JPS62113563A - Ink jet recorder - Google Patents

Abstract

PURPOSE:To enable ink discharge to be changed through temperature variations by providing a temperature sending means, a heater and an air blower and controlling them electrically based on the temperature sensing readings of a printing head. CONSTITUTION:If a control signal Si from a temperature sensing means 11 indicates 'high humidity' state ('high humidity' signal Si1 is ON), a fan 9 and a heater 7 are set to a low temperature (L), and if the signal indicates 'low humidity' state ('low humidity' signal Si2 is ON), the fan and heater are set to a high temperature H. If the signal indicates neither of them, the fan and heater are set to a normal temperature. Thus the fan and heater are controlled. When controlling the heater 7, the readings of temperature data Tn from a temperature sensing means 8 are obtained after checking the elapse of one second, interpreting whether or not the obtained value is lower than a set temperature. If it is lower, the heater 7 is set to 'drive ON' for heating. A blower 9 is also controlled by reading temperature data from the temperature sensing means 8, interpreting whether or not said data is higher than a set temperature. If it is higher, the blower 9 is set to 'drive ON', while, if it is lower, the blower is stopped. Further, it if is not lower, the blower is left operating as it is.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an inkjet recording device that can control print density based on humidity.

[Prior art]

An inkjet recording device is a device that discharges ink based on data signals from multiple ink discharge ports formed in a print head, and records by depositing ink droplets on paper, and is used in printers, facsimiles, etc. ing.

There are two types of inkjet recording devices: the line print type, in which the print head has one line of ink ejection ports arranged and scans in the paper feeding direction, and the print head is mounted on a carriage that moves along the paper. There is also a serial print type that scans in the direction of the paper stack. Furthermore, various arrangements of ink ejection orifices for line printing have been proposed, such as a straight line arrangement and a staggered arrangement.

Furthermore, in the case of a printer for color printing, a plurality of print heads of different colors such as yellow, magenta, cyan, and black are installed.

Such an inkjet recording apparatus generally has a structure in which a print head portion including a print head, a head drive circuit, etc. is formed into a unit, and each unit can be replaced.

However, in this type of inkjet recording device,
The viscosity and other properties of the ink change depending on the temperature of the apparatus, particularly the temperature of the print head, and the amount of ink ejected changes.

For example, when the temperature becomes low (for example, 5° C. or lower), the viscosity of the ink increases and the ejection becomes slow, resulting in a decrease in flight speed and a decrease in the amount of ink ejected. Further, when the temperature is high (for example, 50° C. or higher), the ink viscosity decreases and the ink discharge amount increases.

By the way, when controlling the print immersion level by reducing the amount of ink ejected because the ink becomes difficult to dry due to increased humidity, the conventional temperature control of the print head part is difficult, for example, in the case of an inkjet recording device that uses heat. Drive time during printing cycle, i.e. discharge energy generator (heater)
Increase or decrease the energization time to the heating element, or
The current flow to a heat generating element (heater) for heating the head was performed intermittently based on the detected temperature of the print head.

However, with these conventional methods, it takes time to preheat and cool down, which reduces the actual printing speed, makes it difficult to maintain the optimum ejection temperature, and makes it difficult to control the amount of ink ejected due to changes in humidity. There was a problem.

〔the purpose〕

SUMMARY OF THE INVENTION An object of the present invention is to provide an inkjet recording apparatus that can solve the problems of the prior art described above and can change the amount of ink ejected depending on changes in humidity.

〔overview〕

The present invention provides a printing head unit with a heater and a temperature detection means, and also includes a blower and a humidity detection means in the apparatus, and detects the humidity based on a detection signal of the temperature detection means and a signal from the humidity detection means. The above object is achieved by controlling the amount of ink ejected from printing by controlling the drive of the heater and the blower.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings, taking as an example a case in which the present invention is applied to a line print type color inkjet recording apparatus.

FIG. 1 shows the internal structure of a color inkjet recording apparatus according to one embodiment, in which a print head assembly 2 is provided at the front of a case 1, that is, on the paper (not shown) side. This print head assembly includes a plurality of (four in the illustrated example) print head units 3A, 3B, 3G, and 3D arranged in the vertical direction (paper feeding direction) and installed replaceably.
Each print head unit includes a plurality of print head elements 4 and is configured to print one line (by bit number) at a time. 4 print head units 3
A----3D prints different colors. For example, cyan, magenta, yellow, and 1. black are selected.

For example, an l line is formed by 1792 bits (dots), and each print head unit is formed by 128 bits or 12
It has a structure in which 14 printing elements each having eight ink ejection openings are mounted above and below a base plate 5 in a staggered manner.

At the rear of the case l, each of the print head units 3 A
---Ink container 6 for supplying ink to 3D
A---6D is installed replaceably.

Thus, each print head unit 3A---30 is provided with a heater 7 and a temperature detection means 8. Furthermore, each print head unit (3) is installed in the device.
A blower 9 is provided for cooling A---3D.

FIGS. 2 and 3 show the print head unit 3A.
--- Take any one of the 3Ds and show its temperature control system.

In FIG. 2, the heater 7 and the temperature detecting means 8 are provided at a desired position on the base plate 5 of the print head unit 3, that is, at a position close to each print head element 4 or at a position that indicates a temperature corresponding to the temperature thereof. There is. This print head unit can be cooled by the common blower 9 provided within the apparatus. As the heater 7, for example, a power transistor or a heating element can be used.

The detection signal of the temperature detection means 8 is input to the control unit (microcomputer) of the apparatus, and the control unit controls the drive of the heater 7 and the blower 9 based on this temperature signal, thereby controlling the temperature of the print head portion. properly control.

FIG. 3 shows this control system, and the detected low humidity signal Sil and the detected low humidity signal Si7 from the humidity detecting means 11 (for example, a humidity sensor having characteristics as shown in FIG. 4) are sent to the control unit 10.
and the detected temperature signal S of the temperature detection means 8 is input to the control unit (CPU) 10, and the control unit 10 sends a drive signal DH to the heater 7 when the print head is at a low temperature and needs to be heated. is emitted, and when cooling is required due to high temperature, a drive signal DF is emitted to the blower 9.

For example, if the humidity is high (relative humidity 95% or higher), the head temperature should be lowered to reduce the amount of ink ejected to allow the ink to dry better, and if the humidity is low (relative humidity 5% or lower), the head temperature should be set to a higher temperature to reduce the amount of ink ejected. The discharge amount is increased to make the boundary between adjacent dots less noticeable.

FIG. 5 shows the control procedure. First, if the control signal S+ from the humidity detection means 11 is in the high humidity state yE (the high humidity signal Sil is ON) in step 71, the low temperature L is detected in step 72.
(for example, 30°C), and if the temperature is low in step 73 (low temperature signal Si2 is ON), step 7
Step 4 sets the high temperature H (e.g. 40°C), and if not, sets it to normal temperature M (e.g. 35°C) in step 75, controls the fan in step 76, controls the heater in step 77, and in step 78 Print.

Next, an example of the control operation will be explained with reference to FIGS. 45 to 7.

FIG. 6 shows the procedure for controlling the heater 7. In step 102, the timer is activated for 1 second, and after confirming that 1 second has elapsed in step 103, in step 104 temperature data Tn ( n=0 to 3).

From this temperature data Tn, it is determined in step 105 whether the temperature of the print head portion is lower than the set temperature.

If the temperature is low, the process proceeds to step 106, where the heater 7 is turned on and heated.

When it is determined in step 105 that the temperature is not lower than the set temperature, the process proceeds to step 107 and it is determined whether or not the temperature is higher than the set temperature.If it is higher, the heater 7 is turned off in step 108, and if it is not higher, it is left as it is. .

FIG. 7 shows the procedure for controlling the blower 9. At step 102, temperature data from the temperature detection means 8 is read.

In step 103, it is determined whether the temperature data is higher than the set temperature, and if it is higher, the blower 9 is turned on in step 104. If the temperature is not higher than the set temperature, step 105
Proceed to and determine whether the temperature is lower than the set temperature. If the temperature is lower than the set temperature, the blower 9 is stopped in step 106, and if it is not lower than the set temperature, it is left as it is.

According to the embodiment described above, when the temperature of the print head becomes low or high, the heater 7 or the blower 9 is operated based on the detection signal to actively heat or cool the print head. The temperature of the area could be controlled quickly and accurately, and the print density could be controlled by controlling the amount of ink discharged.

In the illustrated embodiment, the print head unit 3 is provided with one heater 7 and one temperature detection means 8, but a plurality of heaters 7 and temperature detection means 8 may be provided as required, and the temperature may also be controlled for each divided area. can.

Further, the present invention can be similarly applied regardless of the number and structure of print head units, and can be similarly applied to a serial print type in which print heads are mounted on a carriage.

〔effect〕

As is clear from the above description, according to the present invention, a humidity detection means, a heater, and an air blower are provided, and these are electrically controlled based on the detected temperature value of the print head. Temperature control for controlling ejected ink can be quickly and accurately controlled, print density can be controlled by changes in humidity, and ink drying can be controlled.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway perspective view showing the inside of an embodiment of an inkjet recording apparatus according to the present invention, FIG. 2 is an explanatory diagram showing the temperature control means of the print head unit in FIG. 1, and FIG. Fig. 2 is a schematic block diagram showing the control system of the temperature control means, Fig. 4 is a graph showing the characteristics of the humidity sensor, and Figs. 5 to 7 show the heater and blower in the temperature control shown in Figs. 3 is a flowchart illustrating a control operation procedure. 3, 3 A---3D: Print head unit, 4
: Print head element, 7: Heater, 8: Temperature detection means, 9: Air blower, 10: Control unit (CPU), 11: Temperature detection means.

Claims (1)

[Claims] (1) A heater and a temperature detection means are provided in the print head unit, and an air blower and a humidity detection means are provided in the apparatus, and the heater and the air blower are activated based on the detection signal of the temperature detection means and the signal from the humidity detection means. An inkjet recording device characterized by controlling the amount of ink ejected from a print head by controlling driving.