Ball point pen cartridge with refill indicator

Publishing Venue

The IP.com Prior Art Database

Abstract

The present invention is a ball point pen cartridge including a cartridge tube 110 having one end open, a metal tube 130 mounted in the other, a ball 150 rotatably mounted in the metal tube 130, a Marking fluid A 120 within the tube in contact with the ball, and a Marking fluid B 130 in contact with Marking fluid A 120. Marking fluid A 120 and Marking fluid B 130 are of two distinct colors. For example, Marking fluid A 120 might be black, and Marking fluid B 130 might be blue. During the normal life of the ballpoint cartridge, writing will appear in the color of Marking fluid A 120. Near the end of the life of the cartridge, the color of writing produced by the cartridge will change to the color of Marking fluid B 130, indicating it is time to replace the cartridge. In the example, the cartridge would be provided and labelled as a black ink cartridge. Near the end of its useful life, however, the writing produced by the pen in which the cartridge is installed will turn from black to blue. This indicates to the user that it is time to replace the cartridge, though the pen will continue to function for some period of time related to the amount of Marking fluid B 130 used in the cartridge.

Ball point pen cartridge with refill indicator

One of the most ubiquitous writing implements in use is the ball point pen. Many millions of such devices are produced each year. Many different styles and designs exist in the marketplace, some with clear bodies and many with opaque bodies. There is a significant market for both original and refill cartridges for ball point pens.

Ballpoint pens often provide no means of showing the amount of ink remaining in a cartridge. This is particularly true of pens that use an opaque barrel or housing. What is needed is a way for the user of a ballpoint pen to know when an ink cartridge is nearly empty.

Figure 1 Diagram of ink cartridge with low-ink indication

The present invention is a ball point pen cartridge including a cartridge tube 110 having one end open, a metal tube 130 mounted in the other, a ball 150 rotatably mounted in the metal tube 130, a Marking fluid A 120 within the tube in contact with the ball, and a Marking fluid B 130 in contact with Marking fluid A 120. Marking fluid A 120 and Marking fluid B 130 are of two distinct colors. For example, Marking fluid A 120 might be black, and Marking fluid B 130 might be blue. During the normal life of the ballpoint cartridge, writing will appear in the color of Marking fluid A 120. Near the end of the life of the cartridge, the color of writing produced by the cartridge will change to the color of Marking fluid B 130, indicating it is time to replace the cartridge. In the example, the cartridge would be provided and labelled as a black ink cartridge. Near the end of its useful life, however, the writing produced by the pen in which the cartridge is installed will turn from black to blue. This indicates to the user that it is time to replace the cartridge, though the pen will continue to function for some period of time related to the amount of Marking fluid B 130 used in the cartridge.