JP2000225691A - Ink jet recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep ink droplets from a recording head constant, even when the characteristics of a temperature detecting means to be mounted on a recording head differ. SOLUTION: This ink jet recording device comprises a temperature detecting means 18 mounted on a recording head 10 and a storage means 19 for storing the characteristic ranking of the detecting means 18 in the head 10. Thus the device corrects drive parameters using a temperature table stored in ROM 45 in accordance with the characteristic ranking stored in the storage means 19. Consequently, it is possible to optimize the drive parameters and obtain appropriate discharge ink droplets under whatever temperature environments may be.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus used as an ink jet printer or an ink jet plotter. More specifically, the present invention relates to temperature detection of a recording head of an ink jet recording apparatus.

[0002]

2. Description of the Related Art In a conventional ink jet recording apparatus used as an ink jet printer, an ink jet plotter or the like, as shown in FIG. The piezoelectric vibrator 17 contracts the pressure generating chambers 113 communicating with the nozzle openings 111 to discharge ink droplets from the nozzle openings 111. In this ink jet recording apparatus, a plurality of such combinations of the piezoelectric vibrator 17, the pressure generating chamber 113, and the nozzle opening 111 are formed, and any one of the plural piezoelectric vibrators 17 is driven. By controlling which nozzle opening 111 ejects an ink droplet, a predetermined image is recorded on a medium such as recording paper. Such control is performed depending on which piezoelectric vibrator 17 is to be applied with the common drive signal output from the drive signal generation circuit. Here, a drive signal generation circuit for generating a common drive signal is configured on the printing apparatus main body side, and the drive signal is output from the printing apparatus main body to the print head via a flexible wiring cable or the like.

In the case of using a piezoelectric vibrator in the ink jet recording apparatus thus configured, a common drive signal COM having, for example, a waveform shown in FIG. 4 is used. In the drive signal COM, the charging pulse 312 bends in a direction to expand the volume of the pressure generating chamber 113, and generates a negative pressure in the pressure generating chamber 113. Meniscus nozzle opening 1
When the discharge pulse 314 is applied and the discharge pulse 314 is applied, the piezoelectric vibrator 17 bends in a direction to reduce the volume of the pressure generation chamber 113, and a positive pressure is generated in the pressure generation chamber 113.
As a result, ink droplets are ejected from the nozzle openings 111. Here, the inclination of the charge pulse 312 or the discharge pulse 314 is set so that ink droplets are ejected under optimum conditions, for example, based on the case where all the piezoelectric vibrators 17 are driven.

[0004] A method of adapting the optimum conditions is to change the drive voltage in accordance with the ambient temperature of the recording head so as to keep the ejected ink droplet constant. The temperature detector is disposed on the recording head at a position where the ambient temperature can be detected.
When the diode characteristics in C are used, the ambient temperature of the recording head is known from the diode output voltage as shown in FIG. The drive voltage is changed according to this ambient temperature as shown in FIG.

[0005]

However, the diode for measuring the ambient temperature has a characteristic that the output voltage is low when the temperature is high and the output voltage is high when the temperature is low. However, the absolute value of the output voltage with respect to the temperature is high. Is not constant between ICs. This is because the characteristics of the diode change depending on the conditions for forming the temperature detecting diode. Generally, the output voltage of one diode at 25 ° C. is 0.6 to 0.7 [V], and the amount of voltage change due to the ambient temperature is about −2 mV / ° C. to −3 mV / ° C. There is a problem that it is not good.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an ink jet recording apparatus which can maintain a constant discharge ink droplet using a temperature detecting diode even if the characteristics of the temperature detecting diode are different for each IC.

[0007]

SUMMARY OF THE INVENTION In a printhead having a plurality of nozzles and a head driver for driving the plurality of nozzles, a temperature detector mounted on the printhead and a characteristic rank of the temperature detector are assigned to the printhead. The drive condition is corrected by a temperature table corresponding to a characteristic rank selected by the characteristic rank stored in the storage means.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An ink jet recording apparatus to which the present invention is applied will be described with reference to the drawings.

[Overall Configuration of Inkjet Recording Apparatus] FIG. 1 is a perspective view showing the configuration of an inkjet recording apparatus to which the present invention is applied.

In FIG. 1, an ink jet recording apparatus 1 of the present embodiment is used by being connected to a computer (not shown). When a predetermined program is loaded and executed on the computer, the entirety of these devices integrally functions as a recording device. On the computer,
When an application program runs under a predetermined operating system and issues a print command, it converts image data and character data from a memory in a computer into data used by the inkjet recording apparatus 1 and outputs the data to the inkjet recording apparatus 1. I do.

In the ink jet recording apparatus 1, a carriage 101 is connected to a carriage motor 103 of a carriage mechanism 12 via a timing belt 102, and is guided by a guide member 104 to reciprocate in the width direction of the recording paper 105. I have. The recording head 10 receives ink from an ink cartridge 107 mounted on the upper portion of the carriage 101 and ejects ink droplets onto the recording paper 105 in accordance with the movement of the carriage 101 to form dots. To print images and text.

A capping device 108 is provided in a non-printing area (non-recording area) of the ink jet recording apparatus 1, and seals a nozzle opening of the recording head 10 during printing pause. Therefore, it is possible to suppress the ink from thickening or forming an ink film due to the solvent being scattered from the ink during the suspension of printing. Therefore, it is possible to prevent the nozzle from being clogged while the printing is stopped. Further, the capping device 108 receives ink droplets from the recording head 10 due to a flushing operation performed during a printing operation. A wiping device 109 is arranged near the capping device 108.
Is configured to wipe off ink droplets and paper powder attached thereto by wiping the surface of the recording head 10 with a blade or the like.

FIG. 2 is a functional block diagram of the ink jet recording apparatus 1 of the present embodiment.

In FIG. 2, an ink jet recording apparatus 1
1 schematically includes a printing apparatus main body including a print controller 40 and a print engine 5 and a print head 10. The print controller 40 includes an interface 43 for receiving print data including multi-level hierarchical information from a computer (not shown), and a RAM 4 for storing various data such as print data including multi-level hierarchical information.
4, a ROM 45 storing routines for performing various data processing, a control unit 6 including a CPU, etc., an oscillation circuit 47, a drive signal generation circuit 8 for generating a drive signal COM to the recording head 10, The print engine 5 includes a drive signal generation circuit 8 and an interface 49 for transmitting print data and drive signals developed into dot pattern data to the print engine 5.

Print data including multi-level hierarchical information sent from a computer or the like is held in a reception buffer 44A inside the printing apparatus via an interface 43. The recording data held in the reception buffer 44A is sent to the intermediate buffer 44B after the command analysis is performed. In the intermediate buffer 44B, the recording data in the intermediate format converted into the intermediate code by the control unit 6 is held, and the process of adding the print position, the type of modification, the size, the font address, etc. of each character is controlled. This is performed by the unit 6. Next, the control unit 6 analyzes the recording data in the intermediate buffer 44B, and develops and stores the binarized dot pattern data obtained by decoding the hierarchical data in the output buffer 44C as described later.

When dot pattern data corresponding to one scan of the recording head 10 is obtained, the dot pattern data is serially transferred to the recording head 10 via the interface 49 and the flexible wiring cable 90. When dot pattern data corresponding to one scan is output from the output buffer 44C, the contents of the intermediate buffer 44B are erased, and the next intermediate code conversion is performed.

The print engine 5 includes the paper feed mechanism 11 and the carriage mechanism 12. The paper feed mechanism 11 sequentially feeds a recording medium such as recording paper to perform sub-scanning, and the carriage mechanism 12 causes the recording head 10 to perform main scanning.

The recording head 10 discharges ink droplets from each nozzle opening at a predetermined timing. The driving signal COM output from the driving signal generating circuit 8 is recorded via the interface 49 and the flexible wiring cable 90. Output to the head 10.

The recording head 10 has, for example, 64 nozzles in the sub-scanning direction, and discharges ink droplets from each nozzle opening at a predetermined timing. In the print controller 40, the print data SI developed into dot pattern data is serially output to the print head 10 via the interface 49 and the flexible wiring cable 90 in synchronization with the clock signal CLK from the oscillation circuit 7, and the print head 10 Are serially transferred to the shift register 13. This serially transferred recording data S
I is temporarily latched by the latch circuit 14.

The latched print data SI is supplied to the nozzle selection circuit 1 by a level shifter 15 which is a voltage amplifier.
6 (head selecting means), for example, to a predetermined voltage of about several tens of volts. The drive signal boosted to a predetermined voltage is supplied to the nozzle selection circuit 16. A drive signal COM from the drive signal generation circuit 8 is applied to an input side of the nozzle selection circuit 16, and a piezoelectric vibrator as a piezoelectric vibrator 17 is connected to an output side of the nozzle selection circuit 16. . The number of the piezoelectric vibrators 17 is also equal to the number of the nozzle openings (for example, 64) in a one-to-one relationship with the nozzle openings.

Here, the print data SI controls the operation of the nozzle selection circuit 16. For example, nozzle selection circuit 1
During a period in which the recording data SI applied to 6 is "1", the drive signal COM is applied to the piezoelectric vibrator 17, and the piezoelectric vibrator 17 expands and contracts in accordance with this signal. On the other hand, while the recording data SI applied to the nozzle selection circuit 16 is “0”, the supply of the drive signal COM to the piezoelectric vibrator 17 is cut off.

FIG. 3 is an enlarged sectional view showing one of the actuators formed on the recording head 10. As shown in FIG.

In FIG. 3, in the recording head 10, a nozzle opening 111 is formed in a nozzle plate 110, and a through hole for defining a pressure generating chamber 113 is formed in a flow path forming plate 112.
There are formed through holes or grooves defining two ink supply ports 114 communicating on both sides with the pressure generating chamber 113, and through holes defining two common ink chambers 115 communicating with these ink supply ports 114, respectively. I have. Diaphragm 11
Numeral 6 is formed from an elastically deformable thin plate, abuts against the tip of a piezoelectric vibrator such as a piezo element, and is fixed integrally with the nozzle plate 110 with the flow path forming plate 112 interposed therebetween to form a flow path unit 118. I have.

The base 119 is formed with an accommodation chamber 120 for accommodating the piezoelectric vibrator 17 so as to vibrate and an opening 121 for supporting the flow path unit 118, and exposing the tip of the piezoelectric vibrator 17 from the opening 121. In this state, the piezoelectric vibrator 17 is fixed by the fixed substrate 122. The base 119 forms the recording head 10 by fixing the channel unit 118 to the opening 121 in a state where the island portion 116a of the diaphragm 116 is in contact with the piezoelectric vibrator 17.

[First Embodiment] FIG. 5 is an external view of a recording head 10 of the present invention. 110 is a nozzle plate. 130 is a case. 140 is a head drive IC chip including a shift register, a latch, a level shifter, a nozzle selection circuit, and a temperature detector. 141 is a substrate on which the head drive IC chip 140 is mounted and fixed. Reference numeral 19 denotes storage means for storing a characteristic rank on an adhesive seal, a plastic seal, a bar code, or the like in order to store the characteristic rank of the temperature detecting means.

In order to improve the accuracy of the temperature detecting means, the diode output voltage formed in the head driving IC chip 140 is divided into several stages. As a method after IC manufacture,
The diode output voltage is measured in an environment where the ambient temperature is stable, for example, in a thermostat. The measurement is performed in an environment of 25 ° C. and other environments. Thus, a diode output voltage in a 25 ° C. environment and a voltage change amount with respect to an ambient temperature are obtained.
As a result, a display having a characteristic display voltage close to that shown in FIG. 6 is stored in the head. In the example of FIG. 6, 3.55 [V] under a 25 ° C. environment
And the characteristic rank “D” is written in the storage unit 19.

In FIG. 6, seven ranks are prepared and the voltage is 25.
Under the environment of ° C., the characteristic rank “A” is 3.4 [V], the characteristic rank “B” is 3.45 [V], and the characteristic rank “C” is 3.5.
[V], characteristic rank “E” is 3.6 [V], characteristic rank “F” is 3.65 [V], and characteristic rank “G” is 3.7.
[V]. Needless to say, if the range of voltage values is wide, the number of characteristic displays may be increased.

When assembling the ink jet recording apparatus, the characteristic rank stored in the recording head 10 is written in an EEPROM (not shown). Temperature table is ROM
45. EEP not shown when printing
The temperature table of the ROM 45 is selected from the characteristic rank written in the ROM so that the ambient temperature of the recording head 10 can be detected. To detect the ambient temperature, the output voltage of the temperature detector 18 in the recording head 10 is applied to the flexible wiring cable 9.
0, the output voltage is converted from an analog value to a digital value by an analog-to-digital converter in the interface 49, read by the control unit 6, and read by an EEPRO (not shown).
This is performed by associating with the voltage data of the temperature table in the ROM 45 corresponding to the characteristic rank written in M.

An appropriate driving voltage is set based on the ambient temperature of the recording head, and the discharged ink droplet is kept constant. If the ambient temperature around the printhead is low, the viscosity of the ink will be high, and if it is high, the viscosity of the ink will be low. Become. Therefore, when the ambient temperature of the recording head is low as shown in FIG.
To VPSa, and drive waveforms 311a, 312
a, 313a, 314a, 315, 316a, 317a
And change. When the ambient temperature of the recording head is high, the driving voltage is set from VLS to VPSb, and the driving waveforms are 311b, 312b, 313b, 314b, 31
5, 316b, and 317b.

In this manner, variations in diode characteristics are suppressed by rank, accurate ambient temperature of the head can be detected, the drive voltage to the head can be changed, and the ink droplets ejected can be kept constant.

[0031]

As described above, in the ink jet recording apparatus according to the present invention, the characteristic rank of the temperature detecting means is stored and displayed on the recording head. Accurate temperature detection around the head became possible. As a result, the driving conditions can be optimized, and appropriate ejection ink droplets can be obtained under various temperature environments.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a main part of an ink jet recording apparatus to which the present invention is applied.

FIG. 2 is a block diagram of the ink jet recording apparatus shown in FIG.

FIG. 3 is a cross-sectional view of an actuator formed on a recording head of the ink jet recording apparatus shown in FIG.

FIG. 4 is a waveform diagram of a drive signal applied to a piezoelectric vibrator used in the actuator shown in FIG.

FIG. 5 is a perspective view of a recording head of the ink jet recording apparatus shown in FIG.

FIG. 6 is an explanatory diagram showing characteristics of a temperature detecting unit provided in the head driving IC chip of FIG. 5;

FIG. 7 is a characteristic diagram of a temperature detecting unit provided in the head driving IC chip of FIG. 5;

FIG. 8 is a circuit diagram in the case where a diode is used for the temperature detecting means.

9 is a waveform diagram of a drive signal after temperature correction applied to a piezoelectric vibrator used in the actuator shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ink jet recording apparatus 5 Print engine 6 Control part 8 Drive signal generation circuit 10 Recording head 18 Temperature detector 19 Storage means 45 ROM 49 Interface 110 Nozzle plate 130 Case 140 Head drive IC chip 141 Substrate 142 Resistance

Claims (1)

[Claims] 1. A recording head having a plurality of nozzles and a head driver for driving the plurality of nozzles, wherein a temperature detecting means mounted on the recording head and a characteristic rank of the temperature detecting means are stored in the recording head. An ink jet recording apparatus comprising: a storage unit for correcting a driving condition using a temperature table corresponding to a characteristic rank selected by the characteristic rank stored in the storage unit.