Patent ID: 8540241

Claim:
A sheet end detection device comprising: a cylindrical roller rotatable around an axis with conveying of a sheet to be conveyed in a state in which a peripheral surface of the roller contacts one face of the conveyed sheet; a phase detection unit configured to detect a phase in a circumferential direction of the roller, wherein a first piezoelectric element band is provided on the peripheral surface of the roller and extending in the circumferential direction and the axial direction, the first piezoelectric element band being configured to detect a contact of the sheet and extending in an axial direction of the roller over an inside and an outside of a contact area to be contacted with the conveyed sheet on the peripheral surface, and wherein a position of an arbitrary point of the first piezoelectric element band in the axial direction of the roller corresponds one-to-one with the phase in the circumferential direction of the roller; and further comprising a processor and a memory, the memory storing a program that, when executed by the processor, causes the processor to detect a first signal indicating the detection of the contact of the sheet a first time and to determine and end position of the sheet based on detecting a second signal indicating the detection of the contact of the sheet a second time.