JPH02508A - Ink jet recorder - Google Patents

Abstract

PURPOSE:To provide stable driving energy to a heat generating element irrespective of the number of dots to be recorded at once by providing detecting means for detecting the number of energy generating means to be simultaneously driven, and regulating means for regulating the voltage value of a driving pulse to be applied to the energy generating means in response to a detected result. CONSTITUTION:A CPU 20 calculates the number of ON data of a heat generating element 3 contained in each predetermined quantity of data or its average, accesses the voltage regulating data of a RAM 21 based on its result, determines a power source voltage control signal C, and supplies it to a power source 5 for a head. The signal C is input to a decoder 55, any of transistors T1-T4 is selected in response to the value, and turned ON. When resistors R1-R4 are switched in response thereto, the voltage Vin of a power source voltage regulating line is varied, and the power source voltage is varied in response to the number of driving bits. As a result, a stable voltage VH can be supplied to a recording head 1 irrespective of the number of the driving bits.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an inkjet recording device, and in particular, the present invention relates to an inkjet recording device, and in particular, a heating element having a heating resistor and an electrode connected to the heating resistor is used as an ejection energy generating means in a wave path. The present invention relates to an inkjet recording apparatus having a plurality of ejection ports communicating with the liquid path.

[Prior Art] The inkjet recording method has many advantages, such as extremely low noise during recording, easy colorization, and the ability to record on so-called plain paper, and has attracted increasing attention in recent years. is increasing more and more.

Among these, a heating element installed in a liquid path that communicates with a fine ejection port that ejects ink is energized to generate heat, and the sudden volume that occurs when foaming occurs due to heating of ink around the heating element. Inkjet recording devices that use heat energy to perform recording by ejecting ink droplets from an ejection orifice using thermal energy have the advantage of being easy to downsize the device and having a high ejection orifice. It is attracting particular attention because it allows for dense arrangement.

In such an inkjet recording device that utilizes thermal energy, when a recording head is constructed by arranging a large number of ejection ports in a predetermined direction, for example, a so-called full head is configured in which ejection ports are arranged across the entire width of the recording medium in the width direction. In the case of a line type recording head, a voltage is normally supplied to all the heating elements or to each group of a predetermined number of heating elements sequentially to drive the recording head.

[Problems to be Solved by the Invention] However, since there is always wiring resistance in the wiring line between the recording head and the power source, the number of dots recorded at each time will affect the heating element. The driving energy will change. In other words, when the number of dots is small, the number of heating elements involved in driving is small, so the current flowing through the line is small, and the voltage drop is small.On the other hand, when the number of dots is large, the current is large, and therefore the voltage drop is large. Because it will be.

In this way, if the voltage applied to the heating elements differs depending on the number of heating elements involved in driving, the ejection energy acting on the ink changes, so there is a difference in recording quality depending on the number of dots recorded per degree. It will end up being put away.

An object of the present invention is to solve such problems and to provide stable drive energy to the heating element regardless of the number of dots recorded at a time, so that stable ejection energy acts on the ink. By doing so, the purpose is to improve the recording quality of the inkjet recording apparatus.

Means for Solving Problem E] To this end, the present invention includes a plurality of energy generating means that generate energy used to eject ink;
It is characterized by comprising a detection means for detecting the number of energy generation means driven simultaneously, and an adjustment means for adjusting the voltage value of the drive pulse applied to the energy generation means according to the detection result by the detection means. .

Further, in another aspect of the present invention, a plurality of energy generating means for generating energy used for ejecting ink, a detecting means for detecting the number of energy generating means that are operated simultaneously, and a plurality of energy generating means for generating energy used for ejecting ink; The present invention is characterized by comprising an adjusting means for adjusting the driving time of the driving pulse applied to the energy generating means in accordance with the detection result.

[Function] According to the present invention, ink ejection characteristics can be kept stable by adjusting the voltage value or drive time of the drive pulse according to the number of energy generating means driven simultaneously. .

That is, depending on the number of energy generating means driven simultaneously, the voltage adjusting means supplies a high voltage when the number is large, and a low voltage when the number is small. Alternatively, depending on the number of energy generating means driven simultaneously, the driving time adjusting means drives the ejection energy generating element with a long driving time when the number is large, and with a short driving time when the number is small. This makes it possible to supply stable driving energy to the energy generation means by canceling out the effects of fluctuations in voltage drop due to the wiring resistance corresponding to the above number, and it is possible to always apply stable ejection energy to the ink. becomes.

]Example】 Hereinafter, the present invention will be described in detail with reference to the drawings.

[First Example] FIG. 1 is a schematic perspective view showing an example of a recording head used in an inkjet recording apparatus of the present invention. Here, 101 is an ejection element, which includes a wave path in which heating elements, etc., which are thermal energy generating means for generating thermal energy used for ejecting ink, are arranged in parallel, and an ejection port 110 opened in front of each wave path. It also has a common liquid chamber for storing ink supplied to each liquid path, and forms recording droplets by ejecting ink from an ejection port 110.

Reference numeral 103 denotes a base plate for fixing the ejection element lO1 by adhesive or the like, and 102 refers to the ejection element 101.
and a front plate fixed to the end face of the base plate 103 by a tightening member such as a bolt, and has an opening 102a that allows the ejection port 110 to directly face the recording medium. Each part 115, 116 and 117 is a member forming a part of the ink supply system, l15 is an elbow-shaped connecting member that introduces ink into the common liquid chamber in the ejection element 101, and 117
Reference numeral 116 indicates a filter unit disposed in the middle of an ink supply path from an ink tank or the like as an ink supply source, and 116 a supply pipe connecting the connecting member 115 and the filter unit 117.

FIG. 2 is a block diagram showing one embodiment of the inkjet recording apparatus of the present invention. Here, l is a recording head, which is constructed by arranging a plurality of ejection ports in a predetermined direction, for example, across the entire width of the recording medium in the width direction, as shown in FIG. is a heating element provided in each liquid path. Reference numeral 5 denotes a head power supply device that applies voltage to the heating element 3 in the recording head 1, and its configuration will be described in detail with reference to FIG. R indicates the line resistance value between the power supply device 5 and the recording head 1, and Vll indicates the voltage value applied to the recording head 1.

7-1.7-2, . . . , 7- are head drive units provided for each predetermined number of heating elements 3, and each of the heating elements 3 corresponds to one bit of the data signal DATA of one line. Shift register for alignment and latch signal LAT
It has a latch circuit that latches bit data in response to strobe signals 5TRBI to 5TRBk, a switch that turns on/off electricity to the heating element 3 based on the bit data, and the like in response to strobe signals 5TRBI to 5TRBk. Reference numeral 9 denotes an image memory that stores image data I[lAT^ supplied directly or via the CPU 20 from the host device H as an image data supply source.
11 is a recording signal generation section, and CPU! In accordance with the drive timing signal T from 20, the image data developed in the image memory 9 is read out, and in addition to generating the data signal DATA, clock signal CLK, and latch signal LAT, the head drive units 7-1 to 7-k are Strobe signals 5TRBI to 5TRBk, etc. for sequential driving are generated.

The Crt 120 has the form of a microcomputer, for example, and controls each part according to a processing procedure described later with reference to FIG. Reference numeral 21 denotes a ROM, which stores programs corresponding to processing procedures executed by the CPU 20 and voltage adjustment data for adjusting the head power supply device 5.

In addition, C is a CP in order to make the power supply device 5 perform voltage adjustment.
This is, for example, a 2-bit binary power supply voltage control signal generated by U20.

FIG. 3 is a block diagram showing an example of the head power supply device 5. As shown in FIG. Here, 51 is a power supply control unit, which receives a reference voltage signal at one terminal, and receives a voltage 1 from the power supply voltage adjustment line.
It has a voltage control operational amplifier 53 which receives No. 3 at its terminal and applies a predetermined voltage to the recording head 1. In the power supply voltage adjustment line, resistors R~R4 (for example, R1>112>R3>R4) with different resistance values are provided in parallel, and a switching transistor TI-T4 is connected to each resistor RTT~R4. Connect the resistor R in series.
1 to enable old switching.

A decoder 55 generates a switch signal for making one of the transistors T1 to T4 conductive in accordance with the pressure control signal C on the 2-bit binary voltage #t7 supplied from the CPU 20.

In such a configuration, the CPU 20 judges the contents of the data expanded in the memory 9 and adjusts the voltage. That is, the CPt 120 adjusts the voltage for each predetermined amount of data (for example, for each total amount of data within a predetermined time, the head drive unit 7-1 Calculate the number of on data (number of drive bits) of the heating element 3 included in each block or each line of data related to driving by any of the above 7-, or the average thereof, and based on the calculation result. Access the voltage adjustment data in the ROM 21, determine the power supply voltage control signal C, and send it to the head power supply device 5.
supply to.

The control signal C sent in 2-bit binary form from CpH2Q is input to the decoder 55, and one of the transistors T1 to T4 is selected and turned on according to its value. When the resistors R1-R4 are switched accordingly, the voltage V, on the power supply voltage regulation line.

changes, and the power supply voltage changes depending on the number of drive bits. As a result, it becomes possible to supply a stable voltage VH to the recording head 1 regardless of the number of drive bits. For example, when the number of drive bits is large, the voltage drop due to wiring resistance is significant, so the resistor R4 with the smallest resistance value is selected. As the number of driving bits decreases, 11
It is possible to select in the order of 3→n2→old.

FIG. 4 is a flowchart showing an example of the voltage adjustment processing procedure by the CPt 120. First, when a predetermined number of image data (for example, one line) is inputted to the memory 9 from the external host device H in step S1, in step S3, the number of ON data of the heating element 3, that is, the number of drive bits n seek. Then, in step S5, n7m
is calculated, and the 2-bit binary value of the power supply voltage υJi311 signal C is determined by referring to the data area of the ROM 21 according to the calculated value.

Then, in step S9, image data is written from the memory 9! ! The control signal C is sent to the fX generator 11 and the control signal C is supplied to the power supply device 5. When the heating element 3 is driven to perform recording in this state, a stable voltage Vl+ is applied to the heating element 3 regardless of the number of driving bits, so that the ejection energy acting on the ink is also stable.

Next, in step 511, it is determined whether there is image data to be recorded next, and if the determination is affirmative, the process returns to step Sl, and if the determination is negative, the process is terminated.

In this way, according to this embodiment, stable ejection energy can be applied to ink regardless of the number of drive bits, so ink can be ejected stably and images can be recorded stably and with high quality. became. In addition, since the on-data of the image data developed in the image memory 9 is counted and switched, there is a delay in voltage compensation with respect to the number of drive bits compared to, for example, a case where a voltage compensation circuit is added to the T& source device itself. will not occur.

Furthermore, if the number of drive bits is counted by a counter or the like during the process of transferring the image data IDΔTA to the memory 9, it is possible to further speed up the processing time of steps s1 and s3.

In the above embodiment, transistors T1 to T4 and resistors R1 to R4 are provided, and voltage adjustment is performed in four stages using a 2-bit binary control signal C. However, the number of stages and the configuration for switching are different. Of course, can be selected as desired.

Further, in the above embodiment, only the supply voltage of the power supply device is adjusted to keep the supply voltage to the element constant, but in addition to this, the driving time (on time) of the heating element 3 is also adjusted to drive the heating element 3. The energy may be constant.

[Second Embodiment] FIG. 5 shows a second embodiment of the present invention, and each part configured similarly to the embodiment shown in the second figure is given the same reference numeral as the corresponding part.

In FIG. 5, reference numeral 13 denotes a pulse width control section provided integrally with the recording signal generation section 11, which adjusts the pulse width of the strobe signals 5TnB1 to 5TFIBk that define the drive timing or on-time of the heating element 3 under the control of the CPU 20. do. This configuration will be described later with reference to FIG.

In this example, the (:PU20 controls each part according to the processing procedure etc. described later with reference to FIG.
It stores programs corresponding to processing procedures executed by the CPU 20 and pulse width adjustment data for controlling the pulse width control section 13. In addition, CP is the pulse width control section 1
This is, for example, a 2-bit binary pulse width control signal generated by the CPU 20 to cause the CPU 20 to adjust the pulse width.

FIG. 6 is a block diagram showing an example of the pulse width control section 13. Here, R1-R4 are resistors with different resistance values (for example, R1>R2>R
3>R4), Tl-74 are resistors R1 to R4, respectively.
It is a switching transistor installed in series with
Performs switching selection of resistors B1 to R4.

15 is a decoder, and 2 supplied from CPt120
A one-shot generator 317 generates a switch signal that makes any of the transistors T1 to T4 conductive in accordance with the bit-by-naso pulse width control signal CP, and the capacitor C is charged through the selected resistor. When the heating element 3 is turned on, a pulse for determining the energization time of the heating element 3 is generated from the basic clock based on the time until the voltage across the capacitor C reaches a predetermined value.

In such a configuration, the CPU 20 judges the contents of the data developed in the memory 9 and adjusts the voltage. That is, the CPU 20 adjusts the voltage for each predetermined amount of data (for example, for each total amount of data within a predetermined time, the head drive unit 7-1 Calculate the number of on data (number of drive bits) of the heating element 3 included in each block or each line of data related to driving by any of the above 7-, or the average thereof, and based on the calculation result. Access the pulse width adjustment data in ROM21,
A pulse width control signal cp is determined and supplied to the pulse width control section 13.

The control signal CP sent from the CPU 20 in 2-bit binary form is input to the decoder 15, and depending on the value, one of the transistors T1 to T4 is selected and turned on. When the resistors R1 to R4 are switched accordingly, the time it takes for the voltage across the capacitor C to reach a predetermined value changes, and the pulse width, that is, the energization time of the heating element 3 changes depending on the number of drive bits. become.

For example, as shown in FIG. 7, when the number of drive bits is small, the voltage drop due to wiring resistance is small, so the energization time regulation pulse (strobe signal 5TR) with a small pulse width T
81-5TRBk), and as the number of drive bits increases, a resistor that provides a larger pulse width can be selected.

As a result of adjusting the energization time in this way, it is possible to cancel the change in voltage drop due to the wiring resistance R depending on the number of drive bits, so it is possible to supply stable drive energy to the heating element 3. becomes.

FIG. 8 is a flowchart showing an example of a pulse width adjustment processing procedure by the CPU 20 according to the present example. In this example as well, in the same way as above, when a predetermined amount m (for example, one line) of image data is inputted to the memory 9 from the external host device H in step si, in step S3, the heating element The number of on data of 3, that is, the number of drive bits n is determined. Next, in step S5, n7m is calculated, and a 2-bit binary value of the pulse width control signal CP is determined with reference to the data area of the ROM 21 according to the calculated value.

In this example, in step S29, the image data is sent from the memory 9 to the recording signal generator 11, and the control signal CP is supplied to the pulse width controller 13.

When the heating element 3 is driven to perform recording in this state, stable energy is supplied to the heating element 3 regardless of the number of driven bits, so that the ejection energy acting on the ink is also stable.

Next, in step Sit, it is determined whether there is image data to be recorded next, and if the determination is positive, the process returns to step 51, and if the determination is negative, the process is ended.

In this way, according to this embodiment, stable ejection energy can be applied to the ink regardless of the number of drive bits, so the ink can be stably foamed and ejected, and stable and high-quality images can be recorded. It has become possible. In addition, since the on-data of the image data developed in the image memory 9 is counted and the energization time is switched, there is a delay in compensation for the number of drive bits compared to, for example, a case where a voltage compensation circuit is added to the power supply device. will not occur. Further, if the number of drive bits is counted by a counter or the like during the process of transferring the image data IDAT^ to the memory 9, it is possible to further speed up the processing time of steps Sl and S3.

In the above embodiment, the transistor Tl-74 and the resistors R1-R4 are provided, and the energization time is adjusted in four stages using the 2-bit binary control signal CP. Of course, the configuration can be selected as desired.

Further, in the above embodiment, only the energization time of the heating element 3 is adjusted, but in addition to this, the supply voltage of the power supply bag 2 may also be adjusted so that the drive energy is constant.

Using the above configuration, an inkjet recording apparatus as shown in FIG. 9, for example, can be configured. Here,
FIG. 9 is a schematic perspective view showing the appearance of the 1000
1100 is a power switch, and 1200 is an operation panel.

Note that the present invention is not limited to a line printer having a so-called full-line type recording pad 1 in which ejection ports are arranged corresponding to the width of a recording medium as described above, but can also include a plurality of heating elements. Needless to say, the present invention is extremely effective and easy to apply as long as it is driven by a common power source.

Further, in the inkjet head used in the present invention, the direction in which ink is supplied to the heat generating portion of the heat generating element in the liquid path and the direction in which ink is ejected from the ejection port may be almost the same, or They may be different (for example, the two angles may form a substantially right angle).

[Effects of the Invention] As explained above, according to the present invention, stable drive energy is supplied to the ejection energy generation means regardless of the number of drive bits, so stable ejection energy acts on the ink, and therefore the ink The ejection conditions are stable, making it possible to record high-quality images.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view showing an example of a recording head used in an inkjet recording device of the present invention, FIG. 2 is a block diagram showing an example of an inkjet recording head f3 device of the present invention, and FIG. FIG. 4 is a flowchart showing an example of the voltage adjustment processing procedure according to the embodiment shown in FIG. 5; FIG. 6 is a block diagram showing an example of the pulse width control section in FIG. 5, FIG. 7 is a waveform diagram for explaining how the energization time to the heating element is changed, and FIG. 8 is the diagram shown in FIG. 5. FIG. 9 is a flowchart showing an example of the pulse width adjustment processing procedure according to the embodiment, and FIG. 9 is a schematic perspective view showing an example of the external configuration of the inkjet recording apparatus of the present invention. 1... Recording head, 3... Heating element, 5... Head power supply device, 7-1 to 7-k... Head driving section, 9... Image memory, 11... Recording signal Generation unit, 13... Pulse width control unit, 15... Decoder, 17... One shot 2O-CPIJ. 21...ll0M. 51...Power control unit, 55...Decoder. Figure 1, Figure 4, Figure 8

Claims (1)

[Scope of Claims] 1) A plurality of energy generating means that generate energy used to eject ink, a detecting means that detects the number of the energy generating means that are driven simultaneously, and detection by the detecting means. An inkjet recording apparatus comprising: an adjusting means for adjusting a voltage value of a drive pulse applied to the energy generating means according to the result. 2) a plurality of energy generating means for generating energy used to eject ink; a detecting means for detecting the number of the energy generating means driven simultaneously; An inkjet recording apparatus comprising: an adjusting means for adjusting a driving time of a driving pulse applied to a generating means.