JP5064730B2 - Surface with a micro-overhang to guide the substrate - Google Patents

Description

  The present invention relates to a surface for guiding a printing material, which is provided with a micro overhanging portion that comes into contact with the printing material with printing ink.

  Furthermore, the invention relates to a printing press cylinder, in particular an impression cylinder.

  Furthermore, the present invention relates to a printing machine, particularly a sheet-fed offset printing machine used for double-sided printing.

  When printing on both sides of a substrate in one-sided printing, i.e. in a single pass through a printing press, the substrate is already printed after one reversal of this substrate, and in some cases still sufficiently It will be located in each surface of the impression cylinder of a back surface printing unit in the surface which is not dried. When passing through the printing gap of the back surface printing unit, the printing material is pressed against each surface of the impression cylinder under pressure. In order to avoid ink acceptance by the surface of the impression cylinder, surface contamination and subsequent ink back-trapping on the substrate, the surface is usually structured, thereby reducing the surface coverage and / or Alternatively, an ink-repellent coating layer is provided on the surface.

  German Offenlegungsschrift 4 207 119 describes a printing cylinder jacket profile for guiding a sheet used in an impression cylinder in a sheet printing machine used for double-sided printing. In this case, the profile of the printing cylinder jacket is a cylindrical shape which is arranged in a plane parallel to the printing cylinder axis and perpendicular to the printing cylinder axis, forming a counter-pressure surface, distributed statistically uniformly. It consists of the overhanging part. In this case, the printing cylinder jacket profile may be etched in the chrome coating layer of the impression cylinder. Wetting of the printing cylinder jacket profile with a coating layer or liquid has not been proposed.

  German Offenlegungsschrift 10209297 describes a surface for a cylinder for guiding sheets. This surface comes into contact with the printing ink and in this case can become contaminated. In this case, the support layer on the surface has pores. A monolayer or multilayer functional coating layer reaches the inner chamber of the pores. The functional coating layer applied in liquid form enters the pores before being cured by drying and subsequent thermal aftertreatment. No additional wetting of the surface by the liquid has been proposed.

  German Offenlegungsschrift 19 195 393 describes a surface structure for guiding a substrate, which is preferably used for a printing cylinder or its jacket in double-sided printing. This surface structure comprises overhanging structural elements distributed substantially uniformly and statistically and correspondingly arranged structural valleys. In this case, the substrate is supported by the structural element. In this case, the structural element itself is formed with a number of recesses that form a non-uniform network of gaps, grooves and cracks, whereby each supporting surface of a structural element has a number of small surfaces. In this way, the adhesion of the printing ink is reduced. No wetting of the surface structure with a covering layer or liquid has been proposed.

  German patent application 2127021 describes a printing cylinder. This printing cylinder follows the reversing device. Each surface of the printing cylinder is provided with an ink repellent layer. In this case, a moisture film is proposed as the ink repellent layer. This moisture film is deposited on the surface of the printing cylinder from the supplied air with moisture. No structuring of the surface of the printing cylinder, in particular microstructuring, has been proposed.

  European Patent 0873867 describes a single-sided printing machine. In this single-sided printing machine, the lacquer application to the opposite side of the sheet to be printed by the single-sided printing method is performed over the entire surface or in part via the surface of the lacquer cylinder / impression cylinder. Since a given single-sided printing machine is described, there is no problem of ink adhesion to the surface of the lacquer cylinder / impression cylinder, and accordingly no corresponding action has been proposed.

  German Offenlegungsschrift 10 227 758 describes a sheet-fed rotary printing press with a coating unit. The coating unit applies a strong ink-repellent coating liquid to the surface of the impression cylinder. In this case, the coating liquid is fixed by drying, and in the fixed state, forms a stationary layer that is ink repellent and / or prevents abrasion. When the coating layer is exhausted, repeated coating can be performed by the coating unit. However, a structured surface, in particular a microstructured surface, of the impression cylinder has not been proposed. No additional wetting of the surface by the liquid has been proposed.

  German patent application DE 197 16 424 describes a cylinder with a jacket surface arranged behind a reversing device. The jacket surface has an immobile silicone rubber layer. This silicone rubber layer is formed as an uninterrupted and consistently extending surface. The silicone rubber layer avoids ink sticking to the cylinder surface. There is no suggestion of structuring the surface of the cylinder or the deposited layer, in particular microstructures, or wetting with liquids.

Known prior art solutions also do not always guarantee satisfactory print quality, and in particular it is important to prevent the occurrence of so-called “white spots” (see FIG. 3 and the description of affiliation). There is a constant desire for an improved surface to guide.
German Patent Application Publication No. 4207119 German Patent Application Publication No. 10209297 German Patent Application Publication No. 19515393 German Patent Application No. 2127021 European Patent No. 0873867 German Patent Application No. 10227758 German Patent Application Publication No. 19716424

  Therefore, an object of the present invention is to improve the surface that guides the substrate to be printed so that the quality of the printed image can be improved.

  Another or alternative problem of the present invention is to improve the surface that guides the substrate to prevent the occurrence of so-called “white spots”.

  In order to solve this problem, in the first configuration of the present invention, the surface is provided with at least a partly fluid auxiliary agent.

  Furthermore, in order to solve the above-mentioned problems, the printing press cylinder of the present invention is provided with the surface for guiding the printed material.

  Furthermore, in order to solve the above-described problems, the printing machine according to the present invention is provided with the surface for guiding the printed material.

  Further advantageous configurations and embodiments of the invention are described in the dependent claims.

  According to the present invention, a micro-overhang portion and a fluid auxiliary agent are provided. This advantageously improves the quality of the printed image and in particular prevents the occurrence of so-called “white spots”. The so-called “white spots” generated by the micro-overhangs are closed again by the action of the fluidity aid or fluidity aid, thereby making it invisible in the printed image. Accordingly, the surprising result that the so-called “white spot” can be avoided by the cooperation of the micro overhang portion and the auxiliary agent, despite the provision of the micro overhang portion.

  By providing a micro-overhang, on the one hand the surface support is reduced and on the other hand a micro-surface roughness is provided which helps to guide the substrate, in particular to prevent relative movement with respect to the surface. The micro-overhanging portion that contacts the substrate can enter the substrate, or can penetrate the substrate, thus forming a shape connection. This better guides the substrate and better prevents relative movement to the surface which can lead to damage to the printed image.

  By providing a flowable auxiliary agent on the surface, advantageously, the printing ink melts at each point where so-called “white spots” may occur without the use of the present invention. In other words, the fluid auxiliary agent is transferred to the printing material at least at the contact point between the micro-overhang and the printing material, whereupon a so-called “white spot” is closed.

  The flowable adjuvant can be applied in a flowable state and is left on the surface, preferably in a flowable state. That is, it is advantageously an auxiliary that does not cure on the surface. For example, a predetermined liquid is applied, and this liquid is left in a liquid state on the surface. In this state, the liquid also reaches the substrate. In other words, the liquid auxiliary agent remains in a liquid state at least until it is transferred to the substrate by application on the surface.

  In the configuration optimized for improving the print image quality of the surface according to the present invention for guiding the substrate to be printed, mainly the circular top of the micro-overhang is provided with a fluidity aid. In this way, without using the present invention, the fluidity auxiliary agent appropriately reaches each portion where there is a risk of forming so-called “white spots”. Furthermore, it is advantageously avoided that more fluid auxiliary agents reach the surface printing surface of the substrate than is always necessary to avoid so-called “white spots”. In this way, further improvement in the quality of the printed image can be achieved.

  Another surface for guiding the substrate, which has been optimized for improving the quality of the printed image, has at least some of the tops of the at least one recess, each recess being a flowable auxiliary agent. Is characterized in that it is formed as a reservoir that stores at least for a short period of time and at least partially releases to the substrate. By providing the recess, it is possible to further improve the supply and storage or storage of the fluidity auxiliary agent to the circular top of the micro-extrusion part, and furthermore, the fluidity in a desired amount on the surface printing surface of the printing material. Appropriate transfer of adjuvants can be achieved.

  According to another configuration of the invention, the flowable auxiliary agent is a liquid auxiliary agent, in particular an auxiliary agent different from the printing ink, lacquer or dampening medium, the auxiliary agent diluting the printing ink and / or Alternatively, the drying of the printing ink may be delayed and / or extended. The fluidity aids used according to the invention having the above-mentioned action with respect to dilution or drying of the printing ink are preferably used to prevent and / or close the occurrence of so-called “white spots” as a result of the welding of the printing ink. Subsidize.

  Another surface for guiding the substrate, optimized for improved print image quality, is characterized in that the surface is provided with an ink-repellent coating layer at least partly, in particular between the micro-overhangs. It is attached. By providing the ink-repellent coating layer according to the present invention, it is advantageous that the printing ink adheres to the surface from the surface printing surface of the substrate, resulting in a decrease in print image quality due to reverse trapping on the subsequent substrate. Can be prevented. In addition, the ink-repellent coating layer between the micro-overhangs allows the proper application of the flowable adjuvant to be applied to the top of the micro-overhang as long as the flow auxiliary has similar properties to the ink. In this way, the application of the flowable adjuvant is simplified only in the region of the top of the circle.

  Not only printer cylinders, especially impression cylinders, but also printing machines, especially sheet offset printing machines used for duplex printing, can be characterized by a surface for guiding the substrate, as described above with respect to the present invention.

Furthermore, in contact with the substrate provided with a printing ink, comprising a micro-overhangs with cracks or pores, surfaces for guiding the printing substrate is used for applying the flowable adjuvants in the substrate . In this case, the cracks or pores provided in the micro-overhang can advantageously serve as a reservoir for the flowable auxiliary agent and thus flow in the desired amount to the surface printing surface of the substrate. Appropriate transfer of sex adjuvants can be facilitated.

  A printing method according to the invention in which a substrate with printing ink on a first surface contacts a surface having a micro-overhang on the first surface is characterized by applying a flowable adjuvant to the surface. It has been.

It by the present invention, advantages as described above with respect to the surface according to the invention for guiding the printing medium is obtained.

According to chromatic Convenient embodiments, the flowability of the auxiliary agents, mainly applied only to the circular top of the micro-overhang. This also allows an appropriate transfer of the flowable auxiliary agent only at the problematic contact points of the surface to the substrate.

  In the following, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  In FIG. 1, a sheet offset printing machine 100 including one sheet feeding device 102, four offset printing units 104, 106, 108, 110, and one sheet discharging device 112. Is shown. The printing press 100 can be operated in a duplex printing mode. That is, the first printing units 104 and 106 print on the first side of the printing sheet 114, and the subsequent printing units 108 and 110 print on the second side of the printing material 114. For this purpose, the substrate 114 is reversed by the reversing device 116.

  In both the impression cylinders 118 and 120 placed behind the reversing device 116, the printing material 114 is positioned on the first printed surface, and each printing gap of the printing units 108 and 110 is under pressure. Pass through. Inhibition of ink adhesion and ink deposition on the surfaces of the impression cylinders 118, 120 guiding the substrate, and relative movement between the substrate 114 and the surfaces of the impression cylinder, guiding the substrate. For this purpose, these cylinders are provided with a micro-rough ink-repellent surface 122. This surface 122 can advantageously be formed by one or more respective torso jackets.

  FIG. 2 shows a surface 122 for guiding the substrate. The surface 122 has a support 200 made of, for example, a stainless steel sheet with a thickness of about 0.24 mm to about 0.27 mm. This support 200 comprises a micro-roughness coating layer 202 having a microstructure, in particular an oxide ceramic layer made of aluminum or titanium, for example plasma sprayed. The micro-roughness coating layer 202 includes an ink-repellent coating layer 204, for example, silicone, at least in the recesses of the micro-roughness coating layer 202.

  The substrate 114 is guided by a surface 122 that guides the substrate during transport, that is, during rotation of the impression cylinders 118, 120. In this case, the micro overhang portion 206 prevents the relative movement between the sheet 114 and the surface 122 that guides the substrate to be printed, and thus damage to the surface print image.

  In FIG. 3, the full tone surface 300 of the printed product is shown enlarged. A small bright spot 302 can be recognized on the full tone surface 300. This location 302 can disturb the printed image and damage print quality. A bright spot 302 (so-called “white spot”) is generated by contact between the micro overhang portion 206 and the substrate 114. In this case, the ink dissociates from the substrate 114 at the contact point. Accordingly, a bright spot 302 having no ink or having less ink than the surrounding area is generated at the contact point between the substrate 114 and the micro-rough surface 122.

  FIG. 4 is an enlarged view of the portion A shown in FIG. The support 200 is covered with a coating layer 202 having a micro roughness. The thickness of this microroughness coating layer is advantageously in the range between about 40 μm and 70 μm. The micro-roughness coating layer has a micro overhang. This micro overhang has an average height in the range of about 5 μm to about 30 μm. The surface roughness (ie RZ value) of the micro-roughness coating layer is advantageously in the range of about 20 μm to about 40 μm. The diameter of the microoverhang is advantageously in the range of about 10 μm to about 50 μm.

  In FIG. 4, how the micro-overhang 206 is pushed into the substrate 114 with the printing ink 400 and the substrate 114 is removed from the surface 122, and then a bright spot 302, the so-called “white spot” is surface printed. It can be recognized whether or not a recess 402 can be formed in the image.

  The ink-repellent coating layer 204 provided on the micro-roughness coating layer 202 prevents ink reception by the surface 122 that guides the printed material at least in the region between the micro-extrusions 206. In this case, the micro overhang portion having a slight height may be covered with the ink-repellent coating layer 204.

  In order to prevent damage to the surface printed image and in particular to prevent the occurrence of bright spots 302, according to the invention, the surface 122 guiding the substrate to be printed is provided at least in part with a flowable auxiliary agent 404, It has been proposed to be wetted, for example by roller application or spraying.

  As shown in FIG. 1, a coating device 124 is used to apply the fluid auxiliary agent 404 to the surface 122 that guides the substrate. The coating device 124 applies a flowable auxiliary agent 404 in a desired amount and at a desired location to the surface 122 that guides the substrate. The coating device 124 includes a coating roller 126 as illustrated. The application can take place permanently or in a controlled manner, preferably in front of each printed sheet, before it is located on the surface 122 that guides the printed material. . In addition, the application roller 126 can be cleaned or cleaned by scraping. Alternatively, for example, a spraying device that is permanently controlled or timing controlled may be provided.

  The flowable adjuvant 404 may be, for example, an ink dilutable liquid and / or a liquid that delays and / or prolongs ink drying. Alternatively, printing ink may be used.

  Suitable ink-dilutable liquids are, for example, liquids usually used to reduce the stickiness of printing inks (for example “Schmidt Druckfarben” brotherhood product Paste 900) or pressure oil. As a liquid that delays and / or prolongs ink drying, for example oil is suitable, but also oleophobic liquids are suitable.

  According to the invention, the fluidity aid 404 reaches the surface of the substrate 114 by transfer from the surface 122 guiding the substrate, at least at the point of contact of the micro-extrusion 206, and is advantageously bright. Generation | occurrence | production of the location 302 is blocked | prevented. The action of the flowable auxiliary agent 404, which is ink dilutable and / or prolongs and / or delays ink drying, can be achieved during or after separation of the sheet 114 from the surface 122 guiding the substrate to be printed. This is accomplished by being able to fill the contact area again with printing ink before drying 400, thus effectively preventing the occurrence of bright spots 302. In other words, the bright spots 302 are reclosed by printing ink melts that have been diluted or changed with respect to ink drying.

  When the elastic application roller 126 is used, the fluid auxiliary agent 404 wets only the circular top portion 406 (mounting point or mounting surface) of the micro-extrusion portion 206 by appropriately adjusting the pressure applied to the pressure drum 118; In this way, it can be achieved that the micro protruding portion 206 is appropriately brought into contact with the substrate 114. As long as the flowable auxiliary agent 404 has a composition similar to that of the ink, the auxiliary agent 404 is not accepted by the ink-repellent coating layer 204. This aids proper wetting of the micro-overhang 206.

  Advantageously, the pressure is selected so that the micro-overhang is pushed mainly against the elastic surface of the application roller 124 as much as it is pushed into the substrate during the printing process.

  FIG. 5 shows another configuration of the surface 122 according to the invention for guiding the substrate. In this case, the circular top portion of the micro overhang portion is removed or formed as a recess. The micro-extrusion part 500 has a removed circular top part and thus a substantially flat mounting surface 502. The mounting surface 502 includes a fluid auxiliary agent 404. On the other hand, the micro overhang portion 504 has a recess 506 in the region of the top of the circle. The recess 506 is provided with a fluid auxiliary agent 404 and is formed to some extent as a reservoir for the fluid auxiliary agent 404. The recesses can be provided in the region of the top of the micro-overhang 504 as one or more cracks or pores that are created in the manufacturing process.

  Alternatively, the concave portion 506 may be processed into the micro overhang portion 504. For this purpose, the surface 122 that guides the substrate can be pressed towards the opposite surface of the same micro roughness. However, this opposing surface has a larger number of micro-projections and a greater hardness per unit area, so that the micro-projections on the opposing surface allow the micro-projections on the surface 122 to guide the substrate to be printed. Molded into the overhang.

  FIG. 6 shows an alternative configuration of the printing press according to the present invention to the configuration shown in FIG. In this configuration, the application device 124 preferably comprises a simple ink and dampening device 600, a rubber blanket cylinder 602 and a plate cylinder 604. Such a coating device can produce ink application over the entire surface or ink application over a partial surface (eg only within the full-tone surface) or even image-related ink application. Through the pressure between the rubber blanket cylinder 602 and the impression cylinder 118, ink application can be achieved only in the area of the impression cylinder at the top of the micro-overhang of the surface guiding the substrate. The application device 124 can apply not only single color ink but also multicolor ink when a plurality of inking devices and a plate cylinder are used.

1 shows a printing press according to the invention. It is a figure which shows the surface by this invention which guides to-be-printed material. It is an enlarged view of a full-tone surface provided with so-called “white spots”. FIG. 3 is an enlarged view of a portion A of the surface according to the present invention for guiding a substrate shown in FIG. 2. FIG. 6 is an enlarged view of another configuration of a surface according to the present invention for guiding a substrate. It is a figure which shows another structure of the printing machine by this invention.

Explanation of symbols

  100 sheet offset printing machine, 102 sheet feeding device, 104, 106, 108, 110 offset printing unit, 112 sheet discharge device, 114 substrate, 116 reversing device, 118, 120 impression cylinder, 122 Surface, 124 coating device, 126 coating roller, 200 support, 202 coating layer, 204 coating layer, 206 micro-extrusion part, 300 full tone surface, 302 places, 400 printing ink, 402 recess, 404 auxiliary agent, 406 circle top part, 500 Micro overhang part, 502 Mounting surface, 504 Micro overhang part, 506 Concave part, 600 Ink / dampening device, 602 Rubber blanket cylinder, 604 Plate cylinder

Claims (6)

On a surface for guiding a substrate, comprising a support (200) provided with a microroughness coating layer (202) having a micro-overhang (206) in contact with the substrate (114) with printing ink. The surface (122) is provided with an ink-repellent coating layer (204) between the micro-overhangs (206).
A flowable auxiliary agent (404) is provided, the auxiliary agent (404) being a liquid auxiliary agent, which dilutes the printing ink and / or delays drying of the printing ink and / or Or extended,
Since the auxiliary agent (404) is not accepted by the ink-repellent coating layer (204), the round top portion (406) of the micro-overhang portion (206) that is not covered by the ink-repellent coating layer (204 ). However, the surface which guides a to-be-printed object provided with the micro overhang | projection part characterized by not providing the fluid auxiliary agent (404).   At least some of the crests (406) have at least one respective recess (506) as a crack or pore in the production of the micro-roughness coating layer (202), each recess (506) being The surface of claim 1, wherein the surface is formed as a reservoir containing a flowable adjuvant (404). In the printing machine cylinder,
A printing press cylinder according to claim 1 or 2, characterized in that it is provided with a surface (122) for guiding the substrate.   The printing press cylinder according to claim 3, wherein the printing press cylinder is an impression cylinder. In the printing press
Printing machine according to claim 1 or 2, characterized in that it is provided with a surface (122) for guiding the substrate.   The printing machine according to claim 5, wherein the printing machine is a sheet-fed offset printing machine used for double-sided printing.