JPH035148A - Ink jet recorder - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an inkjet recording device.

6) A recording spatula 1- having a plurality of ejection ports is provided, and the means detects the amount of ink droplets ejected from each ejection port and determines corresponding driving conditions for the ejection energy generating element. The inkjet recording apparatus according to claim 1, characterized in that:

7) The inkjet according to any one of claims 2 to 6, wherein the ejection energy generating element has the form of an electrothermal converter that generates thermal energy used for ejecting the ink. Recording device.

(The following is a blank space) [Prior Art] Conventionally, a J-wink sheet printing apparatus is known, which performs printing by ejecting ink onto a recording medium.

An inkjet recording device is a non-impact type recording device, which makes less noise and can record color images by using multicolor ink. It also has the advantage of being easy to use, and has become rapidly popular in recent years.

[Problems to be Solved by the Invention] However, inkjet recording devices perform recording by directly ejecting ink from fine ejection ports, and other methods are required to eject or fly droplets in a stable manner at all times. This requires special considerations that are not found in recording devices based on this method. For example, the diameter of ejected droplets changes due to changes in the amount of wetting in the liquid path inside the ejection port during continuous recording, or changes in the state of the surface on which the ejection port is formed, in other words, image unevenness. This is because it can be triggered.

In view of such problems, it is an object of the present invention to enable appropriate correction by detecting fluctuations in ejected droplets, thereby preventing the occurrence of image unevenness. .

[Means for Solving the Problems] To this end, the present invention provides an inkjet recording apparatus that records an image using a recording head having an ejection port that ejects ink as droplets. 2) The present invention is characterized by comprising the detection means and means for determining, in accordance with the detection result of the detection means, driving conditions during recording of the ejection energy generating elements provided corresponding to the ejection ports.

[Function] According to the present invention, two of the ink droplets ejected from the ejection port are
) By providing the detection means, it becomes possible to detect image unevenness caused by variations in ejected ink droplets and further correct this.

[Example] The present invention will be explained in detail and specifically below.

(Example 1) FIG. 1 shows an example of an inkjet recording apparatus to which the present invention is applied. This example is for a multicolor recording device, where:
Reference numeral 1 denotes a recording head unit consisting of a plurality of recording heads 18 to ID as shown in FIG. 2, and recording liquids of different colors are ejected from each of the recording heads 18 to ID. Each of the recording heads u to 10 is provided with a plurality of ink ejection ports, and the liquid paths communicating with the ejection ports are supplied with an applied voltage or electric heat to generate thermal energy for ejecting the recording liquid. A converter is installed.

Reference numeral 3 designates a recording spatula 1 to 1 which is mounted and moves along the rail 1 to rail 4, 5 a timing heald for moving the carriage 4, and 6 a carriage drive motor. In addition, the recording material (recording sheets 1 to 1) 7 such as sheet I-shaped paper or film is maintained by the sheet 1 to the feed roller pair 9 driven by the sheet 1 to the feed motor 8, and the roller pair 9. The sheet is fed in the direction of the arrow when the recording of the stone bone is finished. 11 is the recording head 18-I
A supply pipe for supplying L ink to D, 12
Pour the ink from the recording spatula lΔ~1[) into tank 1.
3 is the return pipe for returning it, and 14 is the gear ridge 4
This is a cap device for a plurality of recording spatulas facing the recording head unit 1 when the paper is guided to the Baum position H, and in this example, it is used as an ink receiving part when detecting variations in the diameter of ejected droplets between ejection ports. It is also used as good.

FIG. 3 shows an example of the configuration of a detection system for detecting variations in ink consumption among a plurality of ejection ports of a recording spatula i according to the present invention. In this example, the recording spatula [~ with the unit 1 in close contact with the heating device 14, the ink pressure is fed from the ink tank 13 for the recording head to the lower stage 24 and 1] (each liquid path of the recording head via the supply valve 15a). Ink is supplied to the common liquid chamber 30 connected to jT+, the supply valve 15a is closed in response to the inspection command 11, and a certain amount of ink is applied to the electrothermal converter 32 disposed corresponding to the focused discharge "131". Give a discharge pulse,
The ink consumption amount at that time is detected by the ink consumption amount detection means 2a. This is performed for all the ejections I'', and the variation in the amount of ejected droplets between the respective ejection ports is detected as the variation in the amount of ink consumption. Note that the ink consumption amount detection means 2a
You can configure it as appropriate. For example, it may be as described below with reference to FIG.

Reference numeral 50 denotes a controller as an image density unevenness detecting means for controlling such detection processing, and as shown in FIG. ROM,
It has RAM etc. for work. Note that the controller roller 50 may also be used as the main control section of the apparatus.

FIG. 4 shows an example of the basic operating procedure for detecting variations in the amount of ejection between the ejection ports 4J by adjusting the amount of ink consumed.

When an image density unevenness detection command is issued in step 5101, the image density unevenness detection command is issued in step 5102.
1 to the unevenness detection position I], move it to A to face the roughing device 14, and select the ejection port for processing in step 5103. Next, in step 5104, the ink supply valve 15a is closed, and in step 5105, a constant ejection pulse is applied to the nominal nozzle to perform 10 ejections, and then in step 51
06, based on the output of the ink consumption amount detection means 2a.
] Calculate the amount of ink consumed by the ejection ports that are currently in use. Below, 1
Step 510 is performed for each ejection port while refilling the ink after the process is completed.
Steps 5107 and 5108 are performed to detect image unevenness caused by variations in the amount of ejection between the ejection ports as variations in the amount of ink consumed between the ejection ports.

After detecting the variation in the amount of ink consumption, that is, the amount of ejected droplets between the ejection ports in this way, by applying a drive corresponding to the detection result to each electrothermal transducer 52, the corresponding ejection [-1
It is possible to correct for variations in the amount of ink droplets between the two.

i.e., a look-up table of ink droplet detection results and corresponding applied voltages and/or pulse widths required to obtain the correct amount of droplets, as shown in Figure 5, for example. For example, if the detection results are stored in the ROM, then the detection results are stored in the R
It is expanded to AM, and after detecting the amount of ink droplets, the lookup table is referred to to find the correct value! By driving the electrothermal converter under the following driving conditions, the droplet volume can be corrected and a stable image can be obtained. Incidentally, after the above-mentioned detection, driving conditions commensurate with this may be set in advance for the electrothermal transducers 1 to 8, etc.

Such a mode of detection may be performed for a plurality of ejection ports as a unit. Actually 4001 ~ 7 inches (dp
For a recording head in which 256 ejection ports are arranged at a density of i) and an electrothermal converter is used as an ejection energy generating element,
When recording using ink with a dye concentration of 2% by weight, 8
It was possible to sufficiently identify the unevenness even if the unit was a unit of discharge.

In any case, 1 ml of discharge between the discharge ports? By detecting image density unevenness caused by variations in K m as variations in ink consumption, it is possible to detect image density unevenness within the device 1', and it is also possible to detect unevenness in image density within the device 1'. Unlike the conventional method, there is no need for the trouble of detecting unevenness from a recording medium on which a test pattern has been printed, and it is possible to simplify the Itt+ system.

(Example 2) In the previous (Example 1), the supply pipe 11 on the ink j4 supply side
In this embodiment, as shown in FIG. 6, a valve 5b and an ink consumption detection means 2 are provided in the ink return pipe 12.
Set up b. Similarly to (Example 1), the variation in the amount of droplets ejected between each nozzle is detected by the amount of ink consumed that returns to the ink tank 13 via the ink return pipe 12. be. Also, by employing the same controller and processing procedure as in the first embodiment for such a configuration, the same effects can be obtained.

(Example 3) FIG. 7 shows a third embodiment of the invention.

In this example, unlike (Example 1) and (Example 2), a fixed amount of ink is supplied to each ejection port, and each ejection It is designed to represent the variation in the amount of droplets discharged between the outlets.

In FIG. 17, a fixed amount of ink is supplied from the supply-side valve 15c to the ink consumption amount detection means 2C to each ejection port, and the electrothermal converter is driven for each ejection port to form the cap device 14. Discharge is made toward the direction.

Then, the ink consumption amount detection means 2 indicates that the ink has been consumed.
By detecting the number of applied pulses up to the moment when C is detected, that is, the moment when the sensor-type means 2c is turned off, the variation among the ejection ports is determined.

As this sensor 2c, a photocoupler made of an LED and a phototransistor or the like may be used.

1 Also in this example, the same controllers 1 to 1 as in (Embodiment 1) can be applied. Then, a procedure almost similar to that in FIG. 4 can be adopted, but in this example, step 5105
Instead, a procedure is provided in which a counter or the like is incremented each time one driving pulse is applied to the nozzle of interest, and a procedure is provided in which the counter value is read in step 5106 when the sensor is turned off. That's fine.

(Embodiment 4) FIG. 8 shows a fourth embodiment of the present invention. In this example, the present invention is applied to an ink jet recording apparatus having a so-called full multi-type recording head in which ejection ports are aligned over a range corresponding to the entire width of a recording medium.

In the figure, 130 is a fully multi-type recording spatula, and has, for example, 4736 ink ejection ports.

Ink flow paths 111 and 112 communicate the ink tank 113 and the recording head 130, and are provided with valves 101 and 102, respectively. 115 is a tube branched from the ink flow path 111 and having an inner diameter of 0.5 mm, for example, with one end open, and is provided with a valve 103.

Reference numeral 120 denotes ink consumption amount detection means, which is a Michelson type interferometer in this example, and performs consumption-first detection with respect to the ink liquid level appearing on the open end side of the duplex 115. In this Michelson type interference classification, 122 is a laser light source for irradiating the liquid surface with laser light, 124 is a heam splitter,
126 is a fixed mirror, and 128 is a photodetector.

Reference numeral 150 denotes a controller that has the same configuration as that of (Embodiment 1) and executes the processing procedure described later with reference to FIG.
It controls the driving of the laser light source 122 and performs predetermined processing based on the output of the detector 128.

FIG. 9 shows an example of the ink consumption amount detection procedure according to this example.

During normal recording, among the valves provided in the ink supply path to the head 130, valve 101 and valve 102
is open and valve 103 is closed, or when set to ink consumption detection mode, valve 101 and valve 102 are closed, and valve 1 is set to ink consumption detection mode.
03 is opened (step 5201).

Next, 47 provided on the recording spatula 1j130 according to this example.
Of the 36 ejection ports, first, eject 10 drops (dry ejection) from the 8 ejection ports No. 001 to 8 (dry ejection).
S202). The volume of one Kabura is on average 30 picoliters (pu
, 1. pu = 10-15 m"), and the volume of 80 drops is approximately Tel?lOOpx. There is a T in the ink flow path.
Duplex 1 with an inner diameter of 0.5 mm with an “A” added to the shape
The cross-sectional area of 15 is 3.14x (0.25mm)2-20
0 x 10-'m2, the displacement of the liquid level inside the tube when 80 drops are ejected is 2400 x 10-15m
3/200 x 10-9m2-12 x 10-6m
It is about -127z m.

By measuring the displacement of the liquid level using Michelson-type interferometry as shown in Figure 8, it is possible to monitor with an accuracy of λ/2 (λ = 0.3 μm for the lle-Ne laser). Therefore, the variation detection ability of 0.3712-2.5% is sufficient.

When this J2 sea urchin liquid level change (!7) is measured, the set amount is stored in an appropriate area of RAM, for example, in step 520.
3) The same filling is performed for each of the following eight discharge ports (steps 5204, 5205, . . . , 52).
06,5207). In addition, the time required for such processing is 2.5KIIz and electricity (if the converter is moved, 10 pieces each will be discharged from the discharge ports No. 1 to No. 4736). 136X 10/2500
A measurement time of -19 seconds is sufficient.

After that, the ink consumption per drop of each ejection port,
That is, the droplet amount is calculated (step 5208), and the deviation is corrected based on this in the same manner as in Example 1.

(Embodiment 5) FIG. 10 shows another embodiment of the ink consumption amount detection means.

In this example, a voltage V is applied from the power source between the ejection port and the flat plate electrode facing it. This is done so that the voltage is applied. When an ink droplet is ejected under this applied state, a conductive current of 5 i=q·v/d flows until the ink droplet having a charge amount q lands on the electrode. Here, ■ is the particle velocity, and d is the distance between the electrodes. Since the electric charge Blq depends on the particle volume and the variation in the particle velocity at each discharge port is smaller than the variation in particle volume, the bipedal conduction current is measured at each discharge port via the detection circuit 220. It is possible to know the dispersion of the volume of the child.

(Example 6) FIG. 11 shows another embodiment of the ink consumption detection system.

Here, 250 is a controller 1-roller as an image density unevenness detecting means according to this example, and includes a CI'112508, a memory 250B, and the like. 252 is controller] Roller 250
This is means for changing the frequency of the drive pulse given to the recording head 1 or 130 under the control of the recording head 1 or 130. 254 is a means for detecting a non-discharge state of the discharge port, and can be an optical non-discharge detection sensor installed in a cap device or the like.

In general, as the driving frequency is gradually increased, the ink consumption rate by each ejection port or the ink replenishment speed (called the refill speed) in the inner liquid path will be doubled, and the ink replenishment or catch-up speed will become 77 <. Discharge failure occurs. This example utilizes the fact that there is a correlation between the maximum drive frequency that allows ejection for each ejection port and the volume of droplets ejected from each ejection port.

In this example, we will eject one drop at a time while gradually increasing the drive frequency from the lowest to the selected ejection port.
The frequency at which ejection failure is detected by the ejection failure detection means 254 is stored in the memory 250B in correspondence with the ejection port number. Then, the frequencies at which ejection failure occurs are made to correspond to each other for all the ejection ports. Therefore, the 12th
As shown in the figure, the ejection volume of the ejection port can be determined by applying the correlation between the ejection maximum drive frequency and the ejection volume, which are tabulated in a ROM or the like.

[Effects of the Invention] As described above, according to the present invention, it is possible to detect image unevenness caused by variations in ejected ink droplets by providing a means for detecting two ink droplets ejected from an ejection port. recording spatula I that has multiple ejection ports.
In the case of *, there is an effect that a stable image can always be obtained by applying a drive to the ejection energy generating element according to the result of detecting the amount of ink droplets.

[Brief explanation of drawings]

FIG. 1 is a perspective view schematically showing an inkjet recording apparatus according to an embodiment of the present invention, FIG. 2 is an enlarged view of the recording spatula 1 to 3'I, and FIG. 3 is an embodiment of the present invention. FIG. 4 is a flowchart showing an example of the ink consumption detection processing procedure, and FIG. 6, 7 and 8 are diagrams for explaining the look-up tables used in the second invention of the tree invention, respectively. A schematic diagram showing the third and fourth embodiments. FIG. 9 is a flowchart showing an example of the ink consumption detection IA filling procedure adopted in the fourth embodiment of the invention. FIG. FIG. 11 is a block diagram showing a sixth embodiment of the present invention; FIG. 12 is a schematic diagram showing a configuration example of the ink consumption amount detection means according to the example; FIG. It is a diagram showing the relationship with volume. 1, IANID, 130...recording head, 28-2
c... Ink consumption detection means, 11... Ink supply pipe, 12... Ink return pipe, 13.113... Ink tank, 14... Cap device, 15a N15c, 101 to 103-. valve,
31...Discharge port, 9 50.150,250...Controller, 0 120...Michelson type interferometer. Possible person M, first kite fall

Claims (1)

[Scope of Claims] 1) In an inkjet recording apparatus that records an image using a recording head having an ejection port that ejects ink as droplets, the apparatus further comprises: a detection means for detecting the amount of ink droplets ejected from the ejection port; An inkjet recording apparatus characterized by comprising: means for determining driving conditions during recording of an ejection energy generating element provided corresponding to the ejection port in accordance with a detection result of the detection means. 2) The detection means includes means for detecting the consumption amount of the supplied ink when ink is ejected by driving an ejection energy generating element provided corresponding to the ejection port under predetermined conditions. The inkjet recording apparatus according to claim 1. 3) The detection means includes means for detecting the amount of returned ink when ink is ejected by driving an ejection energy generating element provided corresponding to the ejection port under predetermined conditions. The inkjet recording device according to claim 1. 4) After supplying a predetermined amount of ink toward the ejection port, the detection means drives an ejection energy generating element provided corresponding to the ejection port to eject ink, and the drive causes the ejection energy to be ejected. The inkjet recording apparatus according to claim 1, further comprising means for detecting the number of pulses of the drive signal applied until ejection is no longer performed. 5) The detection means includes a means for driving an ejection energy generating element provided corresponding to the ejection port while changing the drive frequency to eject ink, and a means for ejecting ink immediately before the ink ejection stops even with the driving. The ink jet recording apparatus according to claim 1, further comprising means for determining the amount of the ink droplets based on a driving frequency. 6) A recording head having a plurality of ejection ports is provided, and the means detects the amount of ink droplets ejected on each ejection day, and determines corresponding driving conditions for the ejection energy generating element. The inkjet recording apparatus according to claim 1. 7) The inkjet according to any one of claims 2 to 6, wherein the ejection energy generating element has the form of an electrothermal converter that generates thermal energy used for ejecting the ink. Recording device.