Compact plunger pump

Claim 2

A constant flow rate plunger pump comprising: a cylinder block including a cylinder portion; a bush secured to said cylinder portion of said cylinder block; a piston slidably disposed in said bush; a first pressure chamber defined by said cylinder block and one end of said piston; a resilient member secured to the other end of said piston; a second pressure chamber defined by said cylinder block, said piston and said resilient member; drive means for reciprocating said piston within said bush; a first inlet valve communicating with said first pressure chamber for introducing a liquid into said first pressure chamber when said piston is driven to travel in a predetermined direction; a first outlet valve communicating with said first pressure chamber for developing the liquid from said first pressure chamber when said piston is driven to travel in a direction counter to said predetermined direction; a second inlet valve communicating with said second pressure chamber for introducing a liquid into said second pressure chamber when said piston is driven to travel in said predetermined direction; and a second outlet valve communicating with said second pressure chamber for developing the liquid from said second pressure chamber when said piston is driven to travel in a direction counter to said predetermined direction.

Claim 3

The constant flow rate plunger pump of claim 1, wherein said bush is exchangeably secured to said cylinder portion of said cylinder block.

Claim 4

The constant flow rate plunger pump of claim 2, wherein an outer surface of said piston is coated with a film having a high resistance to wear.

Claim 5

The constant flow rate plunger pump of claim 3, wherein said film comprises a tetrafluoroethylene film.

Claim 6

The constant flow rate plunger pump of claim 1, 2, 3 or 4, further comprising adjusting means for adjusting a travel length of said piston within said bush.

Claim 7

The constant flow rate plunger pump of claim 5, wherein said drive means comprises: a plunger connected to the other end of said piston; and a DC solenoid for shifting said plunger in said direction counter to said predetermined direction when said DC solenoid is energized.

Claim 8

The constant flow rate plunger pump of claim 6, further comprising spring means for biasing said piston in said predetermined direction.

Claim 9

An ink liquid supply system for an ink jet system printer, said ink jet system printer comprising a nozzle for emitting an ink liquid supplied from said ink liquid supply system, and a beam gutter for collecting waste ink droplets emitted from said nozzle and for recovering the ink liquid toward said ink liquid supply system, said ink liquid supply system comprising: an ink liquid reservoir for containing the ink liquid therein; and a constant flow rate plunger pump including, a cylinder block including a cylinder portion; a bush secured to said cylinder portion of said cylinder block; a piston slidably disposed in said bush; a first pressure chamber defined by said cylinder block and one end of said piston; a resilient member secured to the other end of said piston; a second pressure chamber defined by said cylinder block, said piston and said resilient member; drive means for reciprocating said piston within said bush; a first inlet valve communicating with said first pressure chamber and with a first conduit connected to said ink liquid reservoir for introducing the ink liquid from said ink liquid reservoir into said first pressure chamber when said piston is driven to travel in a predetermined direction; a first outlet valve communicating with said first pressure chamber and with a second conduit connected to said nozzle for developing the ink liquid from said first pressure chamber toward said nozzle when said piston is driven to travel in a direction counter to said predetermined direction; a second inlet valve communicating with said second pressure chamber and with a third conduit connected to said beam gutter for introducing the waste ink liquid from said beam gutter into said second pressure chamber when said piston is driven to travel in said predetermined direction; and a second outlet valve communicating with said second pressure chamber and with a fourth conduit connected to said ink liquid reservoir for developing the waste ink liquid from said second pressure chamber toward said ink liquid reservoir when said piston is driven to travel in said direction counter to said predetermined direction.

Claim 10

An ink liquid supply system for an ink jet system printer, said ink jet system printer comprising a nozzle for emitting an ink liquid supplied from said ink liquid supply system, and a beam gutter for collecting waste ink droplets emitted from said nozzle and for recovering the ink liquid toward said ink liquid supply system, said ink liquid supply system comprising: an ink liquid reservoir for containing the ink liquid therein; and a constant flow rate plunger pump including, a cylinder block including a cylinder portion; a bush secured to said cylinder portion of said cylinder block; a piston slidably disposed in said bush; a first pressure chamber defined by said cylinder block and one end of said piston; a resilient member secured to the other end of said piston; a second pressure chamber defined by said cylinder block, said piston and said resilient member; drive means for reciprocating said piston within said bush; a first inlet valve communicating with said first pressure chamber and with a first conduit connected to said ink liquid reservoir for introducing the ink liquid from said ink liquid reservoir into said first pressure chamber when said piston is driven to travel in a predetermined direction; a first outlet valve communicating with said first pressure chamber and with a second conduit connected to said nozzle for developing the ink liquid from said first pressure chamber toward said nozzle when said piston is driven to travel in a direction counter to said predetermined direction; a second inlet valve communicating with said second pressure chamber and with a third conduit connected to said beam gutter for introducing the waste ink liquid from said beam gutter into said second pressure chamber when said piston is driven to travel in said predetermined direction; and a second outlet valve communicating with said second pressure chamber and with a fourth conduit connected to said ink liquid reservoir for developing the waste ink liquid from said second pressure chamber toward said ink liquid reservoir when said piston is driven to travel in said direction counter to said predetermined direction.

Claim 11

The ink liquid supply system of claim 8, wherein said bush is exchangeably secured to said cylinder portion of said cylinder block.

Claim 12

The ink liquid supply system of claim 9, wherein said cylinder portion of said cylinder block includes a screwed portion, and an outer surface of said bush includes a screwed portion which is associated with said screwed portion of said cylinder block.

Claim 13

The ink liquid supply system of claim 8, 9 or 10, further comprising a pressure accumulator disposed between said first outlet valve and said nozzle.

Claim 14

The ink liquid supply system of claim 11, further comprising filter means disposed between said pressure accumulator and said nozzle.

Claim 15

The ink liquid supply system of claim 12, further comprising an electromagnetic valve disposed between said filter means and said nozzle.

Claim 16

The ink liquid supply system of claim 13, wherein said constant flow rate plunger pump further comprises an adjusting screw for determining a travel length of said piston within said bush.

Claim 17

The ink liquid supply system of claim 14, wherein said drive means comprises: a plunger connected to the other end of said piston; a DC solenoid for shifting said plunger in said direction counter to said predetermined direction when said DC solenoid is energized; and spring means for biasing said piston in said predetermined direction.

Claim 18

The ink liquid supply system of claim 15, wherein said resilient member comprises a diaphragm, the periphery of said diaphragm being fixed to said cylinder block.