An image forming apparatus, comprising: a carriage configured to mount a recording head for discharging droplets and to move in a main scan direction; a guide member configured to slidably guide the carriage; an encoder scale arranged along the main scan direction; an encoder sensor mounted to the carriage and configured to read the encoder scale; and a partition member; wherein: the carriage includes a head mounting part configured to mount the recording head, and a sensor attaching part to which the encoder sensor is mounted and extending from the head mounting part; the head mounting part is arranged in a first space, and the sensor attaching part and the encoder scale are arranged in a second space; characterized in that: a stay extends downward and parallel to the sensor attaching part and faces an edge of the carriage in the sub-scan direction; and the partition member extends horizontally from the stay to contact the sensor attaching part between the first space and the second space so that the first space is below the second space and so that the guide member and partition member divide the head mounting part from the sensor attaching part. a carriage configured to mount a recording head for discharging droplets and to move in a main scan direction; a guide member configured to slidably guide the carriage; an encoder scale arranged along the main scan direction; an encoder sensor mounted to the carriage and configured to read the encoder scale; and a partition member; wherein: the carriage includes a head mounting part configured to mount the recording head, and a sensor attaching part to which the encoder sensor is mounted and extending from the head mounting part; the head mounting part is arranged in a first space, and the sensor attaching part and the encoder scale are arranged in a second space; characterized in that: a stay extends downward and parallel to the sensor attaching part and faces an edge of the carriage in the sub-scan direction; and the partition member extends horizontally from the stay to contact the sensor attaching part between the first space and the second space so that the first space is below the second space and so that the guide member and partition member divide the head mounting part from the sensor attaching part. the carriage includes a head mounting part configured to mount the recording head, and a sensor attaching part to which the encoder sensor is mounted and extending from the head mounting part; the head mounting part is arranged in a first space, and the sensor attaching part and the encoder scale are arranged in a second space; characterized in that: a stay extends downward and parallel to the sensor attaching part and faces an edge of the carriage in the sub-scan direction; and the partition member extends horizontally from the stay to contact the sensor attaching part between the first space and the second space so that the first space is below the second space and so that the guide member and partition member divide the head mounting part from the sensor attaching part. a stay extends downward and parallel to the sensor attaching part and faces an edge of the carriage in the sub-scan direction; and the partition member extends horizontally from the stay to contact the sensor attaching part between the first space and the second space so that the first space is below the second space and so that the guide member and partition member divide the head mounting part from the sensor attaching part.