JPS60224549A - Ink jet printer - Google Patents

Abstract

PURPOSE:To prevent unloaded striking of an ink head and improve printing quality by providing a means to detect the indication of a remaining ink quantity below a standard value and then of ink replenishment or ink tank change. CONSTITUTION:A comparator 3 compares a detected quantity of remaining ink obtained from an ink level sensor 2 with a certain preset value, and outputs to CPU7 an ink level signal to the effect that an ink shortfall has occurred when the detected quantity has decreased beyond a certain value. CPU7 sends to an indicator 12 an ink tank replenishment indication signal (or an ink tank change indication signal) in response to the ink level signal which was inputted. Following this procedure, CPU7 adds a frequency of ink replenishments and stores the data to a non-volatile memory 9. If the stored frequency of ink replenishments exceeded a preset frequency on account of a correlationship between the life of a head and ink consumption, CPU7 sends a head change indication signal to the indicator 12.

Description

Detailed Description of the Invention [Technical Field] The present invention relates to an inkjet printer that records characters, images, etc. on a recording medium by ejecting ink supplied from an ink tank from a nozzle, and particularly relates to an inkjet printer that records characters, images, etc. on a recording medium, and particularly for ink replenishment and head replacement. The present invention provides an inkjet printer equipped with means for instructing.

[Prior Art] Conventionally, in this type of inkjet printer, when the operator senses that the printing operation is no longer being performed normally,
The operator used to replenish ink or replace the head, but the operator had to detect when it was time to replenish the ink or replace the head by dry-firing the ink.For example, a thermal head forms a bubble to eject ink. In so-called bubble jet recording, the head is heated excessively when the ink runs out, which shortens the life of the head and degrades print quality.

[Objective] An object of the present invention is to provide an inkjet printer that can eliminate the above-mentioned drawbacks, prevent ink skewering in the head, and improve printing quality.

Another object of the present invention is to provide a means for detecting that the remaining amount of ink in an ink tank has become less than a predetermined amount and instructing to replenish ink or replace the ink tank.

Furthermore, the present invention detects the replenishment of ink or the replacement of a cartridge-type ink tank, and when the number of times of replenishment or replacement exceeds a predetermined number determined from the correlation between the life of the head and the amount of ink used, the head is replaced. The purpose is to provide a means of giving instructions.

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

FIG. 1 shows the overall configuration of an embodiment of the present invention, where 1 is an ink tank of an inkjet printer;
Ink is stored to be supplied to a nozzle as shown in FIG. 2, which will be described later. 2 is an ink level sensor that detects the amount of ink remaining in the ink tank l. 3 is a comparator provided on the printer body side, which compares the detected amount of remaining ink obtained from the ink level sensor 2 with a predetermined value and detects that the detected amount is less than the predetermined value. Sometimes, an ink level signal indicating that ink is insufficient is output.

The ink level signal output from the comparator 3 is sent to the input/output interface (
Ilo) 5 and a common bus 6 to a CPU (Central Processing Unit) 7. Reference numeral 8 denotes a system memory, which stores in advance control procedures and the like necessary for operations related to the present invention as shown in FIG. 6, which will be described later. 8 is a non-volatile memory that stores the number of times of ink replenishment or ink tank replacement, which is detected based on the fluctuation of the above-mentioned ink level signal. Further, 10 is a programmable timer, and 11 is an input/output interface (Ilo).

CPII 7 outputs an ink replenishment instruction signal (or an ink tank replacement instruction signal,
The same applies hereafter) is sent to the display section 12 through the interface 11. Replenish ink (or replace ink tank,
), the ink level signal disappears, so the CPU 7 adds up the number of ink refills and stores it in the non-volatile memory 8, and the stored number of ink replenishments correlates with the head life and ink usage. When the predetermined number of times is exceeded, a head replacement instruction signal is sent to the display section 12 through the interface 11.

The display unit 12 displays that ink replenishment is requested in response to the input ink replenishment instruction signal, and displays that head replacement is requested in response to the input head replacement instruction signal. The display unit 12 has a display lamp or a display such as a CRT or liquid crystal for this display.

Furthermore, the CPU 7 operates the programmable timer 10 in synchronization with the sending of the above-mentioned re-instruction signal, and if the ink is not replenished within a predetermined period of time, the printing operation is stopped and a warning buzzer or alarm is sounded. It is also suitable to generate the following.

It can also be applied to a type of printer in which ink is automatically replenished from the main ink tank to the sub ink tank, and ink is supplied from the sub ink tank to the nozzles. In this case, the above-mentioned ink level sensor 2 is installed in the main ink tank. All you have to do is set up the .

FIG. 2 shows an example of a head unit in which the ink level sensor 2 as shown in FIG. 1 is installed. In the head unit shown in this figure, the inkjet head 15 and the ink tank 1 are integrally formed, but the present invention is not limited to this.
A configuration in which the head 15 and the ink tank 1 are separated and connected through an ink supply pipe can also be applied. 16 is an inkjet nozzle established on the front of Herad 21,
The ink supplied from the ink tank 1 is ejected via an internal electrothermal converter or the like in the form of flying droplets in response to a recording signal. Of course, the above-mentioned head unit may be of a shuttle type that records while moving in the main scanning direction by a carriage, or of a full multi-nozzle type having a plurality of nozzles 16 over the entire recording width.

However, although it is necessary that the entire head unit or the head 15 alone can be replaced, the ink tank l may be a cartridge type that can be separated from the head 15 and replaced independently, or an ink refill type that is integrated with the head 15. But that's fine.

FIG. 3 shows an example of the ink level sensor 2 disposed at a predetermined position within the ink tank 1 as described above. As the ink level sensor 2, in addition to the capacitance type liquid level sensor shown in this figure, various types of liquid level sensors can be applied.The sensor 2 shown in the figure has a pair of electrodes, and both electrodes are It is installed at a predetermined position within the ink tough 1 almost vertically with a predetermined gap provided so that the ink 17 is interposed therebetween. Since the capacitance when there is a lot of ink 17 remaining between the two electrodes is different from the capacitance when there is a small amount of ink 17 remaining between the two electrodes, the remaining amount of ink 17 in the ink tank 1 is transmitted as an analog signal through the signal line 21 due to the difference in capacitance. , can be notified to the comparator 3 in FIG. 1, which is one of the control units of the printer main body. Also,
It is also possible to know the number of times of ink replenishment using the output signal of this sensor 2. That is, when the remaining amount indicated by the analog signal changes in a direction indicating an increase, it can be determined that ink has been replenished.

FIG. 4 shows a case where a contact type culture surface sensor is applied as the ink level sensor 2. In FIG. In this case, an AC current is passed between a pair of electrodes placed directly into the ink 17 of the ink tank 1, and the ink shortage is detected based on the change in current caused by the ink 17 running out. Therefore, in this case, the comparator 3 in FIG. 1 can be omitted for simplification. In other words, an inverter is connected instead of comparator 3, and the sensor output is inverted and output as an ink level signal.
This is because it can also be output to the PU 7.

FIG. 5 further shows a case where an optical liquid level sensor is applied as the ink level sensor 2. In this case, a so-called optical fiber sensor is used, and a light emitting diode, semiconductor laser, etc. provided outside the ink tank 1 is used. It has a light emitting section 25, a light receiving section 2B such as a phototransistor, and optical fibers 27 and 28 disposed near the bottom of the ink tank 1.

Both optical fibers 27 and 28 are disposed within the ink tank 1 with a predetermined gap and their ends face each other, so that ink 17 exists between the ends of both optical fibers 27 and 28. When the ink 17 is used up, the light emitted from the light emitting section 25 is not passed through to the light receiving side.
An ink level signal is received by the light receiving unit 26 through the CPU ? can be sent to.

Therefore, in this case, the comparator 3 shown in FIG. 1 is not required, and the configuration becomes simple. In addition, the ink level sensor 2 may be a pressure sensor such as a Bourdon tube having a strain sensor, or a known level sensor such as a thermocouple that detects the liquid level position based on temperature changes.

Next, the operation of the embodiment of the present invention shown in FIG. 1 will be described in more detail with reference to the flowchart shown in FIG.

First, after the power is turned on (step S1), various counters used in the microcomputer system 4 are initialized (step S2), and it is determined whether an ink level signal has been input (step S3).

On the other hand, when the power is turned on, the ink level sensor 2 is turned on and constantly sends a detection signal to the comparator 3 (step Ll). The comparator 3 determines whether the level of the ink 17 in the ink tank 1 is equal to or higher than a predetermined minimum reference position (comparison value) based on the input detection signal.
Step L2), when the level is below the lowest reference position, a level signal is output to the CPIJ 7 through the interface 5 (Step L3).

Therefore, when the level of the ink 17 falls below the reference position, an affirmative determination is made in step S3, and the next time the value of the ink replenishment count stored in the non-volatile memory 8 reaches a predetermined value indicating the head replacement time. It is determined whether or not the ink has been reached (step S4), and if the ink has not been reached, the display section 12 displays an instruction to replenish the ink through the interface 11 (step S5). The prescribed number of times of ink replenishment, which indicates when to replace the head, is determined based on durability tests and the like from the correlation between the life of the head and the amount of ink used, as described above.

When the worker replenishes ink (work procedure T1
), the level of the ink level signal fluctuates, for example, high (H
) level to low (L) level, this is detected and it is determined that ink has been replenished.Step S6
), and at the same time the ink replenishment instruction display disappears, the ink replenishment count in the non-volatile memory 8 is updated by adding °°1゛° (step S7), after which the process returns to step S3 and the above-mentioned processing procedure is repeated. repeat.

When the number of times of ink replenishment increases and the ink replenishment count reaches a specified value, step S determines when to replace the head.
4 is affirmative, so the display section 12 displays an instruction to replace the head 15 through the interface 11 (step S8). When the head is replaced by the operator (work procedure T2), the head replacement instruction is displayed. Since step S9, which determines the presence or absence, is affirmative, the head replacement instruction display disappears, and the process returns to the initialization process of step S2, and the above-described processing procedure is repeated again. Whether or not the above-mentioned head has been replaced can be detected, for example, by a change in the mounting notification signal of the head or head unit.

In addition, in the case of a so-called disposable head unit that is replaced when the ink runs out, the configuration is simpler because it is sufficient to display an instruction to immediately replace the head unit when the ink level sensor 2 detects that the ink is running out. becomes.

Further, the number of ink replenishments or the number of ink cartridge replacements can be mechanically counted, for example, by a rotary counter, and sent as a signal. moreover,
Since the microcomputer system 4 and display unit 12 shown in FIG. 1 can be used in common with those used for printing, there is an advantage that it can be applied to and easily modified existing inkjet printers at low cost. Furthermore, since the number of ink replenishments is stored in the non-volatile memory 8, the history will not be erased even if the power is turned off, and the next printing operation can be processed normally.

[Effects] As described above, according to the present invention, there is a means for detecting that the amount of ink remaining in the ink tank is below a standard value and displaying an instruction to replenish ink or replace the ink tank. It is possible to prevent ink from being ejected from the head, thereby increasing the life of the head and maintaining print quality at a constant level. Furthermore, according to the present invention, when the number of times of ink replenishment or ink tank replacement is detected and the number of times exceeds a standard limit number determined from the correlation between head life and ink usage amount, the head is replaced. Since it has a means to indicate and display instructions, printing quality can be improved,
Unexpected printing mistakes can be prevented by 1F.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an example of the overall configuration of the present invention, Fig. 2 is a perspective view showing the external appearance of a head unit which is a main part of an embodiment of the present invention, and Fig. 3 is a line x-X in Fig. 2. 4 and 5 are sectional views showing other embodiments, and FIG. 6 is a flowchart showing an example of the operation of the embodiment shown in FIG. 1. l... Ink tank, 2... Ink level sensor, 3... Comparator. 4...Microcomputer system, 5, l!・・・
・Interface, 6... Bus, 7... CPU (Central Processing Unit), 8... System memory, 9... Non-volatile memory, 10... Programmable timer, 12... Display section, 15 ···head. 16... Nozzle, 17... Ink, 25... Light emitting section, 26... Light receiving section, 27.28... Optical fiber. Patent applicant: Canon Co., Ltd. Representative: Yoshi Tani, patent attorney −

Claims (1)

[Scope of Claims] Means for detecting that the remaining amount of ink in an ink tank that supplies ink to a head equipped with an ink ejection nozzle has become below a limit amount and instructing replenishment of ink or replacement of the ink tank. and means for detecting that the number of times the ink has been replenished or the ink tank replaced has reached a limit number of times and instructing replacement of the head or a head unit including the head. printer. (Margin below)