JP2019206128A - Printing device and printing method - Google Patents

Abstract

To provide a printing device and a printing method which can print at high speed an ink image formed by inkjet printing on a cylindrical processing work-piece to achieve high production efficiency.SOLUTION: The printing device comprises: a transfer cylinder 110 that turns; an inkjet printing station 150 that forms an ink image P on a surface of the transfer cylinder by inkjet printing; a transfer station 120 that transfers the ink image formed on the surface of the transfer cylinder to an outer peripheral surface of a trunk part of a cylindrical processing work-piece C; and a conveying unit 130 that moves a plurality of self-rotatable mandrels 131 which carry the processing work-piece along a conveyance passage. By making the transfer cylinder contact the processing work-piece while causing the processing work-piece carried and conveyed by the mandrels to self-rotate in the transfer station, the ink image is transferred from the surface of the transfer cylinder to the outer peripheral surface of the trunk part of the processing work-piece.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a printing apparatus and a printing method for forming an image by ink jet printing on an outer peripheral surface of a body portion of a cylindrical workpiece.

Conventionally, in curved surface printing on the body of cylindrical objects such as seamless cans made of metal such as aluminum or steel, plate-type printing using a printing plate, inkjet printing without using a plate, or electrophotographic printing, etc. There is a method using. Examples of the plate-type printing include offset printing in which each color inker plate cylinder is provided with a resin relief plate, each color ink from the resin relief plate is transferred to a blanket, and transferred from the blanket to an object to be processed to form an image. .
However, in plate-type printing, plates are created for each ink color and printed in multiple colors, so it is efficient when mass-producing seamless cans of the same image. Since it is necessary to manufacture a plate, it takes a long time to change the design, and there is a problem that there is no degree of freedom in print design and only limited types of designs can be printed.

On the other hand, since inkjet printing does not require a plate, it does not require plate making costs, and has variable (variable) properties that allow the print design to be freely changed in a short period of time, and can increase the depth of ink. Therefore, there is an advantage that a high-definition image such as a photograph is excellent in reproducibility.
As an apparatus for forming an image by ink jet printing on a body of a cylindrical object to be processed such as a seamless can, Patent Document 1 discloses white (W), yellow (Y), and magenta (M) along a mandrel wheel. Inkjet printing apparatuses are disclosed in which printing stations with inkjet heads corresponding to respective inks of cyan (C) and black (K) are arranged apart from each other. In this ink jet printing apparatus, an object to be processed is carried on a mandrel disposed on a mandrel wheel, and first, the object to be processed is conveyed to the first color (for example, white) printing station by revolving the mandrel wheel. Then, an ink image of the first color (for example, white) is formed by dropping ink from the inkjet head while rotating the object carried on the mandrel at the position where the revolution is stopped. Next, the mandrel wheel is revolved and the object to be processed is transported to the second color (for example, yellow) printing station to form the second color ink image. The single color ink images of the respective colors are sequentially formed and superimposed, whereby a full color ink image is formed on the outer peripheral surface of the body portion of the workpiece.

Japanese Patent No. 6111571

  However, in the ink jet printing apparatus disclosed in Patent Document 1, it is necessary to sequentially convey to each color printing station, which requires a conveyance time, and further, it is necessary to rotate (rotate) the workpiece in each color printing station. . Therefore, since intermittent conveyance is performed at the printing station, there is a problem that the production efficiency is low because the speed (printing speed) of printing an ink image on one object to be processed does not increase.

  The present invention solves these problems, and a printing apparatus capable of printing an ink image by ink jet printing at high speed on the outer peripheral surface of a cylindrical portion of a cylindrical object to be processed, resulting in high production efficiency. It is another object of the present invention to provide a printing method.

The printing apparatus according to the present invention includes a rotating transfer cylinder, an ink jet printing station that forms an ink image on the surface of the transfer cylinder by ink jet printing, and a cylinder-shaped processed image of the ink image formed on the surface of the transfer cylinder. A printing apparatus having a transfer station for transferring to an outer peripheral surface of a body portion of an object, and a transport unit that moves a plurality of self-rotating mandrels carrying an object to be processed along a transport path,
In the transfer station, the transfer cylinder and the object to be processed are brought into contact with each other while rotating the object to be processed carried on the mandrel, whereby the ink image is transferred from the surface of the transfer cylinder to the body of the object to be processed. It transfers to the outer peripheral surface of this.
In the printing apparatus of the present invention, an ink image is formed on the surface of the rotating transfer cylinder by ink jet printing at an ink jet printing station, and the ink image formed on the surface of the transfer cylinder is moved along a transport path. A printing method for transferring at a transfer station to the outer peripheral surface of a cylindrical portion of a cylindrical workpiece to be carried on a plurality of mandrels capable of rotation,
In the transfer station, the transfer cylinder and the object to be processed are brought into contact with each other while rotating the object to be processed carried on the mandrel, whereby the ink image is transferred from the surface of the transfer cylinder to the body of the object to be processed. It transfers to the outer peripheral surface of this.

According to the printing apparatus and the printing method of the present invention, since the ink jet printing station and the transfer station for forming an ink image by ink jet printing are provided with the transfer cylinder, the ink image formed on the surface of the transfer cylinder is transferred to the transfer station. By contacting the transfer object with the transfer cylinder while rotating the object to be processed, the object is transferred all at once to the outer peripheral surface of the body by one rotation of the object. Can be printed with high production efficiency. In addition, since the ink image to be formed is one using ink jet printing, an image with excellent sharpness can be obtained. Further, since ink jet printing does not require a plate, plate making costs are not required, and variable (variable) properties that can freely change the print design in a short time can be obtained. Further, by providing an ink heating mechanism such as a heater inside the transfer cylinder, there is no need to provide a drying station facing the surface of the transfer cylinder, and as a result, the printing apparatus can be miniaturized.
According to the configuration of the second aspect of the present invention, since the drying station is provided on the downstream side of the ink jet printing station, the ink image transferred to the object to be processed can be dried to a state suitable for transfer. High transferability can be obtained, and as a result, a high-definition ink image can be printed.
According to the configuration of the third aspect of the present invention, since a plurality of ink jet printing stations are provided, one ink image P is formed by the plurality of ink jet printing stations, that is, the ink image is increased by increasing the number of passes. The quality of P can be improved. In addition, by forming a plurality of ink images close to each other on the transfer cylinder, the number of workpieces that can be transferred per unit time can be increased, and overall productivity can be improved.
According to the configuration of the fourth aspect of the present invention, since the overcoat processing station is provided, the ink image transferred to the object to be processed at the transfer station is subjected to the overcoat process, whereby the ink image is received. It can be firmly fixed on the processed material. As a result, it is possible to prevent the ink image from being damaged even when it is subjected to various processing in the next step or when it is rubbed by conveyance or the like.
According to the configuration of the fifth aspect of the present invention, since the transport unit includes a mandrel wheel having a plurality of mandrels, the workpiece can be transported easily by the transport unit.

According to the configurations of the sixth and tenth aspects of the present invention, since the transfer station has the transfer nip portion, the workpiece is rotated while passing through the transfer nip portion, and the outer peripheral surface of the barrel portion thereof. Is in rolling contact with the surface of the transfer cylinder to transfer the ink image from the surface of the transfer cylinder to the outer peripheral surface of the body of the object to be processed, so that a plurality of objects can be processed while rotating the transfer cylinder at a constant speed. The transfer process can be performed continuously. As a result, the number of workpieces that can be transferred per unit time can be increased, and the overall productivity can be increased.
According to the configurations of the seventh and eleventh aspects of the present invention, since a plurality of transfer stations are provided on the surface of the transfer cylinder, by performing transfer processing simultaneously and repeatedly at each transfer station, Even in a configuration in which workpieces are conveyed intermittently instead of continuously, the number of workpieces that can be transferred per unit time can be increased, and overall productivity can be increased. Further, the mechanical structure can be simplified by performing intermittent conveyance.
According to the eighth and twelfth aspects of the present invention, since the pre-rotation means for rotating the mandrel in advance is provided, the object to be processed is approximately equal to the peripheral speed of the transfer cylinder as the mandrel rotates. It can be transported to the transfer station while being rotated at the same peripheral speed, and as a result, the occurrence of slip due to the large difference in peripheral speed between the workpiece and the transfer cylinder during the transfer process is prevented. Therefore, the quality of the ink image transferred to the object to be processed can be maintained high. In addition, it is not necessary to synchronize the peripheral speed of the object to be processed with the transfer cylinder by accelerating the object to be processed by contact with the non-image area where the ink image of the transfer cylinder is not formed. The length between the image areas (non-image areas) can be reduced. As a result, the number of workpieces that can be transferred per unit time can be increased, and the overall productivity can be increased. .

1 is an explanatory diagram schematically illustrating an example of a configuration of a printing apparatus according to a first embodiment of the present invention. It is explanatory drawing which shows roughly an example of a structure of the printing apparatus which concerns on the 2nd Embodiment of this invention.

[Printing Apparatus According to First Embodiment]
Hereinafter, a printing apparatus 100 according to a first embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the printing apparatus 100 according to the first embodiment of the present invention has a cylindrical transfer cylinder 110 whose surface rotates along a rotation path, and an inkjet on the surface of the transfer cylinder 110. An ink jet printing station 150 that forms an ink image P by printing, and a transfer station 120 that transfers the ink image P formed on the surface of the transfer cylinder 110 to the outer peripheral surface of the barrel portion of the can C, which is a cylindrical workpiece. And a transport unit 130 for moving a plurality of mandrels 131 capable of rotating on the can C along the transport path.

[Processed object]
In the present invention, the cylindrical object to be processed specifically includes a metal can, a plastic bottle container, a paper container, or the like having a cylindrical or conical body, and as the object to be processed, , Various surface-treated steel plates such as tin-free steel (TFS), various plated steel plates such as tin plating, light metal plates such as aluminum, and various surface-treated light metal plates obtained by surface treatment such as phosphoric acid chromate treatment, or these metals A resin-coated metal plate with a resin coating made of a thermoplastic resin such as polyester resin on the plate is drawn, drawn and ironed, drawn / redrawed, bent and stretched by drawing / redrawing (stretching), For example, seamless cans manufactured by subjecting to known means such as bending / stretching / ironing by drawing / redrawing, impact processing of light metal plate, etc. That. Moreover, the 3 piece can which passed through processes, such as a tin plate cutting process, roll molding, a can body welding process, and a can body stretch molding, is also mentioned. In addition, the three-piece can may be subjected to paneling molding for forming the can body into an irregular shape such as an ellipse, a square, or an embossed shape, flange portion molding, or the like.
It is preferable that a white coat layer for hiding the ground color of the object to be processed is formed on the outer peripheral surface of the body part of the object to be processed in order to express excellent sharpness in the ink image to be formed. The white coat layer can be formed by, for example, a white coat layer forming unit installed on the upstream side of the transfer station 120 in the conveyance path of the object to be processed. As the white coat layer forming means, for example, a plate-type printing machine that prints a white solid image, a roller that applies white ink to the outer peripheral surface of the body of the object to be processed, and an outer periphery of the body of the object to be processed by spraying white ink A sprayer or the like applied to the surface can be used. Instead of forming the white coat layer, a white (W) solid image may be formed on the surface of the transfer cylinder 110 in the inkjet printing station 150 so as to be transferred to the lowermost layer of the object to be processed. Good.
Further, an anchor coat layer is preferably formed on the uppermost surface of the workpiece. By forming the anchor coat layer, the transferred ink image by inkjet printing is firmly held and fixed, and the image adhesion to the object to be processed is improved. In addition, ink bleeding can be reduced. The anchor coat layer can be formed by various conventionally known methods by applying a coating solution in which a transparent resin having thermosetting, ultraviolet curable, or electron beam curable properties is dispersed or dissolved in a predetermined solvent. It can be formed by drying and then curing by heating, ultraviolet irradiation, electron beam irradiation or the like. The anchor coat layer can be formed by an anchor coat layer forming means installed on the upstream side of the transfer station 120 in the conveyance path of the workpiece. The anchor coat layer forming means has an apparatus for applying the transparent resin or the like to the outer peripheral surface of the body of the object to be processed. Examples of such an application apparatus include a plate-type printing machine, the application roller, and a spraying machine. Etc. can be used.
The white coat layer is an anchor coat layer having the function of a white coat layer by adding a white pigment such as titanium dioxide to the coating liquid containing the resin exemplified as the resin used for forming the anchor coat layer. It can also be formed.
Furthermore, instead of forming a white coat layer, a resin-coated metal plate having the function of a white coat layer by containing a white pigment in the resin coating forming the resin-coated metal plate as an object to be processed You may use what used.

  The workpiece to which the ink image P is transferred in the transfer station 120 of the printing apparatus 100 according to the first embodiment of the present invention may have an image formed in advance. Specifically, the ink image P may be formed by the printing apparatus 100 according to the present invention on an object to be processed on which a solid image or the like is printed by, for example, plate printing. At this time, the ink image P may be formed on an image formed by plate printing formed in advance, or may be formed outside the image.

[Transfer cylinder]
The transfer cylinder 110 constituting the printing apparatus 100 according to the first embodiment of the present invention includes a cylindrical roller in which a base material layer and a release layer are laminated in this order.
The release layer has a hydrophobic release surface on its outer surface in order to separate the ink image P from the surface of the transfer cylinder 110 without any residue and transfer it to the can C.
The release layer is not limited to the one formed on the entire surface of the base material layer, and is formed only on a part of the region including at least an image region on which the predetermined ink image P is formed on the base material layer. It may be a thing. Further, the release layer is not limited to the one that is fixedly formed and repeatedly used, and is formed by applying a coating liquid having peelability to an area including at least the image area for each image formation. It may be.
The base material layer holds the release layer on the surface thereof, and may have flexibility, or may have rigidity. As the base material layer, for example, a two-layer structure of a cylindrical metal substrate and a sponge layer can be used so that the pressure between the can C and the transfer cylinder 110 during transfer is suitable.

  The transfer cylinder 110 is configured to be driven by a drive source (not shown).

[Inkjet printing station]
The ink jet printing station 150 constituting the printing apparatus 100 according to the first embodiment of the present invention is provided so as to face the surface of the transfer cylinder 110 along the surface of the transfer cylinder 110. Specifically, the inkjet printing station 150 ejects inks of different colors, for example, for yellow (Y color), magenta (M color), cyan (C color), black (K color), and white (W color). These inkjet heads are arranged along the surface of the transfer cylinder 110 in the above order from the upstream side to the downstream side. These ink jet heads are disposed downward or at an angle close to the ink so as to drop ink substantially perpendicularly to the surface of the transfer cylinder 110. Each inkjet head of the inkjet printing station 150 is controlled so as to be operated in synchronization to form a predetermined ink image P.
The arrangement order of the inkjet heads of the respective colors in the inkjet printing station 150 is not limited to the above example.
Ink jet heads include a piezo method, a thermal method, an electrostatic method, a bubble jet (registered trademark) method, and the like, depending on the ink droplet ejection mechanism, but can be used without particular limitation in the present invention.
The distance between the inkjet head and the surface of the transfer cylinder 110 is, for example, in the range of 0.5 to 4.0 mm from the viewpoint of improving the landing accuracy of ink droplets on the surface of the transfer cylinder 110. If the distance between the inkjet head and the surface of the transfer cylinder 110 is less than 0.5 mm, the inkjet head may come into contact with the surface of the transfer cylinder 110.

In the printing apparatus 100 illustrated in FIG. 1, one inkjet printing station 150 that forms one ink image P is configured using five inkjet heads, but this number may be increased or decreased.
For example, increase or decrease the number of colors (different hues or shades) and increase or decrease the number of inkjet heads accordingly, or increase the number of inkjet heads that discharge droplets of the same color but with different ejection volume Is mentioned. By using a combination of multiple inkjet heads of the same color and different ejection volume, a solid image that requires a high dot density to increase the density or a photo that requires a fine image with small diameter dots An image with excellent sharpness can be printed at high speed so as to satisfy both the image and the character image. In other words, a high density is achieved with an inkjet head with a large amount of one droplet, and a fine image is achieved with an inkjet head that has a small amount of one droplet and can control the size of the dot diameter by the number of drops. This makes it possible to efficiently handle both solid images and photographic images.
In addition, it is possible to increase the number of ink jet heads (the same ink jet heads) having the same color and the same amount of ejected droplets. Specifically, by arranging the same ink jet heads apart in the width direction of the transfer cylinder 110 (direction perpendicular to the paper surface in FIG. 1), the can C is long in the cylinder axis direction of a so-called long can or the like. Even in this case, the ink image P can be accurately formed.

  In the printing apparatus 100 according to the first embodiment, a plurality of inkjet printing stations 150 that form one ink image P may be provided along the transfer cylinder 110. That is, a configuration in which a plurality of ink images P can be formed in one rotation of the transfer cylinder 110 is possible. The printing apparatus 100 of FIG. 1 is an example in which two inkjet printing stations 150 are provided along the surface of the transfer cylinder 110.

〔ink〕
As the ink used for forming the ink image P, it is possible to use a heat-drying ink, a thermosetting ink, an ultraviolet curable ink, an electron beam curable ink, and the like that are used in conventional ink jet printing. Although the curing means and the temporary baking (temporary curing) means differ depending on the type of ink, the heat drying type ink can be preferably used since the equipment cost relating to baking is particularly low.
There are water-based inks, oil-based inks, solvent-based inks, and the like.

In the printing apparatus 100 according to the first embodiment, a printing station (plate printing station) by plate printing may be provided on the rotation path of the transfer cylinder 110. By providing a plate-type printing station, an image having excellent solid image density reproducibility is obtained by plate-type printing, and an image having excellent sharpness is obtained by inkjet printing. It is assumed that high reproducibility of the image density is obtained in the solid portion and excellent sharpness is obtained in the high definition portion.
The arrangement order of the plate-type printing station and the inkjet printing station 150 on the rotation path of the transfer cylinder 110 is not particularly limited. That is, the order of forming the image by plate printing and the ink image P by ink jet printing is not particularly limited, and whether the plate printing station is arranged upstream or downstream of the ink jet printing station 150 depending on the design or the like. Can be determined as appropriate. In addition, it is particularly preferable to perform the plate-type printing first from the viewpoint of easy positioning and design such as overcoating by inkjet printing.
As a printing method for printing, a printing method using a relief plate, a lithographic plate, or the like conventionally used for printing of seamless cans can be adopted, and offset printing can be particularly preferably used. In offset printing, printing ink is supplied from an ink supply unit to a printing plate (not shown) such as a relief plate on the plate cylinder, and the ink on the printing plate halftone dot and the image area is transferred to the blanket. The transferred ink of each color is transferred to the transfer cylinder 110.
In the case where image formation by plate printing is performed before image formation by ink jet printing, it is preferable that the ink related to plate printing is temporarily cured by pre-baking before forming the ink image P in the ink jet printing station 150. As a result, it is possible to prevent bleeding from occurring at the overlapping portion with the ink image P by ink jet printing and obtain an image with excellent sharpness.

[Drying station]
In the printing apparatus 100 according to the first embodiment, a drying station 160 that dries the ink image P formed in the inkjet printing station 150 is provided between the inkjet printing station 150 and the transfer station 120. The drying station 160 is provided on the downstream side of the inkjet printing station 150 and at a position close to the inkjet printing station 150.
The drying station 160 includes a dryer that dries the ink of the ink image P on the transfer cylinder 110.
Any dryer may be used as long as the ink image P exhibits adhesiveness and has an improved ability to adhere to the can C and be transferred. For example, hot air is supplied according to the type of ink used to form the ink image P. A heater or a light source that emits radiation such as ultraviolet rays can be used. For example, when the ink image P is formed using heat-drying type ink, the ink image P is semi-dried or completely dried by receiving hot air from the heater, so that Transferability is improved. Further, for example, when the ink image P is formed using an ultraviolet curable ink, the ultraviolet curable resin constituting the ink of the ink image P is semi-cured by being irradiated with ultraviolet rays from an ultraviolet light source. Transferability to is improved.
The drying station 160 is not limited to actively providing a dryer for drying the ink image P, and may be configured to naturally dry during transportation by ensuring a large distance between the inkjet printing station 150 and the transfer station 120. . Further, the drying station 160 may be configured such that an ink heating mechanism such as a heater is provided inside the transfer cylinder 110.

The printing apparatus 100 is provided with an adhesive layer forming station for forming an adhesive layer on the ink image P on the downstream side of the ink jet printing station 150 and on the upstream side of the transfer station 120 on the circulation path of the transfer cylinder 110. May be. By providing the adhesive layer forming station, an adhesive layer is formed on the ink image P, so that the transfer property to the can C is improved, and the ink image P of excellent quality can be printed on the can C. .
The arrangement order of the drying station 160 and the adhesive layer forming station on the circulation path of the transfer cylinder 110 is not particularly limited. Specifically, the adhesive layer forming station may be located downstream of the inkjet printing station 150 and upstream of the drying station 160, depending on the need for drying of the adhesive layer. Further, it may be arranged upstream of the transfer station 120.

[Transport unit]
The transport unit 130 constituting the printing apparatus 100 according to the first embodiment of the present invention transports the mandrel 131 carrying the can C along the transport path, has a plurality of mandrels 131, and is horizontally disposed. A mandrel wheel 132 is provided that is attached to the extending rotation shaft and is driven to rotate at a peripheral speed slightly lower than the peripheral speed of the transfer cylinder 110. Specifically, a plurality of mandrels 131 are disposed in each of the mandrel formed in the shaft holes formed so that the adjacent distances are equal to each other on the circumference of the outer periphery of the mandrel wheel 132 with a predetermined rotation radius. The wheel 132 is rotatably supported around an axis (mandrel axis) parallel to the rotation axis of the wheel 132. In other words, the transport unit 130 is configured such that the can C fitted to the mandrel 131 is continuously transported along the transport path in one direction along with the mandrel 131 when the mandrel wheel 132 is rotationally driven.
A mandrel shaft that supports the mandrel 131 is supported so as to be able to follow and move along the guide shape of a guide groove (not shown), for example. The guide groove is a groove that meanders in a radial direction on the circumference of a predetermined rotation radius around the rotation axis of the mandrel wheel 132 and forms an annular shape as a whole, and as the mandrel wheel 132 rotates, The mandrel shaft is configured to reciprocate in the radial direction of the mandrel wheel 132. That is, a part of the transport path of the mandrel 131 can be meandered without being completely annular. On the other hand, the transfer cylinder 110 is arranged so that a part of a rotation path on which the surface rotates intersects the circumference of a predetermined rotation radius of the mandrel wheel 132, and the transfer path of each mandrel 131 is the transfer cylinder 110. Is configured to be recessed inward in the radial direction of the mandrel wheel 132, and the conveyance path of such a trajectory can be obtained by appropriately setting the shape of the guide groove. As a result, the can C fitted to the mandrel 131 in the transfer nip N comes into contact with the transfer cylinder 110 while being urged toward the transfer cylinder 110 in the middle of the transfer, and moves along the outer peripheral surface thereof. N is formed.

On the upstream side of the transfer station 120 in the transport path of the mandrel 131, an object supply means (not shown) using, for example, an infeed turret for supplying the can C onto the transport path of the mandrel 131 is provided. .
In addition, the ink image P is transferred to the downstream side of the overcoat processing station 170 in the transport path of the mandrel 131, and the can C subjected to the overcoat processing is transferred to the next process, for example, to be processed using a transfer turret. An object discharging means (not shown) is provided.

[Transfer station]
The transfer station 120 constituting the printing apparatus 100 according to the first embodiment of the present invention has the transfer nip portion N formed as described above. In the transfer nip portion N, pressure is applied to the can C by the transfer cylinder 110 and the transport unit 130. In this transfer nip N, by rotating the can C carried and transported by the mandrel 131 while passing through the transfer nip N, the outer peripheral surface of the barrel is brought into rolling contact with the surface of the transfer cylinder 110. The ink image P is transferred from the surface of the transfer cylinder 110 to the outer peripheral surface of the body portion of the can C.
The length of the transfer nip portion N, that is, the length of movement on the conveyance path while the can C is in contact with the transfer cylinder 110, is the maximum of the printing area where the ink image P is to be printed on the barrel portion of the can C. The circumferential length portion of the can C is equal to or longer than the distance that can be pressed while the can C rotates, and is, for example, equal to or greater than the entire circumferential length of the body portion of the can C. When the transfer nip N is divided and present, the total length of the can C can be pressed while the can C is rotating in the circumferential direction with the maximum circumferential length. What is necessary is just to be more than a distance.
When the length of the transfer nip portion N is too short, it is necessary to rotate the can C in a state where the transfer of the can C by the mandrel wheel 132 is stopped at the transfer station 120, and thus the productivity per unit time decreases. .
In the transfer nip portion N, the can C is pressed with a pressure of, for example, 0 to 1000 kPa.

[Preliminary rotation means]
The printing apparatus 100 according to the first embodiment includes preliminary rotation means (not shown) that rotates the mandrel 131 in advance on the upstream side of the transfer station 120 in the conveyance path of the can C in the conveyance unit 130. Yes.
In the preliminary rotating means, the specific configuration is not limited as long as the mandrel 131 is forcibly rotated so that the peripheral speed of the can C is substantially the same as the peripheral speed of the transfer cylinder 110. As the pre-rotating means, for example, there is a mechanism for applying a rotational driving force by bringing the base end portion of the mandrel 131 that does not contact the can C into contact with an endless press pin belt that obtains the driving force from the transfer cylinder 110 and circulates. As disclosed in Japanese Patent No. 4450159, a rack-like fixed gear is provided along the conveyance path on the upstream side of the transfer station 120, and a pre-rotation gear is provided on the mandrel shaft of each mandrel 131 to engage them. By combining them, it is possible to use one having a mechanism for applying a rotational driving force to the mandrel 131.

[Overcoat processing station]
In the printing apparatus 100 according to the first embodiment, an overcoat process is performed on the can C carried by the mandrel 131 and conveyed from the transfer station 120 on the downstream side of the transfer station 120 of the conveyance unit 130. A coat processing station 170 is provided.
The overcoat processing station 170 is provided with, for example, a varnish application roller 171 that forms an overcoat layer made of varnish on the ink image P transferred to the outer peripheral surface of the body portion of the can C in the transfer station 120. The varnish application roller 171 forms a varnish application nip V between the varnish application roller 130 and the mandrel wheel 132 constituting the conveyance unit 130, and moves along the varnish application nip V on the conveyance path while rotating the can C. The varnish is applied by rolling contact with the varnish application roller 171.
Instead of the varnish application roller 171, the overcoat processing station 170 may be provided with a sprayer that supplies varnish to the outer peripheral surface of the body portion of the can C by spraying.
As the varnish, a transparent paint conventionally used as a top coat such as a seamless can can be used, and in particular, a thermosetting transparent paint can be suitably used.

[Washing station]
A cleaning station 140 for cleaning the surface of the transfer cylinder 110 is provided downstream of the transfer station 120 in the rotational direction on the surface of the transfer cylinder 110. The cleaning station 140 includes a cleaning agent spraying unit 141 that supplies the cleaning agent to the surface of the transfer cylinder 110 by spraying, and a region downstream of the region on the transfer cylinder 110 to which the cleaning agent from the cleaning agent spraying unit 141 is supplied. And a scraper 142 provided so as to abut against. The scraper 142 is made of an elastic plate such as a polyethylene terephthalate plate, a polycarbonate plate, or a stainless plate.

Cooling means for cooling the temperature of the transfer cylinder 110 may be provided on the surface of the transfer cylinder 110 downstream of the cleaning station 140 and upstream of the ink jet printing station 150.
The surface temperature of the transfer cylinder 110 is, for example, the temperature of the region passing through the inkjet printing station 150 is room temperature to 200 ° C., the temperature of the region passing through the drying station 160 is 90 to 300 ° C., and the temperature of the region passing through the transfer station 120. It is set to 80-220 degreeC.

[Printing method]
The printing method of the present invention is a method of printing the ink image P on the outer peripheral surface of the barrel portion of the can C, which is a cylindrical workpiece, using the above-described printing apparatus of the present invention.
Specifically, first, monochrome ink images of different colors are formed by the inkjet head at the inkjet printing station 150 on the surface of the transfer cylinder 110 that is rotationally driven in one direction (counterclockwise in FIG. 1). These are operated in synchronism with each other so that one ink image P is formed. The formed ink image P is transported to the drying station 160 and dried to a state having appropriate adhesiveness, and reaches the transfer station 120 in this state.
On the other hand, the can C fitted and carried on the mandrel 131 on the transport path by the workpiece supply means is in the direction opposite to the transfer cylinder 110 along the transport path defined by the guide groove (clockwise in FIG. 1). 1 and is rotated in the direction opposite to the transfer cylinder 110 (clockwise in FIG. 1) so that the peripheral speed of the can C substantially matches the peripheral speed of the transfer cylinder 110. Then, it is conveyed to the transfer station 120 in a state where the rotation is continued. In the present embodiment, the rotation direction of the transfer cylinder 110 and the circular conveyance direction of the can C by the mandrel wheel 132 are opposite directions, but they may be the same direction. That is, in this embodiment, the can C and the transfer cylinder 110 are transported and moved in the same direction (downward in FIG. 1) at the transfer station 120, but this may be configured to be transported and moved in the opposite direction.
The mandrel 131 and the can C that have reached the transfer nip portion N of the transfer station 120 move along the conveyance path as the mandrel wheel 132 rotates. At that time, the mandrel 131 is moved according to the shape of the guide groove. Move radially inward. Meanwhile, the outer peripheral surface of the barrel portion of the can C comes into contact with the contact start point on the surface of the transfer cylinder 110 and is pressed. The contact start point may be the upstream edge of the ink image P, or may be a region (non-image region) between the ink image P and the ink image P. Then, the can C that has contacted the surface of the transfer cylinder 110 moves along the transport path while rotating while maintaining the contact state. That is, the can C moves from the entrance to the exit of the transfer nip portion N by rolling contact with the transfer cylinder 110 by the movement along the conveyance path and the rotation of the mandrel 131. Along with this rolling contact, the ink image P held on the surface of the transfer cylinder 110 in the transfer nip portion N comes into contact with the outer peripheral surface of the barrel portion of the can C, and the can C is pressed against the transfer cylinder 110. For this reason, the ink image P is transferred from the transfer cylinder 110 to the outer peripheral surface of the body portion of the can C so as to be wrapped around.
The can C onto which the ink image P has been transferred is transported to the overcoat processing station 170 while being fitted to the mandrel 131, and is transported along the transport path by the mandrel wheel 132 and the mandrel 131 is rotated to rotate the overcoat processing station 170. In contact with the varnish application roller 171 rotated in a direction opposite to the rotation of the mandrel 131 (counterclockwise in FIG. 1), and the outer peripheral surface of the body of the can C is overcoated to form an overcoat layer of varnish. It is formed.
Thereafter, the can C is transferred from the mandrel wheel 132 to the workpiece discharge means and conveyed to the next process. In the next step, for example, when a thermosetting ink is used to form the ink image P, the ink of the ink image P is burned simultaneously with the baking of the varnish, and the ultraviolet curable ink is used to form the ink image P. When used, ultraviolet irradiation is performed. Further, another image may be formed on the outer peripheral surface of the body portion of the can C on which the ink image P is formed by plate-type printing or the like.

  After the ink image P is transferred and the can C on which the overcoat processing has been performed is discharged, the mandrel 131 from which the can C has been removed returns again to the first object supply means on the transport path. Further, the transfer cylinder 110 that has passed through the transfer station 120 is supplied with the cleaning agent from the cleaning agent ejecting unit 141 in the cleaning station 140, and after the untransferred ink is removed together with the cleaning agent by the scraper 142, the inkjet printing station 150 again. Return to. By repeating these in synchronization, the can C to which the ink image P has been transferred is continuously obtained.

  The transfer speed for transferring the ink image P from the transfer cylinder 110 to the can C is set to, for example, 500 pieces / minute, and the peripheral speed of the transfer cylinder 110 is set to, for example, 150 to 200 m / minute.

  Since the printing apparatus 100 according to the first embodiment includes the transfer cylinder 110, the inkjet printing station 150, and the transfer station 120, the ink image P formed on the surface of the transfer cylinder 110 is transferred to the transfer station 120. In this case, the can C is brought into contact with the transfer cylinder 110 while rotating, so that the can C is transferred to the outer peripheral surface of the body part by one rotation of rotation. Can be printed with high production efficiency. In addition, since the ink image P to be formed uses ink jet printing, an image with excellent sharpness can be obtained. Further, by providing an ink heating mechanism such as a heater inside the transfer cylinder 110, it is not necessary to provide the drying station 160 facing the surface of the transfer cylinder 110. As a result, the printing apparatus can be downsized. .

The printing apparatus 100 according to the first embodiment of the present invention has been specifically described above. However, the printing apparatus 100 according to the first embodiment is not limited to the above example, and is within the scope of the claims. Various design changes can be made without departing from the described invention.
For example, in the first embodiment described above, it has been described that the can C is transported to the transfer station 120 by the transport unit 130 including the mandrel wheel 132, but the configuration of the transport unit is not limited to this, and the can C is supported. For example, the mandrel may be fixed to a conveyor member and linearly conveyed to the transfer station 120 (linear conveyance).

[Printing Apparatus According to Second Embodiment]
FIG. 2 is an explanatory diagram schematically showing an example of the configuration of a printing apparatus according to the second embodiment of the present invention.
The printing apparatus 200 according to the second embodiment is the first except that a plurality of transfer stations 220 are provided on the surface of the transfer cylinder 110, and a transport unit 230 is provided corresponding to each transfer station 220. The configuration is the same as that of the printing apparatus 100 according to the embodiment. Components having the same configuration as that of the printing apparatus 100 according to the first embodiment are denoted by the same reference numerals.
Specifically, a plurality of, for example, three transfer stations 220 are provided on the surface of the transfer cylinder 110 on the downstream side of the inkjet printing station 150 in the rotational direction. Each transport unit 230 provided corresponding to each transfer station 220 transports the mandrel 231 carrying the can C along the transport path, and has a plurality of mandrels 231 and a horizontally extending rotating shaft. And a mandrel wheel 232 that is pivotally attached to and rotated. Specifically, a plurality of mandrels 231 are provided in each of the shaft holes formed so that the adjacent distances are equal to each other on the circumference of a predetermined rotation radius of the outer periphery of one mandrel wheel 232. The mandrel wheel 232 is rotatably supported around an axis (mandrel axis) parallel to the rotation axis of the mandrel wheel 232. That is, the transport unit 230 is configured such that the can C fitted to the mandrel 231 is transported in one direction along the transport path together with the mandrel 231 when the mandrel wheel 232 is rotationally driven.
The mandrel 231 is configured to be cyclically conveyed on a circumference having a predetermined radius of rotation around the rotation axis of the mandrel wheel 232 as the mandrel wheel 232 rotates. The barrel portion of the can C carried on the mandrel 231 is configured to come into contact with one location (transfer location) on the surface of the transfer cylinder 110 at the end of the transport path of the mandrel 231. A transfer nip portion is not formed between the transport unit 230 and the transfer cylinder 110. The can C may be configured to be pressed to a transfer location on the surface of the transfer cylinder 110 as necessary.

In such a printing apparatus 200 according to the second embodiment, first, an ink image P is formed at the inkjet printing station 150 on the surface of the transfer cylinder 110 that is rotationally driven in one direction (clockwise in FIG. 2). This is dried in the drying station 160 to a state having appropriate tackiness, and reaches the transfer station 220 in this state.
On the other hand, the can C, which is fitted and supported on the mandrel 231 on the transport path by the workpiece supply means, is transported in a direction opposite to the transfer cylinder 110 (counterclockwise in FIG. 2) along the transport path. The transfer station 220 is reached.
When the can C reaches the transfer position of the transfer cylinder 110 of the transfer station 220, the transport of the can C by the transport unit 230 is temporarily stopped, and the transfer cylinder 110 is rotated at a peripheral speed synchronized with the peripheral speed of the transfer cylinder 110. Rotation of the mandrel 231 in the opposite direction (counterclockwise in FIG. 2) is started. As a result, the outer peripheral surface of the body portion of the can C comes into contact with the ink image P held on the surface of the transfer cylinder 110, and the can C is pressed against the transfer cylinder 110. And the can C which has contacted the transfer location on the surface of the transfer cylinder 110 rotates while maintaining the contact state. Along with this rotation, since the ink image P held on the surface of the transfer cylinder 110 is in contact with the outer peripheral surface of the body portion of the can C, the ink image P is separated from the transfer cylinder 110 and wound. The can C is collectively transferred to the outer peripheral surface of the body portion of the can C. Thereafter, the same process as that of the printing apparatus 100 according to the first embodiment is performed on the can C in which the ink image P is transferred to the outer peripheral surface of the body portion.
In the printing apparatus 200 according to the second embodiment, the can C is intermittently transported by the transport unit 230, and the transfer process of one ink image P to the one can C is performed at three simultaneous transfer stations 220. Done. Specifically, three ink images P are formed at the same separation distance as the separation distance of the adjacent transfer stations 220 on the transfer cylinder 110, and these are conveyed to the respective transfer stations 220, while the three conveyances are performed. In the unit 230, the cans C are simultaneously conveyed to the transfer location on the surface of the transfer cylinder 110. Then, at the three transfer stations 220, the transfer cylinder 110 rotates and the can C carried on the mandrel 231 of each transport unit 230 rotates, so that the transfer process of the ink image P is simultaneously performed at three locations.
After discharging the can C onto which the ink image P has been transferred, in each of the three transport units 230, each of the mandrels 231 from which the can C has been removed returns to the first object supply means on the transport path. The transfer cylinder 110 that has passed through the transfer station 220 returns to the inkjet printing station 150 again. By repeating these in synchronization, a plurality of cans C to which the ink image P has been transferred are obtained intermittently.

  According to the printing apparatus 200 according to the second embodiment as described above, it is possible to obtain the same effect as that of the printing apparatus 100 according to the first embodiment, and further, transfer onto the surface of the transfer cylinder 110. Since a plurality of stations 220 are provided, the cans C can be transferred per unit time even when the cans C are intermittently transported by performing simultaneous transfer processing at each transfer station 220. Can increase the overall productivity. Further, by performing intermittent conveyance, it is possible to easily perform control related to the conveyance of the object to be processed, the circulating movement of the transfer belt, and the synchronization of the formation of the ink image.

The printing apparatus 200 according to the second embodiment of the present invention has been specifically described above. However, the printing apparatus 200 according to the second embodiment is not limited to the above example, and is defined in the claims. Various design changes can be made without departing from the described invention.
For example, in the printing apparatus 200 provided with a plurality of transfer stations 220, the can C has been described as being intermittently conveyed by the conveyance unit 230. However, by providing a transfer nip portion in each of the transfer stations 220, for example, The can C may be configured to be continuously conveyed.

  Since the printing apparatus of the present invention can print an image by inkjet printing at a high speed, it can be suitably used for a seamless can used for a beverage container or the like that requires decoration and productivity.

100, 200 Printing device 110 Transfer cylinder 120, 220 Transfer station 130, 230 Transport unit 131, 231 Mandrel 132, 232 Mandrel wheel 140 Cleaning station 141 Cleaning agent jetting unit 142 Scraper 150 Inkjet printing station 160 Drying station 170 Overcoat processing station 171 Varnish application roller C Can N Transfer nip P Ink image V Varnish application nip

Claims (12)

A rotating transfer cylinder, an ink jet printing station for forming an ink image by ink jet printing on the surface of the transfer cylinder, and an outer peripheral surface of the barrel of the cylindrical object to be processed on the surface of the transfer cylinder A transfer station having a transfer station, and a transport unit that moves a plurality of self-rotating mandrels carrying an object to be processed along a transport path,
In the transfer station, the transfer cylinder and the object to be processed are brought into contact with each other while rotating the object to be processed carried on the mandrel, whereby the ink image is transferred from the surface of the transfer cylinder to the body of the object to be processed. The printing apparatus is characterized by being transferred to the outer peripheral surface of the printer.   The printing apparatus according to claim 1, wherein a drying station for drying an ink image formed in the inkjet printing station is provided between the inkjet printing station and the transfer station.   The printing apparatus according to claim 1, wherein a plurality of the inkjet printing stations are provided.   An overcoat process is performed on the ink image transferred to the outer peripheral surface of the body portion of the workpiece carried by the mandrel and transported from the transfer station, on the downstream side of the transfer station of the transport unit. The printing apparatus according to claim 1, further comprising a station.   The printing apparatus according to claim 1, wherein the transport unit includes a mandrel wheel having the plurality of mandrels. The transfer station has a transfer nip portion where pressure is applied to an object to be processed by the transfer cylinder and the transport unit;
In the transfer nip portion, the workpiece carried and conveyed by the mandrel is rotated while passing through the transfer nip portion, and the outer peripheral surface of the barrel portion is brought into rolling contact with the surface of the transfer cylinder. The ink image is transferred from the surface of the transfer cylinder to the outer peripheral surface of the body of the object to be processed,
The printing apparatus according to claim 1, wherein the transport unit is configured to continuously transport a plurality of objects to be processed carried on the mandrels.   The printing apparatus according to claim 1, wherein a plurality of the transfer stations are provided on a surface of the transfer cylinder.   The printing apparatus according to claim 1, further comprising a pre-rotation unit that rotates the mandrel in advance on the upstream side of the transfer station of the transport unit. An ink image is formed on the surface of the rotating transfer cylinder by ink jet printing at an ink jet printing station, and the ink image formed on the surface of the transfer cylinder is transferred to a plurality of rotatable mandrels moved along the transport path. A printing method for transferring at a transfer station to the outer peripheral surface of the body of a cylindrical object to be carried,
In the transfer station, the transfer cylinder and the object to be processed are brought into contact with each other while rotating the object to be processed carried on the mandrel, whereby the ink image is transferred from the surface of the transfer cylinder to the body of the object to be processed. The printing method characterized by transferring to the outer peripheral surface of this. The transfer station has a transfer nip portion where pressure is applied to an object to be processed by the transfer cylinder and the transport unit;
In the transfer nip portion, the workpiece carried and conveyed by the mandrel is rotated while passing through the transfer nip portion, and the outer peripheral surface of the barrel portion is brought into rolling contact with the surface of the transfer cylinder. The ink image is transferred from the surface of the transfer cylinder to the outer peripheral surface of the body of the object to be processed,
The printing method according to claim 9, wherein a plurality of objects to be processed carried on the mandrels are continuously conveyed by the conveyance unit.   A plurality of the transfer stations are provided on the surface of the transfer cylinder, and each of the plurality of ink images formed on the surface of the transfer cylinder at each transfer station is transferred to the outer peripheral surface of the body portion of the object to be processed. The printing method according to claim 9 or 10, wherein: 12. The mandrel moved along a transport path by the transport unit is rotated in advance by a pre-rotation unit and then transported to the transfer station. Printing method.

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