Printer

1. A printer configured to perform printing to a print medium by using an ink ribbon, the printer comprising:

a printing unit configured to print on the print medium;

a ribbon shaft configured to hold the ink ribbon;

a partition member swingably provided between a close position where gears that transmit drive force to the ribbon shaft mesh with each other and an open position where meshing between the gears is released; and

a lock mechanism configured to hold the partition member with respect to the printing unit when the partition member is at the close position.

2. The printer according to claim 1 , further comprising:

a casing in which the printing unit is accommodated, wherein

a motor configured to transmit the drive force to the gears is provided in the casing.

3. The printer according to claim 1 , further comprising:

a sensor having a light emitting portion and a light receiving portion, the sensor configured to detect a position of the print medium in a feed direction, wherein

at least one of the light emitting portion and the light receiving portion is provided in the partition member.

4. The printer according to claim 1 , wherein

the partition member comprises guiding surfaces with which the print medium is brought into sliding contact.

5. The printer according to claim 1 , further comprising:

a cover configured to open and close a casing of the printer, wherein

when the partition member is at the close position, the printing unit is accommodated in the cover, and

when the partition member is at the open position, the printing unit is exposed from the cover.

6. The printer according to claim 5 , further comprising:

a unit lock mechanism configured to hold the printing unit with respect to the cover when the partition member is at the close position.

7. The printer according to claim 1 , wherein

the lock mechanism includes:

an engaged portion provided in one of the printing unit and the partition member; and

an engagement portion provided in the other one of the printing unit and the partition member, the engagement portion configured to be engaged with the engaged portion by bias force of a spring following movement of the partition member from the open position to the close position, and

by an operation force for moving the partition member from the close position to the open position, the lock mechanism is configured to cancel engagement between the engagement portion and the engaged portion against the bias force of the spring.

8. The printer according to claim 7 , wherein

the lock mechanism further includes:

a hook swingably supported with respect to the printing unit or the partition member, and

the hook comprises the engagement portion and is configured to be swung in the direction in which the engagement portion is engaged with the engaged portion by the bias force of the spring.

9. The printer according to claim 8 , wherein

the hook further comprises a regulating portion configured to regulate swing of the hook with respect to a casing of the printer.

10. The printer according to claim 1 , wherein

the partition member is supported by the printing unit with one end side of the partition member as a supporting point, and

the lock mechanism positions the other end side of the partition member with respect to the printing unit.

11. The printer according to claim 1 , wherein

the partition member is supported by the printing unit with one end side of the partition member as a supporting point, and

lock mechanisms are arranged in both end portions of the partition member in the axial direction of the supporting point.