a third embodiment.

  In the present embodiment, an air cylinder (or solenoid) 37 serving as a head pressing unit is disposed in the vicinity of the upper portion of the recording head 5. The air cylinder 37 is arranged corresponding to each of the printing position and the maintenance position of the recording head 5.

  The air cylinder 37 is fixedly supported by a frame (not shown), and a contact member 55 is attached to the tip of the rod 56. When the contact member 55 contacts the recording head 5, the recording head 5 is disposed at an appropriate angle with respect to the center of the drum 4 at the printing position.

  Similarly, when the contact member 55 contacts the recording head 5, the recording head 5 is positioned and disposed so as to face the maintenance unit 19 in the maintenance position. The air cylinder 37 is provided with sensors 57 and 58 for detecting the positions of the movement start end and movement end of the rod 56.

As a means for moving the recording head 5, any method such as the above-described embodiment may be used. Other configurations are the same as those of the first embodiment.
Next, the operation of the present embodiment will be described.

  When the recording head 5 is moved by the sensor (not shown) to reach the printing position or the maintenance position and stops, the rod 56 of the air cylinder 37 arranged at the optimum angle at each position is fed out, and the contact member 55 is moved to each position. The recording head 5 is pressed down at each position. This state is maintained during printing or maintenance, and the rod 56 is pulled into the cylinder when the printing operation or maintenance work is completed. The positions of the movement start end and movement end of the rod 56 at this time are detected by the sensor 57 and the sensor 58.

According to the present embodiment, it is possible to accurately adjust the angle of the recording head 5 corresponding to the work during printing or maintenance.
(Fourth embodiment)
21 to 25 are diagrams showing a fourth embodiment.

  In the present embodiment, as shown in FIG. 21, an alignment plate 39 as an angle adjusting plate is disposed above the guide plate 7 and, for example, upstream and downstream in the medium transport direction (arrow direction) of the guide plate 7. Racks 41 and 40 are arranged on the side. A pinion 42 that meshes with one rack 41 is attached to the upstream side of the guide plate 7.

  Further, a gear 43 fixed to the output shaft of the lifting motor 38 is disposed at a position where it engages with the other rack 40. The maintenance unit 19 ′ is arranged at a position spaced apart from the alignment plate 39 and the guide plate 7 so that it can be inserted horizontally between the alignment plate 39 and the guide plate 7 (in the direction of the arrow). Yes.

  As shown in FIGS. 22 and 23, a stopper 59 and a compression spring 60 are disposed below each recording head 5. In the unloaded state, each recording head 5 is set to an angle with the center of the drum 4 as the center of curvature.

Next, the operation of the present embodiment will be described.
In FIG. 21, during maintenance, the lifting motor 38 is driven, so that the guide plate 7 is meshed with the rack 40 meshed with the gear 43 fixed to the output shaft of the lifting motor 38 and the upstream pinion 42. It moves upward through the rack 41.

  Then, as shown in FIG. 24, when the recording head 5 that rises together with the guide plate 7 comes into contact with the alignment plate 39, the rise of the guide plate 7 is stopped by a sensor (not shown). At this time, the plurality of recording heads 5 are parallel to each other by the alignment plate 39. When each recording head 5 comes into contact with the alignment plate 39, each recording head 5 rotates so as to be substantially parallel and moves away from the stopper 59. At the same time, one end of each recording head 5 compresses the compression spring 60 as an elastic member (see FIG. 23).

  As shown in FIG. 24, when the recording head 5 comes to a predetermined raised position, the maintenance unit 19 ′ enters between the drum 4 and the recording head 5 by a moving means (not shown). When the maintenance unit 19 ′ and the recording head 5 reach a position facing each other, the recording head 5 is stopped by a sensor (not shown).

  Further, as shown in FIG. 25, when the maintenance unit 19 ′ is raised by a moving means (not shown) and the maintenance unit 19 ′ contacts the recording head 5, the upper end of the maintenance unit 19 ′ is detected by a sensor (not shown). And perform maintenance operations there. As described above, the maintenance operation at this time is performed by vacuum-adsorbing the fixed ink or by a wiping operation.

  When returning the recording head 5 from the maintenance position to the printing position again, the maintenance unit 19 ′ is moved downward by a moving means (not shown), and the lower end of the maintenance unit 19 ′ is detected by a sensor (not shown). When the maintenance unit 19 ′ stops at the lower end, the maintenance unit 19 ′ is retracted from between the drum 4 and the recording head 5 by a moving means (not shown). When the maintenance unit 19 ′ is retracted, the elevating motor 38 is rotated next, the guide plate 7 is moved downward by the rack 40 and the rack 41, and each recording head 5 is also moved downward.

  Eventually, when the recording head 5 is separated from the alignment plate 39, the compressed compression spring 60 lifts one end of the recording head 5 and the other end abuts against the stopper 59, thus returning to the original printing state angle. . Further, when the guide plate 7 is stopped at the lower end position by a sensor (not shown), a printing state is entered.

  According to the present embodiment, the maintenance operation can be performed by moving the guide plate 7 and the recording head 5 in the vertical direction during maintenance, and the center of the drum 4 is accurately positioned at the center of curvature during printing. can do.

1 is an overall perspective view of an inkjet printer according to a first embodiment. It is an external appearance perspective view of a printing part same as the above. It is a schematic side view of a printing part same as the above. It is an A section enlarged view same as the above. It is an external view of a belt holding part. It is an external view of a belt holding part. FIG. 3 is an external view illustrating a state in which a recording head is moved. It is a B section detailed drawing same as the above. It is a partial enlarged view same as the above. FIG. 3 is an external view illustrating a state in which a recording head is moved. It is detail drawing same as the above. It is front sectional drawing same as the above. It is an external view of a maintenance unit. It is a whole perspective view of the inkjet printer of the modification 1 of 1st Embodiment. It is a whole perspective view of the inkjet printer of the modification 2 of 1st Embodiment. It is an external view of the principal part of the inkjet printer of 2nd Embodiment. It is a figure which shows the state which connected the axis | shaft of the recording head and the pulse motor. FIG. 5 is a diagram illustrating a flowchart regarding angle adjustment of a recording head. It is explanatory drawing of the angle adjustment operation | movement of a recording head. It is an external view of the principal part of the inkjet printer of 3rd Embodiment. It is a side view around the drum of the inkjet printer of 4th Embodiment It is a figure which shows the angle setting state of the recording head in a printing part. It is a side view same as the above. FIG. 6 is a diagram illustrating a state in which a recording head is moved upward during maintenance and a maintenance unit is disposed below the recording head. It is a figure which shows a maintenance state same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inkjet printer 2 Printing part 3 Recording medium 4 Drum 5 Recording head 5a Curved surface part 5b Horizontal part 6 Bearing 6a V groove 7 Guide plate 7a Arc part 7b Horizontal part 7c Guide groove 8 Link mechanism 9a Sensor 9b Sensor 10 Belt mechanism 11 Belt 12 Motor 13 Pulley 14 Pulley 15 Tension roller 16 Belt holding part 17 Fixing plate 18 Groove 19 Maintenance unit 19a Cleaner member 19b Support plate 19 'Maintenance unit 20 Lifting guide 21 Rack 22 Lifting motor 22a Pinion 26 Chain 27 Chain mechanism 28a Sensor 28b Sensor 30 Air cylinder 33 Cylinder mechanism 34a Sensor 34b Sensor 36 Pulse motor 37 Air cylinder 38 Motor 39 Alignment plate 40 Rack 41 Rack 42 Pinion 43 Gear 50 Angle adjustment plate 50a Curve Surface 51 Angle adjusting plate 52 Tension roller 55 Contact member 56 Rod 57 Sensor 58 Sensor 59 Stopper 60 Compression spring 61 Origin sensor 62 Sensor 63 Bearing 64 Coupling 70 Cleaning head

Claims (8)

A plurality of recording heads arranged along a circumferential direction of the cylindrical medium support surface at an image recording position for recording an image on a medium supported on the cylindrical medium support surface;
A maintenance unit for performing maintenance on each of the plurality of recording heads at a maintenance position provided at a position different from the image recording position;
In the inkjet printer having the plurality of recording heads, a head moving unit that moves between the image recording position and the maintenance position.
Head support means for rotatably supporting the plurality of recording heads;
At the image recording position, the angle for image recording that makes the ink ejection directions of the plurality of recording heads different from each other, and at the maintenance position, the angle for maintenance that makes the ink ejection directions of the plurality of recording heads parallel to each other, Angle adjusting means for adjusting the angles of the plurality of recording heads, respectively;
An inkjet printer characterized by comprising: The angle adjusting means includes
Image recording angle adjusting means for adjusting to the image recording angle;
Maintenance angle adjusting means for adjusting to the maintenance angle;
The inkjet printer according to claim 1, comprising: The image recording angle adjusting means includes:
An angle adjuster provided in each recording head;
An angle adjusting plate disposed on a moving path of the plurality of recording heads and in contact with the angle adjusting unit;
In the process of moving the plurality of recording heads to the image recording position by the head moving means, the angle adjusting unit of the recording head is brought into contact with the angle adjusting plate;
The inkjet printer according to claim 2. The angle adjustment plate is configured to be shared with respect to the angle adjustment unit of the plurality of recording heads,
The inkjet printer according to claim 3. The image recording angle adjusting means includes:
Each of the recording heads is a motor that rotates the recording heads.
The inkjet printer according to claim 2. The image recording angle adjusting means includes:
It is arranged on the back side of each recording head at the image recording position, and has a head pressing means for pressing the recording head from the back side,
The head pressing means presses the recording head from the opposite sides toward the medium support surface across the rotation center of the recording head in the circumferential direction on the back surface of the recording head;
The inkjet printer according to claim 2. The image recording angle adjusting means includes:
A stopper for restricting rotation of the recording head;
An elastic member that urges the recording head toward the stopper,
The inkjet printer according to claim 2. The maintenance angle adjusting means includes:
An angle adjuster provided in each recording head;
An angle adjustment plate disposed at the maintenance position,
In the process of moving the plurality of recording heads to the maintenance position by the head moving means, the angle adjusting portion of the recording head is brought into contact with the angle adjusting plate.
The inkjet printer according to claim 2.