CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on and claims priority under 35 USC 119 from Japanese Patent Application No. 2020-055346 filed Mar. 26, 2020.

BACKGROUND

1. Technical Field

The present disclosure relates to a decurling device and an image forming apparatus.

2. Related Art

There are decurling devices that remove curl in a sheet that is curled due to, for example, image formation, by causing the sheet to pass through a contact portion where two members are in contact with each other. If a device that remove upward curl and a device that remove downward curl are provided separately, the size of an image forming apparatus increases. JP-A-2016-164644 proposes one decurling device that can remove both curls in different orientations.

SUMMARY

A decurling device is required to have a strong capability to remove a curl in a sheet while maintaining transport capability that allows the sheet to smoothly pass through the decurling device without causing a transport failure.

Aspects of non-limiting embodiments of the present disclosure relate to providing (i) a decurling device having an improved capability to remove a curl in a sheet while maintaining high transport capability as compared with a decurling device that has a structure in which a member that presses upstream and downstream portions of a belt in a sheet transport direction from an inner side of the belt exists only on an inner side of a virtual circle, and (ii) an image forming apparatus including the decurling device.

Aspects of certain non-limiting embodiments of the present disclosure address the above advantages and/or other advantages not described above. However, aspects of the non-limiting embodiments are not required to address the advantages described above, and aspects of the non-limiting embodiments of the present disclosure may not address advantages described above.

According to an aspect of the present disclosure, there is provided a decurling device including: a first transport unit including a transport roller, the first transport unit that sandwiches a transported sheet and transports the transported sheet further downstream; and a second transport unit including an endless belt that is in contact with the transport roller. The transport roller has an elasticity that, when the belt is pressed against the transport roller, allows the belt to bite into the transport roller by a bite amount corresponding to a pressing force, the second transport unit includes an abutting member disposed inside the belt, and a guide member, the abutting member pressing the belt from an inside of the belt and causing the belt to abut against the transport roller, the abutting member includes an upstream protrusion, an downstream protrusion, the upstream protrusion and the downstream protrusion being provided at positions away from each other at an upstream portion and a downstream portion in a sheet transport direction, each of the upstream protrusion and the downstream protrusion protruding toward an inner surface of the belt, and a recess provided in an intermediate portion between the upstream protrusion and the downstream protrusion in the sheet transport direction, the recess being recessed away from a straight line connecting a top portion of the upstream protrusion and a top portion of the downstream protrusion, the guide member includes a contact surface that is in contact with the inner surface of the belt, the contact surface defining a part of a circulation track of the belt, and the upstream protrusion protrudes beyond a virtual circle that is tangent to the contact surface.

