NL2026664B1 - A method of handling and inspecting sheets in a sheet processing system - Google Patents

A method of handling and inspecting sheets in a sheet processing system Download PDF

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Publication number
NL2026664B1
NL2026664B1 NL2026664A NL2026664A NL2026664B1 NL 2026664 B1 NL2026664 B1 NL 2026664B1 NL 2026664 A NL2026664 A NL 2026664A NL 2026664 A NL2026664 A NL 2026664A NL 2026664 B1 NL2026664 B1 NL 2026664B1
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NL
Netherlands
Prior art keywords
sheet
sheets
stack
rejected
marking
Prior art date
Application number
NL2026664A
Other languages
Dutch (nl)
Inventor
M Gerrits Antionus
Original Assignee
Canon Production Printing Holding Bv
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Filing date
Publication date
Application filed by Canon Production Printing Holding Bv filed Critical Canon Production Printing Holding Bv
Priority to NL2026664A priority Critical patent/NL2026664B1/en
Application granted granted Critical
Publication of NL2026664B1 publication Critical patent/NL2026664B1/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J13/00—Devices or arrangements of selective printing mechanisms, e.g. ink-jet printers or thermal printers, specially adapted for supporting or handling copy material in short lengths, e.g. sheets
    • B41J13/26—Registering devices
    • B41J13/28—Front lays, stops, or gauges
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J11/00—Devices or arrangements  of selective printing mechanisms, e.g. ink-jet printers or thermal printers, for supporting or handling copy material in sheet or web form
    • B41J11/0095—Detecting means for copy material, e.g. for detecting or sensing presence of copy material or its leading or trailing end
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J13/00—Devices or arrangements of selective printing mechanisms, e.g. ink-jet printers or thermal printers, specially adapted for supporting or handling copy material in short lengths, e.g. sheets
    • B41J13/10—Sheet holders, retainers, movable guides, or stationary guides
    • B41J13/106—Sheet holders, retainers, movable guides, or stationary guides for the sheet output section
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2203/00—Embodiments of or processes related to the control of the printing process
    • B41J2203/01—Inspecting a printed medium or a medium to be printed using a sensing device

Landscapes

  • Separation, Sorting, Adjustment, Or Bending Of Sheets To Be Conveyed (AREA)

Abstract

A method of handling sheets in a sheet processing system (10) that includes an inspection device (18) for inspecting the sheets and deciding whether or not a sheet has to be rejected, characterized by a step of controlling, upon a signal (32) from the inspection device (18), an automated marking device (36) to apply a visible marking (34) to each rejected sheet.

Description

P6296NLO0O 1
A METHOD OF HANDLING AND INSPECTING SHEETS IN A SHEET PROCESSING
SYSTEM The invention relates to a method of handling sheets in a sheet processing system that includes an inspection device for inspecting the sheets and deciding whether or not a sheet has to be rejected. More particularly, the invention relates to a method of handling printed sheets in a printing system. Then, the inspection device may for example be a device for image capture and image processing that is capable of inspecting the images that have been printed on the sheets.
US 2018170077 A1 discloses a roll-to-sheet-printer having such an inspection device.
When a printed image is found defective, the web is rewound so that the rejected image, as well as all images that belong to the same copy of a multi-page document and have been printed already, are withdrawn until the leading edge of the first image reaches a switch from where it can be diverted to a reject port. Thus, not only the defective image is rejected but also all other images associated therewith, in order to prevent the page order from being disrupted. This method, however, is not applicable to cut sheet processing apparatus.
It is therefore an object of the invention to provide a method that permits to efficiently handle defective sheets in a cut sheet or roll-to-sheet processing apparatus.
In order to achieve this object, the method according to the invention comprises a step of controlling, upon a signal from the inspection device, an automated marking device to apply a visible marking to each rejected sheet.
This method has the advantage that it can be performed without interrupting the production process, so that a high productivity can be maintained even in the case that one or more sheets are defective. Rather than diverting the defective sheets to a reject port immediately, these sheets remain in a workflow, at least for a while, and they are only marked as defective sheets by applying the visible marking. Then, in a later stage of the production process, it is possible and easy to locate the rejected sheets and then
P6296NLO0 2 not only to remove these sheets from the collection of sheets but also to replace them by replacement sheets on that occasion.
Consequently, the production of waste prints is reduced because only those sheets need to be rejected that actually have a defect.
More specific optional features of the invention are indicated in the dependent claims.
If the sheets that are leaving the processing apparatus, including the sheets that have been marked as defective, are deposited on a stack, the visible marking is applied such that it is visible at least from one side of the stack, even when only an edge of the sheet is visible.
The marking may for example be applied by applying colored ink to a portion of the edge of the sheet or by punching out, tearing-off or folding-over a portion of the sheet that is adjacent to an edge or preferably to a corner of the sheet.
In a particularly useful embodiment, the marking consists of a slight offset of the sheet relative to the other sheets in the stack, so that defective sheets are easily visible because their edge is somewhat projecting from at least one side face of the stack.
In that case, the automated marking device is a device that determines the positions of the sheets when they are deposited on the stack.
Embodiment examples will now be described in canjunction with the drawings, wherein: Fig. 1 is a schematic side view of a cut sheet printing system; Fig. 2 is a top plan view of parts of a cut sheet printing system according to another embodiment, Fig. 3 is a side view of a stack of sheets as output from the printing system shown in Fig. 2; Fig. 4 is a partial to plan view of a printing system according to another embodiment; Figs. 5and 6 are plan views of sheets having a visible marking in one corner; and
P6296NLO0O 3 Fig. 7 is a side view of a stack of sheets including sheets that have been marked as in Fig. 5 or 6. As an example of the sheet processing system 10, Fig. 1 shows a printing system that comprises a sheet supply section 12, a printer 14 having an image forming unit 18, an image inspection device 18, and a stacker 20. In operation, cut sheets are separated from one or more holders in the sheet supply section 12 and are conveyed through the printing system along a sheet transport path 22. Images are printed on at least one side of each sheet by means of the image forming unit 16, and then the quality of the images is inspected by the inspection device 18 that may for example comprise a camera and suitable image processing software for recognizing defects in the images. The stacker 20 is configured to deposit the sheets that are received one after the other from the inspection device 18 on a stack 24. The stack is formed on a lift table 26 which is gradually lowered as the height of the stack increases, so that the top end of the stack 24 is always located close to an alignment mechanism 28 which is configured to precisely adjust the horizontal positions of the sheets before the sheets are dropped or pushed onto the top of the stack 24. The alignment mechanism 28 is capable of aligning the sheets not only in the sheet transport direction (from right to left in Fig. 1) but also in a lateral direction {normal to the plane of the drawing in Fig. 1), so that the stack 24 being formed on the left table 26 will have smooth surfaces on all four sides. In the example shown, the alignment mechanism 28 has a stop 30 against which the leading edge of an incoming sheet will abut, so that the position of the sheet in transport direction is precisely defined.
In the embodiment shown in Fig. 1, the alignment mechanism 28 is configured to adjust the position of the stop 30 in response to a signal 32 received from the inspection device 18. During normal operation of the printer, the stop 30 is aligned with the front face of the stack 24. However, when the inspection device 18 has detected a defect in the image on one of the sheets and decides that this sheet should be rejected, then the signal 32 causes the alignment mechanism 28 to move the stop 30 to the position shown in Fig. 1, which position is slightly offset from the face of the stack. As a consequence, when the defective sheet arrives, it will be deposited on the stack in a slightly offset
P6296NLO0O 4 position, so that an edge portion of the sheet will project from the face of the stack and constitutes a visible marking 34 which will enable an operator to easily locate the defective sheets. Thus, the alignment mechanism 28 in conjunction with a circuit processing the signal 32 constitutes an automated marking device 36 configured to form the markings 34.
When a defective image is detected on a sheet, a controller 38 of the inspection device 18 will not only produce the signal 32 but will also store the number of the sheet in the print sequence as well as the contents that should have been printed on that sheet, so that, when the print job has been completed, replacement sheets for the defective sheets may automatically be printed. For example, these replacement sheets may be deposited on top of the stack 24 or may be output separately after the entire stack 24 has been removed from the lift table 26. Then, at any convenient point in time, the operator may replace the defective sheets, which can be identified by their markings 34, by the replacement sheets. For example, the operator may lift the top part of the stack 24 that comprises the sheets above the topmost marking 34, remove the defective sheet and replace it by the replacement sheet and then restore the top part of the stack back in place. The same procedure may be repeated for all defective sheets in the stack.
Conveniently, the sheet replacement procedure will start only when the print job has been completed, so that it is not necessary to interrupt the print process which will typically be a high speed process in a high production printer.
In a further embodiment, the replacement sheets are printed in reverse order so that the order in the stack of replacement sheets coincides with the order of the defective sheets in the stack 24. Although the visible markings 34 are formed only on one face of the stack 24 in the example shown, the alignment mechanism 28 may also be configured for controlling also an offset in the lateral direction, so that the visible marking will be constituted by two projecting edges of the sheet. Furthermore, instead of a displacement offset, the marking device may apply a rotational offset to the sheet also resulting in multiple projecting edges.
P6296NLO0 Alternatively, the marking device may apply a tag, for example an adhesive tag, to the sheet such that the tag projects from the edge of the sheet.
5 Fig. 2 shows a top plan view of an inspection device 18 and a conveyer 40 of a printing system according to a modified embodiment. The conveyer 40 is provided for conveying the sheets that have been inspected in the inspection device 18 into a stacker which has not been shown here.
In this embodiment, an automated marking device 36’ is constituted by an inking roller on a pivotable lever which can be pivoted against an edge of a sheet 42 that is leaving the inspection device. The marking device 36' is disposed between two pairs of transport rollers 44 of the conveyer. When a defect of an image is detected, the marking device 36' is controlled to pivot against the edge of the sheet 42 having the image defect, so that colored ink is applied to a portion of the edge of the sheet while the sheet if firmly held in the nips of the transport rollers 44.
Fig. 3 is a side view of a stack 42' formed by sheets that have been supplied by the conveyer 40 and have then been stacked. Visible markings 34' of the rejected sheets are constituted by colored streaks formed by the ink on the edges of these sheets.
Fig. 4 is a view similar to Fig. 3 and shows an embodiment in which an automated marking device 36" is constituted by a punch mechanism disposed on one side of the conveyer 40 for punching out a portion of each rejected sheet 42, more particularly a square corner.
Fig. 5 is a top plan view of a stack 24" with a rejected sheet 42 on top. A visible marking 34" is constituted by a missing square portion at a corner of the sheet.
As an alternative, Fig. 6 illustrates a visible marking 34" that has been formed not by punching the sheet but by folding-over part of the sheet by folding device 38”, more particularly by folding-over a corner of the sheet.
P6296NLO0 6 Fig. 7 is a side view of the stack 24" with the markings 34" visible along a corner of the stack.
In the embodiments shown in Figs. 2 to 7, the markings are detectable even when the sheets have been separated from the stack, so that it has the further advantage that after the process of replacing the rejected sheets the rejected sheets are still recognizable as rejected sheets allowing an operator to confirm that the separate sheets remaining are rejected sheets and not replacement sheets that still need to substitute rejected sheets.
P6296NLO0 7
EMBODIMENTS
1. A method of handling sheets (42) in a sheet processing system (10) that includes an inspection device (18) for inspecting the sheets and deciding whether or not a sheet has to be rejected, characterized by a step of controlling, upon a signal (32) from the inspection device (18), an automated marking device (38; 36"; 36") to apply a visible marking (34; 34"; 34"; 34") to each rejected sheet.
2. The method according to claim 1, wherein the sheets, including the rejected sheets (42), are stacked on a stack (24; 24"; 24") and the visible markings (34; 34’; 34") are applied such that they are visible from at least one side of the stack.
3. The method according to claim 2, wherein the visible marking (34) is constituted by a portion of the sheet that is offset relative to the other sheets in the stack (24) so that an edge portion of the sheet projects from a face of the stack.
4. The method according to claim 1 or 2, wherein the visible marking (34) is formed by applying a marking material to an edge of the sheet (42).
5. The method according to claim 1 or 2, wherein the visible marking (34") is applied by removing sheet material from an edge or corner of the sheet.
6. The method according to claim 1 or 2, wherein the visible marking (34") is formed by a folding over a part of the sheet, such as a corner of the sheet (42).
7. A sheet processing system comprising a sheet inspection device (18), the system characterized by further comprising an automated marking device (36; 36"; 36") and a controller (38) configured to perform the method according to any of the claims 1 to 6.

Claims (7)

P6296NLO0 8 CONCLUSIESP6296NLO0 8 CONCLUSIONS 1. Werkwijze voor het verwerken van vellen (42) in een vellenverwerkingssysteem (10) dat een inspectie-inrichting omvat (18) voor het inspecteren van de vellen en het beslissen of een vel al dan niet afgewezen wordt, gekenmerkt door een stap van het aansturen, op een signaal (32) van de inspectie-inrichting (18), van een automatische markeerinrichting (36; 36"; 36") om een visuele markering (34; 34"; 34"; 34") op of aan elk afgewezen vel aan te brengen.A sheet processing method (42) in a sheet processing system (10) comprising an inspection device (18) for inspecting the sheets and deciding whether or not a sheet is rejected, characterized by a step of actuating, upon a signal (32) from the inspection device (18), from an automatic marking device (36; 36"; 36") to make a visual mark (34; 34"; 34"; 34") on or on each to apply rejected skin. 2. De werkwijze volgens conclusie 1, waarbij de vellen, inclusief de afgewezen vellen (42), gestapeld worden op een stapel (24; 24"; 24") en waarbij de visuele markeringen (34; 34" 34") zo aangebracht worden dat zij zichtbaar zijn van ten minste een zijde van de stapel.The method of claim 1, wherein the sheets, including the rejected sheets (42), are stacked in a stack (24; 24"; 24") and wherein the visual markings (34; 34" 34") are so applied that they are visible from at least one side of the stack. 3. De werkwijze volgens conclusie 2, waarbij de visuele markering (34) gevormd wordt door een deel van het vel dat verschoven is relatief ten opzichte van de andere vellen in de stapel (24) zo dat een randgedeelte van het vel uitsteekt uit het vlak van de stapel.The method of claim 2, wherein the visual mark (34) is formed by a portion of the sheet which is offset relative to the other sheets in the stack (24) such that an edge portion of the sheet protrudes from the plane off the stack. 4. De werkwijze volgens conclusie 1 of 2, waarbij de visuele markering (34') gevormd wordt door het aanbrengen van markeringsmateriaal op een rand van het vel (42).The method of claim 1 or 2, wherein the visual mark (34') is formed by applying marking material to an edge of the sheet (42). 5. De werkwijze volgens conclusie 1 of 2, waarbij de visuele markering (34") is aangebracht door het verwijderen van velmateriaal van een rand of hoek van een vel.The method of claim 1 or 2, wherein the visual marking (34") is applied by removing sheet material from an edge or corner of a sheet. 6. De werkwijze volgens conclusie 1 of 2, waarbij de visuele markering (34") gevormd wordt door het omvouwen van een deel van het vel, zoals een hoek van het vel (42).The method of claim 1 or 2, wherein the visual mark (34") is formed by folding over a portion of the sheet, such as a corner of the sheet (42). 7. Velverwerkingssysteem omvattende een velinspectie-inrichting (18), het system gekenmerkt door het verder omvatten van een automatische markeerinrichting (36; 36’; 36") en een stuureenheid (38) en ingericht om de werkwijze volgens een van de conclusies 1 tot 6 uit te voeren.A sheet processing system comprising a sheet inspecting device (18), the system characterized by further comprising an automatic marking device (36; 36'; 36") and a control unit (38) and arranged to carry out the method according to any one of claims 1 to 6 to perform.
NL2026664A 2020-10-13 2020-10-13 A method of handling and inspecting sheets in a sheet processing system NL2026664B1 (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2093807A (en) * 1981-02-20 1982-09-08 Europa Systems Ltd Offsetting sheets in stacks
US5705020A (en) * 1994-06-17 1998-01-06 Bobst Sa Device for controlling the production quality of a press that produces package blanks from sheets of material
JP2003053938A (en) * 2001-08-10 2003-02-26 Dainippon Screen Mfg Co Ltd Apparatus and method for checking image for sheet-fed printer
US20180170077A1 (en) 2016-12-16 2018-06-21 Océ Holding B.V. Printer with image inspection device

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2093807A (en) * 1981-02-20 1982-09-08 Europa Systems Ltd Offsetting sheets in stacks
US5705020A (en) * 1994-06-17 1998-01-06 Bobst Sa Device for controlling the production quality of a press that produces package blanks from sheets of material
JP2003053938A (en) * 2001-08-10 2003-02-26 Dainippon Screen Mfg Co Ltd Apparatus and method for checking image for sheet-fed printer
US20180170077A1 (en) 2016-12-16 2018-06-21 Océ Holding B.V. Printer with image inspection device

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