Conveyance speed control in a printing apparatus

A printing apparatus capable of double-sided printing, comprising:

• a printing unit configured to print an image on one of two sides of a first recording sheet;
• a sheet feeder configured to feed the first recording sheet to the printing unit;
• a discharge unit configured to settle the first recording sheet with the image printed thereon;
• a sheet path comprising:
• a feeding path configured to guide the first recording sheet from the sheet feeder to the printing unit,
• a discharge path configured to guide the first recording sheet through the printing unit to the discharge unit, and
• a reversing path divergent from the discharge path, the reversing path merging into the feeding path at a first position upstream from the printing unit, the reversing path configured to reverse the first recording sheet during a double-sided printing operation;
• a manual sheet inlet configured to receive a second recording sheet manually inserted by a user;
• a manual sheet path that merges into the sheet path at a merging point upstream from the printing unit, the manual sheet guiding the second recording sheet to the merging point;
• a detecting unit configured to detect the manual sheet inlet receiving the second recording sheet manually inserted by a user;
• a processor;
• and
• non-transitory memory storing computer-readable instructions that, when executed by the processor, cause the apparatus to:
• detect the manual sheet inlet receiving the second recording sheet while the double-sided printing operation is being performed with the first recording sheet,
• determine whether the detecting unit detected the second recording sheet, and
• change a speed of conveying the first recording sheet in the sheet path from a first speed to a second speed, the second speed slower than the first speed and greater than zero, the change being performed in response to determining that the detecting unit detected the second recording sheet.