JPH10175314A - Ink residual amount detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To certainly detect the residual amt. of ink in an ink supply tank. SOLUTION: This ink residual amt. detector has a case 22 housing an ink impregnating member 26, the heating member arranged in the ink impregnating member 26 to generate a voltage corresponding to temp., a voltage detection means detecting the voltage generated by the heating member, a current supply means for supplying a current to the heating member, and a residual amt. detection means for detecting the residual amt. of ink on the basis of the change of voltage generated accompanied by the supply of a current. When a current is supplied to the heating member, the heating member generates heat itself but, since the ink in the case 22 cools the heating member, the voltage generated across both ends of the heating member changes corresponding to the residual amt. of ink.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for detecting the remaining amount of ink in an ink supply tank of an ink jet printer.

[0002]

2. Description of the Related Art Conventionally, in an ink jet printer, printing is performed by discharging ink from an orifice of an ink jet head, and an ink supply tank is provided for supplying ink to the ink jet head. . FIG. 2 is a sectional view of a conventional ink supply tank.

In the figure, reference numeral 11 denotes an ink supply tank, 1
Reference numeral 2 denotes a case, and 13 denotes a partition wall. The partition wall 13 partitions the inside of the case 12 into a main ink chamber 14 and an auxiliary ink chamber 15. The main ink chamber 14 contains an ink impregnated body 16 impregnated with ink, and the auxiliary ink chamber 15 contains ink. At the bottom of the main ink chamber 14, an ink supply pipe 18 is provided.
Is supplied to an ink jet head (not shown). An ink filter 19 is provided in the ink supply pipe 18, and the ink filter 19 prevents foreign matters in the main ink chamber 14 from being supplied to the inkjet head.

The main ink chamber 14 and the auxiliary ink chamber 15 are connected to the communication port 1 formed in the lower portion of the partition wall 13.
When the ink in the main ink chamber 14 becomes low, the ink in the auxiliary ink chamber 15 is supplied to the main ink chamber 14. In addition, an air communication hole and an ink inlet (not shown) are formed on the top surface of the case 12.

In the ink supply tank 11 configured as described above, ink is consumed as printing is performed. Therefore, the number of ink droplets ejected from the orifice of the ink jet head is counted, and the count value is set to the set number. When it reaches, it is determined that the ink supply tank 11 is empty.

[0006]

However, in the conventional ink jet printer, when an image having a special print pattern is printed, the number of ink droplets may not correspond to the amount of ink consumed. The remaining amount of ink in the supply tank 11 cannot be reliably detected.

If the ink supply tank 11 is replaced with another ink supply tank before the ink supply tank 11 becomes empty, the count value becomes invalid. Therefore, the remaining amount of ink in the ink supply tank 11 is reliably detected. Can not do. SUMMARY OF THE INVENTION It is an object of the present invention to solve the problems of the conventional ink jet printer and to provide an ink remaining amount detecting device capable of reliably detecting the remaining amount of ink in an ink supply tank.

[0008]

For this purpose, in the ink remaining amount detecting device according to the present invention, a case accommodating the ink impregnated body and a heat generating device disposed in the ink impregnated body and generating a voltage corresponding to the temperature are provided. A member, voltage detecting means for detecting a voltage generated by the heat generating member, current supplying means for supplying a current to the heat generating member, and ink supply based on a change in the voltage caused by supplying the current. And a remaining amount detecting means for detecting the remaining amount.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a perspective sectional view of an ink supply tank according to an embodiment of the present invention, FIG. 3 is a sectional view of the ink supply tank according to an embodiment of the present invention, and FIG. 4 is a plan view of the ink supply tank according to the embodiment of the present invention. FIG.

In FIG. 1, reference numeral 21 denotes an ink supply tank;
Reference numeral 2 denotes a case made of a material such as polypropylene, and an ink impregnated body 26 is accommodated in an ink chamber 24 formed in the case 22. The ink impregnated body 26 is made of a material such as polyurethane foam and is impregnated with ink. An air communication hole 44 and an ink inlet 45 are formed on the top surface of the case 22.

An ink supply pipe 28 is provided at the bottom of the ink chamber 24 so that the ink in the ink chamber 24 can be supplied to an ink jet head (not shown) via the ink supply pipe 28. Has become. In addition,
An ink filter 29 is provided in the ink supply pipe 28 to prevent foreign matter in the ink chamber 24 from being supplied to the inkjet head. As the ink filter 29, a net made of metal, ceramic, or the like, or a felt can be used.

In order to detect the remaining amount of ink in the ink chamber 24, a silicon diode 31 is provided in the ink impregnated body 26 as a heat generating member. Leads 32 are respectively connected to both ends of the silicon diode 31, and each lead 32 is connected to a terminal 3 formed on the case 22.
Detection circuit board 3 as voltage detection means via 6, 37
5 respectively. Each lead 32 is covered with a vinyl tube 33 to be waterproof. The terminals 36 and 37 are plated with gold to prevent rust.

In the ink supply tank 21 having the above-described structure, when the ink jet head is driven, a suction force acts on the ink supply pipe 28, and the ink impregnated in the ink impregnating body 26 passes through the ink supply pipe 28. Inhaled by the inkjet head. At this time, the pressure in the ink chamber 24 decreases, but the air in the ink chamber 24 returns to the original pressure because the air is taken in from the air communication hole 44. Such an operation is repeated during printing, and the ink impregnated body 26 is
The ink impregnated is consumed.

By the way, the silicon diode 31 has a characteristic of changing the generated voltage when the temperature changes. In the present embodiment, the silicon diode 31
Has a characteristic of -2 [mV / ° C], and when the temperature rises by 1 [° C], the voltage V _AK generated at both ends decreases by -2 [mV]. Therefore, the voltage V across the silicon diode 31
_AK is detected by the detection circuit board 35, and the remaining amount of ink in the ink chamber 24 is detected based on the detected voltage.

Next, the voltage detection circuit provided on the detection circuit board 35 will be described. FIG. 5 is a diagram illustrating a voltage detection circuit according to an embodiment of the present invention, FIG. 6 is a diagram illustrating a relationship between the remaining amount of ink and a temperature rise value according to the embodiment of the present invention, and FIG. FIG. 8 is a diagram showing a temperature rise value / ink remaining amount conversion table, and FIG. 8 is a flowchart showing the operation of the ink remaining amount detecting device according to the embodiment of the present invention. In FIG. 6, the horizontal axis indicates the remaining amount of ink, and the vertical axis indicates the temperature rise value.

In the figure, AMP is an operational amplifier used as a non-inverting amplifier, R1 to R5 are resistors, and Tr is a transistor. The base of the transistor Tr is connected to a control unit (not shown), and a switch signal SW1 generated in the control unit is input to the base via a resistor R4. Then, the switch signal SW1 is turned on, the transistor Tr is turned on is connected between the emitter and the collector, the supply voltage V _CC is applied to the cathode terminal of the silicon diode 31 via a resistor R3. The anode terminal of the silicon diode 31 is connected to the ground. Incidentally, the resistor R3 is arranged for adjusting the current I _F flowing through the silicon diode 31.

In the present embodiment, the predetermined power supply voltage V _CC is applied to the cathode terminal of the silicon diode 31 so that the self-heating amount in the silicon diode 31 is increased, and the current _IF is increased (for example, 50 μm).
[MA]). And the operational amplifier AM
At P, a non-inverting terminal (+) is connected to a connection Q1 between the resistor R3 and the silicon diode 31, and an inverting terminal (-) is connected to ground via the resistor R1. The resistors R1 and R2 are connected to the operational amplifier A
Provided to adjust the MP gain.

In this case, the output V _{OUT of the} operational amplifier AMP
Is generated corresponding to the voltage V _AK and can be expressed by equation (1). V _OUT = V _AK (R ₁ + R ₂ ) / R ₁ [V] (1) Note that R ₁ and R ₂ are resistance values of the resistors R ₁ and R ₂ , respectively. Incidentally, when the current supply means of the control unit turns on the switch signal SW1, the transistor Tr is turned on, a current I _F flows through the silicon diode 31, a silicon diode 31 temperature rises by self-heating. The silicon diode 31 is connected to the ink impregnated body 26.
3, the temperature rise value of the silicon diode 31 changes according to the change in the remaining amount of ink in the ink chamber 24. That is, since the ink impregnated body 26 itself functions as a heat sink, when the remaining amount of ink in the ink chamber 24 is large, the ink cools the silicon diode 31 and the temperature of the silicon diode 31 decreases. When the remaining amount of ink in the ink chamber 24 decreases, the cooling capacity of the ink decreases, and the temperature of the silicon diode 31 increases accordingly. For example, when the temperature of the ink chamber 24 is 25 [℃], the temperature rise value of the silicon diode 31 when the supplied 1 minute current I _F on the silicon diode 31, corresponding to the remaining amount of the ink drawing 6 as shown.

[0019] Thus, the residual amount detection means of the control section, by detecting the change in the output V _OUT after a predetermined time has elapsed from the switch signal SW1 is turned on, the change of the output V _OUT The corresponding change in voltage V _AK is determined, and the temperature rise value of silicon diode 31 is further determined based on the change in voltage V _AK . Then, the remaining amount detecting means detects the remaining amount of ink from the relationship shown in FIG.

As described above, based on the voltage V _AK generated across the silicon diode 31, the case 22
Since the actual remaining amount of ink in FIG. 1 can be detected, even if an image of a special print pattern is printed, another ink supply tank 21 is required before the ink supply tank 21 becomes empty. Even if it is exchanged, the remaining amount of ink in the ink supply tank 21 can be reliably detected.

For this purpose, a temperature rise value / ink remaining amount conversion table as shown in FIG. 7 is set in the memory of the control unit, and data of the ink remaining amount n calculated by the equation (2) is stored. Is stored. n = Q / C · ΔT (2) where Q is the self-heating amount (constant) of the silicon diode 31 when the current _IF is supplied to the silicon diode 31, C is the specific heat of the ink, and ΔT is the temperature rise value. It is.

Next, the flowchart will be described. Step S1 The output V _{OUT of the} operational amplifier AMP is read. Step S2: Set the output V _OUT to the voltage V ₀ . Step S3: The switch signal SW1 is turned on, and at the same time, a timer (not shown) starts counting time. Step S4: Wait until one minute elapses. Step S5 The output V _OUT is read. Step S6 sets the output V _OUT to voltage V _1. Step S7: The silicon diode 31 is set to −2 [mV /
° C], the temperature rise value ΔT is calculated by equation (3).

ΔT = (V ₀ −V ₁ ) / 2 (3) Step S8 The temperature rise value ΔT is converted into the remaining ink amount n with reference to the temperature rise value / ink remaining amount conversion table. Step S9: The switch signal SW1 is turned off. It should be noted that the present invention is not limited to the above-described embodiment, but can be variously modified based on the gist of the present invention, and they are not excluded from the scope of the present invention.

[0024]

As described above in detail, according to the present invention, in the ink remaining amount detecting device, the case accommodating the ink impregnated body and the voltage corresponding to the temperature provided in the ink impregnated body are provided. A heat generating member, a voltage detecting means for detecting a voltage generated by the heat generating member, a current supply means for supplying a current to the heat generating member, and a change in the voltage caused by supplying the current. Remaining amount detecting means for detecting the remaining amount of ink based on the remaining amount.

In this case, when a current is supplied to the heat generating member by the current supply means, the heat generating member generates heat by itself and generates a voltage corresponding to the temperature at both ends. Then, since the ink in the case cools the heat generating member, the voltage generated at both ends of the heat generating member changes according to the remaining amount of the ink. Therefore, the remaining amount of the ink can be detected based on the change in the voltage detected by the voltage detecting unit.

Since the actual remaining amount of ink in the case can be detected, when an image having a special print pattern is printed, and before the ink supply tank becomes empty, another ink supply tank is required. In any case of replacement, the remaining amount of ink in the ink supply tank can be reliably detected.

[Brief description of the drawings]

FIG. 1 is a perspective sectional view of an ink supply tank according to an embodiment of the present invention.

FIG. 2 is a sectional view of a conventional ink supply tank.

FIG. 3 is a sectional view of an ink supply tank according to the embodiment of the present invention.

FIG. 4 is a plan view of an ink supply tank according to the embodiment of the present invention.

FIG. 5 is a diagram showing a voltage detection circuit according to the embodiment of the present invention.

FIG. 6 is a diagram illustrating a relationship between a remaining amount of ink and a temperature rise value according to the embodiment of the present invention.

FIG. 7 is a diagram illustrating a temperature rise value / ink remaining amount conversion table according to the embodiment of the present invention.

FIG. 8 is a flowchart illustrating an operation of the ink remaining amount detecting device according to the embodiment of the present invention.

[Explanation of symbols]

22 Case 26 Ink Impregnated Body 31 Silicon Diode 35 Detection Circuit Board _IF Current n Remaining Ink V _AK , V ₁ , V ₀ Voltage

Claims (1)

[Claims] (A) a case containing an ink impregnated body; (b) a heating member arranged in the ink impregnated body to generate a voltage corresponding to a temperature; and (c) a heating member generated by the heating member. Voltage detecting means for detecting a voltage to be applied,
(D) current supply means for supplying a current to the heat generating member;
(E) a remaining amount detecting unit for detecting a remaining amount of the ink based on a change in the voltage caused by supplying a current.