SHEET-FED PRINTING PRESS

Abstract

A sheet-fed printing press comprises: a screen printing unit for printing one surface of a sheet being transported; a drying unit, provided downstream of the screen printing unit in a transport direction, for drying the screen-printed one surface of the sheet; a gravure printing unit, provided downstream of the drying unit in the transport direction, for performing printing on the dried sheet; and a reversing unit, provided between the drying unit and the gravure printing unit, for switching between double-sided printing in which the other surface on the side opposite to the screen-printed one surface of the sheet is gravure-printed, and single-sided printing in which the screen-printed sheet is reversed, and the one surface of the reversed sheet is gravure-printed.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:

FIG. 1 is a schematic view of a sheet-fed printing press according to a first embodiment of the present invention; and

FIG. 2 is a schematic view of a sheet-fed printing press according to a second embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

A sheet-fed printing press according to the present invention will be described in detail by embodiments with reference to the accompanying drawings. In each embodiment, members having the same structures and functions are assigned the same numerals, and their explanations will be omitted in a later embodiment.

Embodiment 1

FIG. 1 is a schematic view of a sheet-fed printing press according to a first embodiment of the present invention.

As shown in FIG. 1, a sheet-fed printing press 1 is equipped with a feeder 11, a screen printing unit (a first printing unit, a stencil printing unit) 12, a drying unit 14, a reversing unit 13, a gravure printing unit (a second printing unit, an intaglio printing unit) 15, and a delivery unit 16. A sheet (a sheet) S passes through these devices sequentially, and is thereby printed on.

The feeder 11 is provided with a sheet feeding plate 21, and feeds the sheets S, one by one, from the sheet feeding plate 21 to the screen printing unit 12 via a swing arm shaft pregripper (not shown) provided at the leading end of the sheet feeding plate 21.

The screen printing unit 12 is provided with an impression cylinder 23 which receives the sheet S fed from the sheet feeding plate 21 via the swing arm shaft pregripper. A rotary screen (stencil printing cylinder) 24 in contact with the impression cylinder 23 is provided downstream of the sheet feeding plate 21 in the rotating direction of the impression cylinder 23. That is, the point of contact between the impression cylinder 23 and the rotary screen 24 serves as the point of screen printing. A transfer cylinder 25 in contact with the impression cylinder 23 is provided downstream of the rotary screen 24 in the rotating direction of the impression cylinder 23.

The rotary screen 24 is composed of a hollow cylinder which is a thin screen (comprising stainless steel, nickel or the like) etched with small holes corresponding to a pattern and rotatably supported in a cylindrical form, and an ink fountain and a squeegee fixed to and supported by a frame within the hollow cylinder. That is, the hollow cylinder rotates in accordance with the rotation of the impression cylinder 23, and ink within the ink fountain is pushed out through the small holes of the hollow cylinder by the squeegee, whereby the rotary screen 24 can perform printing, which corresponds to the small holes of the hollow cylinder, on the sheet S held by the impression cylinder 23. Thus, the screen printing unit 12, which is composed of the impression cylinder 23 and the rotary screen 24 located above and contacting the impression cylinder 23, applies printing to one surface of the sheet S. The one surface of the sheet S refers to the first surface to be printed by the printing press. The other surface of the sheet S refers to the surface on the side opposite to the one surface of the sheet S.

The drying unit 14 is provided with UV lamps 29a, 29b′ and 29c which oppose the upper peripheral surface of an attraction cylinder 26 in contact with the transfer cylinder 25, and which are arranged in parallel. That is, the UV lamps 29a, 29b′ and 29c throw ultraviolet rays from above the attraction cylinder 26 toward the upper peripheral surface of the attraction cylinder 26 to dry the ink on the one surface of the sheet S attracted to the attraction cylinder 26.

The reversing unit 13 is provided with the attraction cylinder (transport cylinder) 26 in contact with the transfer cylinder 25, as mentioned above. A reversing cylinder 27 in contact with the attraction cylinder 26 is provided downstream of the transfer cylinder 25 in the rotating direction of the attraction cylinder 26. A transfer cylinder 28 in contact with the reversing cylinder 27 is provided downstream of the attraction cylinder 26 in the rotating direction of the reversing cylinder 27.

In the reversing unit 13, during single-sided printing, a rear end portion of the one surface of the sheet S sucked by the attraction cylinder 26 is once held by a holding member of the reversing cylinder 27 at a site in the vicinity of the point of contact between the attraction cylinder 26 and the reversing cylinder 27. With the sheet S being passed from the attraction cylinder 26 on to the reversing cylinder 27, the rear end portion of the sheet S is similarly passed from the holding member on to and gripped by a gripper of a gripper device of the reversing cylinder 27. By this action, the sheet S is reversed by the reversing unit 13, and transported such that the one surface of the sheet S is pointed outward on the reversing cylinder 27. Then, the sheet S is supplied to the gravure printing unit 15 via the transfer cylinder 28.

During double-sided printing, on the other hand, a leading end portion of the one surface of the sheet S sucked by the attraction cylinder 26 is directly accepted and gripped by the gripper of the gripper device of the reversing cylinder 27 at a site in the vicinity of the point of contact between the attraction cylinder 26 and the reversing cylinder 27. By this action, the sheet S is not reversed by the reversing unit 13, but is transported such that the other surface of the sheet S is pointed outward on the reversing cylinder 27. Then, the sheet S is supplied to the gravure printing unit 15 via the transfer cylinder 28. Since a reversing mechanism in the reversing unit 13 has already been known publicly, a detailed description of its structure is omitted herein.

In the gravure printing unit 15, an impression cylinder 30 in contact with the transfer cylinder 28 is provided. A gravure plate cylinder (intaglio printing cylinder) 31 in contact with the impression cylinder 30 is provided downstream of the transfer cylinder 28 in the rotating direction of the impression cylinder 30. That is, the point of contact between the impression cylinder 30 and the gravure plate cylinder 31 serves as the point of gravure printing. An ink roller 32 in contact with the gravure plate cylinder 31 is provided downstream of the impression cylinder 30 in the rotating direction of the gravure plate cylinder 31. A lower side of the ink roller 32 is immersed in an ink reservoir 33 where ink is stored inside. A doctor 34 in contact with the gravure plate cylinder 31 is provided downstream of the ink roller 32 in the rotating direction of the gravure plate cylinder 31 and upstream of the impression cylinder 30 in the rotating direction of the gravure plate cylinder 31. The doctor 34 removes surplus ink deposited on non-image areas of the gravure plate cylinder 31. Thus, the gravure printing unit 15, which is composed of the impression cylinder 30, the gravure plate cylinder 31 located below the impression cylinder 30 and contacting the impression cylinder 30, the ink roller 32, and the ink reservoir 33, applies printing to the other surface of the sheet S.

In the delivery unit 16, sprockets 35a and 35b, one of which contacts the impression cylinder 30, are provided, and a delivery chain 36 is looped between the sprockets 35a and 35b. A plurality of gripper bars (not shown) for receiving the sheet S from the impression cylinder 30 are mounted on the delivery chain 36 at predetermined intervals along the travel direction of the delivery chain 36. Upon travel of the delivery chain 36, the sheet S is delivered downwardly of the delivery chain 36.

Because of the above-described features, when single-sided printing is performed, the sheet S fed to the sheet feeding plate 21 is passed onto the impression cylinder 23 via the swing arm shaft pregripper. Then, the sheet S accepted by the impression cylinder 23 is supplied between the impression cylinder 23 and the rotary screen 24. At this site, the ink pushed out through the small holes of the hollow cylinder is transferred to the sheet S, whereby screen printing is done on one surface of the sheet S. The sheet S subjected to screen printing is passed on to the attraction cylinder 26 via the transfer cylinder 25, and has the one surface dried by irradiation from the UV lamps 29a, 29b′ and 29c. Then, the dried sheet S is supplied between the attraction cylinder 26 and the reversing cylinder 27, and reversed by the reversing unit 13. As a result, the reversed sheet S is transported, with the one surface thereof being pointed outward on the reversing cylinder 27. Then, the sheet S is passed on to the impression cylinder 30 via the transfer cylinder 28.

The sheet S accepted by the impression cylinder 30 is supplied between the impression cylinder 30 and the gravure plate cylinder 31. At this time, the ink is supplied from the ink reservoir 33 to the gravure plate cylinder 31 via the ink roller 32, and surplus ink adhering to the non-image areas of the gravure plate cylinder 31 is removed by the doctor 34. Then, the ink is transferred from recessed image areas, which are lower in height than the non-image areas of the gravure plate cylinder 31, to the one surface of the sheet S held by the impression cylinder 30, whereby gravure printing is done. Then, the sheet S subjected to gravure printing is passed on to the delivery chain 36, and then delivered.

When double-sided printing is performed, the sheet S supplied between the attraction cylinder 26 and the reversing cylinder 27 is not reversed in the reversing unit 13. That is, the sheet S is not reversed by the reversing unit 13, but is transported, with the other surface thereof being pointed outward on the reversing cylinder 27, and is then passed on to the impression cylinder 30 via the transfer cylinder 28.

The sheet S accepted by the impression cylinder 30 is supplied between the impression cylinder 30 and the gravure plate cylinder 31. At this time, the ink is supplied from the ink reservoir 33 to the gravure plate cylinder 31 via the ink roller 32, and surplus ink adhering to the non-image areas of the gravure plate cylinder 31 is removed by the doctor 34. Then, the ink is transferred from the recessed image areas, which are lower in height than the non-image areas of the gravure plate cylinder 31, to the other surface of the sheet S held by the impression cylinder 30, whereby gravure printing is done. Then, the sheet S subjected to gravure printing is passed on to the delivery chain 36, and then delivered.

The sheet-fed printing press according to the present invention, therefore, can print the one surface of the sheet S (single-sided printing) and/or both of the one surface and the other surface of the sheet S (double-sided printing) in one pass when performing printing on the sheet S by screen printing and gravure printing. Consequently, an operator need not perform a reversing operation for or registration of the sheet S between the screen printing unit 12 and the gravure printing unit 15. Thus, the operating efficiency can be improved. Moreover, the screen printing unit 12 and the gravure printing unit 15 can be combined, so that a saving in the space required for the machines can be achieved.

Embodiment 2

FIG. 2 is a schematic view of a sheet-fed printing press according to a second embodiment of the present invention.

As shown in FIG. 2, a sheet-fed printing press 2 is equipped with a feeder 41, a gravure printing unit (a first printing unit, an intaglio printing unit) 42, a drying unit 43, a reversing unit 44, a screen printing unit (a second printing unit, a stencil printing unit) 45, and a delivery unit 46. A sheet (a sheet) S passes through these devices sequentially, and is thereby printed on.

The feeder 41 is provided with a sheet feeding plate 21, and feeds the sheets S, one by one, from the sheet feeding plate 21 to the gravure printing unit 42 via a swing arm shaft pregripper (not shown) and a transfer cylinder 51 provided at the leading end of the sheet feeding plate 21.

The gravure printing unit 42 is provided with an impression cylinder 30 which receives the sheet S fed from the sheet feeding plate 21 via the swing arm shaft pregripper and the transfer cylinder 51. The gravure printing unit 42 is composed of the above-mentioned impression cylinder 30, a gravure plate cylinder 31, an ink roller 32, an ink reservoir 33, and a doctor 34. A transfer cylinder 52 in contact with the impression cylinder 30 is provided downstream of the gravure plate cylinder 31 in the rotating direction of the impression cylinder 30.

The drying unit 43 is provided with a transfer cylinder 53, which contacts the transfer cylinder 52 downstream of the impression cylinder 30 in the rotating direction of the transfer cylinder 52, and UV lamps 29a, 29b′ and 29c which are arranged in parallel so as to oppose the lower peripheral surface of the transfer cylinder 53. That is, the UV lamps 29a, 29b′ and 29c throw ultraviolet rays from below the transfer cylinder 53 toward the lower peripheral surface of the transfer cylinder 53 to dry ink on one surface of the sheet S gripped by the transfer cylinder 53.

The reversing unit 44 is provided with an attraction cylinder 26 in contact with the transfer cylinder 53, and a reversing cylinder 27 in contact with the attraction cylinder 26.

The screen printing unit 45 is provided with an impression cylinder 23 in contact with the reversing cylinder 27, and a rotary screen 24 in contact with the impression cylinder 23. A transfer cylinder 54 in contact with the impression cylinder 23 is provided downstream of the rotary screen 24 in the rotating direction of the impression cylinder 23.

In the delivery unit 46, sprockets 35a and 35b, one of which contacts the transfer cylinder 54, are provided, and a delivery chain 36 is looped between the sprockets 35a and 35b.

Because of the above-described features, therefore, when single-sided printing is performed, the sheet S fed to the sheet feeding plate 21 is passed on to the transfer cylinder 51 via the swing arm shaft pregripper. Then, the sheet S accepted by the transfer cylinder 51 is passed on to the impression cylinder 30, and then supplied between the impression cylinder 30 and the gravure plate cylinder 31. At this time, ink is supplied from the ink reservoir 33 to the gravure plate cylinder 31 via the ink roller 32, and surplus ink adhering to non-image areas of the gravure plate cylinder 31 is removed by the doctor 34. Then, the ink is transferred from recessed image areas, which are lower in height than the non-image areas of the gravure plate cylinder 31, to the one surface of the sheet S held by the impression cylinder 30, whereby gravure printing is done.

Then, the sheet S subjected to gravure printing is passed on to the transfer cylinder 53 via the transfer cylinder 52, and has the one surface dried by irradiation from the UV lamps 29a, 29b′ and 29c. Then, the dried sheets is supplied between the attraction cylinder 26 and the reversing cylinder 27, and reversed by the reversing unit 44. As a result, the reversed sheet S is transported, with the other surface thereof being pointed outward on the reversing cylinder 27. Then, the sheet S is passed on to the impression cylinder 23. The sheet S accepted by the impression cylinder 23 is supplied between the impression cylinder 23 and the rotary screen 24. At this site, ink pushed out through the small holes of the hollow cylinder is transferred to the sheet S, whereby screen printing is done on the one surface of the sheet S. Then, the sheet S subjected to screen printing is passed on to the delivery chain 36, and then delivered.

When double-sided printing is performed, on the other hand, the sheet S supplied between the attraction cylinder 26 and the reversing cylinder 27 is not reversed in the reversing unit 44. That is, the sheet S is not reversed by the reversing unit 44, but is transported, with the one surface thereof being pointed outward on the reversing cylinder 27, and is then passed on to the impression cylinder 23. The sheet S accepted by the impression cylinder 23 is supplied between the impression cylinder 23 and the rotary screen 24. At this site, the ink pushed out through the small holes of the hollow cylinder is transferred to the sheet S, whereby screen printing is done on the other surface of the sheet S. Then, the sheet S subjected to screen printing is passed on to the delivery chain 36, and then delivered.

The sheet-fed printing press according to the present invention, therefore, can print the one surface of the sheet S (single-sided printing) and/or both of the one surface and the other surface of the sheet S (double-sided printing) in one pass when performing printing on the sheet S by gravure printing and screen printing. Consequently, an operator need not perform a reversing operation for or registration of the sheet S between the gravure printing unit 42 and the screen printing unit 45. Thus, the operating efficiency can be improved. Moreover, the gravure printing unit 42 and the screen printing unit 45 can be combined, so that a saving in the space required for the machines can be achieved.

The present invention, as described above, can be applied to a combined sheet-fed printing press for performing intaglio printing and stencil printing on a sheet.

The invention thus described, it will be obvious that the same may be varied in many ways. In the above-described embodiments, gravure printing is disclosed as an example of intaglio printing, but engraved intaglio printing may be used. Also, screen printing is disclosed as an example of stencil printing, but mimeographing may be used. Furthermore, the attraction cylinder is disclosed as the transport cylinder which opposes the reversing cylinder on the side upstream of the reversing cylinder in the transport direction of the sheet to hold the leading end of the sheet transported from the first printing unit. However, the transport cylinder may be an impression cylinder or a transfer cylinder. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.

Claims

1. A sheet-fed printing press, comprising: a first printing unit for printing one surface of a sheet being transported;a drying device, provided downstream of the first printing unit in a sheet transport direction, for drying the one surface of the sheet printed by the first printing unit;a second printing unit, provided downstream of the drying device in the sheet transport direction, for performing printing on the sheet dried by the drying device; anda reversing device, provided between the drying device and the second printing unit, for switching between double-sided printing in which another surface of the sheet on a side opposite to the one surface of the sheet printed by the first printing unit is printed by the second printing unit, and single-sided printing in which the sheet printed on by the first printing unit is reversed, and the one surface of the reversed sheet is printed by the second printing unit, andwherein the first printing unit is one of a stencil printing unit and an intaglio printing unit, and the second printing unit is another of the stencil printing unit and the intaglio printing unit.

2. The sheet-fed printing press according to claim 1, wherein the stencil printing unit comprises an impression cylinder for transporting the sheet, and a stencil printing cylinder, provided above the impression cylinder, for performing printing on the sheet being transported, andthe intaglio printing unit comprises an impression cylinder for transporting the sheet, and an intaglio printing cylinder, provided below the impression cylinder, for performing printing on the sheet being transported.

3. The sheet-fed printing press according to claim 2, wherein the stencil printing cylinder is a rotary screen.

4. The sheet-fed printing press according to claim 2, wherein the intaglio printing cylinder is a gravure plate cylinder.

5. The sheet-fed printing press according to claim 1, wherein the reversing device is equipped with a reversing cylinder which accepts and grips a rear end of the sheet transported from the first printing unit, with a leading end of the sheet being held, thereby reversing the sheet, or which accepts and grips the leading end of the sheet transported from the first printing unit, with the leading end of the sheet being held, thereby not reversing the sheet.

6. The sheet-fed printing press according to claim 5, further comprising: a transport cylinder which opposes the reversing cylinder on a side upstream of the reversing cylinder in the sheet transport direction to hold the leading end of the sheet transported from the first printing unit.

7. The sheet-fed printing press according to claim 6, wherein the transport cylinder is an attraction cylinder.

8. The sheet-fed printing press according to claim 6, wherein the drying device opposes the transport cylinder.

9. The sheet-fed printing press according to claim 1, wherein the stencil printing unit performs screen printing.

10. The sheet-fed printing press according to claim 1, wherein the intaglio printing unit performs gravure printing.