JPH0327951A - Ink jet recording device - Google Patents

Abstract

PURPOSE:To make it possible to extend the range of temperature and humidity at which ink viscosity can be maintained within an appropriate range by providing a device to detect the ambient temperature and humidity of the subject device, then changing a diluent for ink viscosity adjustment to a specified value in an ink circulation system based on the detection data and adding the diluent to the system. CONSTITUTION:A temperature detection device 11 and a humidity detection device 12 are installed near a section where particles emitted from a particulate generation part 3 are recorded into a recording medium 5, and detect the temperature and humidity of that section. A control device 13 specifies an optimal diluent addition amount based on the detected temperature and humidity and gives a command to a control device 14. A diluent addition device 10 adds a diluent 17 for ink viscosity adjustment from a diluent liquid tank 9 to an ink circulation system by the amount specified by the control device 14. Thus the effect of environmental conditions (temperature and humidity) on a change in ink viscosity can be minimized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an inkjet recording apparatus in which the viscosity of the ink used must be controlled within a certain range in order to stabilize the state in which ink particles are generated.

[Conventional technology]

The conventional inkjet recording device is
As described in No. 62 and JP-A No. 58-201664, a device for detecting viscosity or specific gravity is provided in the ink circulation system, and based on the device, a diluent or ink is added into the circulation system to adjust the viscosity. I took a method of adjustment. However, this method requires a complicated viscosity or specific gravity detection mechanism, which makes the device expensive and makes maintenance of the device difficult.

In addition, if the above detection mechanism is not provided, the amount of diluent added must be fixed, so the viscosity fluctuates greatly due to changes in environmental conditions (temperature, humidity), and the range of environmental conditions that can maintain the viscosity within an appropriate range is limited. It had the disadvantage of being narrow.

[Problem that the invention seeks to solve]

In the above-mentioned conventional technology, the viscosity or specific gravity detection mechanism is complicated, so the device tends to be expensive and the maintenance of the device becomes difficult.

In addition, when these detection mechanisms are not provided, there is a problem that the range of environmental conditions (temperature, humidity) that can maintain the ink clay degree within an appropriate range is narrowed.

An object of the present invention is to enable ink to be controlled within a suitable viscosity range under a wide range of environmental conditions without requiring an expensive and complicated mechanism.

[Means for solving problems]

The above object is achieved by using temperature and humidity, which can be easily detected by an indirect method, as detection targets for controlling the amount of diluent added, rather than viscosity or density. The increase in ink viscosity is mostly due to evaporation at the ink ejection area. Experiments have confirmed that the state of this evaporation varies depending on the temperature and humidity of the ink ejecting area. Therefore, by detecting the temperature and humidity around this area, it is possible to predict the situation of viscosity increase due to evaporation, and based on the predicted values, it is possible to add the most suitable diluent. [Operation] The temperature and humidity detection device detects the temperature and humidity at the detection position. Based on this, the controller adds the optimum amount of diluent into the ink circulation system. The detection device can be installed anywhere as long as there is a certain relationship between the temperature and humidity at that location and the moisture evaporation of the ink, but in order to make diluent addition more accurate, it is necessary to It is better to use the inside of the recording device housing where there is less difference in

As explained above, since the amount of diluent is added depending on the state of evaporation, the range of environmental conditions (temperature, humidity) that can maintain the ink viscosity within the appropriate range is wider than when adding a fixed amount of diluent. 6. Also, there is no need for complicated viscosity or specific gravity detection equipment. [Example] An example of the present invention will be described below with reference to FIG. The ink 15 in the ink circulation system is pressurized from the ink tank 1 to a predetermined pressure by the circulation device 2, and then supplied to the particle generation section 3, where it becomes ink particles, and the ink particles used for recording are particles. It is deflected by the deflection device 4 and attached to the recording medium 5 for recording. Ink particles not used for recording are collected into the ink collection groove 6 and returned to the ink tank 1 by the collection device 7. Since the ink capacity holding device 8 is supported by the ink tank 1 and does not have an opening at the top, it serves to replenish ink 16 of standard viscosity when the amount of ink 15 becomes less than a predetermined amount. Diluent addition device 1
0 adds the diluent l7 in the diluent tank 9 for adjusting the ink viscosity to the ink circulation system in an amount commanded by the control device l4.

The temperature detection device 11 and the humidity detection device 12 are installed near a portion where particles generated from the particle generation section 3 are recorded on the recording medium 5, and detect the temperature and humidity at that position. The control device 13 specifies the optimum amount of diluent to be added based on the detected temperature and humidity and gives a command to the control device 14.

Next, the environmental resistance when operating the inkjet recording device having the ink circulation system of this example will be explained.
General information on circulating ink, 400+am. The amount of diluent added every hour was changed according to the range shown in Figure 2 in three stages: 0.2 mQ, 0.3 mQ, and 0.4 rnQ, with a small amount at low temperature and high humidity, and a large amount at high temperature and low humidity. The environmental conditions under which ink particle generation is stable and recording is not affected were investigated by adding the ink using the control device 13.

For reference, a case in which the amount of diluent added was always 0.3 mA per hour regardless of temperature and humidity was also investigated in the same manner as the prior art. Figure 2 shows the experimental results. In this embodiment, as compared to the prior art, the environmental conditions that do not impede recording are expanded.

As described above, in this embodiment, the diluent can be added depending on the temperature and humidity of the ink ejecting portion, so that the influence of environmental conditions (temperature, humidity) on ink viscosity fluctuations can be reduced.

In this embodiment, the amount of diluent added is changed stepwise, but if the control device 13 performs calculations based on temperature and humidity using a predetermined function to change the amount added steplessly, the environmental conditions can be wider. You get the range.

Furthermore, by using the present invention in combination with other methods for improving viscosity control, it is possible to further expand the range of environmental conditions that do not hinder recording.

〔Effect of the invention〕

According to the present invention, the range of environmental conditions (temperature, humidity) surrounding the recording device that can maintain the ink within the appropriate viscosity range is expanded, so compared to the conventional technology, it is necessary to have more complicated mechanisms such as viscosity and density detection devices. This has the effect of eliminating the need to strictly control the temperature and humidity around the recording device.

[Brief explanation of drawings]

FIG. 1 is an ink circulation system diagram of an embodiment of the present invention, and FIG. 2 is a diagram showing a comparison between the above embodiment and the prior art regarding the range of environmental conditions in which ink viscosity can be controlled. DESCRIPTION OF SYMBOLS 1... Ink tank, 3... Ink particle generator, 5... Inkjet recording medium, 6... Ink collection groove, 10... Diluent addition device, 1l... Temperature detection device, 12... Humidity detection device, 13... Diluent addition amount command control device, l4... Ink circulation system control device. Figure 1 2nd item

Claims (1)

[Scope of Claims] 1. In an inkjet recording device that performs recording by making ink into particles and jetting them from a nozzle in a circulation system and spraying them onto a recording medium while circulating the ink, the temperature and humidity near the device Based on the information obtained from the device, the amount of diluent added per unit time to adjust the ink viscosity in the ink circulation system is adjusted according to the temperature and humidity. 1. An inkjet recording apparatus comprising a device for changing the ink to a predetermined value and adding the ink to a circulation system. 2. The inkjet recording device according to claim 1, characterized in that the device for detecting temperature and humidity is located inside the device housing. 3. An inkjet recording apparatus according to claim 1, characterized in that the amount of change in the dilution liquid per unit time is changed in stages according to temperature and humidity.