JPS62214962A - Ink supply mechanism of on-demand type ink jet printer - Google Patents

Abstract

PURPOSE:To provide an ink supply mechanism of an on-demand type ink jet printer capable of always printing under satisfactory condition by keeping the internal pressure of a sub-ink tank in a carrier at a constant level. CONSTITUTION:A sub-ink tank 6 which temporarily stores ink is installed on a carrier 11 and air 7 is sealed there with the ink. In addition, a pressure sensor 8 is provided and the ink of the sub-ink tank 6 is increased by an ink supply pump 4. At the same time, the pressure of the sealed-in air increases. If the pressure sensor 8 detected that an increase in the pressure has reached a set pressure level, the drive of the supply pump 4 is stopped to terminate the ink supply. In addition, the flowback of ink in a supply tube 3 due to the existence of an internal pressure in the sub-ink tank 6, is prevented by a check valve 5. During printing, this process is sequentially performed, making it possible to carry out satisfactory printing all the time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ink supply mechanism for an on-demand inkjet printer, and particularly to a sub-ink tank section on a carrier that has a function of keeping the ink supply pressure to the bed constant. The present invention relates to an ink supply mechanism for an on-demand inkjet printer.

[Conventional technology]

In recent years, with the spread of office automation, the demand for creating and printing documents in offices has increased, and printers with low noise and good print quality are in demand. Inkjet kanji printers and inkjet color printers are being put into practical use as printers that meet these demands.

Conventionally, this type of printer uses a technique such as photoetching on the surface of a glass tube or plate to form a nozzle part, an ink pressure chamber, and an ink supply part, and a piezo vibrator bonded to the outside of the ink pressure chamber. The bending deformation of the nozzle pressurizes the ink pressurizing chamber, causing ink droplets to be ejected from the nozzle tip.

What is the ink supply to this inkjet head?

As shown in FIG. 2, a sub-ink tank 6 supplies ink directly to an inkjet head 9 installed on a carrier 11 that can be scanned along the platen 12 in order to print on the printing paper 13 wrapped around the platen 12. This is accomplished by connecting an ink supply port 2 installed at an arbitrary position within the apparatus with a flexible supply pipe 3, and connecting the ink supply port 2 to a replaceable ink cartridge 1.

[Problem that the invention seeks to solve]

In such an ink supply mechanism, various disturbances that the ink supply system from the ink cartridge to the head receives, such as a decrease in ink in the ink cartridge and a change in ink supply pressure due to a bend in the supply pipe, act on the head, causing printing problems. This has the drawback of deteriorating the quality of printing, and even sucking air bubbles from the head, making printing impossible.

An object of the present invention is to improve the drawback that the ink supply system of the conventional ink supply mechanism described above easily transmits disturbances directly to the head, and to maintain a constant internal pressure in the sub-ink tank on the carrier. Accordingly, it is an object of the present invention to provide an ink supply mechanism for an on-demand inkjet printer that enables printing in good condition at all times.

[Means for Solving the Problems] The ink supply mechanism of the on-demand inkjet printer of the present invention includes air for absorbing disturbances in the ink supply system sealed in a part of the sub-ink tank.

It is characterized by having a pressure sensor that senses the pressure of the air, a supply pump that supplies ink into the sub-ink tank, and a check valve for preventing backflow of internal pressure within the sub-ink tank.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an embodiment of an ink supply mechanism for an on-demand inkjet printer according to the present invention.

On-demand inkjet printer has platen 1
In order to print characters and figures on printing paper 13 wound around printing paper 2, an inkjet head 9 is installed on a carrier 11 that scans along a platen 12 using a guide shaft 10 as a guide. Further, a sub-ink tank 6 is installed on the carrier 1 to temporarily store the supplied ink. This sub-ink tank 6 contains air 7 in addition to the supplied ink, and is provided with a pressure sensor 8 to measure the pressure of the air 7.

Ink supply is performed by driving the ink supply pump 4 when the pressure sensor 8 senses that the ink in the sub-ink tank 6 decreases due to continued printing and the pressure of the sealed air 7 falls below a certain set pressure. It will be done as follows. The ink in the sub-ink tank 6 increases due to this supply, and at the same time, the pressure of the enclosed air also increases. When the pressure sensor 8 senses that this pressure increase has reached the set pressure, the supply pump 4 stops driving and the ink supply ends.

Further, backflow of ink within the supply tube 3 due to the presence of internal pressure within the sub-ink tank 6 is prevented by a check valve 5 provided between the ink supply pump 4 and the sub-ink tank 6. During actual printing, such processes are performed sequentially when necessary, and good printing is always possible.

〔Effect of the invention〕

As explained in detail above, according to the ink supply mechanism of the present invention, it is possible to almost completely eliminate fluctuations caused by disturbances in the ink supply system, and moreover, it is possible to finely adjust the ink supply pressure, so that the ink supply pressure is always constant and constant. This has the effect that printing can continue under good conditions.

In addition, by setting the ink supply pressure to the maximum pressure that will prevent ink from leaking from the head tip, air bubble suction from the head tip can be prevented.

Print omissions caused by this can be avoided. In addition, the ink supply to the sub-ink tank is now dripped into the enclosed air rather than directly into the ink, which eliminates the negative effects on printing caused by ink pulsations caused by the supply pump drive. This has the effect of being able to prevent such problems from occurring.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of an ink supply mechanism according to the present invention, and FIG. 2 is a block diagram showing a conventional ink supply mechanism. 1... Ink cartridge, 2... Ink supply port,
3... Supply tube, 4... Ink supply pump, 5
... Check valve, 6 ... Sub ink tank, 7 ... Enclosed air, 8 ... Pressure sensor, 9 ... Inkjet head, 10 ... Guide shaft, 11 ... Carrier, 12 ...Platen, 13...Print paper

Claims (1)

[Claims] (1) A disturbance absorbing air for the ink supply system sealed in a part of the sub-ink tank, a pressure sensor that detects the pressure of the air, a supply pump that supplies ink into the sub-ink tank, and a sub-ink supply system. An ink supply mechanism for an on-demand inkjet printer, comprising a check valve for preventing backflow of internal pressure in an ink tank.