Ink-jet printer with ink path and method of forming the ink path

An ink-jet printer, comprising:

• a printhead unit that ejects ink onto a printing medium;
• an ink source external to the printhead unit;
• and
• an ink path through which ink is delivered from the ink source to the printhead unit, the ink path including:
• a first ink path forming member that has a head with a maximum-diameter portion and an open end tapered down from the maximum-diameter portion, and a neck extending from the head and having a smaller diameter than the maximum-diameter portion;
• and
• a second ink path forming member that is formed of at least a flexible elastic material and has an inner diameter smaller than the maximum diameter of the first ink path forming member, wherein the head and the neck of the first ink path forming member are inserted into the second ink path forming member, the second ink path forming member radially expanding at the maximum-diameter portion and radially contracting at the neck of the first ink path forming member, thereby establishing a connection between the first and second ink path forming members, wherein the ink path further includes a locking member fitted over the second ink path forming member and having a first inner-diameter portion whose inner diameter is smaller than an outer diameter of a connection between the maximum-diameter portion of the first ink path forming member and the second ink path forming member, the first inner-diameter portion pressing an outer periphery of the second ink path forming member and locking the connection.

An ink-jet printer, comprising:

• a printhead unit that ejects ink onto a printing medium;
• an ink source external to the printhead unit;
• and
• an ink path through which ink is delivered from the ink source to the printhead unit, the ink path including:
• a first ink path forming member having an open end;
• a second ink path forming member having an open end opposed to the open end of the first ink path forming member;
• and
• a sealing member placed between the opposed open ends and sandwiched by end faces formed around openings at the open ends of the first and second ink path forming members, wherein inner peripheries of the first ink path forming member, the sealing member, and the second ink path forming member are one of flush with each other and gradually reduced in inner diameter in a direction of flow of ink.

A method of forming an ink path for an ink-jet printer that has a printhead unit ejecting ink onto a printing medium and an ink source external to the printhead unit, the ink being delivered through the ink path from the ink source to the printhead unit, the method comprising the steps of:

• connecting first and second ink path forming members by inserting the first ink path forming member into the second ink path forming member, wherein the first ink path forming member has a large-diameter portion larger than an inner diameter of the second ink path forming member, and an open end tapered down from the large-diameter portion and having an outer diameter smaller than the inner diameter of the second ink path forming member;
• reducing a pressure of an inside of the connected first and second ink path forming members;
• supplying a filling liquid into the inside of the connected first and second ink path forming members;
• and
• returning the pressure of the inside of the connected first and second ink path forming members to an atmospheric pressure, thereby filling a gap created between the open end of the first ink path forming member and the second ink path forming member with the filling liquid.

An ink-jet printer, comprising:

• a printhead unit that ejects ink onto a printing medium;
• an ink source external to the printhead unit;
• and
• an ink path through which ink is delivered from the ink source to the printhead unit, the ink path including:
• an ink tube having a first layer formed of a material with low vapor and gas permeability and a second layer radially thicker than the first layer and formed of a flexible material;
• a joint inserted into the ink tube and having a maximum-diameter portion whose outer diameter is larger than an inner diameter of the ink tube;
• a locking member fitted over the ink tube and having an inner-diameter portion whose inner diameter is smaller than an outer diameter of a connection between the maximum-diameter portion of the joint and the ink tube, the inner-diameter portion of the locking member pressing an outer periphery of the ink tube and locking the connection.

An ink-jet printer, comprising:

• a printhead unit that ejects ink onto a printing medium;
• an ink source external to the printhead unit;
• and
• an ink path through which ink is delivered from the ink source to the printhead unit, the ink path including:
• a first ink path forming member that has a head with a maximum-diameter portion and an open end tapered down from the maximum-diameter portion, and a neck extending from the head and having a smaller diameter than the maximum-diameter portion;
• a second ink path forming member that is formed of at least a flexible elastic material and has an inner diameter smaller than the maximum diameter of the first ink path forming member, wherein the head and the neck of the first ink path forming member are inserted into the second ink path forming member, the second ink path forming member radially expanding at the maximum-diameter portion and radially contracting at the neck of the first ink path forming member, thereby establishing a connection between the first and second ink path forming members;
• a third ink path forming member having an open end;
• wherein the first ink path forming member has an open end opposed to the open end of the third ink path forming member;
• and
• a sealing member placed between the opposed open ends and sandwiched by end faces formed around openings at the open ends of the third and first ink path forming members, the inner peripheries of the third ink path forming member, the sealing member, and the first ink path forming member are one of flush with each other and gradually reduced in inner diameter in a direction of flow of ink, wherein the second ink path forming member is an ink tube, comprising:
• a first layer formed of a material with low vapor and gas permeability;
• and
• a second layer radially thicker than the first layer and formed of a flexible material, one of the first and second layers being an inner layer and the other being an outer layer.