Pump device and an ink jet recording apparatus having the pump device

Claim 2

A pump device for use in an ink jet recording apparatus comprising a cylinder, a piston mounted for reciprocally moving within a predetermined range of movement in said cylinder to generate pressure and a liquid inlet in said cylinder, wherein; said liquid inlet is disposed outside of the predetermined range of movement of said piston and a negative pressure is generated in said cylinder between said piston and said liquid inlet during movement of said piston; said piston includes a sealing member biased into sealing engagement with said liquid inlet when said piston is in a first portion of its predetermined range of movement; and said liquid inlet is sealed by said sealing member against negative pressure in said cylinder when said piston is in the first portion of its predetermined range of movement and said liquid inlet is open to negative pressure in said cylinder when said piston is in a second portion of its predetermined range of movement.

Claim 3

A pump device according to claim 1, wherein said liquid inlet is provided in a side of said cylinder opposed to said piston.

Claim 4

A pump device according to claim 1, wherein said sealing member is an elastic member.

Claim 5

An ink jet recording apparatus comprising an ink jet head for discharging liquid from an opening and effecting recording, a cap for covering said opening and a pump device for producing negative pressure for sucking air and/or liquid in said cap, said pump device including a cylinder, a piston mounted for reciprocally moving within a predetermined range of movement in said cylinder to generate pressure, and a liquid inlet in said cylinder connected to said cup, wherein: said liquid inlet is disposed outside of the predetermined range of movement of said piston and a negative pressure is generated in said cylinder between said piston and said liquid inlet during movement of said piston for sucking air and/or liquid in said cap; said piston includes a sling member biased into sealing engagement with said liquid inlet when said piston is in a first portion of its predetermined range of movement; and said liquid inlet is sealed by said sealing member against negative pressure in said cylinder when said piston is in the first portion of its predetermined range of movement and said liquid inlet is open to negative pressure in said cylinder when said piston is in a second portion of its predetermined range of movement.

Claim 6

An ink jet recording apparatus comprising an ink jet head for discharging liquid from an opening and effecting recording, a cap for covering said opening and a pump device for producing negative pressure for sucking air and/or liquid in said cap, said pump device including a cylinder, a piston mounted for reciprocally moving within a predetermined range of movement in said cylinder to generate pressure, and a liquid inlet in said cylinder connected to said cup, wherein: said liquid inlet is disposed outside of the predetermined range of movement of said piston and a negative pressure is generated in said cylinder between said piston and said liquid inlet during movement of said piston for sucking air and/or liquid in said cap; said piston includes a sling member biased into sealing engagement with said liquid inlet when said piston is in a first portion of its predetermined range of movement; and said liquid inlet is sealed by said sealing member against negative pressure in said cylinder when said piston is in the first portion of its predetermined range of movement and said liquid inlet is open to negative pressure in said cylinder when said piston is in a second portion of its predetermined range of movement.

Claim 7

An ink jet recording apparatus according to claim 4, wherein said liquid inlet is provided in a side of said cylinder opposed to said piston.

Claim 8

An ink jet recording apparatus according to claim 4, wherein said sealing member is an elastic member.

Claim 9

An ink jet recording apparatus according to claim 4, wherein said pump device and the interior of said cap are communicated with each other by a tube.

Claim 10

An ink jet recording apparatus according to claim 7, wherein said tube is forced into a tube receiver and said tube receiver is forced into a hole communicating with said liquid provided in said cylinder.

Claim 11

An ink jet recording apparatus according to claim 8, wherein said tube receiver is fixed by a keep member.

Claim 12

An ink jet recording apparatus according to claim 8, wherein said tube receiver has a mounting portion with respect to said cylinder and a mounting portion for said tube.

Claim 13

An ink jet recording apparatus according to claim 10, wherein said mounting portion for said tube is a hole.

Claim 14

An ink jet recording apparatus according to claim 11, wherein the inside diameter of said hole is equal to the outside diameter of said tube.

Claim 15

An ink jet recording apparatus according to claim 11, wherein the inside diameter of said hole is smaller, than the outside diameter of said tube.

Claim 16

An ink jet recording apparatus according to claim 4, wherein said piston is driven by a piston driving lever fixed to a piston driving gear and rotatably supported about a shaft.

Claim 17

An ink jet recording apparatus according to claim 14, wherein said piston driving gear is substantially sector-shaped.

Claim 18

An ink jet recording apparatus according to claim 14, wherein said piston driving gear is provided with a contact piece for detecting the rotated position of said piston driving gear.

Claim 19

An ink jet recording apparatus according to claim 4, having a holding lever used to move said cap.

Claim 20

An ink jet recording apparatus according to claim 17, wherein said holding lever is provided with a contact piece for detecting a rotated position of said holding lever.

Claim 21

An ink jet recording apparatus according to claim 4, wherein said ink jet head including electrothermal converting elements.

Claim 22

A pump device for use in an ink jet recording apparatus comprising a piston mounted in a hollow member for reciprocally moving within a predetermined range of movement to generate pressure in the hollow member and a liquid inlet in said hollow member, wherein: said liquid inlet is disposed outside of the predetermined range of movement of said piston and a negative pressure is generated in the hollow member between said piston and said liquid inlet during movement of said piston; said piston includes biasing means for biasing a sealing member into sealing engagement with said liquid inlet; and said liquid inlet is sealed by the sealed member against negative pressure in the hollow member during a first portion of the predetermined range of movement of said piston and said liquid inlet is open during a second portion of the predetermined range of movement of said piston.

Claim 23

A pump device for use in an ink jet recording apparatus comprising a piston mounted in a hollow member for reciprocally moving within a predetermined range of movement to generate pressure in the hollow member and a liquid inlet in said hollow member, wherein: said liquid inlet is disposed outside of the predetermined range of movement of said piston and a negative pressure is generated in the hollow member between said piston and said liquid inlet during movement of said piston; said piston includes biasing means for biasing a sealing member into sealing engagement with said liquid inlet; and said liquid inlet is sealed by the sealed member against negative pressure in the hollow member during a first portion of the predetermined range of movement of said piston and said liquid inlet is open during a second portion of the predetermined range of movement of said piston.

Claim 24

An ink jet recording apparatus comprising an ink jet head for discharging liquid from an opening and effecting recording, a cap for covering said opening and a pump device for producing negative pressure for sucking air and/or liquid in said cap, said pump device including a piston mounted in a hollow member for reciprocally moving within a predetermined range of movement to generate pressure in the hollow member and a liquid inlet in the hollow member connected to said cap, wherein: said liquid inlet is disposed outside of the predetermined range of movement of said piston and a negative pressure is generated in the hollow member between said piston and said liquid inlet during movement of said piston for sucking air and/or liquid in said cap; said piston includes biasing means for biasing a sealing member into sealing engagement with said liquid inlet; and said liquid inlet is sealed by the sealing member against negative pressure in the hollow member during a first portion of the predetermined range of movement of said piston and said liquid inlet is open during a second portion of the predetermined range of movement of said piston.

Claim 25

An ink jet recording apparatus comprising an ink jet head for discharging liquid from an opening and effecting recording, a cap for covering said opening and a pump device for producing negative pressure for sucking air and/or liquid in said cap, said pump device including a piston mounted in a hollow member for reciprocally moving within a predetermined range of movement to generate pressure in the hollow member and a liquid inlet in the hollow member connected to said cap, wherein: said liquid inlet is disposed outside of the predetermined range of movement of said piston and a negative pressure is generated in the hollow member between said piston and said liquid inlet during movement of said piston for sucking air and/or liquid in said cap; said piston includes biasing means for biasing a sealing member into sealing engagement with said liquid inlet; and said liquid inlet is sealed by the sealing member against negative pressure in the hollow member during a first portion of the predetermined range of movement of said piston and said liquid inlet is open during a second portion of the predetermined range of movement of said piston.

Claim 26

An ink jet recording apparatus according to claim 21, wherein said ink jet head includes electrothermal converting elements.