PRINTING APPARATUS FOR CONTAINERS OF CIRCULAR CROSS SECTION

Abstract: The invention has its object to effect simultaneous multi-color printing on a container having drum sections recessed from a drum portion by means of a simple construction. To attain such object, according to the invention, a timing screw (35) conveys containers (1), a transfer drum (10) is rotated, a first marking roll (31) transfers ink to stationary shoulder transfer surface portions (11) and stationary drum transfer surface portions (13), a second marking roll transfers ink to movable transfer surface portions (20), and after ink is transferred to shoulder portions (4), drum portion (6) and a neck portion (5) of a container (1) held between a guide (34) and the transfer roll (10) and moved in rotation and printing is performed, a cleaning roll (30) removes the remaining ink on the stationary shoulder transfer surface portions (11), stationary drum transfer surface portions (13) and the movable transfer surface portions (20).

Description: The present invention relates to apparatus for printing on a container of circular cross section having a radially reduced portion, particularly such a container having a shoulder portion, a circular section radially reduced portion of smaller radius than the shoulder portion, and a barrel portion having the same radius as the shoulder portion. In our Japanese Patent Application Publication No. 63-37707 we describe a technique for simultaneously printing in multiple colours on a container as shown in Fig. 6 of the accompanying drawings, namely one having a shoulder portion 4, a radially reduced portion 5 and a barrel portion 6, the barrel portion 6 having the same radius as the shoulder portion 4, the container also having a cap 2 and a tapered mouth portion 3. This known technique uses a transfer surface member for the radially reduced portion which is caused to protrude from a flat surface of a transfer drum by means of cams and springs, but this structure is very complicated. According to the present invention there is provided apparatus for printing on a container of circular cross section having a radially reduced portion, said apparatus comprising an ink transfer drum, an imprint roll for each portion of such a container having a different radius, said imprint rolls being arranged such that a first imprint roll for printing a container portion having the largest radius is located at an upstream position along the rotational direction of the said transfer drum, then at least one other imprint roll for printing a said container portion of smaller radius is located downstream of the first roll, said transfer drum having a fixed transfer surface member and a movable transfer surface member, said movable transfer surface member being biased by resilient means to protrude from the surface of the said transfer drum. The said resilient means preferably comprises a spring. If a shoulder portion, a barrel portion, and a radially reduced portion of the container are all of different radii, a transfer surface member for the container portion of greatest radius is treated as a fixed transfer surface member and other transfer surface members are treated as movable transfer surface members. In such a case, the amount of protrusion of each movable surface member is controlled by the said resilient means. The imprint rolls are preferably arranged in decreasing order of the radius of each corresponding container portion, so that ink is first transferred by an imprint roll to a transfer surface member for the container portion having the greatest radius. It is preferable to form the movable transfer surface member with a protruding portion of a shape corresponding to that of the portion of the container to be printed. Thus the protruding portion is preferably shaped into a corner cut shape, a chamfered shape, a round corner shape, or a curved shape to prevent friction or interference with other portions on contacting the imprint roll. Both the fixed transfer surface member and the movable transfer surface member are preferably surfaced with an elastic material such as rubber where they contact the container. In printing on a circular cross section container as described above, when an imprint roll which prints on a portion of the container other than the said radially reduced portion engages an already inked movable transfer surface member, ink transferred from the movable transfer surface member causes a problem. However, in the apparatus of the present invention, since the imprint roll for printing a container portion of greater radius is positioned upstream relative to the rotational direction of the transfer drum, the movable transfer surface member for printing a container portion of reduced radius is pressed by the imprint roll but ink is not transferred. Thus the above disadvantage is avoided. If a container has a plurality of the radially reduced portions the present invention can also be applied in the same way. The present invention can be applied to printing on a circular cross sectional container having a shoulder portion, a radially reduced portion, and a barrel portion. In operation, the container is usually carried by a timing screw. While rotating a transfer drum, ink is transferred onto the transfer drum for printing on the shoulder portion and the barrel portion by way of the first imprint roll, and onto the movable transfer surface member by way of the second imprint roll. The second imprint roll is positioned away from the fixed transfer surface member by the distance by which the movable transfer surface member protrudes from the transfer drum, so that the second imprint roll transfers ink only to the protruding movable transfer surface member. Ink on the fixed transfer surface members for the shoulder portion and the barrel portion is transferred to the shoulder portion and the barrel portion of the container, which is located between the arc-shaped guide member and the transfer drum and rotates about its axis, while at the same time the ink on the movable transfer surface member is transferred to the radially reduced portion of the container. Any remaining ink on the fixed and movable transfer surface members is removed by means of a cleaning roll. The present invention is also applicable to printing on a container having a shoulder portion, a barrel portion and a radially reduced portion all of different radii. In such a case, the transfer surface member for the container portion having the greatest radius is taken as the fixed transfer surface member and other transfer surface members are taken as the movable transfer surface members. The degrees of protrusion of the movable transfer surface members are controlled by resilient means, for example a spring. The imprint rolls may be arranged in decreasing order of the radius of each corresponding container portion, so that ink is first transferred from an imprint roll to a transfer surface member to print on the container portion having the greatest radius, then by an imprint roll for the container portion having the second greatest radius, and so on. Incidentally, there is a difference in circumferential speed between a fixed transfer surface and a movable transfer surface in apparatus according to the invention, caused by the movable transfer surface member protruding from the transfer drum. When a radially reduced portion of the container has an arcuately shaped cross section, the movable transfer surface member can intimately contact it because of the preferred elasticity of its material, but there is a difference in circumferential speed between top and bottom parts and a central part of the movable transfer surface member. These problems may be resolved by allowing a slip to occur between the container material and the transfer surface member. Distortion of a print image resulting from such slip can be ignored when the difference between the greatest radius and the least radius of the container is less than twenty percent. Some embodiments of the invention will now be described by way of example and with reference to the accompanying drawings, in which: Fig. 1 is a top view of an embodiment of the present invention; Fig. 2 is a fragmentary perspective view of a main part of the apparatus of Fig. 1; Fig. 3 is a perspective view of a transfer member for printing on a recessed portion of a container; Fig. 4 is an exploded view of the apparatus of Fig. 3; Fig. 5 is a side elevational view of another embodiment of a second imprint roll; Fig. 6 is a side elevational view of an example of a container to be printed on by apparatus of the present invention; Fig. 7 is a side elevational view of still another such container; Fig. 8 is a plan view of a main part of another embodiment of the invention; and Fig. 9 is a fragmentary enlarged sectional view of the apparatus of Fig. 8. Referring to Figs. 1 and 2, an apparatus according to the present invention comprises a transfer drum 10, a cleaning roll 30 slidable on the drum 10, a first imprint roll 31 and a second imprint roll 32 arranged around one side of the transfer drum 10 with the roll 31 upstream of the roll 32 relative to the rotational direction of the drum indicated by an arrow. A guide 34, a timing screw 35 and a guide rail 36 are arranged around the other side of the transfer drum 10. The transfer drum 10 has a fixed transfer surface member 11 for printing on a shoulder portion 4 (see Fig. 6) of a container 1, a ring-shaped groove 12 which carries a plurality of movable transfer surface members 20 (six members in the drawing) for printing on a radially reduced portion 5 of the container, and a fixed transfer surface member 13 for printing on a barrel portion 6 of the container, all arranged in the order just described beginning from upstream along the rotational direction of the transfer drum. The movable transfer surface member 20 is mainly defined by a transfer member 21 and a holder 27 as shown in Figs. 3 and 4. The transfer member 21 comprises an arc-shaped transfer piece 22, a yoke 23 mounting the transfer piece 22 by means of screws a, an axle member 24 extending from the yoke 23, and a holding pin 25 extending through the axle member 24 at right angles thereto. A holder 27 comprises a main body 28 mounting the axle member 24 in slidable fashion, and a base member 29 mounting the main body 28 by means of screws b. The base member 29 is fixed to the bottom surface of the transfer drum 10 with screws c. A spring 26 received in an inner hole 28a of the body 28 and an inner hole 24a of the axle member 24 biases the transfer member 21 outwardly along a radius of the transfer drum 10. The transfer member 21 is held against axial rotation by the holding pin 25. The cleaning roll 30 is of a conventional nature. The first imprint roll 31 is also conventional; an imprint member 31a for the container shoulder portion 4 and another imprint member 31 b for the barrel portion 6 are provided on the peripheral surface thereof. The second imprint roll 32 is again conventional and is at a clearance CS (almost equal to the thickness of the transfer piece 22) from the transfer drum 10; a movable imprint member 32a is provided on the peripheral surface thereof. The imprint rolls 31 and 32 are biased toward the transfer drum 10 by springs (not shown) having a larger force than that of the springs 26. Doctor blades 33 of known form contact the peripheries of the imprint rolls 31 and 32. An arcuate guide 34 is located coaxially with the transfer drum 10, at a clearance C1 which is slightly less than the outside diameter of a container 1 so that a container can be held in the gap between the guide 34 and the rotating transfer drum 10 and moved along in rotating fashion, by friction. The timing screw 35 and the guide rail 36 are based on a well known technique. A plurality of movable transfer surface members 20 can be provided at vertically spaced locations, and a plurality of imprint rolls 32 and cleaning rolls 30 can also be provided. A printing process using the apparatus described above will now be explained. A container 1 is carried along by the timing screw 35, and the transfer drum 10 is concurrently rotated in the direction of the arrow. Ink on the imprint member 31a for the shoulder portion 4 and the imprint member 31b for the barrel portion 6 is transferred to the fixed transfer surface member 11 for the shoulder portion and the fixed transfer surface member 13 for the barrel portion. At this time the movable transfer surface member 20 is pressed into the ring-shaped groove 12 of the transfer drum 10 by the pressure of the roll 31 and is thus at the same surface level as the fixed transfer surface members 11 and 13. Ink on the second imprint member 32a is next transferred with pressure to the transfer piece 22 which is urged away from the transfer drum 10 by the spring 26. The ink on the transfer drums 11 and 13 is then transferred to the shoulder portion 4 and the barrel portion 6 of the container 1, rotating along the guide 34, and concurrently the ink on the transfer piece 22 is transferred to the reduced portion 5 of the container. Finally residual ink on the transfer surface members 11, 13 and 20 is removed by the Leaning roll 30. Another embodiment of the second imprint roll is shown in Fig. 5. A movable imprint member 32A is of comparatively large height and is made vertically movable. Plural date designations 32b are provided on the imprint member 32A (6 dates in the example) and the member is moved vertically to align a desired date and transfer the ink, so that the period of use of the member 32A is extended. Another embodiment of the invention is shown from Figs. 7 to 9. A container 41 is of circular cross section having a mouth portion 43, a shoulder portion 44, a reduced portion 45 and a barrel portion 46 as shown in Fig. 7, the radii of such mouth, shoulder, barrel, and reduced portions all being different. In order to print on a container 41 having this shape, a transfer drum 50 and other members are structured as shown in Fig. 8. Thus a rotatable cleaning roll 30, a first imprint roll 51, a second imprint roll 52, and a third imprint roll 53 are arranged around one side of the transfer drum 50 in the order mentioned, relative to the rotational direction of the drum as shown by the arrow. A fixed transfer surface member is arranged to transfer ink to the barrel portion 46 of the container 41, and has a similar structure to the fixed transfer surface member 13 of the previous embodiment. A movable transfer surface member 20a for the reduced portion 45 and a movable transfer surface member 20b for the shoulder portion 44 are housed in a ring-shaped groove in the transfer drum 50 (see Fig. 9). The imprint rolls 51, 52 and 53 are respectively arranged to supply ink for printing on the barrel portion 46, the reduced portion 45, and the shoulder portion 53. The movable transfer surface members 20a and 20b are urged outwardly by springs 26a and 26b respectively. The movable transfer surface members 20a and 20b are respectively shaped to correspond to the reduced portion 45 and the shoulder portion 44 of the container 41, the surface of the movable transfer surface member 20a being curved and that of the movable transfer surface member 20b being chamfered. This eliminates friction and interference between the movable transfer surface members 20a, 20b and the imprint rolls 51, 52 and 53. Thus a container having a reduced portion in its surface and another portion of greater radius can be printed in a single operation in multiple colours by means of a simple structure. Even when the radii of a shoulder portion, a barrel portion, and a reduced portion are all different from each other, simultaneous printing on all of such portions can be satisfactorily performed.

Claims: Apparatus for printing on a container (1) of circular cross section having a radially reduced portion (5), said apparatus comprising an ink transfer drum (10), an imprint roll (31,32) for each portion of such a container having a different radius, said imprint rolls being arranged such that a first imprint roll (31) for printing a container portion having the largest radius (6) is located at an upstream position along the rotational direction of the said transfer drum then at least one other imprint roll (32) for printing a said container portion (5) of smaller radius is located downstream of the first roll, said transfer drum having a fixed transfer surface member (11,13) and a movable transfer surface member (20), said movable transfer surface member being biased by resilient means (26) to protrude from the surface of the said transfer drum.

Inventors: NO SHINICHIRO, WATANABE SHINICHIRO, NO, SHINICHIRO, WATANABE, SHINICHIRO, NO, SHINICHIRO, KABUSHIKI KAISHA YAKULT HONSHA
Applicants: YAKULT HONSHA KK, KABUSHIKI KAISHA YAKULT HONSHA
Application year: 1996
Main classification: B41F17
IPC codes: B41F17, B65G33