Pressure control device

A pressure control device inside an ink reservoir for maintaining a negative pressure together with a pressure regulator, the pressure control device comprising:

• a vent on a interior wall of the ink reservoir, wherein the vent has a hole for linking up the interior of the ink reservoir with the exterior and a groove at the upper end of the hole;
• a plugging block positioned inside the groove for isolating the interior of the ink reservoir from the exterior;
• and
• a spring-loaded structure mounted onto the interior wall of the ink reservoir, wherein the spring-loaded structure includes a first section and a second section connected to each other, the first section presses on the outer edge of the plugging block elastically and the second section couples with the pressure regulator, when the negative pressure inside the ink reservoir changes, the pressure regulator pushes the second section of the spring-loaded structure and lifts the first section off from the outer edge of the plugging block, and the spring-loaded structure further includes a third section connected to the second section, one end of the third section runs along the direction of movement of the pressure regulator and extends towards the interior wall of the ink reservoir but separate from the wall by a short distance so that a range of movement for the third section and hence the second section and the first section are all limited.