CS207513B1 - Sheet rotary printing machine - Google Patents

Abstract

A rotary sheet printing machine provided with a selection mechanism, e.g. transfer and turning drum 10, between two impression cylinders to allow the second impression to be made on either side of a sheet bearing a first impression, includes a drying mechanism arranged between the first impression zone and the second impression cylinder. Preferably, drying equipment 12 is positioned adjacent the first impression cylinder 5 downstream of the first impression zone but upstream of the drum 10. <IMAGE>

Description

(54) Sheet-fed rotary printing press

BACKGROUND OF THE INVENTION The present invention relates to a sheet-fed rotary printing press of aggregate construction with an optional printing and reverse printing machine.

When using optional printing and reverse printing devices, some special features arise from the face printing operation. The printed sheet is adjacent to the printing and printing device 8 with the printed side facing the nearest printing cylinder and there are sticking problems (dampening the printing cylinder with ink), thereby causing loss of color value or changes in color value.

To prevent sticking, the print rollers must either be washed at short intervals, or they should be designed to prevent sticking as much as possible (DAS 1 258 873).

a freshly printed sheet during the inverting process comes into contact with the sheet guide arranged below the printing cylinder and transfer roller, and there are wiping problems. · Devices are also known to prevent wiping (German Pat. No. 125 394).

In printing and backing devices which operate according to the principle of inverting the back edge and the sheet is taken over by the inverting device from the closed surface of the pre-printing cylinder, problems arise which are caused by the fact that the sheet is due to adhesive

207 51.3

207 $ 13 • Do not release the loose from the pre-biased printing cylinder^ythey must create a trimming^rela^tivná in^E!to^E 0I! Y>^for poilpwu uⁱⁿolⁿO^vawhose^ho poc^hO^du are therefore onM^uvolňo sheet feeder (German Pat. No. 101 '337).

Finally, drying devices are known which dry the sheet before unloading (DOS 2 402 435) or between printing devices in a separate aggregate (German Pat. No. 123 071). The amount of p ^{oužitých ERI} zen ^I to solution ^{p p} s roblámů use device lic ^P ro ^ck and ^ru BNI printing makes high technical demands, the space requirement for these devices is extremely high.

The aim of the invention is to reduce the technical costs for solving the problems that arise and the operation of the printing press for the installation of these devices while improving the print quality.

SUMMARY OF THE INVENTION The object of the present invention is to provide a single device which optimally solves the adhesion problems of wiping the sheets.

According to the invention, the object is achieved by arranging a drying device on the path of the sheet between the printing contact area of the printing device, the upstream device for any face and reverse printing and the sheet transfer point for the printing cylinder downstream of the selectable and reverse printing device. The drying device is arranged in the area of the sheathed area covered by the sheet during face-up printing, the printing cylinder, the front-end device for the liner and the reverse printing. In contrast to the ink-bearing rollers, the drying device is covered with insulating sheets with the dyeing rollers. Printing roller cooperating with a drying device is provided chladícfa strojím ^p. In the casing ^Juice b ^{s pl} ochy junket weighing ^l ce, - having olupracuj ^{p i,} and a drying device are arranged in an air suction device.

Problems that arise with the operation of the printing and printing device are solved by one single device. The ink n of the freshly printed sheet is so dried that it cannot be wiped off either on the sheet guide or with the printing cylinder closest to the next printing unit. Due to the accumulation of heat produced within the boundaries which are controllable according to the invention, the adhesion forces which hold the sheet on the printing cylinder are removed and the sheet is released from the printing cylinder. This is achieved by the known drying device, which was first efficiently arranged on the sheet-coated honeycomb surface of the printing cylinder in the inventive manner, despite the notion that drying is not possible in printing machines due to heating problems. .

V 'next to' the invention is further explained on an exemplary embodiment, wherein: FIG. 1 ^sr cho ^{above T} i ^and k ^of the above rotational ^t swarm with a printing device for the reverse face a- ^ ⁱ - printing, FIG. 2 is a detail of the inventive device of FIG.

Sheet-fed rotary printing machine - aggregate construction consists of loader χ, loading printing device 2, a number of successive printing devices J, which consist of unloading unit 4 »

Each printing device has a printing cylinder 4, as well as a mold roller 6, and using an offset printing method, the offset cylinder 2 · The mold roller 6 works together with the dyeing device 8 and the dampening device 2 ·

A transfer roller 10 or an optional face-and-face printing device 11 is provided between the printing devices, which is formed as an inverting roller. This device is formed in a known manner; acts as a transfer roller after conversion to printing.

Between the printing devices there is arranged a drying device 12 acting on the sheet-coated honeycomb surface of the printing cylinder 2, the upstream printing and printing device 11.

This drying device 12 is designed as an ultraviolet drying device due to the need for a flat construction at this location. The drying device 12 is obscured by the insulating sheets 13 relative to the color guiding rollers 6, 2 and the dyeing rollers. The printing cylinder 5 is provided with a cooling device 14, and air extraction devices 15 are further provided in the region of the drying device 12, thereby preventing negative effects on the printing result due to the detrimental heat build-up.

The color of the freshly printed side of the sheet 16, which is adjacent to the printing cylinder 6, by the drying device, is so dried that it cannot be wiped off on the sheet guide 17.

For this reason, the sheet guide device 17 need not be designed as an expensive sheet guide device without wiping.

In particular, the sheet release device provided in the pressure cylinder in front of the face and reverse printing device 11 for the accumulation of heat used within certain limits is omitted.

Claims (5)

OBJECT OF THE INVENTION * ⁱ 1 «Aggregate structure printing rotary printing press with an optional printing or printing device, characterized in that it has a drying device (12) arranged on the sheet path between the printing contact area of the printing device, an upstream printing device (11) for the optional printing device and the printing device. and a sheet transfer point for the printing cylinder (5), downstream of the optional printing and printing device (11). Sheet-fed rotary printing press according to claim 1, characterized in that the drying device (12) is arranged in the area of the sheet-coated surface of the printing cylinder (5) of the pre-casting and rubbing device (11). Sheet-fed rotary printing press according to claim 1, characterized in that the drying device (12) is inclined against the barium-bearing rollers (6, 7) and the dyeing rollers (β) by insulating sheets (13). Sheet-fed rotary printing press according to claim 1, characterized in that the printing cylinder (5) cooperating with the drying device (12) is provided with a cooling device (14). Sheet-fed rotary pressure machine according to claim 1, characterized in that air extraction devices (1ЗД ·) are provided in the area of the surface of the printing cylinder (5) which cooperates with the drying device (12).