Keyless lithography with single printing fluid

• US 5,372,067 A
• Filed: 08/11/1993
• Issued: 12/13/1994
• Est. Priority Date: 04/25/1991
• Status: Expired due to Term

• Current Assignee: Goss International Corporation (City of Shanghai)
• Original Assignee: Rockwell International Corporation
• Inventors: Doyle, deceased, Frank J.
• Primary Examiner(s): Burr, Edgar S.
• Assistant Examiner(s): Funk, Stephen R.
• Application Number:
  US08/105,486
• Time in Patent Office: 489 Days
• Field of Search: 101/450.1, 101/451, 101/452, 101/148, 101/350
• US Class Current: 101/148
• CPC Class Codes: B41F 7/36 Inking-rollers serving also to apply ink repellants

Abstract

Keyless lithographic printing system with single printing fluid. A lithographic printing press has a blanket cylinder (101) and a plate cylinder (102) with a printing plate (100) mounted thereon, a form roller system (103) having at least one form roller rotationally contacting the plate cylinder (102), a printing fluid supply system for supplying a controlled composition of printing fluid to the form roller system (103). A reservoir system (110, 124, 126, 107, 128) is provided for containing the printing fluid, the printing fluid being a predetermined composition of dampening water and ink. A pickup roller (106) removes the printing fluid from the reservoir system, the pickup roller (106) having an oleophilic and hydrophobic surface. A drum roller (104) transfers the printing fluid to the form roller system (103), the drum roller (104) having an oleophilic and hydrophobic surface and interfacing with the form roller system (103). A roller (105) forms a uniform thin film of printing fluid on the surface of the drum roller (104), the roller (105 ) for forming the uniform thin film being in rotational contact with the drum roller (104) and the pickup roller (106). A printing fluid removal device (108) is provided for removing at least a portion of printing fluid from at least one of the surface of the drum roller (104) and a surface of the at least one form roller in the form roller system (103).

Claims

1. In a lithographic printing press having a blanket cylinder, a plate cylinder with a printing plate mounted thereon and a form roller system having at least one form roller for rotational contact with the plate cylinder, the improvement being a printing fluid supply system, comprising:

a reservoir containing printing fluid composed of a predetermined composition of dampening water and ink, said reservoir being the only supply of dampening water for the plate cylinder;

a pickup roller for removing said printing fluid from said reservoir, said pickup roller having an oleophilic and hydrophobic surface;

a wear resistant noncelled drum roller having an oleophilic and hydrophobic surface in rolling contact with the form roller system for transferring the printing fluid to the form roller system; and

means for forming a uniform thin film of printing fluid on said surface of said wear resistant noncelled drum roller including a transfer roller in rotational contact with both said drum roller and said pickup roller.

2. The printing fluid supply system of claim 1 including means for removing at least a portion of the printing fluid from the surface of the drum roller.

3. The printing fluid supply system according to claim 2, wherein said printing fluid removal means contacts said surface of said drum roller on a return side of said drum roller and wherein the printing fluid removed is returned to said reservoir.

4. The printing fluid supply system of claim 3 in which the printing fluid removal means on the return side of the drum roller is the only printing fluid removal means in contact with the drum roller which returns the printing fluid to the reservoir.

5. The printing fluid supply system of claim 2 in which the printing fluid removal means includes a single scraping blade in contact with a return side surface of the drum roller and in which

the single scraping blade is the only means for removing the printing fluid from the drum roller and returns the printing fluid to the reservoir.

6. In a lithographic printing press having a blanket cylinder, a plate cylinder with a printing plate mounted thereon and a form roller system having at least one form roller for rotational contact with the plate cylinder, the improvement being a printing fluid supply system, comprising:

a reservoir containing printing fluid composed of a predetermined composition of dampening water and ink, said reservoir being the only supply of dampening water for the plate cylinder;

a wear resistant noncelled drum roller having an oleophilic and hydrophobic surface in rolling contact with the form roller system for transferring the printing fluid to the form roller system; and

means for removing at least a portion of the printing fluid from said surface of said drum roller, said printing fluid removal means including a member contacting said surface of said drum roller only on a return side of said drum roller and said contacting member being the only means for removing the printing fluid from the drum roller and returning the printing fluid to said reservoir.

7. The printing fluid supply system of claim 6 including means for removing the printing fluid from the reservoir including a pickup roller with an oleophilic and hydrophobic surface.

8. The printing fluid supply system of claim 7 including means for forming a uniform thin film of printing fluid on the surface of the drum roller including a transfer roller in rotational contact with both the drum roller and the pickup roller.

9. The printing fluid supply system of claim 8 in which the member includes a single scraping blade in contact with the return side of the drum roller.

10. In a lithographic printing press having a blanket cylinder and a plate cylinder with a printing plate mounted thereon, the improvement being a printing fluid supply system, comprising:

a reservoir containing printing fluid of a predetermined composition of dampening water and ink, said reservoir being the only supply of dampening water for the plate cylinder;

a form roller system having at least one form roller for rotational contact with the plate cylinder;

a drum roller having an oleophilic and hydrophobic surface in rolling contact with the form roller system for transferring the printed fluid to the form roller system;

means for transferring a uniform thin film of the printing fluid from the reservoir to the drum roller; and

means for removing at least a portion of the printing fluid from a surface of said at least one form roller in said form roller system, said printing fluid removal means contacting a surface of said at least one form roller in said form roller system on a return side thereof and the printing fluid removed being returned to said reservoir.

11. The printing fluid supply system of claim 10 in which the printing fluid removal means includes a single scraping blade in contact with the return side of the form roller and being the only means for removing the printing fluid from the form roller which returns the printing fluid to the reservoir.

12. The printing fluid supply system of claim 11 in which the printing fluid transferring means includes means for removing the printing fluid from the reservoir including a pickup roller with an oleophilic and hydrophobic surface.

13. The printing fluid supply system of claim 12 in which the printing fluid transferring means further includes means for forming the uniform thin film of printing fluid on the surface of the drum roller including a transfer roller in rotational contact with both the drum roller and the pickup roller.

14. In a lithographic printing press having a blanket cylinder, a plate cylinder with a printing plate mounted thereon and a form roller system having at least one form roller for rotational contact with the plate cylinder, the improvement being a printing fluid supply system, comprising:

a reservoir containing printing fluid composed of a predetermined composition of dampening water and ink, said reservoir being the only supply of dampening water for the plate cylinder;

a pickup roller for removing said printing fluid from said reservoir, said pickup roller having an oleophilic and hydrophobic surface;

a drum roller having an oleophilic and hydrophobic surface in rolling contact with the form roller system for transferring the printing fluid to the form roller system;

means for forming a uniform thin film of printing fluid on said surface of said drum roller including a transfer roller in rotational contact with both said drum roller and said pickup roller; and

means for removing at least a portion of the printing fluid from a surface of the at least one form roller in the form roller system.

15. The printing fluid supply system according to claim 14, wherein said printing fluid removal means contacts said surface of the at least one form roller in said form roller system on a return side thereof and wherein the printing fluid removed is returned to said reservoir.

16. The printing fluid supply system of claim 14 in which the printing fluid removal means includes a single scraping blade in contact with a return side surface of the at least one form roller and being the only means for removing the printing fluid from the form roller which returns the printing fluid to the reservoir.