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EP-4737127-A1 - A ROLL PRINTER COMPRISING A SLIPPING ENABLER

EP4737127A1EP 4737127 A1EP4737127 A1EP 4737127A1EP-4737127-A1

Abstract

A compact device to prevent or reduce the formation of wrinkles in print media during roll-to-roll printing on a printer comprising an endless transport belt is provided. The printer (1) comprises: - a transporter (7) for transporting a print medium (20, 27) from a feed roller (11) via an upstream roller (12) along a printing assembly (2) to a take-up roller (16), wherein the upstream roller (12) defines a turn in the print medium (20, 27), characterized by a slipping enabler (30) positionable at the upstream roller (12) between the print medium (20, 27) and the upstream roller (12) with during use moving surfaces on opposite sides of the slipping enabler (30), so that the slipping enabler (30) remains substantially stationary while the print medium (20, 27) and the upstream roller (12) move.

Inventors

  • VAN BOHEEMEN, Stan P.

Assignees

  • CANON KABUSHIKI KAISHA

Dates

Publication Date
20260506
Application Date
20241104

Claims (14)

  1. A roll printer (1) comprising: - a feed roller (11) configured to feed a print medium (20, 27) from a roll; - a printing assembly (2) configured to print an image on the print medium fed by the feed roller (11); - a take-up roller (16) configured to take up the print medium (20, 27) printed by the printing assembly (2); - a transporter (7) configured for transporting the print medium (20, 27) along the printing assembly (2) and comprising an upstream roller (12) defining a turn in the print medium (20, 27), characterized in that a slipping enabler (30) is positioned at the upstream roller (12) and is configured to support a side of the print medium (20, 27) facing the upstream roller (12), wherein the slipping enabler (30) remains substantially stationary while the print medium (20, 27) and the upstream roller (12) move.
  2. The roll printer (1) according to claim 1, further comprising a slip holder (32) which holds the slipping enabler (30) stationary while the print medium (20, 27) and the upstream roller (12) move with respect to the slipping enabler (30).
  3. The roll printer (1) according to any of the previous claims, wherein the slipping enabler (30) is in direct contact with the during use moving surfaces, which then slide past the slipping enabler (30).
  4. The roll printer (1) according to any of the previous claims, wherein the transporter (7) comprises an endless belt (8) extending over a suction chamber assembly (18), and wherein the slipping enabler (30) is positionable at the upstream roller (12) between the belt (8) and the print medium (20, 27), so that the slipping enabler (30) remains substantially stationary while the print medium (20, 27) and the belt (8) move.
  5. The roll printer (1) according to claim 4, wherein the slipping enabler (30) is positionable between the belt (8) and the print medium (20, 27), so that it extends in a contact area (CA) of the turn, where the print medium (20, 27) would contact the belt (8) in absence of the slipping enabler (30).
  6. The roll printer (1) according to claim 5, wherein the contact area (CA) extends over an angle of at least 90° around an axis of the upstream roller (12).
  7. The roll printer (1) according to any of the previous claims, wherein the slipping enabler (30) comprises a slip sheet (31) with a width corresponding to a width of the upstream roller (12).
  8. The roll printer (1) according to claim 7, wherein the slip sheet (31) is flexible, so that it can conform to a radius of the take-up roller (12).
  9. The roll printer (1) according to claim 7 or 8, wherein the slip sheet (31) is formed of a smooth and low frictional material.
  10. The roll printer (1) according to claim 2 and any of the claims 7 to 9, wherein the slip sheet (31) is securable to the slip holder (32), which slip holder (32) is positioned in a V-shaped region, wherein the belt (8) and the print medium (20, 27) are coming together at the upstream roller (12).
  11. The roll printer (1) according to claim any of the previous claims, wherein the printer (1) is configured to operate in a roll-to-roll print mode, wherein the slipping enabler (30) is applied to convey the print medium over the upstream roller (12) and in a rigid print mode, wherein the slipping enabler (30) is arranged remote from the print medium (25).
  12. A transporter (7) for use in a roll printer (1) the according to any of the previous claims, which transport (7) comprises: - an upstream roller (12) defining a turn in the print medium (20, 27); - a slipping enabler (30) positionable at the upstream roller (12) and configured to support the print medium (20, 27), such that that the slipping enabler (30) remains substantially stationary while the print medium (20, 27) and the upstream roller (12) move.
  13. A method of printing comprising the steps: - transporting a print medium (20, 27) from a feed roller (11) via an upstream roller (12) along a printing assembly (2) to a take-up roller (16), wherein the upstream roller (12) defines a turn in the print medium (20, 27), characterized by the step of a slipping enabler (30) remaining substantially stationary, while two opposing surface it is in contact with slide past it, wherein one of the opposing surface is formed by the print medium (20, 27) and the slipping enabler is positioned at the upstream roller (12) between the print medium (20, 27) and the upstream roller (12).
  14. The method according to claim 13, wherein the slipping enabler (30) comprises a slip holder (32) which holds a slip sheet (31) stationary while the print medium (20, 27) and the upstream roller (12) move with respect to it.

Description

BACKGROUND OF THE INVENTION 1. Field of the invention The invention relates to a roll printer and to a method of printing. 2. Description of Background Art The invention relates to a roll printer. Roll printers may operate in a roll-to-roll print mode, wherein a print medium is unwound from a feed roller, passed along a printing assembly, and re-wound at a take-up roller. The print medium generally extends upwards from the feed roller towards an upstream roller, around which the print medium is curved onto a horizontal plane and extends towards the printing assembly. The upstream roller may be one of a plurality of support rollers, which support an endless transport belt, which moves the print medium past the printing assembly. It was found that wrinkles could be introduced into the print medium by its passage over the upstream roller. SUMMARY OF THE INVENTION It is an object of the invention to provide an improved roll printer, specifically one wherein wrinkling is reduced and/or prevented. In accordance with the present invention, a roll printer according to claim 1, a transporter for a roll printer according to claim 12, and a method of printing according to claim 13 are provided. The roll printer comprises: a feed roller configured to feed a print medium from a roll;a printing assembly configured to print an image on the print medium fed by the feed roller;a take-up roller configured to take up the print medium printed by the printing assembly; The transporter is configured for transporting a print medium along the printing assembly and comprises an upstream roller defining a turn in the print medium. The transporter is characterized in that a slipping enabler is positioned at the upstream roller and is configured to support a side of the print medium facing the upstream roller, wherein the slipping enabler remains substantially stationary while the print medium and the upstream roller move. It is an insight of the inventor that wrinkles in the print media are caused by local velocities differences between the portion of the print medium over the upstream roller and the portion extending along the printing assembly. It is the further insight of the inventor that the velocity at the upstream roller will be similar if there locally the print medium is substantially and/or significantly decoupled from the forces of the transporter. The inventor further realized that this decoupling can be achieved in a simple and compact manner by positioning a slipping enabler at the upstream roller between the print medium and the transporter, such that the print medium and the transporter can slide along it at the upstream roller. The slipping enabler during use is in contact with two moving surfaces on opposite sides of the slipping enabler. One moving surface is formed by the print medium, which is generally on top of the slipping enabler. The other moving surface is formed by the transporter, specifically a portion thereof located at the upstream roller. The other moving surface generally engages the bottom side of the slipping enabler during use. The slipping enabler during use is arranged to remain its position, while allowing the print medium and the transporter to move along it in the vicinity of the upstream roller. The slipping enabler has at least one fixed point, which remains stationary with respect to the moving surfaces. The slipping enabler locally decouples or disengages the print medium from the transporter, locally allowing for different velocities. This allows the path of the print medium to be substantially similar or the same when the slipping enabler is present, as compared to when it would be absent. This results in a compact and low-costs solution to prevent or reduce wrinkles in print media. Thereby the object of the present invention has been achieved. More specific optional features of the invention are indicated in the dependent claims. In an embodiment, the slipping enabler is in direct contact with the during use moving surfaces, which then slide past the slipping enabler. The slipping enabler contacts the print medium and the transporter, while allowing these to slide past it, while the slipping enabler maintains its position. In an embodiment, the moving surfaces are positioned on opposite sides of the slipping enabler during use. The print medium is preferably on a top side of the slipping enabler, while the transporter moves along a downwards facing side of the slipping enabler. The slipping enabler extends between the print medium and the transporter. In an embodiment, the turn defined by the upstream roller orients the print medium in a horizontal orientation. Before the upstream roller the print medium preferably extends upwards, while after the upstream roller the print medium moves in a horizontal direction. In a preferred embodiment, the transporter further comprises an endless belt extending over a suction chamber assembly, and wherein the slipping enabler is positionable at the