Drive circuit for printing apparatus, light-emitting element unit, and printing apparatus

A drive circuit for a printing apparatus, comprising:

• a first driver arranged on an electrical path from a first current supply unit to a first connection portion for a light-emitting element;
• a second driver arranged on an electrical path from a second current supply unit to the first connection portion;
• a third driver arranged on an electrical path from a third current supply unit to a second connection portion for a light-emitting element;
• and
• a controller configured to selectively activate one of the second current supply unit and the third current supply unit and inactivate the other of the second current supply unit and the third current supply unit when the one of the second current supply unit and the third current supply unit is activated.

An electrophotographic printing apparatus comprising:

• a first light-emitting element configured to irradiate a photosensitive drum with light;
• a second light-emitting element configured to irradiate the photosensitive drum with light;
• a first current supply unit configured to supply a current to the first light-emitting element;
• a second current supply unit configured to supply a current to at least one of the first light-emitting element and the second light-emitting element;
• a first driver arranged on an electrical path between the first light-emitting element and the first current supply unit;
• a second driver arranged on an electrical path between the first light-emitting element and the second current supply unit;
• a third driver arranged on an electrical path between the second light-emitting element and the second current supply unit;
• and
• a switch unit configured to selectively connect the second current supply unit to one of the second driver and the third driver and disconnect the connection between the second current supply unit and the other of the second driver and the third driver when the second current supply unit is connected to the one of the second driver and the third driver.

An electrophotographic printing apparatus, comprising:

• a first light-emitting element configured to irradiate a photosensitive drum with light;
• a second light-emitting element configured to irradiate the photosensitive drum with light;
• a first current supply unit configured to supply a current to the first light-emitting element;
• a second current supply unit configured to supply a current to the second light-emitting element;
• a third current supply unit configured to supply a current to the first light-emitting element and different from the first current supply unit;
• a first driver arranged on a path between the first light-emitting element and the first current supply unit;
• a second driver arranged on a path between the second light-emitting element and the second current supply unit;
• a third driver arranged on a path between the first light-emitting element and the third current supply unit;
• and
• a controller configured to selectively activate one of the second current supply unit and the third current supply unit and inactivate the other of the second current supply unit and the third current supply unit when the one of the second current supply unit and the third current supply unit is activated.