A screen printing machine for appropriately contact between a mask and a board, comprising: a mask-holding device configured to hold a mask; a board-positioning device configured to hold a board and to position the held board with respect to a mask held by the mask-holding device from below; a squeegee device configured to spread a cream solder with respect to the mask; a height-measuring device configured to measure the height of the mask and the board; a control device configured to control each device, and to calculate the thickness of a mask lower layer, integrally formed with the mask, based on the measurement values obtained from the height-measuring device; and an operation display device configured to input operation and to display calculation values from the control device, and the like.

There is described a process of measuring print-to-print register of a multicolour print (A-D) provided in an effective printed area (EPA) of the surface of printed material, which multicolour print (A-D) is formed on the printed material by means of one or more printing presses and includes at least a first pattern (A) and a second pattern (B) distinguishable from the first pattern (A), the effective printed area (EPA) being provided with a matrix arrangement of individual imprints (P) which are each provided with the multicolour print (A-D) and are repeated over the surface of the effective printed area (EPA) along a pattern of rows and columns. Measurement of an actual print-to-print register between the first and second patterns (A, B), as reflected on the printed material, is derived from processing and finding a correspondence between (i) at least one sample image (SI.sub.A, SI.sub.B) of the printed material covering at least a portion of the first and second patterns (A, B), and (ii) at least one corresponding reference image (RI.sub.A, RI.sub.B) generated using prepress design data of the first and second patterns (A, B). Furthermore, the process is repeated for multiple ones of the individual imprints (P) so as to derive a set of multiple measurements of the actual print-to-print register between the first and second patterns (A, B) at various imprint locations over the effective printed area (EPA), which set of multiple measurements is mapped into a corresponding print-to-print register map (M.sub.B-A, M.sub.C-A, M.sub.D-A, . . . ) that is representative of print-to-print register deviations at the various imprint locations. Also described is a measuring device for carrying out this process and a process of measuring and correcting print-to-print register of a multicolour print.

A can inspection device includes a rotation device rotating cans, an imaging device taking images of rotating cans, and an image processor processing taken images. The imaging device includes a first camera taking an image of an entire can and a second camera taking an image of an opening-side end portion of the can. The image processor includes an image inspection means for inspecting whether printing is performed properly as compared with a master image by using the image taken by the first camera, a density measurement means for measuring densities in designated positions for respective colors by using the image taken by the first camera, and a printing misalignment value measurement means for measuring misalignment values with respect to set positions of printing misalignment inspection marks printed on the opening-side end portion of the can for respective colors by using the image taken by the second camera.

A screen printer comprising: a board positioning device configured to convey and hold a board to a work position in the screen printer; a mask holding device configured to hold a mask above the work position; a squeegee device configured to spread a cream solder on a mask on the board; a correction device configured to correct a relative position between the board of the board positioning device and the mask of the mask holding device; a control device configured to acquire inspection data of a print state from a print inspection device provided inside or outside the screen printer and perform correction control on the correction device by a correction value corrected according to a deviation amount of printing based on the inspection data; and an input device configured to include an instruction input section that senses an inspection instruction operation of an operator and transmit, to the control device, an inspection data acquisition signal for acquiring the inspection data of the print state from the print inspection device based on an instruction operation of the operator to the instruction input section.

There is described a process of measuring print-to-print register of a multicolour print (A-D) provided in an effective printed area (EPA) of the surface of printed material, which multicolour print (A-D) is formed on the printed material by means of one or more printing presses and includes at least a first pattern (A) and a second pattern (B) distinguishable from the first pattern (A), the effective printed area (EPA) being provided with a matrix arrangement of individual imprints (P) which are each provided with the multicolour print (A-D) and are repeated over the surface of the effective printed area (EPA) along a pattern of rows and columns. Measurement of an actual print-to-print register between the first and second patterns (A, B), as reflected on the printed material, is derived from processing and finding a correspondence between (i) at least one sample image (SI.sub.A, SI.sub.B) of the printed material covering at least a portion of the first and second patterns (A, B), and (ii) at least one corresponding reference image (RI.sub.A, RI.sub.B) generated using prepress design data of the first and second patterns (A, B). Furthermore, the process is repeated for multiple ones of the individual imprints (P) so as to derive a set of multiple measurements of the actual print-to-print register between the first and second patterns (A, B) at various imprint locations over the effective printed area (EPA), which set of multiple measurements is mapped into a corresponding print-to-print register map (M.sub.B-A, M.sub.C-A, M.sub.D-A, . . . ) that is representative of print-to-print register deviations at the various imprint locations. Also described is a measuring device for carrying out this process and a process of measuring and correcting print-to-print register of a multicolour print.

A can decorator having a blanket wheel and a plurality inking stations. Each of one or more of the inking stations comprises a rotatable shaft geared to the blanket wheel, a print cylinder mounted on the shaft for rotation with the shaft during printing operations, and an adjustment mechanism for adjusting the angular position of the print cylinder on the rotatable shaft during set-up and for fixing the angular position for printing operations. There is further provided a rotary encoder for determining the angular position of the print cylinder relative to the rotatable shaft during set-up and for providing an electrical signal indicative of the angular position to an operator interface device.

A method for registering a printing press, said printing press including a plurality of printing stations each for printing a respective color-image on a web, each said printing stations being associated with a respective different color, at least two pairs of said printing stations being un-registered, the method includes the procedures of identifying at least two regions-of-interest in the image to be printed, each including a respective different pair of two partially overlapping color-images, acquiring an image of the common area on the web, for each region-of-interest, chromatically separating the acquired image to determine two monochrome images respective of each region-of-interest, for each region-of-interest registering the two monochrome images respective thereof, registering a monochrome image respective of one region-of-interest with a monochrome image respective of another region-of-interest and determining a registration correction for each printing station according to the registration between the monochrome images.

A method for checking the maintenance of register of printing images to be printed on two opposite sides of a printing material, in which the first side of the printing material is printed in a rotary printing press by a first printing unit cylinder, and in which the second side of the printing material, which lies opposite to first cite, is printed in the printing press by a second printing unit cylinder which interacts with the first printing unit cylinder. A printed image is printed by the first printing unit cylinder under the second printing unit cylinder. Afterwards, the printing material is printed in contact with the two interacting printing unit cylinders with the printing image, which is printed under the second printing unit cylinder, being printed onto the same side of the printing material together with an identical or a different printing image which is to be printed by the second printing unit cylinder during continuous printing of the rotary printing press. The printed images, which are printed together onto the same side of the printing material, are subsequently checked, with regard to their maintenance of register.

A method for checking the maintenance of register of printing images to be printed on two opposite sides of a printing material, in which the first side of the printing material is printed in a rotary printing press by a first printing unit cylinder, and in which the second side of the printing material, which lies opposite to first cite, is printed in the printing press by a second printing unit cylinder which interacts with the first printing unit cylinder. A printed image is printed by the first printing unit cylinder under the second printing unit cylinder. Afterwards, the printing material is printed in contact with the two interacting printing unit cylinders with the printing image, which is printed under the second printing unit cylinder, being printed onto the same side of the printing material together with an identical or a different printing image which is to be printed by the second printing unit cylinder during continuous printing of the rotary printing press. The printed images, which are printed together onto the same side of the printing material, are subsequently checked, with regard to their maintenance of register.

The machine comprises: a plurality of printing units each of which has a printing cylinder movable so as to allow adjustment of the position of the image printed by that cylinder in two perpendicular adjustment directions relative to the web of printing material; first manually-operated adjustment means arranged to allow a user to adjust manually the position of each printing cylinder; image acquisition means arranged to acquire images of register marks printed by the printing units along one or both sides of the web of material; and display means arranged to show, on an enlarged scale, the images acquired by the image acquisition means, so as to allow the user to detect any misalignments between the register marks and to properly adjust the position of one or more printing cylinders to clear said misalignments. The image acquisition means comprise a plurality of cameras each of which is arranged to frame.