JPS58201660A - Ink jet recorder - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] It is.

In an ink jet recording device that performs a desired print on recording paper by ejecting ink from an ink jet, an ink jet recording device that circulates and reuses ink has a problem in that the viscosity of the ink increases due to the evaporation of water while the ink is flying. As a result, the ink ejection condition becomes unstable and good printing cannot be performed. Therefore, it is necessary to detect the viscosity of the ink and adjust the ink viscosity in response to an increase in the viscosity of the ink.

Conventionally, ink viscosity detection devices detect changes in electrical resistance due to increases in ink viscosity by installing two electrodes in the ink, applying voltage to these electrodes, and measuring the current flowing between the electrodes. Alternatively, a dummy nozzle is provided, which is periodically opened by a valve, and the viscosity is detected based on changes in the flow rate of the dummy nozzle, or a float is provided in the ink tank that moves based on the difference in specific gravity with the ink.
There are devices that detect the amount of movement of the float using a detection device to detect the viscosity. Then, in accordance with the ink viscosity detected by the ink viscosity detecting means, the ink viscosity is controlled by mixing a diluent into the ink. However, in the ink viscosity detection means, since the ink viscosity itself is greatly affected by changes in environmental temperature, temperature compensation means such as temperature control of the detection section is required. Furthermore, it is necessary to install a special detection section in the ink supply system, which makes the device complicated and expensive.

In order to eliminate the drawbacks of the conventional example, the present invention installs an ink circulation tank where ink is pumped and collected independently of the ink tank, and detects the amount of ink consumed within the ink circulation tank. By detecting the increase in ink viscosity based on the consumption amount and replacing the ink in the ink circulation tank with new ink, the viscosity can be controlled without being affected by the environmental temperature, providing a simple and inexpensive viscosity compensation method. The present invention provides an inkjet recording apparatus having the following.

The present invention will be described in detail below with reference to the drawings.

The figure is a schematic system diagram of an embodiment of the present invention, in which ink in an ink circulation tank 1 equipped with a liquid level detection device 1a inside is pumped by a pop 2, pulsating flow is suppressed by an accumulator 3, and the ink is filtered through a filter. At step 4, foreign matter is removed, and at valve 5, if printing is not to be performed, it is stopped just before valve 5, and if printing is to be performed, it is sent to head 6.

Then, before being ejected, a filter 7 removes foreign substances, and a heating element 8 controls the temperature before use for printing. In addition, when the pressure feeding of ink to the spatula 6 side is stopped, in order to rapidly release the pressure between the valve 5 and the spatula 6 to the atmosphere, the gap between the valve 5 and the ink circulation tank 1 is is opened, and the ink for which the pressure is evacuated is collected into the ink circulation tank l. Ink that is not used for printing is stopped by the gutter 9, foreign matter is removed by the filter 10, sucked in by the pop 11, and pumped out between the I pump 11 and the circulation tank 1, and the ink tank 12. and ink circulation tank 1
The ink circulation tank l is connected via a valve 13 that switches between
will be sent to The ink circulation tank 1 also communicates with a recovery tank 15 via a valve 14. Then, the valve 14 is opened by the output of the liquid level detection device equipped with liquid level detection means such as a float, and the ink in the ink circulation tank 1 whose viscosity has increased is discharged to the recovery tank 15, and the valve 13 is opened. It is recommended to open between the circulation tank l and the ink tank 12, and the ink tank 12. .

The new ink inside is supplied to the ink circulation tank 1.

In the above devices, the relationship between the amount of ink lost due to evaporation during ink flight and the amount of ink actually consumed by printing on recording paper is usually overwhelmingly the former, and the increase in viscosity due to ink evaporation is Approximate to ink consumption. Therefore, in this embodiment, the volume of the ink circulation tank 1 is set to 10c.
c, and when using ink with 15% wetness and 2% dye, the upper limit of viscosity at which good prints can be obtained is 3.5'
If c and p are used, the moisture evaporation rate of usable ink when heated to 915°C or higher by temperature control is about 40%.9 Considering the moisture content in the ink is 15 cm and the dye is 2 cm, The ink volume after water evaporation of 40 L% is 668 cc, and when a change of about 3.3 cc due to a float or the like is detected by the liquid level detection device 1a, the ink is replaced.

As explained above, the present invention detects an increase in viscosity by detecting the liquid level, so there is no need for temperature control or temperature compensation of the detection section, and the structure is simple, and there is no need to attach a special detection section. Furthermore, the device has advantages such as being inexpensive.

[Brief explanation of drawings]

The figure is a schematic system diagram of one embodiment of the present invention. 1... Ink circulation tank, 1a... Liquid level detection device,
2.11...Pump, 3...Accumulator, 4,
7゜10...filter, 5,13.14...valve,
6 Head, 8... Heating element, 9... Gutter, 12
...Ink tank, 15...Recovery tank.

Claims (1)

[Claims] In the ink supply system of an inkjet recording device that pumps ink to the head, ejects it for printing, collects unnecessary ink in a gutter, and reuses it, it is connected to an ink tank and a collection tank through valve means that are controlled to open and close, respectively. 1. An inkjet recording apparatus, comprising: an ink circulation tank, the valve means being controlled to open or close in accordance with a detection output corresponding to an amount of ink consumption from a liquid level detection device installed in the ink circulation tank.