The disclosure provides transitorially erasable ink compositions, including an aliphatic hydrocarbon solvent, a rubber dissolved in the aliphatic hydrocarbon solvent, a hydrophilic pigment, and a surfactant. The disclosure further provides methods of preparing transitorially erasable ink compositions and writing instruments comprising transitorially erasable ink compositions. The disclosed erasable ink compositions write well, have strong color and erase easily transitorially, and demonstrate color stability.

Provided is a writing instrument suited to ballpoint pens, marking pens and the like in which a flow pressure of an ink applied to a pen tip is controlled to a fixed level to prevent an ink direct flow phenomenon reverse flow phenomenon. The above writing instrument comprises a pen tip disposed at a front part of an ink tank, an ink received in the ink tank, a follower filled at a rear part of the ink, and a capillary porous member provided with a capillary force, which is arranged at a space part between a rear part of the follower and a rear end part of the ink tank in a state in which the follower is filled, wherein the pen tip is sealed when a cap is put on the writing instrument.

Provided is a writing instrument suited to ballpoint pens, marking pens and the like in which a flow pressure of an ink applied to a pen tip is controlled to a fixed level to prevent an ink direct flow phenomenon reverse flow phenomenon. The above writing instrument comprises a pen tip disposed at a front part of an ink tank, an ink received in the ink tank, a follower filled at a rear part of the ink, and a capillary porous member provided with a capillary force, which is arranged at a space part between a rear part of the follower and a rear end part of the ink tank in a state in which the follower is filled, wherein the pen tip is sealed when a cap is put on the writing instrument.

A water-based ink composition capable of forming depicted lines with excellent drying property and with little bleed is described. Also, a water-based ballpoint pen using the water-based ink composition is described. The water-based ink composition includes a polyoxyethylene alkyl ether, a water-soluble organic solvent, a colorant and water, wherein the HLB value of the polyoxyethylene alkyl ether is from 14 to 15, and wherein the polyoxyethylene alkyl ether has an alkyl group contains 8 to 10 carbon atoms.

A water-based ink composition capable of forming depicted lines with excellent drying property and with little bleed is described. Also, a water-based ballpoint pen using the water-based ink composition is described. The water-based ink composition includes a polyoxyethylene alkyl ether, a water-soluble organic solvent, a colorant and water, wherein the HLB value of the polyoxyethylene alkyl ether is from 14 to 15, and wherein the polyoxyethylene alkyl ether has an alkyl group contains 8 to 10 carbon atoms.

The disclosure provides transitorially erasable ink compositions, including an aliphatic hydrocarbon solvent, a rubber dissolved in the aliphatic hydrocarbon solvent, a hydrophilic pigment, and a surfactant. The disclosure further provides methods of preparing transitorially erasable ink compositions and writing instruments comprising transitorially erasable ink compositions. The disclosed erasable ink compositions write well, have strong color and erase easily transitorially, and demonstrate color stability.

The disclosure provides transitorially erasable ink compositions, including an aliphatic hydrocarbon solvent, a rubber dissolved in the aliphatic hydrocarbon solvent, a hydrophilic pigment, and a surfactant. The disclosure further provides methods of preparing transitorially erasable ink compositions and writing instruments comprising transitorially erasable ink compositions. The disclosed erasable ink compositions write well, have strong color and erase easily transitorially, and demonstrate color stability.