JPS6277946A - Ink jet recording apparatus - Google Patents

Abstract

PURPOSE:To make it possible not only to alter the diameter of a printing dot by selection but also to increase the density of a printing image or the degree of freedom of printing grade, by setting the bias temp. of a recording head by the temp. setting command from a host computer and changing said bias temp. by changing the temp. setting command. CONSTITUTION:The bias temp. of a recording head 6 is set by the temp. setting command from a host computer CPU and controlled by set reference temp. By changing the temp. setting command by the option of a user, the reference temp. can be altered over a plurality of stages. A temp. detector 7 and a heater 8 are provided to a head unit 24 and the bias temp. of the recording head 6 is controlled on the basis of the reference temp. By selecting the temp. setting command from the host computer CPU by a user, the bias temp. of the recording head 6 is controlled to desired temp. and the diameter of a printing dot can be selectively changed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a means for controlling the bias temperature of a recording head in an ink jet recording apparatus equipped with a bubble jet recording head.

[Prior art]

2. Description of the Related Art An inkjet recording device equipped with a bubble jet recording head is used as a type of recording device such as a printer or a facsimile.

This type of inkjet recording device provides an electrothermal converter made of a heating resistor, etc., corresponding to each of the plurality of ink ejection ports that form print dots, and drives each electrothermal converter based on print data. This causes bubbles to grow within the liquid ink, and the extrusion force causes the ink to be ejected to form flying ink droplets, thereby forming printed dots on the recording medium (paper, plastic sheet, etc.). .

By the way, in this type of bubble jet recording head, the head driving voltage is usually set to a constant value, so when the temperature of the recording head is low, the ink ejection amount and ejection speed decrease, and the print dot diameter becomes smaller. When the temperature of the recording head is high, the amount and speed of ink ejection increases, resulting in a larger print dot diameter.

Therefore, in order to obtain a stable print dot diameter, it is necessary to maintain the recording head within a predetermined temperature range.

Therefore, it has been proposed to provide the recording head with a heater and a temperature sensor, set the bias temperature of the recording head, and control the heater based on this set temperature.

However, in the bubble jet type inkjet recording device related to this existing proposal, the bias temperature of the recording head was set so that the diameter of the printed dots was constant, so it was difficult to select the shading of the printed image, or to It was not possible to meet requests such as reducing the dot diameter and increasing resolution to improve print quality.

〔the purpose〕

The purpose of the present invention is to provide an inkjet recording device that can solve the problems of the prior art, can change the printing dot diameter according to the user's selection, and can increase the degree of freedom in the shading of printed images and printing quality. It is to provide.

Summary of the Invention The present invention achieves the above object by setting the bias temperature of the recording head using a temperature setting command from a host computer, and changing the bias temperature of the recording head by changing the temperature setting command. be.

〔Example〕

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

FIG. 1 shows the main structure of an inkjet recording apparatus according to an embodiment of the present invention.

In FIG. 1, a recording medium 1, such as paper or a plastic sheet, is supported by conveyance rollers 2 and 3, each consisting of a pair of upper and lower rollers, and is conveyed in the direction of arrow A. A guide shaft 4.4 is provided in front of and parallel to the transport rollers 2, 3, and the carriage 5 is reciprocated in the direction of arrow B along the guide shaft.

A bubble jet recording head 6 is mounted on the carriage 5.

On the front surface of this bubble jet recording head, that is, on the surface facing the recording medium l at a predetermined interval (for example, 0.8 mm), there are a plurality of ink ejection ports 10 (for example, 24 or 32) in a vertical row (Fig. 2). By driving the electrothermal transducer 11 (Fig. 2) of each ink ejection port based on print data, flying ink droplets are formed and print dots are attached to the recording medium l in a predetermined pattern. Recording is performed while

To the above record ・2 draw (specifically its heat sink)
A temperature detector 7 consisting of a thermistor or the like and a heater 8 consisting of an electrothermal converter are provided.

The CPtJ (microprocessor) of the recording device is connected to the host computer via an interface, and receives command signals (
command) and print data signals and CPU ROM
The recording operation is controlled based on a program stored in the .

FIGS. 2A and 2B schematically show the ink ejection ports 10 of the recording head 6. FIG.

In Fig. 2 (A) and (B), each ink discharge port 1
0 is provided with an electrothermal transducer 11, and by applying a head drive voltage of 111 to these, the ink 12 in the ink ejection port is heated, bubbles 13 grow, and the expansion force of the bubble causes flying ink to be ejected. A droplet 14 is formed and a printed dot is formed on the recording medium 1.

When the head drive voltage is constant, if the bias temperature of the recording head 6 is low, the growth of the bubble 13 is small and the ink ejection amount and ejection speed are small, as shown in FIG. The diameter becomes smaller.

When the bias temperature of the recording head 6 is high, as shown in FIG. 2(B), the growth of the bubble 13 becomes large, and the amount and speed of ink ejection becomes large, so that the ink droplet 14 becomes large and the diameter of the printed dot becomes large.

Note that when the bias temperature of the recording head 6 is constant, increasing the head drive voltage increases the ink ejection amount and ejection speed as shown in FIG. 2 CB), and the print dot diameter increases.

Accordingly, the bias temperature of the recording head 6 according to the present invention is set by a temperature setting command from the host computer, and is controlled by the set reference temperature. Also, this group! The $-type temperature is configured so that it can be changed in multiple stages by changing the 'IFA degree setting command according to the user's selection.

FIG. 3 is a block diagram of a control system suitable for implementing the present invention.

In FIG. 3, a CPU (microprocessor) 20 of the recording device is connected to a host computer via an interface 21, and a motor driver 22
The drive source 23 such as the general feed motor (carriage motor, recording medium) is controlled via the drive source 23, and the recording nozzle 6 is controlled via the head driver 25 mounted on the head unit 24.
control.

The CPU 20 reads a temperature setting command from the host computer via the interface 21 to set a reference temperature, and can change the set value of the reference temperature by changing the read temperature setting command.

The head unit 24 (specifically, the recording throat 6
A temperature detector 7 and a heater 8 are provided in the heat sink), and the bias temperature of the recording head 6 is controlled based on the reference temperature.

In this way, by selecting a temperature setting command from the host computer, the user can control the bias temperature of the recording head 6 to a desired temperature and selectively change the print dot diameter.

Therefore, by setting the base 4 temperature low, it is possible to record with small print dot diameter and light print or high resolution print, and by setting the reference temperature high, it is possible to record with large print dot diameter and dark print. Now I can do it. Therefore, according to the user's preferences or requests for improving print quality, the temperature setting command read along with the print data can be used to freely select the four shades of the print image and improve the print quality without having to set the recording device each time. It is possible to improve the degree.

In addition, by applying a predetermined bias temperature to the recording head 6, the same state as performing interface ejection with a drive voltage higher than the head drive voltage that is actually applied can be obtained, resulting in a faster ejection speed. This makes it possible to obtain a larger amount of ink discharge and lower the ink viscosity, making it possible to easily increase the print dot diameter.

Furthermore, by applying a predetermined bias temperature to the print head 6, it is possible to reduce the thermal energy applied during printing and to increase the response frequency of the print head. Since it can be obtained from a lower voltage, it has become possible to record with a lower voltage, and it has become possible to improve the reliability and durability of the recording device.

FIG. 4 is a flowchart showing the operating procedure of the control system shown in FIG.

In FIG. 4, when the recording operation is started in step 100, the CPLI reads a temperature setting command from the host computer in step 101, and in step 10
2 and vi, quasi? A degree is set.

Next, the process proceeds to step 103, where the temperature detector 7 detects the bias temperature of the recording head 6 and compares it with the reference temperature.

Step 10 if the detected temperature is lower than the lower limit of the reference temperature
4, the heater 8 is turned on for a certain period of time to heat the heat sink of the recording head 6, and the process returns to step 103 again.

If the detected temperature is higher than the upper limit of the reference temperature, step 10
The process proceeds to step 5, where recording is interrupted, a certain period of time is allowed to cool down, and the process returns to step 103.

If the detected temperature is between the lower and upper limits of the reference temperature, that is, if it is appropriate, the process advances to step 106 to record, and then returns to step 1 and step 101 to repeat the above operations.

Note that the present invention can be similarly applied to the case where a plurality of bubble jet recording heads 6 are used for color printing, grayscale printing, etc., and can also be applied to a line print method that records one line at a time instead of carriage scanning, or Page printing method inkjet recording that records one page at a time 2
The same can be applied to two devices.

〔effect〕

As is clear from the above description, according to the present invention, bubble jet inkjet recording allows the printing dot diameter to be changed according to the user's selection without operating the recording device, thereby setting the density of printing and improving the printing quality. A device is obtained.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the main parts of an inkjet recording apparatus according to an embodiment of the present invention, and FIG. (B) is a schematic cross-sectional view illustrating the state of ink droplet formation at the ink ejection port, FIG. 3 is a block diagram showing the control system of the inkjet recording apparatus according to the present invention, and FIG. 4 is the control system of FIG. 3. 3 is a flowchart showing the operating procedure. 6--recording head, 7--1 temperature detector, 8--
-----Heater, 10---・Ink discharge port, 14-
・－・－Ink drops.

Claims (1)

[Claims] (1) In an inkjet recording apparatus equipped with a bubble jet recording head, the bias temperature of the recording head is set by a temperature setting command from the host computer,
An inkjet printing apparatus characterized in that the bias temperature of a printing head is changed by changing a temperature setting command.