JPS5867459A - Ink jet printer - Google Patents

Abstract

PURPOSE:To provide an ink jet printer which has been reduced in size, made easier to maintain, stabilized in print quality and reduced in cost by a method wherein a pump system is mounted on a carriage and motive power for driving a pressurizing pump and a recovery pump is obtained from the operation of the carriage. CONSTITUTION:As a carriage is caused to reciprocate several times with a 3- way valve 27 kept turned OFF, an air chamber 37 is filled up with ink at a specified pressure. When a print instruction is given, since NC terminal of the 3-way valve 27 is connected, ink pressure is applied to a head and ink particles are generated and it bcomes possible to perform printing. If the amount of ink to be sent out from a pressurizing piston 17 is set larger than the amount of ink particles to be spouted from a nozzle assembly 16, an eccentric cam 24 applies a fixed amount of pressure to the air chamber 37, since a carriage 39 is caused to slide upon completion of printing. During printing, a recovery piston 21 is also caused to slide and ink accumulated in a gutter 5 is returned to an ink tank 28 by means of a pipe 36.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inkjet printer that is small in size and has a high printing speed.

A conventional inkjet printer is shown in FIG.

In the figure, A is the carrier, one of which is the nozzle,
2 is the electrostrictive element, 3 is the charge 7L electrode, 4 is the deflection electrode, 5 is the gutter, 6 is the carrier, no frame, mater, B is the pump system, and 7 of them is the pressurization 4? 8 is a drive source for pressurization, 9
10 is an air chamber, 10 is an ink tank, 11 is a collection pump, 12 is a collection drive method, 13 is a three-way valve, and the printer is also comprised of paper 14 and a bin tractor 15.

In this operation, ink pressurized by the pressure pump 7 passes through the air chamber 9, 3 and the directional valve 13, is guided to the nozzle 1, and is ejected. At this time, the nozzle 1 is vibrated by the electrostrictive element 2, and ink columns are formed into particles. Further, at this time, a voltage corresponding to the video signal is applied to the charging electrode 3, and the particles are charged according to the video signal, deflected by the deflection electrode 4, and fly to a predetermined position on the paper 14 to be printed.

On the other hand, particles to which printing information is not given are not electrically charged, so they are not deflected even if they pass through the deflection electrode 4, and they hit the gutter 5 and are returned to the ink tank 10 by the collection ring 1. Therefore, conventionally, the pressurizing pump 7 and the recovery pump 7'77 each have a driving source composed of a renoid and a motor, making the pump system B heavy and large, so it is necessary to mount the pump system B on the carrier/edge system A. Therefore, (1) the pressure decreases because the ink tube becomes longer. ■Since the resistance of the tube is large, the flight speed of particles changes greatly depending on the temperature, and the size of the printed figure changes. ■The device becomes larger,
It's also expensive. ■The carrier system and pump system were connected by a tube containing ink, which made maintenance difficult.

In order to eliminate these conventional drawbacks, the present invention has a pump system mounted on a carrier so that the drive source for the pressurizing pump and recovery pump is derived from the movement of the carrier.The purpose of the present invention is to: The purpose is to miniaturize the device, facilitate maintenance, stabilize printing quality, and reduce the cost. An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 2 is a side view showing an embodiment of the inkjet printer of the present invention, and FIG. 3 is a sectional view taken along the line 2--2 in FIG. In the figure, 16 is a nozzle assembly, 17 is a pressure piston, 18 is a pressure spring, 19 is a bellofram, 20 is a check valve, 21 is a recovery piston, 22 is a recovery spring,
23 is a pipe, 24 is an eccentric cam, 25 is a coupling,
26 is a nori, 27 is a three-way valve, 28 is an ink tank,
30 is a wire, 31, 32, 33, 34, 35° 36 is an air chamber, 37 is an air chamber, 38 is an ink cartridge, and 39 is a carrier.

Next, the operation will be explained. First, the carrier is reciprocated several times with the three-way valve 27 in the OFF state. At this time, since both ends of the wire 30 wound around the Zori 26 are fixed to the frame, the Zori 26 rotates. Therefore, the eccentric cam 24 operates via its rotating shaft, causing the pressure piston 17 and the collection piston 2 to slide, and the pressure piston 17 is moved by the eccentric cam 24 during the pulling process, and by the pressure streak ring 1 during the pushing process.
8, the air chamber 37 is filled with ink at a constant pressure. Further, in this state, the pressure inside the share chamber is kept constant due to the action of the check valve 2o. At this time, if there is a print command, the three-way valve 27 is turned on, and the NC (N
ORMAL CLO8E) terminal is connected, so C
Ink pressure is applied to the head via the 0M terminal, ink particles are generated, and the head becomes ready for printing. Also, since the carrier (y39) slides when printing is performed, the amount of ink sent out from the pressure piston 17 by the eccentric cam 24 is set to be larger than the amount of ink particles ejected from the nozzle assembly 16. If the pressure piston 17 is pressed by the pressure spring 18 as described above, a constant pressure will be applied to the air chamber 37.

Furthermore, since the recovery piston 21 also slides at the same time during printing, the ink accumulated in the gutter 5 is returned to the ink tank 28 by the i4 eve 36. Then, when the printing command is completed, the 3-way valve 27 is turned OFF.
Since the RMAL 0PEN) terminal and the nozzle 32 are connected, the ink to the nozzle 16 is cut off, so the ejection of ink from the nozzle 16 immediately stops, and the pressure in the air chamber 37 rarely decreases. Of course, if the pulling steps of the pressure piston 12 and the recovery piston 21 are performed alternately, the spring pressure of the pressure spring 18 and the recovery spring 22 can be applied to the eccentric cam 2.
4 and 26 at the same time, the operation becomes smooth. In addition, if the printer is not used for a long time (2 to 3 days) and the power is turned off, the operation of reciprocating several times before printing starts.
This is necessary only when N is selected, and normally printing can be performed immediately. Furthermore, it goes without saying that the present invention is applicable not only to serial printers but also to line printers.

As explained in detail above, the present invention eliminates the drive sources for the pressure pump and recovery pump, which are essential to charge amount control type inkjet printers, and installs them in the carrier as a single unit, thereby reducing the size of the device. Since it is lightweight and inexpensive, and therefore easy to maintain, it can be used not only for printers but also for facsimile machines and X-Y printers, which is very effective.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram showing a conventional inkjet printer.
FIG. 2 is a side view showing an embodiment of the inkjet printer of the present invention, and FIG. 3 is a sectional view taken along the line m--■ in FIG. DESCRIPTION OF SYMBOLS 1... Nozzle, 2... Electrostrictive element, 3... Charge electrode, 4... Deflection electrode, 5... Gutter, 6... Carriage frame, 7... Pressure input 8... Drive source for pressurization, 1... Recovery pump, 12... Drive source for recovery, 16... Nozzle assembly, 17... Pressure piston, 21... Recovery piston, 24... Eccentric cam, 25... Coupling, 26... Zori, 27.
...3-way valve, 28... Ink tank, 30... Wire, 37... Air chamber, 38... Ink cartridge, 39... Carriage. Patent applicant Oki Electric Industry Co., Ltd.

Claims (1)

[Claims] A conversion mechanism for converting carrier movement into rotational motion in a charge amount control type inkjet printer used for recording by charging ink particles ejected from a nozzle and deflecting the charged ink particles by passing between deflection plates. , an eccentric cam rotated by the conversion mechanism, and a pressure piston and a collection piston that are reciprocated by the eccentric cam are mounted on the carrier, and movement of the carrier drives the pressure piston to eject and collect ink. An inkjet printer 0 characterized by collecting ink by driving a piston