JP2798948B2 - Ink jet recording device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus, and more particularly to an ink jet recording apparatus having an ink remaining amount detection in which erroneous detection due to a change in an ink component is improved.

[Related Art] Conventionally, in an ink jet recording apparatus, the following method has been adopted as a method of detecting the remaining amount of ink.

A method to detect ON / OFF resistance change due to the presence or absence of ink between two electrodes. A method of detecting an analog resistance change in volume resistance of ink between two electrodes. A detection method based on an analog resistance change between two electrodes present in an absorber.

[Problems to be Solved by the Invention] However, the conventional method has the following drawbacks.

In the cases (1) and (2), the ink liquid surface is in a wave state due to the vibration or shock accompanying the movement of the carriage, which causes erroneous detection.
In the case of, false detection due to vibration or impact has been improved, but when the same remaining amount detection device is used, ink with different components (difference in color or change in composition due to difference in paper) can be used. A change occurs in the volume resistance of the ink, resulting in erroneous detection.

[Means for Solving the Problems] According to the present invention, an ink tank for storing ink and / or an ink jet recording head for discharging ink is detachably configured, and ink is discharged from the ink jet recording head onto a recording medium. In the ink jet recording apparatus for performing recording, the ink tank or the ink jet recording head is obtained according to at least a pair of electrodes provided at a position where the ink can be in contact with the ink inside, and an electric resistance between the pair of electrodes. An ink jet recording apparatus is provided, comprising: correction means for correcting an electric signal; and detection means for detecting the electric signal corrected by the correction means.

In particular, the correction unit is connected to one of the at least one pair of electrodes, and corrects an electric signal obtained according to an electric resistance between the electrodes, or corrects an electric resistance of a different ink according to an ink composition. The resistance value differs depending on the ink contained in the ink tank or the ink jet recording head.

With such a configuration, even when inks having different ink compositions are used in the same head, the remaining amount of the ink can be accurately detected.

The remaining amount detection may be performed in the head unit or the tank unit, and the head and the ink tank may be provided with an absorber. The correction circuit may add a signal indicating a resistance change equivalent to ink to perform the correction. Further, the temperature of the printing apparatus or the ink may be monitored, corrected according to the change in the resistance of the ink due to the temperature, and the remaining amount may be accurately detected.

[Examples] The present invention will be described below with reference to the drawings.

Embodiment 1 In this embodiment, the resistance of the ink is changed by the difference in the color of the ink, that is, the dye. The characteristics are the same.

FIG. 1 shows a disposable type ink jet recording cartridge.

In FIG. 1, reference numeral 1 denotes a recording head chip, and reference numeral 2 denotes an ink ejection unit having a function of ejecting ink, for example, an ejection port for ejecting ink and heat energy used for generating droplets. Energy generating element. Reference numeral 3 denotes a liquid chamber for temporarily storing ink for sending ink to the ink discharge unit, 4 denotes a flow path for sending ink to the liquid chamber, and 5 denotes a filter for removing bubbles, dust, and the like. Reference numeral 6 denotes an ink absorber made of a porous or fibrous material, and includes pin-shaped ink remaining amount detection electrodes 7a and 7b, 7c, 7d, 7e, 7f for detecting the amount of ink absorbed. Exists. Details of a method of switching these detection electrodes will be described later. The above constitutes the recording head chip 1. Next, 9 is an ink tank in which the absorber 6 'and the ink 10 are contained. The ink tank 9 and the recording head chip 1 are configured to be detachable via an insertion pin 8 or the like. Here, an O-ring 14 prevents ink leakage. The ink tank 9 is designed to prevent ink from leaking out when it is present alone, and has a configuration in which ink flows when a recording head chip is inserted.

The ink tank 9 is provided with an ink absorber 6 ′ therein so that the water head pressure of the ink tank 9 alone can be adjusted so that the water head pressure is not applied to the recording head chip 1, so that downward printing is possible. I have.

 Next, a specific method of detecting the remaining amount of ink will be described.

When the ink in the ink tank 9 is consumed due to printing or recovery operation, and the amount of ink in the ink tank 9 decreases, the amount of ink guided to the ink absorber 6 also decreases, and the amount of ink absorbed in the ink absorber 6 decreases. It becomes possible to detect that the remaining amount of ink has reached a limit value due to the small amount of air bubbles mixed therein and the electric resistance between the remaining amount detection electrodes 7a and 7b gradually increasing, so that the current between them has decreased. . By monitoring the current value at this time, the remaining ink amount l
It can be seen that there is a relationship shown in FIG. In FIG. 2, the curves A, B, C, and D show the difference in ink color (dye difference), where A is Black ink (dye concentration 3.0%) and B is Red ink (dye concentration 2.5%).
%), C is Blue ink (2.5% dye concentration), D is Green ink (2.0% dye concentration), E is flesh color ink (2.5% dye concentration).
%). It can be seen from FIG. 2 that the volume resistance of each ink is different due to the difference in the color of the ink. Therefore, when the remaining amount is to be detected only between 7a and 7b,
When the remaining amount detection is activated at the same resistance value R _R and the residual detection lamp (not shown) is turned on, a difference occurs in the amount of remaining ink in each of A, B, C, and D inks, which is preferable. Absent. When the remaining amount detection is to be performed with a certain remaining amount for any of the inks A, B, C, and D, the difference between the resistance values of the inks for each of A, B, C, and D is determined based on the combination of the detection electrodes. Switching by a switching device such as a switch,
For example, when using ink D having a low resistance value, increase the distance between the electrodes to increase the apparent resistance. Is increased, the curve is corrected as a whole, and the remaining amount detection may be turned on when the resistance value is R _R , and when the ink A having a high resistance value is used, the electrode is reversed. remaining amount detection may be to operate at between distance shorter curve to reduce the resistance of the apparent to totally corrected resistance R _R. Similarly, the electrode positions may be combined so that the remaining amount is the same when the resistance value is R _R for the ink E having different resistance values.

It is desirable that the combination at this time be combined so as to have an up-down relationship (or an oblique arrangement) with respect to the direction of gravity.
FIG. 3 shows a graph in which resistance values are measured in the vertical direction and the horizontal direction with respect to the direction of gravity. Needless to say, the distance between the detection electrodes shifts in the α direction when the distance increases, and shifts in the β direction when the distance is short.

It is desirable that the surface of the detection electrode be made of a material having high corrosion resistance such as SUS, gold plating, and platinum. Incidentally, the distance between the electrodes varies depending on the structure of the absorber 6 of the chip, but is 5 to 30 mm.
The resistance value of the ink at this time is preferably several tens k to
It is several hundred kΩ. In a printing apparatus that performs printing using this cartridge, after the ink remaining lamp is turned on, the ink is changed from C ink to B ink, and the electrode position is changed from 7a to 7e to 7a.
When the residual lamp was turned on again in place of −7d, when the remaining ink amounts of both ink tanks were checked, there was almost no difference. However, after the conversion to another ink, it is desirable that the ink be suction-replaced by a certain recovery sequence and the color changed completely before printing. Further, even when the ink tank is replaced during printing, the same operation is performed, so that the remaining amount can be accurately detected.

In addition, the ink remaining amount detection circuit of the present invention may generate bubbles due to electrolysis of ink by being constantly energized. Therefore, the circuit may be configured with the circuit diagram shown in FIG. This makes it possible to perform one measurement in a short time, and by inverting the polarity for each measurement, it is possible to eliminate the generation of bubbles due to electrolysis. The time required for one measurement is about several milliseconds.

Embodiment 2 FIG. 5 is a view showing a second embodiment of the present invention. In the present embodiment, resistance change of the ink due to the difference in the composition of the ink, that is, the mixing ratio of the solvent, is corrected by attaching a correction resistor to the detection unit of the head measurement, and the resistance output characteristic to the printing apparatus main body is made the same. It was done.

That is, by providing the correction means for correcting the electric signal obtained in accordance with the electric resistance between the electrodes 7A and 7B in the recording head provided with the electrodes, the output characteristic of the electric signal output to the printing apparatus main body is provided. Can be the same even if the electric resistance is different depending on the composition of the ink. Therefore, even if the electrical resistance in the ink differs depending on the composition of the ink, the same output can be obtained on the printing apparatus main body side if the ink state between the electrodes is the same, and the printing apparatus main body side can obtain the same output. It is possible to detect a decrease in the remaining amount of ink without any change in the configuration for detecting the electric signal obtained from.

FIG. 5 shows a disposable type ink jet recording cartridge. This cartridge also has the recording head chip 1 and the ink tank 9 detachable. Since this cartridge does not contain an absorber in the ink tank, the head pressure of the tank must be maintained by the meniscus of the nozzle of the discharge unit.
It is a horizontal printing type. Attachment and removal can be performed in the same manner as in the first embodiment. The feature of this cartridge is that there is no absorber on the recording head chip side, and the plate-shaped ink remaining amount detection electrodes 7A and 7B are 7A from the top in the ink supply chamber.
B is arranged while being supported from below, and the liquid level height h shown in FIG.
This is to detect the ink resistance between 7A and 7B, which changes according to the amount, and to detect the remaining amount.

For example, with respect to the composition of the ink, when each ink such as the ink for plain paper, the ink for coated paper, and the ink for TP is optimized, the resistance value of the ink changes because they are different from each other. For this change in resistance, a correction resistor R _B by a variable,
The apparent resistance value was always kept constant, and it was possible to accurately detect the remaining amount even when the ink was changed.

Here, a simple correction circuit is added to the head side.
The correction may be performed by a circuit equivalent to ink. Although the variable resistor is of a variable type, the resistor may be switched in series or in parallel for correction. The switching may be manual or automatic.

Embodiment 3 FIG. 7 is a view showing a third embodiment of the present invention. This embodiment is obtained by allowing the corresponding by attaching the correction resistor R _B changes in accompanying ink resistance on the remaining amount detecting apparatus of the tank side to change the dye concentration of the ink. The ink jet recording apparatus shown in FIG. 7 is a permanent type head, and the recording head 1 and the ink tank 9 are connected to a supply tube 12.
It is inherited by.

This is designed to reduce the number of electrical components in the head, improve the reliability of the head alone, and detect the remaining amount on the tank side to prevent bubbles from being mixed into the head. As a result, it is possible to prevent a printing failure (non-discharging or the like) due to mixing of bubbles into the head discharging unit due to erroneous detection of the remaining amount detection.

Also in this embodiment, as in the previous embodiment 2, the output characteristics of the electric signal output to the printing apparatus main body can be made the same even if the electric resistance differs according to the ink composition. It is possible to detect a decrease in the remaining amount of ink without changing the configuration for detecting the electric signal obtained from the electrode on the device body side.

As described above, according to the present invention, an electrode for detecting a decrease in the remaining amount of ink is provided on a replaceable ink tank or a recording head which is configured to be detachable from the apparatus, and is provided with a replaceable electrode provided with this electrode. By providing a correction means for correcting an electric signal corresponding to the resistance value between the electrodes in any part, it is possible to detect a decrease in the remaining ink amount without changing the configuration for detecting the electric signal on the apparatus main body side at all. Can be.

[Effects of the Invention] As described above, in the ink remaining amount detecting device for detecting the remaining ink amount based on the resistance value of the ink, it is possible to correct the ink resistance value in the recording head or the tank portion, so that the ink composition is reduced. Even if it changes, the resistance output characteristics to the main body side can be kept constant, and the remaining amount can be accurately detected even if a large number of inks are used without replacing the head. In addition, printing defects due to erroneous detection can be prevented.

[Brief description of the drawings]

FIG. 1 is a schematic view of a cartridge with ink remaining amount detection correction of the present invention, FIG. 2 and FIG. 3 are diagrams showing the relationship between ink remaining amount and ink resistance, FIG. FIG. 6 is a schematic view of a cartridge showing a second embodiment of the present invention, FIG. 6 is a perspective partial cutaway view of a cartridge showing a second embodiment of the present invention, and FIG. It is the schematic of the head tank which showed the Example. DESCRIPTION OF SYMBOLS 1 ... Recording head chip 2 ... Ink ejection part 3 ... Liquid chamber 4 ... Flow path 5 ... Filter 6, 6 '... Absorber 7 ... Ink remaining amount detection electrode 8 ... Insertion pin 9 ... Ink tank 10 Ink 11 Lead frame 12 Supply tube 13 Ink remaining amount detection circuit 14 O-ring

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Norifumi Kotabashi 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (56) References JP-A-62-190421 (JP, A) (58) Surveyed field (Int.Cl. ⁶ , DB name) B41J 2/175

Claims (4)

(57) [Claims] An ink jet recording apparatus, wherein an ink tank containing ink and / or an ink jet recording head for discharging ink is detachably configured, and the ink jet recording head discharges ink onto a recording medium to perform recording. The ink tank or the ink jet recording head includes at least a pair of electrodes provided at a position where the ink tank or the ink jet recording head can contact the ink therein, and a correction unit that corrects an electric signal obtained according to an electric resistance between the pair of electrodes. An ink jet recording apparatus, further comprising a detecting unit for detecting the electric signal corrected by the correcting unit. 2. An ink jet recording apparatus according to claim 1, wherein said correction means is connected to one of said at least one pair of electrodes, and corrects an electric signal obtained according to an electric resistance between the electrodes. An ink jet recording apparatus characterized by the above-mentioned. 3. An ink jet recording apparatus according to claim 1, wherein said correction means is a correction resistor for correcting an electric signal obtained according to an electric resistance between electrodes.
An ink jet recording apparatus having a resistance value corresponding to ink contained in the ink tank or ink ejected by the recording head. 4. An ink jet recording apparatus according to claim 3, wherein the composition of said ink varies depending on the color tone of the ink.