JP2015039676A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus in which interference between a can body transported toward image forming means and the image forming means is avoided and besides, the can body can be arranged near the image forming means.SOLUTION: As shown in (A), a can body 10 is stopped below an inkjet head 170. Thereafter, a linear servo is driven and, thereby, as shown in (B), the can body 10 rises to directly under the inkjet head 170. Subsequently, ink is ejected from the inkjet head 170 and an image is formed image on the can body 10 (refer to (C)). Therein, when the image is formed, the can body 10 rotates in the circumferential direction. Subsequently, the linear servo is driven and, as shown in (D), the can body falls. Thereafter, as shown in (E), the can body 10 is moved toward the next inkjet head.

Description

  The present invention relates to an image forming apparatus.

  In Patent Document 1, a plurality of digital print heads fixed to the main body side of the apparatus and forming an image on the can body, and a drive for carrying the can body and rotating the can body at a position opposite to the digital print head. A printing apparatus having a mechanism is disclosed.

US Patent Application Publication No. 2007/0089619

Here, in the configuration in which the can body is transported to the image forming means to form an image on the can body, when a part of the image forming means is located on the transport path of the can body, Interference with the image forming means is caused. On the other hand, in order to avoid interference between the can body and the image forming means, if the transport path of the can body is separated from the image forming means, the can body is separated from the image forming means, and the quality of the formed image is deteriorated. There is a risk of inviting.
An object of the present invention is to allow the can body to be disposed near the image forming means while avoiding interference between the can body conveyed toward the image forming means and the image forming means.

An image forming apparatus to which the present invention is applied is formed to have an image forming means for forming an image on a can and to extend in one direction and to pass by the side of the image forming means. A transport unit that transports the can body along the transport path, and the can body on the transport path is moved in a direction intersecting the one direction, and the can body is moved toward the image forming unit. And a can body moving means.
Here, the can body is formed in a cylindrical shape, and the image forming means performs image formation on the can body in a state where the axial center of the can body is arranged at a predetermined arrangement location, The can body moving means starts moving the can body toward the image forming means, starting from a predetermined location on the transport path, and then moves the shaft to the predetermined arrangement location. The can is arranged so that a heart is located, the perpendicular to the conveyance path and passing through the predetermined arrangement location, the position of the intersection with the conveyance path, and the position of the start point , The starting point is located on the upstream side of the intersection in the conveyance direction of the can body. In this case, compared to the case where the movement of the can body toward the image forming means is started from the intersection of the perpendicular line and the conveyance path, the movement distance of the can body can be shortened and image formation can be performed per unit time. You can increase the number of bodies.
Further, the image forming means is directed to the can body from an ink discharge port formed on the facing surface that faces the can body and is inclined with respect to a direction in which the transport path extends. The can body is ejected to form an image on the can body, and when the can body moving means moves the can body toward the image forming means, the can body moves in a direction crossing the one direction. And the said can can be moved so that the said opposing surface may extend along the direction. In this case, compared to the case where the can body moves without being along the direction in which the facing surface extends, the movement distance of the can body can be shortened, and the number of can bodies that can form an image per unit time can be increased.
From another viewpoint, an image forming apparatus to which the present invention is applied is formed with an image forming unit that forms an image on a can body, and is formed so as to extend in one direction and beside the image forming unit. A transport unit that transports the can along the transport path formed so as to pass through, a movement of the image forming unit toward the transport path, and the image forming unit in a direction away from the transport path An image forming apparatus.
Here, the image forming unit includes a plurality of image forming heads for forming an image, and the moving unit moves the plurality of image forming heads when the image forming unit moves, thereby forming the plurality of image forming units. The head may be supported by a common support member and move together as the head is moved by the moving means. In this case, it is easier to maintain the positional relationship of the individual image forming heads included in the plurality of image forming heads as compared to the case where the plurality of image forming heads individually move.
From another viewpoint, the image forming apparatus to which the present invention is applied conveys the can body from the upstream side to a predetermined location along the conveyance path, and then proceeds from the predetermined location to the downstream side. And a transport means for further transporting the can body, and a part of the transport body is disposed on the side of the transport path, and at least one of the upstream side and the downstream side of the predetermined location. An image forming unit that is provided so as to protrude on the conveyance path and forms an image on the can body located at the predetermined position, and the part of the image forming unit is disposed on the conveyance path. And an evacuation unit that evacuates the image forming apparatus.
Here, the retreating unit can retreat from the part of the transport path by rotating the image forming unit around a predetermined rotation center. In this case, by rotating the image forming unit, a part of the image forming unit can be retracted from the conveyance path.
From another point of view, the image forming apparatus to which the present invention is applied transports the cylindrical can body to the first location along the transport path, and is positioned downstream of the first location. A conveying means for further conveying the can body to a second location; a first image forming head for forming an image on a first portion of the outer peripheral surface of the can body located at the first location; The second image forming head is disposed on the downstream side of the first image forming head in the conveyance direction of the can body, and is a second portion of the outer peripheral surface of the can body located at the second location, and in the axial direction of the can body An image forming apparatus comprising: a second image forming head that forms an image with respect to the second part whose position is different from that of the first part.

  According to the present invention, the can body can be arranged near the image forming means while avoiding interference between the can body conveyed toward the image forming means and the image forming means.

1 is a diagram illustrating an image forming apparatus according to an exemplary embodiment. It is a figure for demonstrating an inkjet head. It is a figure explaining movement of a can when a can reaches the ink-jet head. It is the figure which showed the other movement aspect of the can. It is the figure which showed other structural examples, such as an inkjet head. It is a figure for demonstrating the moving mechanism of an inkjet head. It is the figure which showed other structural examples, such as an inkjet head. It is a figure for demonstrating the rotation mechanism of an inkjet head. It is the figure which showed other structural examples, such as an inkjet head. It is a figure explaining the rotation mechanism which rotates a 1st inkjet head and a 2nd inkjet head. It is the figure which showed other structural examples, such as an inkjet head. It is the figure which showed the moving mechanism which moves a 1st inkjet head and a 2nd inkjet head to the axial direction of a can body. It is the figure which showed the other arrangement | positioning aspect of the 1st inkjet head and the 2nd inkjet head. It is the figure which showed the example of discharge of the ink to a can.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a diagram illustrating an image forming apparatus 100 according to the present embodiment. 2A shows a state when the image forming apparatus 100 is viewed from above, and FIG. 2B shows a state when the image forming apparatus 100 is viewed from the front.

  As shown in FIGS. 2A and 2B, the image forming apparatus 100 of the present embodiment is provided with a disk-shaped turning table 110 called a turret. A servo amplifier 120 that drives the servo motor 140 is disposed on the turning table 110. Further, a holding member (mandrel) 130 that is formed in a cylindrical shape and is inserted into the can body 10 and holds the can body 10 is provided on the outer peripheral portion of the turning table 110.

  In addition, the can body 10 of this embodiment is formed in a cylindrical shape, and includes a bottom portion at one end portion in the axial direction and an opening at the other end portion. Here, the holding member 130 is inserted into the can body 10 through the opening of the can body 10. In the present embodiment, a plurality of holding members 130 are provided and arranged radially. Further, in the present embodiment, a plurality of servo motors 140 that rotate the holding member 130 in the circumferential direction are provided.

  Further, as shown in FIG. 1B, a linear servo (servo control linear motion system) 150 that moves the can body 10 up and down by moving the holding member 130 up and down is provided on the outer periphery of the turning table 110. ing. In this embodiment, when the holding member 130 moves up and down, the servo motor 140 also moves up and down to accompany the holding member 130. In the present embodiment, as shown in FIG. 1B, a direct servo drive 160 that rotates the turning table 110 in the circumferential direction is provided below the turning table 110.

  Further, in the present embodiment, an inkjet head (digital print head) that functions as an image forming unit that forms an image on the can 10 above a moving path (circular moving path) through which the holding member 130 moves. ) 170 is provided. In addition, the image forming apparatus 100 according to the present embodiment is provided with an ink jet head 170 that forms an image on the can 10 based on digital image information. In the present embodiment, a total of six inkjet heads 170 are provided radially, so that six colors of ink can be supplied to the can 10.

  As the ink jet head 170, one belonging to a classification called on-demand type can be adopted. Specifically, a piezo method in which ink is ejected from a minute hole by pressure generated by deforming a piezo element (piezoelectric element) or a thermal method in which ink is ejected from a minute hole by vapor pressure may be employed. it can. In addition, it is also possible to employ a method of ejecting ink by an electric force or the like belonging to a classification called a continuous type.

Here, a basic operation in the image forming apparatus 100 will be described.
When forming an image on the can 10, first, the direct servo drive 160 rotates the turning table 110 (in the present embodiment, the rotation in the counterclockwise direction). Thereby, each of the holding members 130 also moves in the counterclockwise direction.
And in this embodiment, whenever one holding member 130 reaches 100 A of can body insertion parts (refer FIG. 1 (A)), rotation of the turning table 110 is stopped and holding | maintenance of the can body 10 by the holding member 130 is stopped. Done. Specifically, when the can body 10 is sucked by the holding member 130, the holding member 130 enters the inside of the can body 10, thereby starting the holding of the can body 10 by the holding member 130.

  In the present embodiment, the rotation of the turning table 110 is stopped every time the can body 10 reaches each of the six inkjet heads 170 provided. Next, the linear servo 150 is driven, and the can 10 is raised. As a result, the can 10 approaches the inkjet head 170. Then, an image is formed on the can body 10 by the ink jet head 170. Specifically, when the holding member 130 rotates, the can body 10 rotates in the circumferential direction, and the ink from the inkjet head 170 adheres to the outer peripheral surface of the rotating can body 10.

  Thereafter, the linear servo 150 is driven, and the can 10 is lowered. Next, in the present embodiment, the rotation of the turning table 110 is resumed, and the can body 10 moves toward the next (adjacent) inkjet head 170. Thereafter, these operations are repeated. As a result, an image composed of a plurality of colors is formed on the can body 10. In the present embodiment, when the holding member 130 reaches the can body discharging portion 100B (see FIG. 1A), the can body 10 is detached from the holding member 130. This separation is performed by supplying compressed air into the holding member 130.

  In addition, although there is no restriction | limiting in particular in the color of the ink discharged from each inkjet head 170, For example, four colors, C (cyan), M (magenta), Y (yellow), and K (black) can be used. For example, W (white) is prepared as necessary. Furthermore, it is also possible to prepare a special color (for example, corporate color) ink whose color has been prepared in advance.

  FIG. 2 is a diagram for explaining the inkjet head 170. 2A is a view when the inkjet head 170 is viewed from the direction of the arrow IIA in FIG. 1A, and FIG. 2B is the direction of the arrow IIB in FIG. 2A (can body). FIG. 10 is a view when the inkjet head 170 is viewed from (10 axial directions). In addition, in the same figure (A) and (B), the can 10 is also displayed.

  As shown in FIG. 2A, in this embodiment, two inkjet heads, a first inkjet head 171 and a second inkjet head 172, are provided as the inkjet head 170. Here, each of the 1st inkjet head 171 and the 2nd inkjet head 172 is arrange | positioned so that the position in the circumferential direction of the can 10 may mutually differ. As a result, in the present embodiment, as shown in FIG. 5B, the first inkjet head 171 and the second inkjet head 172 are arranged radially with the central portion in the radial direction of the can body 10 as the center. Become.

  In addition, each of the first inkjet head 171 and the second inkjet head 172 is arranged such that the position of the can body 10 in the axial direction is different from each other. Further, in the present embodiment, the first inkjet head 171 and the second inkjet head 172 are overlapped in the axial direction of the can 10.

  Here, the size of the inkjet head may be limited. In this case, it is difficult to prepare one large inkjet head, and two small inkjet heads (first inkjet head 171, A second inkjet head 172) may be used. By the way, when two ink jet heads are used in this way, if the two ink jet heads are arranged in a straight line, a region where ink is not supplied is generated in a part of the can 10.

  More specifically, it is common that an ink discharge port is not formed at the end in the longitudinal direction of the inkjet head, and when such an inkjet head is arranged in a straight line as described above, A region where no ink discharge port exists is generated at a location where the respective ink jets are adjacent to each other. In this case, as described above, a region where ink is not supplied is generated in a part of the can 10.

  On the other hand, in the present embodiment, as described above, each of the first inkjet head 171 and the second inkjet head 172 is arranged so that the positions in the circumferential direction of the can body 10 are different from each other. In the direction, the first inkjet head 171 and the second inkjet head 172 are overlapped. In this case, in the axial direction of the can body 10, the ink discharge ports are arranged at regular intervals, and the occurrence of the above-described problem that ink is not supplied to a part of the can body 10 is suppressed.

  By the way, when the two inkjet heads of the first inkjet head 171 and the second inkjet head 172 are shifted in the circumferential direction of the can body 10 as in the present embodiment, the two inkjet heads can be As shown in FIG. 2B, at least one ink jet head is installed at a position off from directly above the can body 10. In this case, as shown in the figure, the inkjet head is inclined with respect to the vertical direction, and the lower surface of the inkjet head (the surface on which the ink discharge ports are formed) is also inclined with respect to the horizontal direction. It becomes like this.

  By the way, in this case, interference between the can 10 that has moved from the upstream side and the inkjet head comes to occur. Specifically, when the can body 10 has moved along the horizontal direction, the portion indicated by reference numeral 2A in the second inkjet head 172 interferes with the can body 10. And when interference arises in this way, it becomes impossible to arrange the can 10 directly under the inkjet head 170.

  In addition, as shown in FIG. 2B, when the two inkjet heads of the first inkjet head 171 and the second inkjet head 172 are displaced in the circumferential direction of the can body 10 as in the present embodiment. As described above, a part of the ink jet head 170 protrudes on the conveyance path of the can body 10 on the upstream side and the downstream side of the can body 10. In this case, when the can body 10 is transported to the ink jet head 170 and when the can body 10 is transported from the ink jet head 170 to the downstream side, interference between the can body 10 and the ink jet head 170 may occur. become.

  Therefore, in the present embodiment, as described above, the linear servo 150 is used to perform the process of moving the can 10 up and down. Accordingly, the can body 10 can be disposed directly below the ink jet head 170 after avoiding interference between the ink jet head 170 and the can body 10. Further, as will be described later, in the present embodiment, by moving the inkjet head 170, a portion of the inkjet head 170 that protrudes on the conveyance path is retreated from the conveyance path, and is directly below the inkjet head 170. The can body 10 is transported and the can body 10 is transported from the inkjet head 170 to the downstream side.

  In addition, if the can body 10 is moved along the transport path shifted downward as in the path indicated by reference numeral 2B (see FIG. 2B), interference between the can body 10 and the inkjet head 170 can be avoided. However, in this case, the gap between the can body 10 and the ink jet head 170 is widened, and the quality of the image formed on the can body 10 may be deteriorated. In addition, in this case, the accuracy of the adhesion position when the ink droplets ejected from the inkjet head 170 adhere to the can body 10 is deteriorated, which may cause the quality of the formed image to deteriorate. is there.

  In the embodiment shown in FIG. 1, the can body 10 is moved and the can body 10 is disposed directly below the ink jet head 170 without moving the ink jet head 170. However, as described later, the ink jet head 170 may be moved. The can 10 can be disposed directly under the inkjet head 170. When the inkjet head 170 is moved, there is a possibility that problems such as the inability to eject ink may occur until the ink inside the inkjet head 170 stops shaking after the movement of the inkjet head 170 is stopped. When the body 10 is moved, the occurrence of such a problem can be suppressed.

FIG. 3 is a diagram for explaining the movement of the can body 10 when the can body 10 reaches the inkjet head 170.
In the present embodiment, first, as shown in FIG. 3A, the can 10 is moved to the lower side of the ink jet head 170 by the rotation of the turning table 110 (see FIG. 1A) that functions as a part of the conveying unit. While being conveyed, the can 10 stops below the inkjet head 170. The can 10 is stopped by stopping the rotation of the turning table 110.

Thereafter, the linear servo 150 (see FIG. 1B) that functions as the can moving means is driven, and the can 10 ascends directly below the inkjet head 170 as shown in FIG. 3B.
In addition, in the present embodiment, in FIG. 3B, the conveyance path formed so as to go from the right direction to the left direction (conveyance path extending along the horizontal direction, hereinafter referred to as “horizontal direction conveyance path”). The can body 10 is transported along the line, but when the can body 10 reaches just below the ink jet head 170, the can body 10 moves toward a direction intersecting (orthogonal) with the direction in which the horizontal transport path extends. Move toward the inkjet head 170.

  More specifically, in this embodiment, the horizontal conveyance path is formed so as to pass by the side of the inkjet head 170. When the can body 10 reaches the side of the inkjet head 170, the can body 10 The directional conveyance path is deviated toward the inkjet head 170.

Next, ink is ejected from the inkjet head 170 to form an image on the can body 10 (see FIG. 3C). In addition, when image formation is performed, the can 10 rotates in the circumferential direction. Next, the linear servo 150 is driven, and the can body 10 is lowered as shown in FIG. Thereafter, the rotation of the turning table 110 is resumed, and the can body 10 moves toward the next inkjet head 170 as shown in FIG.
3A to 3E, the interference between the can body 10 and the ink jet head 170 can be avoided, and the can body 10 can be disposed immediately below the ink jet head 170. Become.

  Here, in the embodiment shown in FIG. 3, the can body 10 is moved from directly below the inkjet head 170 toward the upper direction in the vertical direction, and after the image formation on the can body 10 is completed, the can body is moved downward in the vertical direction. The body 10 was moved. By the way, the vertical movement of the can body 10 can be performed as shown in FIG. 4 (a diagram showing another movement mode of the can body).

  In the aspect shown in FIG. 4, the movement of the can 10 toward the ink jet head 170 (movement upward) is started from the near side (upstream side from just below) immediately below the ink jet head 170. Further, the downward movement of the can body 10 is not performed directly below the ink jet head 170 but is performed downstream of the ink jet head 170. When such a process is performed, the moving distance of the can 10 is shortened as compared with the aspect shown in FIG. In this case, the time required to move the can 10 is reduced, and the number of cans 10 that can perform image formation per unit time can be increased.

  More specifically, in the present embodiment, when an image is formed on the can body 10 by the inkjet head 170, the axial center of the can body 10 is a portion indicated by reference numeral 4A in FIG. It is arranged at the center arrangement location 4A ”. And in this embodiment, arrangement | positioning of the axial center (can body 10) to the axial center arrangement | positioning location 4A is directed to this axial center location 4A from the upstream side rather than this axial center location 4A. To move.

  More specifically, in the present embodiment, the movement of the can body 10 toward the axis center location 4A is started from a predetermined location on the horizontal conveyance path extending in the left-right direction in FIG. 4A. However, in the present embodiment, this starting point is located on the upstream side of the axial center arrangement location 4A. More specifically, as shown in FIG. 4 (A), the perpendicular to the horizontal conveyance path and passing through the axial center location 4A, the position of the intersection of the horizontal conveyance path, and the position of the start point Are compared, the starting point is located upstream from the intersection.

  More specifically, in the embodiment shown in FIG. 4, when the can body 10 is moved toward the ink jet head 170 (moving upward) as shown in FIG. The can 10 is moved along the direction in which 172A extends. Similarly, when moving the can body 10 downward, the can body 10 is moved along the direction in which the lower surface 171A of the first inkjet head 171 extends, as shown in FIG.

  In addition, in the present embodiment, a plurality of ink discharge ports are formed on the lower surfaces 171A and 172A as an example of the facing surface, and the lower surfaces 171A and 172A are opposed to the can body 10. Then, ink is discharged onto the can body 10 to form an image on the can body 10. Further, in the present embodiment, the lower surfaces 171A and 172A are arranged in an inclined state with respect to the direction in which the horizontal conveyance path extends. In the present embodiment, the can body 10 is moved along the direction in which the lower surfaces 171A and 172A arranged in an inclined state extend.

  In this case, the movement distance of the can body 10 can be minimized while avoiding interference between the can body 10 and the inkjet head 170. Here, for example, when the can body 10 moves along the path indicated by reference numeral 4C in FIG. 4A, the moving distance of the can body 10 can be further reduced. In this case, the can body 10 and the inkjet head 170 can be reduced. Interference. Further, when the can body 10 moves along the path indicated by reference numeral 4B, interference between the can body 10 and the ink jet head 170 can be avoided, but the moving distance of the can body 10 is increased.

FIG. 5 is a diagram showing another configuration example of the inkjet head 170 and the like.
In this configuration example, as shown in FIG. 5A, the first inkjet head 171 is lowered, while the second inkjet head 172 is raised. Thereafter, as shown in FIGS. 4A and 4B, the can 10 reaches the lower part of the ink jet head 170.

  At this time, the second inkjet head 172 is raised, and interference between the second inkjet head 172 and the can 10 can be avoided. Next, as shown in FIGS. 2B and 2C, the second inkjet head 172 is lowered, and the can 10 is positioned immediately below the first inkjet head 171 and the second inkjet head 172. In other words, the second inkjet head 172 moves toward the horizontal conveyance path, and the second inkjet head 172 is arranged in a state of approaching the can body 10.

  Thereafter, similarly to the above, ink is ejected from the inkjet head 170 to form an image on the can 10 (see FIG. 4D). Thereafter, as shown in FIG. 5E, the first inkjet head 171 and the second inkjet head 172 are raised. In other words, the first inkjet head 171 and the second inkjet head 172 are moved in a direction away from the horizontal conveyance path.

  And as shown to the same figure (E) and (F), the can 10 is moved toward a downstream side. Here, at this time, the first inkjet head 171 is positioned above, and interference between the can 10 and the first inkjet head 171 can be avoided. After the can body 10 has moved downstream (after the state shown in FIG. 5F), the first inkjet head 171 is lowered and returned to the state shown in FIG.

  Here, a mechanism for moving the first inkjet head 171 and the second inkjet head 172 up and down will be described with reference to FIG. 6 (a diagram for explaining a moving mechanism of the inkjet head 170). 1A is a top view, FIG. 1B is a front view, and FIG. 1C is a side view.

In this configuration example, as shown in FIGS. 6A to 6C, linear servos 180 that move the first inkjet head 171 and the second inkjet head 172 up and down are provided. By driving, the first inkjet head 171 and the second inkjet head 172 move up and down.
In this configuration example, two linear servos 180 are provided so as to correspond to each of the first ink jet head 171 and the second ink jet head 172. However, with one linear servo 180, the first ink jet head 171 and The second inkjet head 172 may be moved up and down.

In addition, each of the first inkjet head 171 and the second inkjet head 172 may not be moved individually, but the first inkjet head 171 and the second inkjet head 172 may be moved together (integrated).
More specifically, for example, the first inkjet head 171 and the second inkjet head 172 are moved together (integrally) by supporting the first inkjet head 171 and the second inkjet head 172 with a common support member. be able to.
In this case, the relative displacement between the first inkjet head 171 and the second inkjet head 172 is less likely to occur, and the formed image is caused by the relative displacement between the first inkjet head 171 and the second inkjet head 172. Quality degradation is suppressed.

FIG. 7 is a diagram illustrating another configuration example of the inkjet head 170 and the like.
In this configuration example, as shown in FIG. 6A, the second inkjet head 172 is rotated counterclockwise around a predetermined rotation center 7A, and the second inkjet head 172 is moved along the vertical direction. Let them stand by in the same state. In this configuration example, the can 10 reaches below the inkjet head 170 in this state. At this time, the second inkjet head 172 is retracted above the conveyance path of the can body 10, and interference between the second inkjet head 172 and the can body 10 can be avoided.

  Next, as shown in FIGS. 2B and 2C, the second inkjet head 172 rotates clockwise around the rotation center 7A, whereby the first inkjet head 171 and the second inkjet head 172 are rotated. The can body 10 comes to be located immediately below the position. Thereafter, as described above, ink is ejected from the first inkjet head 171 and the second inkjet head 172, and an image is formed on the can 10 (see FIG. 4D).

  Next, in the present embodiment, as shown in FIG. 5E, the first inkjet head 171 is rotated clockwise around the rotation center 7A so that the first inkjet head 171 is in a state along the vertical direction. . Then, as shown to the same figure (E) and (F), the can 10 is moved toward a downstream side. When the can body 10 is moved toward the downstream side, each of the first inkjet head 171 and the second inkjet head 172 rotates counterclockwise about the rotation center 7A, and FIG. Return to the state shown in A).

  Here, a mechanism for rotating the first inkjet head 171 and the second inkjet head 172 will be described with reference to FIG. 8 (a diagram for explaining the rotation mechanism of the inkjet head 170). 1A is a top view, FIG. 1B is a front view, and FIG. 1C is a side view.

  In this configuration example, as shown in FIGS. 8A to 8C, two ink jet heads 171 and 172 are provided so as to correspond to the first ink jet head 171 and the second ink jet head 172, respectively. A direct servo drive 190 that rotates the inkjet head 172 is provided. When the direct servo drive 190 is driven, the first ink jet head 171 and the second ink jet head 172 rotate around the position indicated by reference numeral 8A in FIG. 8C. In this embodiment, the first inkjet head 171 and the second inkjet head 172 are moved up and down by this rotation.

Another configuration example of the inkjet head 170 and the like will be further described.
FIG. 9 is a diagram illustrating another configuration example of the inkjet head 170 and the like.
In this configuration example, the first ink-jet head 171 and the second ink-jet head 171 are centered on a portion indicated by reference numeral 9A in FIG. 9A (a portion where the axis of the can body 10 is disposed, hereinafter referred to as “rotation center 9A”). The inkjet head 172 is rotated in the counterclockwise direction in the drawing, and the second inkjet head 172 is disposed above the reach of the can 10.

  And in this state, as shown to the same figure (A) and (B), the can 10 reaches | attains the 2nd inkjet head 172 below. At this time, the second inkjet head 172 is located at a location deviated from the conveyance path of the can body 10 (withdrawn from the horizontal direction conveyance path), and the interference between the second inkjet head 172 and the can body 10 is can avoid.

  Thereafter, the first inkjet head 171 and the second inkjet head 172 are rotated in the clockwise direction in the drawing around the rotation center 9A. As a result, as shown in FIG. 6C, the can 10 is positioned directly below the first inkjet head 171 and the second inkjet head 172. Next, similarly to the above, as shown in FIG. 9D, ink is ejected from the first inkjet head 171 and the second inkjet head 172, and image formation on the can 10 is performed.

  Thereafter, as shown in FIG. 9E, the first inkjet head 171 and the second inkjet head 172 are rotated in the clockwise direction in the drawing around the rotation center 9A. As a result, the first inkjet head 171 is positioned above the can 10. In other words, the first inkjet head 171 is retracted from the horizontal conveyance path.

  Further, when the first ink jet head 171 and the second ink jet head 172 are rotated in the clockwise direction in the drawing around the rotation center 9A, the second ink jet head is located upstream of the can body 10 in the transport direction of the can body 10. The head 172 comes to be positioned. After that, similarly to the above, conveyance to the downstream side of the can 10 is performed. In addition, if conveyance to the downstream of the can 10 is made, it will return to the state shown to FIG. 9 (A).

  Next, the rotation mechanism will be described in detail with reference to FIG. 10 (a diagram illustrating a rotation mechanism that rotates the first inkjet head 171 and the second inkjet head 172). Similarly to the above, FIG. 4A is a top view, FIG. 4B is a front view, and FIG. 4C is a side view.

  As shown in FIG. 10C, the rotating mechanism is provided with an arcuate curve guide 201 arranged along the outer peripheral surface of the can 10 stopped at the printing position. Further, in the present embodiment, a head mount 202 that supports the first inkjet head 171 and the second inkjet head 172 is provided.

  Here, the head mount 202 is guided by a curved guide 201 via a bearing case 203 (see FIG. 5B) that contains a bearing. Further, in the present embodiment, the first inkjet head 171 and the second inkjet head 172 move along the outer peripheral surface of the can body 10 by the head mount 202 being guided by the curved guide 201. Yes.

  Further, in the present embodiment, as shown in FIG. 5C, a moving mechanism 205 that moves the head mount 202 is provided. The moving mechanism 205 includes a servo motor 207 having a rotating shaft 206 and a ball screw portion 208 that converts the rotational motion of the rotating shaft 206 into a linear motion.

  Here, when the servo motor 207 is driven, the rotating shaft 206 rotates, and when the rotating shaft 206 rotates, the ball screw portion 208 performs linear motion along the axial direction of the rotating shaft 206. Then, the head mount 202 is moved by this linear motion, whereby the first inkjet head 171 and the second inkjet head 172 are moved along the outer peripheral surface of the can body 10. In addition, in this embodiment, the moving mechanism 205 functions as a retracting means, and driving the moving mechanism 205 causes the first inkjet head 171 and the second inkjet head 172 to move from the horizontal conveyance path. Evacuation is performed.

  In the present embodiment, each of the first inkjet head 171 and the second inkjet head 172 does not move individually, and the first inkjet head 171 and the second inkjet head 172 move together. In other words, the first inkjet head 171 and the second inkjet head 172 are supported by a common support member called a head mount 202 and move together. In this case, the relative displacement between the first inkjet head 171 and the second inkjet head 172 is less likely to occur, and the formed image is caused by the relative displacement between the first inkjet head 171 and the second inkjet head 172. Quality degradation is suppressed.

Another configuration example of the inkjet head 170 and the like will be further described.
FIG. 11 is a diagram illustrating another configuration example of the inkjet head 170 and the like. FIG. 11 shows a state when the inkjet head 170 and the like are viewed from above.
In this configuration example, the first inkjet head 171 and the second inkjet head 172 are movably provided along the axial direction of the can body 10, and the first inkjet head 171 and the second inkjet head 172 are in this axial direction. As shown in FIG. 3A, the first inkjet head 171 and the second inkjet head 172 are arranged at a location (side the transport path) that is out of the transport path of the can body 10 as shown in FIG.

Specifically, the first inkjet head 171 is located on one side of the conveyance path of the can body 10, and the second inkjet head 172 is located on the other side. The retraction of the ink jet head 170 is not limited to such a mode, and the two ink jet heads, the first ink jet head 171 and the second ink jet head 172, are retreated on either one side or the other side. You may do it.
However, if the ink jet head is retracted to one side and the other side, the moving distance when moving the ink jet head can be reduced, and the number of cans 10 that can form an image per unit time can be increased. It becomes like this.

  Here, a series of processing flows will be described. First, the can 10 is transported from the upstream side along the horizontal transport path as described above (see FIG. 11A). And this can 10 stops at a predetermined stop location. Thereafter, as shown in FIGS. 2B and 2C, the first ink jet head 171 and the second ink jet head 172 are moved along the axial direction of the can body 10, and above the can body 10, A first inkjet head 171 and a second inkjet head 172 are arranged.

  Next, ink is discharged onto the can body 10 as described above. Thereafter, in the present embodiment, as shown in FIG. 4D, the first inkjet head 171 and the second inkjet head 172 are retracted to the side of the conveyance path of the can 10. And as shown to the figure (E), the conveyance of the can 10 to a downstream is performed.

FIG. 12 is a view showing a moving mechanism for moving the first ink jet head 171 and the second ink jet head 172 in the axial direction of the can body 10.
As shown in the figure, the movement of the first inkjet head 171 and the second inkjet head 172 in the axial direction of the can body 10 is performed by a linear servo 220 disposed along the axial direction of the can body 10.

In addition, in this configuration example, two linear servos 220 are provided corresponding to the two inkjet heads of the first inkjet head 171 and the second inkjet head 172, and by driving each linear servo 220, The first inkjet head 171 and the second inkjet head 172 move along the axial direction of the can 10.
In the present embodiment, the case where two linear servos 220 are provided has been described as an example. However, two linear servos 220 are used, and the two inkjet heads 170 of the first inkjet head 171 and the second inkjet head 172 are used. You may make it move.

(Other)
In the above, the case where the total length of the can body 10 is larger than the total length of each inkjet head has been described as an example. However, in the configuration described above, the total length of the can body 10 is greater than the total length of each inkjet head. It can also be applied to small cases.

For example, if the total length of the can body 10 is smaller than the total length of each inkjet head, a plurality of inkjet heads may be provided radially around the can body 10 and ink of different colors may be ejected from each inkjet head. While the can body 10 makes one rotation, it becomes possible to supply ink of a plurality of colors instead of one color to the can body 10. In this case, the efficiency of image formation on the can 10 can be increased.
By the way, in this case, the interference described above occurs. However, by using the configuration described above, the can body can be disposed directly under the inkjet head while avoiding this interference.

  In the above description, the case where the inkjet head 170 is provided above the conveyance path of the can body 10 has been described as an example. However, the configuration described above is provided on the side or below the conveyance path of the can body 10. The present invention can also be applied to an aspect in which an inkjet head is provided.

  Furthermore, in the present embodiment, as illustrated in FIG. 1, a mode has been described in which six inkjet heads 170 are arranged radially about the rotation center of the turntable 110. By the way, the arrangement | positioning aspect of the inkjet head 170 is not specifically limited, For example, you may make it the 6 inkjet heads 170 line up along one straight line. In this case, image formation on the can body 10 is performed in the process in which the can body 10 moves linearly.

  Further, in the above, the can body 10 is rotated below the individual ink jet heads 170, and two ink jet heads (the first ink jet head 171 and the second ink jet head 172 are applied to the rotating can body 10. Ink was discharged simultaneously in parallel. By the way, in this case, as described above, at least one of the two inkjet heads is inclined with respect to the vertical direction so that interference between the can 10 and the inkjet head occurs. Become.

  Here, although ink cannot be ejected in parallel at the same time, the configuration shown in FIGS. 13A and 13B in FIG. 13 (a diagram showing another arrangement mode of the first inkjet head 171 and the second inkjet head 172). In this case, it becomes possible to form an image on the can body 10 without tilting the two inkjet heads, and the movement of the inkjet head (movement as shown in FIGS. 5 to 12) or the can body 10 Even if this movement (movement as shown in FIGS. 3 and 4) is not performed, interference between the inkjet head and the can 10 can be avoided.

  In the configuration example shown in FIG. 13, the first inkjet head 171 and the second inkjet head 172 which are two inkjet heads included in each of the six inkjet heads 170 provided are illustrated. In addition, in this configuration example, six inkjet heads (six sets of the first inkjet head 171 and the second inkjet head 172) are provided as described above. In FIG. 13, one inkjet head is provided. Only 170 (a set of the first inkjet head 171 and the second inkjet head 172) is illustrated.

  Further, FIG. 13A shows the state when viewed from above, and FIG. 13B shows the state when viewed from the right side. In FIG. 13, six ink jet heads 170 are arranged along one straight line, and image formation on the can body 10 is performed in a process in which the can body 10 moves linearly. .

  Here, in this configuration example, as shown in FIG. 5B, the movement of the can body 10 is temporarily stopped at the first location 13E located below the first ink jet head 171, and the can body 10 is moved to the can body 10. Image formation is performed. Here, in this configuration example, since the second inkjet head 172 is not located immediately beside the first inkjet head 171, the first inkjet head 171 is arranged along the vertical direction.

In this case, even if the first inkjet head 171 is not moved (moved as shown in FIGS. 5 to 12) or the can 10 is moved (moved as shown in FIGS. 3 and 4), Interference between the can 10 and the first inkjet head 171 can be avoided.
Here, as shown in FIG. 13A, the first inkjet head 171 causes a region (indicated by reference numeral 13A) located on the opening side of the can 10 (the side opposite to the side where the bottom is provided). An image is formed in (region).

  Thereafter, the can 10 moves to the second location 13H below the second inkjet head 172 and stops below the second inkjet head 172, as shown in FIG. Then, ink is discharged from the second inkjet head 172, and image formation by the second inkjet head 172 is performed. In this case as well, since the first inkjet head 171 is not located immediately next to the second inkjet head 172, the second inkjet head 172 is arranged along the vertical direction.

  In this case, as described above, interference between the can body 10 and the second ink jet head 172 can be avoided without moving the second ink jet head 172 or moving the can body 10. In the second inkjet head 172, as shown in FIG. 13A, an image is formed in an area (area indicated by reference numeral 13B) located on the bottom side of the can body 10.

  By the way, in the present embodiment, an image formation area (first area) formed by a first inkjet head 171 as an example of the first image formation head, as indicated by reference numerals 13A and 13B in FIG. 1) and an image formation region (second formation site) formed by a second inkjet head 172 as an example of the second image forming head overlap, and the first inkjet head 171 is overlapped. A blank area is prevented from being formed between the image formed by the above and the image formed by the second inkjet head 172.

  Here, the first inkjet head 171 and the second inkjet head 172 may be separated from each other in the axial direction of the can 10 due to the dimensional tolerance of the member, and in this case, the blank area is formed. End up. In addition, as in the present embodiment, the image formation region formed by the first inkjet head 171 and the image formation region formed by the second inkjet head 172 are shifted in the axial direction of the can body 10. If the first inkjet head 171 and the second inkjet head 172 are separated from each other (when adjacent to each other), a blank area where no image is formed is formed between the two formation areas.

On the other hand, if the two image forming areas are overlapped in advance as in the present embodiment, even if the first inkjet head 171 and the second inkjet head 172 are separated from each other, a blank area is formed. It will be suppressed.
In the overlap region, it is preferable to reduce the ink discharge amount (discharge amount per ink droplet discharged from the ink discharge port) less than the ink discharge amount in the region other than the overlap region. .

  For example, FIG. 14 (a diagram showing an example of ink ejection to the can body 10) shows the state of ink ejected from the first inkjet head 171 to the can body 10, but in FIG. In the area to be discharged, the ink discharge amount is suppressed, and the size of the dot-like image is reduced. The same applies to the second inkjet head 172, and the amount of ink discharged can be suppressed in the overlapping region.

  Here, if an image is formed in an overlapping region without suppressing the ink discharge amount, an image having an image density higher than the original image density is formed in the overlapping region. . As described above, when the ink discharge amount is suppressed, the increase in the image density can be suppressed. The embodiment in which the two image forming areas are overlapped and the aspect in which the two image forming areas are overlapped and the ink discharge amount is reduced are the embodiments described with reference to FIGS. The present invention can be similarly applied to an embodiment in which the first inkjet head 171 and the second inkjet head 172 are arranged close to each other.

  Note that the specific ejection amount of ink is, for example, ejected from the first inkjet head 171 in the overlap region when the amount of ink ejected in the non-overlap region is 1. The amount of ink discharged can be set so that the sum of the amount of ink per droplet and the amount of ink discharged from the second inkjet head 172 in the overlap region is equal to 1. .

DESCRIPTION OF SYMBOLS 10 ... Can body, 100 ... Image forming apparatus, 110 ... Turning table, 150 ... Linear servo, 170 ... Inkjet head (digital print head), 171 ... First inkjet head, 172 ... Second inkjet head, 172A ... Lower surface, 202 ... Head mount, 205 ... Movement mechanism

Claims (8)

Image forming means for forming an image on a can body;
A transport unit configured to extend in one direction and transport the can body along a transport path formed to pass by the side of the image forming unit;
A can body moving means for moving the can body on the transport path in a direction intersecting the one direction, and moving the can body toward the image forming means;
An image forming apparatus comprising: The can body is formed in a cylindrical shape,
The image forming means performs image formation on the can body in a state where the axial center of the can body is arranged at a predetermined arrangement location,
The can body moving means starts moving the can body toward the image forming means, starting from a predetermined location on the transport path, and then moves the shaft to the predetermined arrangement location. Place the can so that the mind is located,
When the vertical line that passes through the predetermined arrangement location and is perpendicular to the transport path and the position of the intersection with the transport path are compared with the position of the start point, the start point is the intersection The image forming apparatus according to claim 1, wherein the image forming apparatus is located upstream of the portion in the conveyance direction of the can body. The image forming unit is configured so that ink is directed toward the can body from an ink discharge port formed on the facing surface facing the can body and inclined with respect to a direction in which the transport path extends. To form an image on the can body,
When the can body moving means moves the can body toward the image forming means, the can body moving means moves in a direction intersecting the one direction and along a direction in which the facing surface extends. The image forming apparatus according to claim 1. Image forming means for forming an image on a can body;
A transport unit configured to extend in one direction and transport the can body along a transport path formed to pass by the side of the image forming unit;
Moving means for moving the image forming means toward the transport path and moving the image forming means in a direction away from the transport path;
An image forming apparatus comprising: The image forming means includes a plurality of image forming heads for forming an image,
The moving unit moves the plurality of image forming heads when the image forming unit moves.
The image forming apparatus according to claim 4, wherein the plurality of image forming heads are supported by a common support member, and move together as the moving unit moves. After transporting the can body from the upstream side to a predetermined location along the transport path, a transport means for further transporting the can body from the predetermined location toward the downstream side,
Located on the side of the transport path, and provided at least on one side of the upstream side and the downstream side of the predetermined location so that a part thereof protrudes on the transport path, Image forming means for forming an image on the can located at a predetermined location;
A retracting means for retracting the part of the image forming means from the transport path;
An image forming apparatus comprising:   The image forming apparatus according to claim 6, wherein the retreating unit retreats the part from the transport path by rotating the image forming unit around a predetermined rotation center. apparatus. A transporting means for transporting the cylindrical can body to the first location along the transport path, and further transporting the can body to a second location located downstream of the first location;
A first image forming head for forming an image with respect to a first portion of the outer peripheral surface of the can located at the first location;
The second image forming head is disposed on the downstream side of the first image forming head in the conveyance direction of the can body, and is a second portion of the outer peripheral surface of the can body located at the second location, and in the axial direction of the can body A second image forming head for forming an image on the second part whose position is different from the first part;
An image forming apparatus comprising:

Images