JP3320147B2 - Thermal inkjet recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal ink jet recording apparatus, in which ink flowing between a heating resistor and an orifice provided opposite to the heating resistor is applied to the heating resistor by applying power thereto. The present invention relates to a thermal ink jet printing apparatus that causes a change in state of a hot drop in ink and ejects ink from an orifice to perform printing.

[0002]

2. Description of the Related Art Conventionally, in a thermal ink jet recording apparatus of this type, FIG. 3 shows a typical configuration diagram of a thermal ink jet cartridge as a component, and FIG. 4 shows a perspective view of a thermal head in FIG. 5 is a sectional view taken along the line AA in FIG. 4, and the thermal ink jet cartridge 1 is composed of an ink supply means 2 and a thermal head 3 provided therein. The ink supply means 2 is connected to the ink supply means 2 through a slot 10 which is an inflow port of the ink inside. The thermal head 2 has an ink flow path 9 formed by an ink flow path material 8, and a heating resistor 11 is provided facing the ink flow path 9, and an orifice 7 faces the heating resistor 11. It has a structure covered with an orifice plate 6.

In the above configuration, when driving power is applied to the heating resistor 11 from a signal applying means (not shown), heat energy generated from the heating resistor 11 causes
The ink 12 in the ink flow path 9 above the heating resistor 11 causes a thermal state change (film boiling or homogeneous nucleate boiling) in which bubbles are instantaneously generated on the surface in contact with the heating resistor 11, A part or almost all of the ink 12 present in the ink flow path 9 is discharged from the orifice 7 by the action force based on this state change. On the other hand, the heating resistor 11
When the supply of thermal energy from the
The bubbles formed therein are instantaneously reduced in volume and either disappear or are reduced to almost negligible volume.
The ejected ink 12 is immediately supplied to the ink flow path 9 through the slot 10 by the action of contracting the volume of the bubble and the capillary force.

[0004]

In the above-described conventional thermal ink jet recording apparatus, the ink is ejected by the heating resistor heating a part of the ink in the ink flow path to cause a thermal state change. A pulse width, an applied voltage, and a drive timing are set in advance for a signal applying unit that supplies a signal for generating thermal energy for forming a droplet to the heating resistor. However, the amount and speed of ink droplets ejected from the orifice and flying greatly depend on the structure of the thermal head, the amount of applied thermal energy, the surface tension and viscosity of the ink, and especially the surface tension and viscosity of the ink Since the temperature varies depending on the temperature, there is a problem that when the recording apparatus is used away from the recommended operating environment, quality deterioration such as blurring of printing, white spots and feathering occurs.

[0005]

According to the thermal ink jet recording apparatus of the present invention, the ink supplied from the ink supply means to the surface of the heating resistor via the ink inlet and the ink passage material is supplied from the signal applying means to the heating resistor. In the thermal ink jet recording apparatus in which a thermal state change is caused by the applied power and ink droplets are ejected in a predetermined direction from an orifice facing a heating resistor surface to perform recording on a recording medium, an ink supply unit is separated. Temperature measuring means for measuring the temperature of the ink stored inside the heating resistor side ;
Storage means for holding optimum applied power information of the heating resistor with respect to the temperature of the ink; control means for reading the optimum applied power information for the temperature measured by the temperature measuring means from the storage means; Signal applying means for outputting applied power to the heating resistor according to the applied power information.

[0006]

Next, the present invention will be described with reference to the drawings.

FIG. 1 is a configuration diagram of a means for applying power to a heating resistor used in the first embodiment of the present invention. FIG. 2 is a longitudinal sectional view showing the structure of the thermal ink jet cartridge including the temperature measuring means shown in FIG. 1. The structure of the thermal head in the embodiment is the same as that of the conventional one shown in FIGS.

In the thermal ink jet cartridge 1 shown in FIG. 2, the ink supply means 2 is separated by providing a filter 5 near the thermal head 3 and a temperature detecting means 4 is provided inside the filter to stabilize the ink near the thermal head. The temperature can be detected.

The power applying means shown in FIG. 1 comprises a temperature detecting means 4, a control section 13, a storage section 14, a signal applying section 15, and a heating resistor 11. The storage section 14 has a surface for each temperature of the ink. Information on the optimum applied power for obtaining a preferable flying ink droplet from the values of the tension and the viscosity is held as a table. The control unit 13 periodically measures the temperature of the ink by the temperature detecting unit 4, obtains information on the optimum applied power corresponding to the measured temperature with reference to the storage unit 13, and sends the pulse width and the applied voltage to the signal applying unit 15. Indicate the voltage and drive timing value. The signal applying means 15 outputs a driving pulse to the heating resistor 11 according to the indicated value.

In the second embodiment of the present invention, a surface tension / viscosity detecting means is used in place of the temperature detecting means 4 shown in FIGS.
The information of the optimum applied power for obtaining a preferable flying ink droplet with respect to the viscosity is held as a table, and the other configuration is the same as that of the first embodiment. Therefore, information on the optimum applied power is obtained based on the surface tension and viscosity of the ink instead of the temperature of the ink in the first embodiment, and a drive pulse is output to the heating resistor 11 based on this information.

In the third embodiment of the present invention, a print dot shape measuring means for measuring the shape of a print dot discharged from an orifice and attached to a recording medium is used in place of the temperature detecting means 4 shown in FIG. The print dot shape measuring means is provided on the thermal head scanning line on the side of the thermal ink jet cartridge. The storage means 14 stores in advance a table of correction driving conditions based on the difference between the optimum print dot shape and the actual print dots, and the other configuration is the same as that of the first embodiment. The control means 12 periodically measures the print dot shape by the print dot shape measurement means, obtains the correction driving conditions corresponding to the measured print dots with reference to the storage unit 14, and applies the pulse width and the applied Indicate the fluctuation value of the voltage and the drive timing. The signal applying means 15 outputs a drive pulse to the heating resistor 11 according to the instruction.

[0012]

As described above, according to the present invention, the temperature of the ink held in the ink supply means is measured by the temperature detection means before the ink is supplied to the thermal head, and the temperature is held in advance by the control unit. With reference to the information of the temperature and the optimum applied power, the signal applying unit is controlled under the optimum driving condition based on the information, and the surface tension and viscosity of the ink held in the ink supply unit are determined. Measured by the surface tension / viscosity detecting means before being supplied to the thermal head, refer to the information held in advance by the control unit, and control the signal applying means under the optimal driving condition based on the information The print dot shape is measured by the print dot shape measuring means for measuring the print dot shape discharged from the orifice and adhered to the recording medium, and the control unit refers to the information held in advance to check the print dot shape. By controlling the signal applying means at the proximal not a Ki optimum drive condition information, a change in any environment, or even change happens to the print medium, an appropriate amount and droplet velocity of the ink droplets ejected from the orifice is constant,
As a result, high quality and stable printing can be performed on the recording medium.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a means for applying power to a heating resistor used in a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a thermal ink jet cartridge including the temperature detecting means shown in FIG.

FIG. 3 is a longitudinal sectional view of a thermal inkjet cartridge used in a conventional thermal inkjet recording apparatus.

FIG. 4 is a perspective view of a thermal head used in the thermal inkjet cartridge of FIG.

5 is a sectional view of the thermal head of FIG. 4 taken along the line AA.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Thermal inkjet cartridge 2 Ink supply means 3 Thermal head 4 Temperature detection means 7 Orifice 11 Heating resistor 12 Ink 13 Control unit 14 Storage unit 15 Signal application means

Claims (1)

(57) [Claims] 1. A thermal state change is caused by electric power applied from a signal applying means to a heating resistor from ink supply means to an ink flowing into a heating resistor surface via an ink inlet and an ink flow path material, In a thermal ink jet recording apparatus that performs recording on a recording medium by discharging ink droplets from an orifice facing a heating resistor surface in a predetermined direction, the temperature of the ink stored inside the heating resistor divided by an ink supply unit is measured. A temperature measuring unit that performs the operation, a storage unit that holds information on the optimum applied power of the heating resistor with respect to the temperature of the ink, a control unit that reads the optimum applied power information on the temperature measured by the temperature measuring unit from the storage unit, Signal applying means for outputting applied power to the heating resistor according to the optimum applied power information read by the control means. Thermal inkjet recording device.