Apparatus for controlling ink in a continuous inkjet printer. A second adsorbent bed may be employed to more thoroughly remove these oxygenates. A linear brake is partially disposed within the brake housing. The book cover is dimensioned so that when the book cover is placed on a book, the rear cover’s left edge can be folded inward, which allows the attachment means on the rear cover’s inner surface to interface with the attachment means on the retaining member’s outer surface. The washing machine comprises a rotatable drum that receives laundry, a motor that rotates the drum, a balancer that is connected to the drum, the balancer changing a center of gravity of the drum, and a controller that rotates the motor at a constant rotational speed and then calculates a temperature of the balancer based on a period of a variation in rotational speed of the motor.