Plant and method for manufacturing corrugated board with an order change detector

A plant for producing corrugated board sheets;

• wherein the plant comprises:
• a single facer for producing a corrugated board web comprising a first web of flat paper and a web of fluted paper;
• a converting system for converting the corrugated board web into single sheets, each sheet having at least one printed image;
• the corrugated board web containing sheets of a plurality of consecutive orders, the sheets of two consecutive orders of said plurality of consecutive orders differing from each other in the at least one printed image;
• a visual inspection system comprising at least one visual inspection unit provided upstream of the converting system with respect to a feed direction of the corrugated board web, wherein the visual inspection unit is adapted to detect the at least one printed image printed on the corrugated board web when the corrugated board web, fed along the plant for producing corrugated board sheets, passes in front of the visual inspection unit;
• a control system adapted to control the converting system;
• wherein the control system comprises a lookup table containing, for each order, of said plurality of consecutive orders, associated with a respective image of said at least one printed image, information for setting the converting system to produce said order;
• so that the control system sets the converting system for producing a subsequent order before the image associated with the subsequent order arrives in the converting system, when, through the visual inspection unit, the passage of the at least one printed image associated with the subsequent order is detected.

A method for producing corrugated board sheets, comprising steps as follows:

• producing a corrugated board web comprising at least a flat paper web and a fluted paper web;
• wherein the flat paper web has at least one printed image;
• wherein the corrugated board web contains sheets of subsequent orders, each of said subsequent orders having at least one printed image different from the at least one printed image of the previous order;
• feeding the corrugated board web along a feed path in front of a visual inspection unit adapted to detect the at least one printed image;
• feeding the corrugated board web through a converting system downstream of the visual inspection unit, and converting the corrugated board web into single corrugated board sheets;
• when the visual inspection unit detects a change in the at least one printed image of a subsequent order with respect to the at least one printed image of a previous order, collecting, from a look-up table, information associated with the at least one printed image printed on the corrugated board web and associated with the subsequent order, so as to set the converting system to produce the subsequent order before the corrugated board web, containing the at least one printed image associated with the subsequent order, arrives in the converting system.