Sheet stacker and printing apparatus

A sheet stacker comprising:

• a loader to which a sheet bundle is to be loaded;
• a guide to:
• receive a leading end of a sheet conveyed to an area above the loader;
• and
• guide the sheet along a guide path above the loader in a conveyance direction;
• a blower disposed above the guide path of the guide to blow air downward to the sheet;
• and
• multiple lines:
• disposed above the guide path of the guide;
• and
• extending in a direction inclined relative to the conveyance direction,
• wherein:
• the multiple lines are disposed apart from each other with an interval in a width direction intersecting the conveyance direction, and
• the interval increases toward downstream in the conveyance direction.