JP3305132B2 - Method and apparatus for detecting remaining amount of ink in ink jet recording apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting the amount of ink remaining in an ink tank in an ink jet recording apparatus for supplying an ink from an ink tank to a recording head and flying an ink droplet from a nozzle of the recording head to obtain an image. The present invention relates to an ink jet recording apparatus having a remaining amount detecting device. Here, the recording includes ink application (printing) to all ink supports to which ink is applied, such as cloth, thread, paper, and sheet material. The present invention includes a printer as the output device, and the present invention can be used for them.

[0002]

2. Description of the Related Art A recording device having functions such as a printer, a copying machine, a facsimile, or a recording device used as an output device of a composite electronic device or a workstation including a computer or a word processor is made of paper or plastic based on image information. It is configured to record an image on a recording medium such as a thin plate. Such recording apparatuses can be classified into an ink jet type, a wire dot type, a thermal type, a laser beam type, and the like according to a recording method.

An ink jet recording apparatus (ink jet recording apparatus) performs recording by discharging ink from a recording means (recording head) onto a recording medium, and has the following advantages. It is easy to make the recording means compact,
High-definition images can be recorded at a high speed, recording can be performed on plain paper without special processing, running costs are low, and noise is reduced due to the non-impact method. It is easy to record a color image using color inks.

[0004] In particular, an ink jet recording means (recording head) for discharging ink by using thermal energy is an electrothermal converter or electrode formed on a substrate through a semiconductor manufacturing process such as etching, vapor deposition or sputtering. By forming a liquid path wall, a top plate, and the like, a device having a liquid path arrangement (discharge port arrangement) with high density can be easily manufactured, and further downsizing can be achieved.

In an ink jet recording apparatus, an ink storage device such as an ink tank for storing ink to be supplied to a recording head is mounted on a predetermined fixed portion of the ink jet recording apparatus, or mounted on a carriage together with the recording head. Sometimes. In the former case, an ink supply path such as an ink tube is provided between the recording head and the storage device so that the ink supply path follows the movement of the carriage. In the latter case, the ink supply path between the recording head and the storage device can be relatively short. Therefore, the configuration in which the ink storage device is mounted on the carriage can be said to be a configuration suitable for downsizing the inkjet recording device, simplifying the configuration, and the like.

[0006] Among the configurations in which the recording head and the ink storage device (ink tank) are both mounted on the carriage, a configuration in which the recording head and the ink tank are integrally formed, or a configuration in which the recording head and the ink tank are separated from each other. There are configurations that can be mounted.

In the former configuration in which the recording head and the ink tank are integrally formed, when the ink in the ink tank runs out, the cartridge in which the ink tank and the recording head are integrated is replaced with a new one. Has become popular in recent years because of its easy handling.
Since the expensive head is replaced every time the ink runs out, the running cost increases.

In the latter configuration, in which the recording head and the ink tank are separably mounted, only the ink tank storing the ink is replaced when the ink runs out, and the head itself has reached the end of its life. It can be replaced at times.

In normal use, it is generally impossible for the head to become unusable due to its life before the ink in the ink tank is used up. Therefore, the number of replacements for expensive heads is less than the number of replacements for ink tanks,
Running costs can be reduced. However, in a configuration in which the recording head and the ink tank are separably mounted, the connection between the ink tank and the recording head needs to be precisely manufactured so that ink does not leak.

Further, in a recording apparatus using an ink jet system, it is possible to satisfactorily supply ink corresponding to the amount of ink ejected from a recording head at the time of recording. An ink supply system without such is required.

The ink leakage from the discharge port is a problem peculiar to the field of ink jet recording, and in order to solve the problem, the pressure at the discharge port is generally set to a state lower than the atmospheric pressure. In the ink jet recording apparatus, a negative pressure generating mechanism is provided in the ink supply system in order to realize the above-described pressure state. The negative pressure here is a back pressure in the ink supply direction to the ejection port, and particularly means a pressure state in which the ejection port is lower than the atmospheric pressure as described above.

When the ink storage section is of a replaceable type, in addition to the above-mentioned problems, the ink storage section can be smoothly attached and detached. It is required to be able to supply.

One form of an ink container as an ink container used in the above-described ink jet recording apparatus is disclosed in Japanese Patent Application Laid-Open No. 63-87242 (hereinafter referred to as a first conventional example). This first conventional example shows a configuration of an ink jet recording cartridge in which a foaming material is disposed almost entirely in an ink container and provided with a plurality of ink ejection orifices.

In this ink container, a negative pressure is generated and the ink is retained (prevention of ink leakage from the ink container) due to the capillary force of the foam for storing the ink in a porous medium such as polyurethane foam which is a foaming material. Is possible.

However, in the first conventional example, since the foam is required almost entirely in the ink storage section, the filling amount of ink is limited, and the amount of ink remaining without being used in the foam increases. There has been a problem that ink use efficiency is poor.

Japanese Patent Application Laid-Open No. 6-40043 proposes a technique for increasing the ink filling amount in such a configuration in which a foam material is disposed as a negative pressure generating member in the ink storing means. According to the present application, by using an ink storage container in which a negative pressure generating member storage section and an ink storage section for storing ink are separated, almost all of the ink can be used except for the ink that adheres to the wall surface in the ink storage section. In addition, the capacity of the ink storage container can be increased. Further, the stored negative pressure generating member prevents the ink from leaking from the recording head, and can maintain a stable ink supply performance for a long period of time.

In any of the various ink jet recording apparatuses as described above, it is desirable to replace the ink storage means at an appropriate time, and it is necessary to accurately detect the amount of ink remaining in the ink storage means, It is necessary to provide a configuration for appropriately detecting the time at which the battery runs out.

When the ink in the ink storing means runs out during printing, the discharging means for discharging the ink from the recording head generates energy for discharging in a state where there is no ink. In particular, a so-called bubble jet method is provided in which thermal energy generating means such as an electrothermal conversion element is provided as an ejecting means, and thermal energy is applied to the ink, and the ink is ejected using pressure generated by a state change due to heat of the ink. In an ink jet recording apparatus,
Driving the thermal energy generating means in a state where there is no ink not only unnecessarily raises the temperature of the print head but also causes damage to the print head itself.

Further, in an ink jet recording apparatus of the type in which ink is ejected using a mechanical pressure generating means such as a piezo element as the ejection means, the ejection of the ink is performed by driving the ejection means in a state where there is no ink. Pressure continues to be generated in the absence of a load, resulting in deterioration of the ejection means and reduction in durability.

Conventionally, as a configuration for detecting the depletion of ink (ink end) in an ink storage container or the like of an ink jet recording apparatus, see Japanese Patent Application Laid-Open No. 54-133733.
Japanese Patent Application Publication No. Hei 1-1741 discloses a configuration for detecting the light transmitting state of an ink tank using an optical element as disclosed in
No. 65, the structure of detecting by conduction of electrode members (or these are referred to as “sensor type”).
There is. Another method is disclosed in Japanese Patent Laid-Open No. 59-1948.
A configuration (hereinafter, referred to as a “dot count method”) for counting the number of ejection pulses and estimating the number based on the amount of ink used as disclosed in Japanese Patent Publication No. 53-53 is known.

The function of detecting the remaining amount of ink in such an ink jet recording apparatus has the effect of preventing a recording failure due to recording without ink. That is, the amount of ink in the ink tank is detected and the remaining amount is displayed, or a warning is issued or the recording operation is stopped when the remaining amount is low.

[0022]

However, the conventional ink end detecting device (ink remaining amount detecting device) described above.
In a configuration in which a foam material is arranged as a negative pressure generating member in the above-described ink storing means, or in an ink storage container configuration in which a negative pressure generating member accommodating portion and an ink accommodating portion are separated, the ink remaining amount state is accurately determined. It was difficult to detect.

For example, of the above-mentioned sensor systems, those that detect the light transmitting state of the ink tank using an optical element and those that detect the conduction of the electrode member are provided with a negative pressure generating member due to the structure of the ink storage container. It is difficult to detect that the ink in the stored ink tank has run out. Further, even if the state of remaining ink in only the ink storage unit is detected in a configuration in which the negative pressure generation member storage unit and the ink storage unit are separated, a considerable amount of ink still remains in the negative pressure generation member storage unit. It could only be applied to warnings that a certain reduction had occurred.

In the configuration in which the remaining amount is detected by the conduction of the electrode member, if the negative pressure generating member is pressed by the installation of the electrode, a desired negative pressure cannot be obtained, which adversely affects the ink supply. It can be.

Also, in the dot counting method, a large error occurs because the amount of discharge varies per unit discharge, the amount of initial injection of the ink tank varies, and the amount of use varies depending on the use environment. This error may reach nearly half of the total ink amount considering all errors such as errors for each device and the effects of the environment, etc., and as a result, a warning that the remaining amount has decreased or a stop of the recording device may be issued. In order to surely perform the operation before the ink is exhausted, it is necessary to perform the operation while leaving nearly half of the ink. When the warning or the stop is performed with such a large amount of ink remaining, the detection of the remaining amount is meaningless or the ink is wasted. If an attempt is made to accurately detect the remaining amount by the dot count method, the cost becomes extremely high. Further, with the increase in the capacity of the ink storage container, accurate detection of the remaining amount of ink has become more difficult.

However, among the above-mentioned sensor systems, the system using electrodes requires an electrode for each ink tank, so that the cost of an ink tank or an ink cartridge in which an ink tank and a recording head are integrated is increased. I will. There is also a problem that the ink absorber provided as a negative pressure generating mechanism for stably ejecting ink is pressed by the electrode, which may adversely affect the supply of ink.

The present applicant has previously developed a method of detecting the remaining amount of ink by detecting the light reflectance of the ink absorber in order to improve the problems of the prior art.

According to this method, since the light reflectance changes depending on the presence or absence of ink in the absorber, the remaining ink amount can be detected accurately and accurately even in an ink tank having a built-in ink absorber. It is possible.

The present invention is a further development of such a method for detecting the remaining amount, such as a variation in output of a means (sensor) for detecting light reflectance, a variation due to mounting accuracy, a variation in manufacturing of an ink tank, and the like. It is an object of the present invention to provide a method and an apparatus for detecting the remaining amount of ink with high accuracy and with a desired remaining amount of ink without causing a malfunction and a decrease in detection accuracy due to the above.

It is still another object of the present invention to provide a method and apparatus for accurately detecting the remaining amount of ink without depending on the carriage position, even in an ink jet recording apparatus capable of selecting a plurality of carriage positions according to the thickness of the recording material. .

Furthermore, if the ink tank is replaced with a new ink tank after the display or warning sound indicates that the ink level is low, means for canceling the display or warning sound is provided in the ink jet recording apparatus. It is an object of the present invention to provide a method and an apparatus for detecting the remaining amount of ink which can be automatically performed without any need.

[0032]

According to a first aspect of the present invention, there is provided an ink tank having a built-in ink absorber, and the ink supplied from the ink tank is ejected and deposited on a recording material. An ink jet recording head for forming an image by causing the ink tank to detect a change in light reflectance at a boundary portion between the wall surface of the ink tank and the ink absorber through the wall surface of the ink tank; A method for detecting the amount of reflected light at a predetermined timing by said detection means and outputting data obtained by said detecting means, and an n-th time (n ≧ 2,
Integer) and the (n-1) th or (n-
1) a comparison step of comparing the output results up to the first time, and in the comparison step, when there is a change equal to or more than a predetermined value α, the remaining amount of ink in the ink tank is reduced. It is characterized by informing. According to a second aspect of the present invention, there is provided an ink tank having a built-in ink absorber, and discharging ink supplied from the ink tank onto a recording material.
A printhead for forming an image by attaching the printhead, a carriage for mounting the ink tank and the printhead, and a wall of the ink tank and the ink absorption through a wall of the ink tank mounted on the carriage. Ink remaining amount of an ink jet recording apparatus comprising: detecting means for detecting a change in light reflectance at a boundary with a body; and means for moving the carriage up and down to a plurality of positions corresponding to the thickness of the recording material. A detection method, wherein the detection means detects the light reflection amount at a predetermined timing and outputs acquired data, and the detected light reflection amount corresponds to the position of the carriage. A calculating step of performing a predetermined calculation, wherein the longer the distance between the detection unit and the ink tank, which differs corresponding to the position of the carriage, the more the distance A calculation step of performing calculation for increasing the amount of reflection, n-th obtained through the calculation step (n ≧ 2,
Integer) and the (n-1) th or (n-
1) a comparison step of comparing the output results up to the first time, and in the comparison step, when there is a change equal to or more than a predetermined value α, the remaining amount of ink in the ink tank is reduced. It is characterized by informing. According to a third aspect of the present invention, in the second aspect, in the calculating step, the light reflectance R1 is detected at the end of each page of the recording material, and the carriage position is changed before the subsequent page is recorded. If there is, the light reflectance R2 is detected before the start of recording on the subsequent page, a correction coefficient corresponding to the ink tank in use is calculated from the R1 and R2, and the correction coefficient is set to the carriage position using the correction coefficient. The output value is corrected in accordance with the calculation step. According to a fourth aspect of the present invention,
In any one of the first to third aspects, the predetermined timing is the amount of ink consumption calculated from the number of ejections of ink ejected from the recording head and the number of suctions for recovery of the recording head. Has reached a predetermined amount or after the predetermined amount has been reached. According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the light reflectance is detected before and after all recovery operations of the recording head in the inkjet recording apparatus, and the light reflection before and after the recovery operation is detected. When the difference between the rates is equal to or less than the predetermined value β, all the output results of the light reflectance detected before the recovery are reset. According to a sixth aspect of the present invention, in the fifth aspect, in the case where it is notified that the remaining amount of ink is low before the recovery operation, the resetting is performed to notify that the remaining amount of ink is low. It is characterized by stopping. According to a seventh aspect of the present invention, in any one of the second to fourth aspects, the detecting means for detecting the amount of light reflection is used to detect the light reflectance from the carriage, whereby the plurality of light reflections are detected. The position of the carriage is detected. According to an eighth aspect of the present invention,
In the first or second aspect, an output value of the detection step is an average value of past acquired data and current acquired data. According to a ninth aspect of the present invention, in the first or second aspect, the output value of the detection step is:
It is characterized by being an average value of data acquired repeatedly m times. According to a tenth aspect of the present invention, in any one of the first to ninth aspects, the recording head is provided by an energy generating element including an electrothermal converter that generates thermal energy that causes film boiling of the ink. Is discharged. An eleventh aspect of the present invention provides:
In any one of the first to tenth aspects, the recording head is detachable from a recording apparatus main body. According to a twelfth aspect of the present invention, there is provided an ink tank having a built-in ink absorber, and a recording head for discharging and attaching ink supplied from the ink tank onto a recording material to form an image. An ink remaining amount detecting device for an ink jet recording apparatus, wherein data obtained by detecting a change in light reflectance at a boundary portion between the wall surface of the ink tank and the ink absorber through a wall surface of the ink tank at a predetermined timing. Detecting means for comparing the output result of the n-th time (n ≧ 2, an integer) with the output result of the (n−1) th or up to the (n−1) th time; A detection unit for notifying that the remaining amount of ink in the ink tank is low when the comparison unit changes by a predetermined value α or more. According to a thirteenth aspect of the present invention, there is provided an ink tank containing an ink absorber, a recording head for forming an image by discharging and attaching ink supplied from the ink tank onto a recording material, and An ink remaining amount detecting device for an ink jet recording apparatus, comprising: a carriage for mounting a tank and the recording head; and means for vertically moving the carriage at a plurality of positions corresponding to the thickness of the recording material. Detecting means for outputting data obtained by detecting at a predetermined timing a change in light reflectance at a boundary portion between the wall surface of the ink tank and the ink absorber through the wall surface of the ink tank mounted on the carriage,
Calculating means for performing a predetermined calculation on the detected light reflectance according to the position of the carriage, wherein the distance between the detecting means and the ink tank, which differs according to the position of the carriage, is long. Computing means for performing an operation for increasing the light reflection amount, an n-th (n ≧ 2, integer) output result obtained through the computing means, and an (n−1) -th or (n) -1) comparing means for comparing the output results up to the first time, and informing the user that the remaining amount of ink in the ink tank is low when the comparing means changes by a predetermined value α or more. And a detecting means. According to a fourteenth aspect of the present invention, in the twelfth or thirteenth aspect, the detection means outputs an average value of past acquired data and current acquired data. According to a fifteenth aspect of the present invention, in the twelfth or thirteenth aspect, the detecting means outputs an average value of data repeatedly acquired m times. According to a sixteenth aspect of the present invention, in the twelfth to fifteenth aspects, the recording head ejects the ink by an energy generating element including an electrothermal converter that generates thermal energy that causes film boiling of the ink. Characterized in that: According to a seventeenth aspect of the present invention, in any one of the twelfth to sixteenth aspects, the recording head is detachable from a recording apparatus main body.

[0033]

[0034]

[0035]

[0036]

[0037]

[0038]

[0039]

[0040]

[0041]

[0042]

[0043]

[0044]

[0045]

[0046]

[0047]

[0048]

[0049]

[0050]

[0051]

[0052]

According to the present invention, since the amount of change in light reflectance with respect to the ink absorber can be detected, even if there is a variation in sensor output or a variation in mounting accuracy, or a variation in ink tank manufacturing, The remaining amount of ink in the ink tank can be accurately detected.

Even in an apparatus for obtaining an image by changing the position of the carriage according to the thickness of the recording material, a predetermined calculation is performed on the light reflectance with respect to the ink absorber in accordance with the position of the carriage, so that an accurate calculation is always performed. The remaining amount of ink can be detected.

Further, when the ink tank is replaced with a new ink tank after detecting that the remaining amount of ink is small, it is detected that the change in the output of the sensor is small.
The automatic notification that the remaining amount of ink is low can be stopped.

[0055]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments.

(First Basic Configuration Example) First, a first basic configuration example showing the principle of the ink remaining amount detection method of the present invention will be described with reference to FIGS.

FIG. 1 is a side view of a carriage portion when an ink remaining amount detecting device is mounted on an ink tank and an ink jet recording device proposed in the above-mentioned JP-A-6-40043, and FIG. FIG. 3 is a view showing a state in which a tank is mounted, FIG. 3 is a view showing a state in which the carriage shown in FIG. 1 is viewed from the direction of arrow A in FIG. 1, and FIG. 4 is a schematic perspective view of the entire inkjet recording apparatus.

In FIG. 4, reference numeral 8 denotes a chassis to which various components are attached. Reference numeral 9 denotes a paper feed roller provided in the longitudinal direction of the apparatus and for conveying a recording paper (not shown). Reference numeral 10 denotes a paper feed roller provided in parallel with the paper feed roller 9 to feed the recording paper. Is a pinch roller for pressing the sheet. Reference numeral 2 denotes a guide shaft which is provided in parallel with the paper feed roller 9 and reference numeral 11 denotes a scale portion of a magnetic linear encoder which is provided in parallel with the guide shaft 2.

Reference numeral 1 denotes a carriage that moves along the guide shaft 2. Reference numeral 12 denotes a head cover for fixing an ink jet head (not shown) to the carriage 1, and 13 denotes a flexible substrate, which sends a recording data signal from the apparatus control unit to the ink jet head mounted on the carriage 1, An output signal from a sensor (not shown) of the provided magnetic linear encoder can be sent to the device control unit.

3 is provided in parallel with the guide shaft 2,
A support shaft that maintains the posture of the carriage 1 that is provided rotatably about the guide shaft 2,
Reference numeral 14 denotes a carriage motor for scanning the carriage 1 along the guide shaft 2, and reference numeral 15 denotes a timing belt for transmitting the driving force of the carriage motor 14 to the carriage 1. Reference numeral 16 denotes a transmission type photo interrupter provided in the scanning area of the carriage 1 for setting a reference position in the scanning of the carriage 1.

Reference numeral 17 denotes a suction cap used to prevent defective ejection of the ink jet head or to recover them, and 18 denotes drying the inside of the discharge port (hereinafter also referred to as a nozzle) of the ink jet head while the ink jet head is on standby. It is a protective cap to prevent. Reference numeral 5 denotes a paper position switching lever provided on the carriage 1 for switching the clearance between the recording paper and the ink jet head according to the thickness of the recording paper. Reference numeral 6 denotes a paper position switching lever provided near the home position of the carriage 1. A reflection type photo interrupter 19 as an ink sensor is provided to prevent clogging of a nozzle portion of the inkjet head.
These are preliminary ejection holes for receiving ink droplets when performing preliminary ejection prior to recording.

In FIGS. 1, 2 and 3, reference numeral 1b denotes a hole provided at the bottom of the carriage 1 for transmitting light from the photo interrupter 6.

In FIG. 2, reference numeral 21 denotes a nozzle 2 at the tip of the nozzle.
2 is a recording head for performing recording by discharging ink from the recording head 2. 7 is an ink tank mounted on the carriage 1, 7a is an absorber as a negative pressure generating member provided in the ink tank, 7b is a boundary between the absorber in the ink tank and an outer wall 7e of the ink tank, 7c is a state in which the ink is not mixed with other members in the ink tank (hereinafter, referred to as a state below).
An ink storage portion (hereinafter, also referred to as a raw ink storage portion) 7d for storing with the raw ink is a boundary portion between the raw ink in the ink tank and the ink tank outer wall 7e. The material of the ink tank 7 is transparent to the detection light of the photo interrupter 6, such as transparent plastic. 24
Are supply ports for supplying ink to the recording head 21;
Reference numeral 8 denotes an air communication port for performing gas-liquid exchange accompanying consumption of ink.

The head 21 and the ink tank 7 are integrally mounted on the carriage 1 and slide along the shafts 2 and 3 to scan in a direction perpendicular to the drawing.

FIG. 5 is a plan view of the substrate on which the photo interrupter 6 is mounted, where 6c shows a light emitting unit and 6d shows a light receiving unit. In FIG. 1, reference numeral 6a denotes light emitted from the light emitting unit 6c, and an optical path (hereinafter, also referred to as a return optical path) from which the light 6b is reflected and returned, and is received by the light receiving unit 6d shown in FIG. . This optical path may be a reflection surface in the plane of FIG. 1 as shown in FIG. 1, or a reflection plane may be a plane perpendicular to the plane of FIG. However, when the posture of the carriage 1 is largely changed by the operation of the above-described paper position switching lever 5, the influence of the posture difference is less likely to be obtained by setting the reflection surface in the direction perpendicular to the paper surface of FIG. Also, in FIG. 1, this optical path is drawn as a simple straight line so as not to complicate the drawing, but is actually a light beam having a certain spread.

The photo-interrupter 6 is installed so as to irradiate detection light to a portion of the absorber 7a in the ink tank 7 slightly closer to the raw ink storage portion 7c. This position affects the remaining recordable number at the time of detection as described later. Regarding the position of the photo-interrupter 6 in the height direction, it is desirable to arrange the photo-interrupter 6 such that the boundary 7b between the wall surface of the ink tank 7 and the absorber 7a comes near the focal position of the photo-interrupter 6. If the detection light deviates from the focus position of the photo interrupter 6, the spread of the detection light increases, and the S / N of the detection is lowered due to the light reflected and scattered at the edge of the hole 1b of the carriage 1 or the like. .

In this embodiment, as shown in FIG. 4, a color ink jet recording apparatus configured to be capable of discharging a plurality of different color inks will be described as an example. A plurality of inks of different colors are stored in corresponding ink tanks and mounted on a carriage. Therefore, the ink absorbed by the absorber 7a is one of the four colors of black, cyan, magenta, and yellow that are usually used in a color printer. After the ink flows from the absorber 7a through the supply port 24 and the flow path 30 in the recording head 21 sequentially, the heat energy is applied to the ink by a heat generating means (hereinafter also referred to as a heater) 31 provided in the nozzle 22 as a discharging means. The application of sufficient thermal energy causes the ink to foam and be discharged from the discharge port at the tip of the nozzle 22. Recording is performed by the ink ejected in this manner adhering to a medium such as paper.

As described above, the photo interrupter 6 is formed by integrating the LED, which is the light emitting element 6c of the light source, with the light receiving element 6d. This LED emits infrared light having transparency to any of the above four color inks.
The light receiving element 6d also has sufficient sensitivity to the wavelength of the LED.

The photo interrupter 6 is installed separately from the carriage 1 and irradiates infrared light to the bottom surface of the absorber 7a through a hole 1b formed in the carriage 1 and a wall 7e of the transparent ink tank 7 to reflect the infrared light. The detected light is detected by the light receiving element 6d. As described above, the photointerrupter 6, which is a detection system, is installed separately from the carriage 1 by:
A power supply line and a signal line from the main body of the recording apparatus to the carriage 1, which is a movable portion, are not necessary, and the configuration can be simplified and the cost can be reduced.

FIG. 6 is an enlarged view of the vicinity of the photointerrupter 6 of the photointerrupter 6 on the lower surface of the absorber 7a where light is irradiated when the ink tank 7 has sufficient ink.
FIG. 4 is an enlarged view when ink runs out at the same position.
FIG. 8 is a graph showing a change in the output of the light receiving unit 6d of the photo interrupter 6 according to the remaining ink amount.

Next, the principle of detecting the remaining amount of ink according to the present invention will be described.

In general, the Fresnel's formula indicating the amplitude reflectance of light at the interface between the media 1 and 2 having different refractive indices is as follows.

[0073]

(Equation 1)

In this embodiment, if the light from the light emitting portion 6c of the photo interrupter 6 is incident on the ink tank 7 at an angle nearly perpendicular, it can be considered that cos θ = 1, and the above-described amplitude reflectance If the square is used to describe the energy reflectance instead of the following, the following equation is obtained.

[0075]

(Equation 2)

First, when there is sufficient ink in the ink tank 7, the gap between the wall 7e of the ink tank 7 and the absorber 7a is filled with ink as shown in FIG. Ink tank 7
The absorber 7a is made of plastic and has a refractive index of about 1.5 and ink has a refractive index of about 1.4, so that the reflectance on the inner wall 7e of the ink tank 7 and the surface of the absorber 7a is only about 0.1% from the above formula. Absent.

Next, with the consumption of ink, air enters into the gap between the wall surface 7e of the ink tank 7 and the absorber 7a through the atmosphere communication port 8 in FIG. 6, as shown in FIG. The reflectance on the surface of the tank inner wall 7e and the surface of the absorber 7a when the ink is exhausted is about 4%. That is, when the ink runs out, the amount of reflected light increases by about 40 times (however, actually, the output difference up to that point is affected by the light other than the reflected light from the boundary 7c such as the reflected light from the outer bottom surface of the ink tank 7 or the electric noise). As not detected).

Here, even if detection is performed at the boundary 7d between the ink tank 7 and the raw ink storage section 7c by the photo interrupter 6, a difference in reflectance occurs. However, when compared with that case, the number of reflective elements is reduced. There are the following differences.

[0079]

[Table 1]

As described above, when the detection is performed by the absorber, the number of the reflection elements is three times as large, and the amount of reflected light itself is increased by that amount, so that the above-described noise-resistant detection can be performed.

As shown in FIG. 7, air that has entered between the absorber 7a and the ink tank 7 often exists as many fine bubbles while passing through the absorber 7a. The reflected light amount further increases due to the scattering effect.

As described above, these reflectances are represented by cos θ =
The value is 1 in the case of 1. However, in other cases, there is a considerable difference in reflectance with and without ink. In either case, a large output difference occurs in the light receiving portion 6d of the photointerrupter 6 in accordance with the reflectance difference, so that the presence or absence of ink in the ink tank 7 can be detected based on the output difference.

Actually, the area where the photo interrupter 6 irradiates light is not a point even at its focal position.
It has a certain size, and the output of the photointerrupter 6 changes continuously as the ink gradually escapes from that area.

In FIG. 8, the abscissa represents the remaining number of printable sheets from the time when the ink is exhausted to the time when the ink is not ejected. On the basis of the output change curve, when a predetermined threshold level is exceeded (in FIG. 8, the remaining amount capable of recording about 15 remaining sheets is set as the threshold), the amount of ink in the ink tank 7 becomes small. Judge that Then, by illuminating a warning display LED or the like on the display panel of the ink jet recording apparatus main body, it is possible to notify the user that the remaining amount of ink is low.

The remaining number of sheets when displaying that the remaining ink amount is low can be increased or decreased by changing the threshold level. However, as can be seen from FIG. 8, it is difficult to display the number before the output rises (about 30 remaining in FIG. 8). On the other hand, the number of recordable sheets when the output rises can be changed by changing the position where the photo interrupter 6 performs detection. In this way, a warning can be issued with a desired remaining number.

Alternatively, in order to ensure that no recording failure occurs, the recording operation may be stopped instead of or simultaneously with the warning. In this case, there is an effect that a stronger warning is given by temporarily stopping.

Incidentally, actually, the photo interrupter 6
The area irradiated with light has a certain size, not a point, and the output of the photointerrupter 6 changes continuously because it is detected that the ink is gradually depleted in that area.

FIG. 9A schematically shows this state. The output (vertical axis) of the photointerrupter 6 when recording is performed from the initial state until the ink in the ink tank 7 is exhausted (horizontal axis). After the number of recordings X has passed, the amount of ink in the area where the photo interrupter 6 irradiates light decreases, and the output of the photo interrupter 6 increases.

Therefore, the remaining amount can be detected by detecting a change in the output of the photointerrupter 6 after the number of recordings X has passed.

FIG. 23 shows the actual output characteristics of the ink tanks used in the more specific embodiments 1 to 4. When the predetermined image is recorded using four different ink tanks, This is a plot of the measurement result of the output value for every × 106 pulse. The output value on the vertical axis is LED OFF
LE from the output (dark voltage) from the photo interrupter at the time
Output from photointerrupter when D is ON (bright voltage)
Is shown.

As is apparent from FIG. 10, since the output value differs depending on the ink tank, it is difficult to determine the threshold value of the output value and accurately detect the remaining ink amount. It is understood that the remaining amount of ink can be detected more accurately by measuring the amount of change.

When an image is obtained by changing the position of the carriage according to the thickness of the recording material, the photo interrupter 6 is used.
When the distance between the photo-interrupter 6 and the ink tank 7 is appropriately set in consideration of the focal length, the output becomes smaller as the distance is longer and the output becomes larger as the distance is shorter as shown in FIG. 9B. Become like Therefore, in this case, if the output change amount of the photo interrupter 6 is measured in consideration of the distance between the photo interrupter 6 and the ink tank 7, the remaining amount of ink can be detected more accurately.

On the other hand, the output of the photointerrupter 6 is constant before the number of recordings reaches X. This is because there is sufficient ink in the area where the light from the photo interrupter 6 is irradiated, and when the replacement with a new ink tank is performed after the remaining amount is detected, it is detected that the output change is small. Automatically stop indicating that the remaining amount is low.

According to the first basic configuration described in detail above, the ink tank 7 having the absorber 7a as the negative pressure generating member is provided.
On the other hand, the reflected light of the light emitted from the light emitting unit 6c is detected by the light receiving unit 6d, and the output level accurately detects that the remaining amount of ink in the ink tank 7 is smaller than a predetermined amount. be able to.

At this time, the absorber 7a functions as a negative pressure control member for controlling the negative pressure of the ink supplied from the ink tank 7, and a reflection control member for controlling the amount of light reflected by the light emitting section 6c. , It is possible to accurately detect a decrease in the remaining amount of ink in the ink tank in which the absorber 7a is disposed.

In this case, as described above, the present invention is applied to a color printer, and four ink tanks 7 are arranged side by side in correspondence with four colors. Therefore, the carriage 1
, The ink tanks of the respective colors are sequentially made to face the photointerrupter 6, and the remaining ink amounts of the respective ink tanks are detected. Since it is necessary to individually track output changes in each color, a memory means corresponding to the output change is provided. In this case, it is desirable that the indication that the amount of remaining ink is low is displayed separately for each of the four colors. However, only one color is simply reduced because the display panel of the ink jet recording apparatus becomes complicated. May be displayed.

According to the configuration described above, the remaining amount of ink in each of the four color ink tanks can be accurately detected by one detection system with respect to the ink tank containing the ink absorber of the color ink jet recording apparatus.

In the first basic configuration, the detection is performed from the bottom of the ink tank 7. However, the method of the present invention is not limited to the configuration in which the detection is performed from the bottom surface of the ink tank 7, and the detection may be performed from the side surface or the upper surface.

However, for the following reason, the ink tank 7
It is more desirable to perform detection from the bottom surface.

The density distribution of the absorber 7a is usually not uniform, and the ink is spotted as the ink runs out. Therefore, even if there is still ink in the surroundings, only the place where the photo interrupter 6 happens to detect the ink is exhausted first, or vice versa. The number of sheets varies, and in the worst case, the ink may run out without warning.

However, since the bottom of the ink tank 7 is apt to accumulate ink due to the effect of gravity, the absorber 7a
The effect of the density distribution is reduced. Therefore, by performing detection from the bottom surface of the ink tank 7, it is possible to detect the remaining amount of ink with high accuracy.

The first basic configuration of the present invention has been described above, and will be described in more detail below using specific embodiments.

(Embodiment 1) FIG. 10 is a schematic view of a recording section of a color ink jet printer to which the present invention can be applied.

Reference numeral 101 denotes a recording head which has a plurality of nozzle rows and forms dots on the recording medium 110 by discharging ink droplets. The recording head 101 is detachably attached to the carriage 103 by a recording head fixing lever described later. I have. As will be described later, the recording head used in the present embodiment is configured integrally with recording heads for four colors of yellow (Y), magenta (M), cyan (C), and black (K or Bk). Thus, a color image is formed on the recording medium 110 by mixing colors of the ink droplets.

The carriage 103 is driven by a motor 113 for driving the carriage and a motor pulley 112 and a driven pulley 1.
11 and the guide shaft 1 via the timing belt 107.
05 in the directions of arrows a and b.

The recording medium 110 includes two sets of the transport rollers 10.
It is conveyed by 6, 107, 108 and 109. The recording paper 110 has its back surface supported by a platen (not shown) so as to form a flat recording surface at a position facing the nozzles of the recording head.

The image data is transferred from the electric circuit of the printer body to the recording head 10 by a flexible cable (not shown).
1 is transmitted.

At the home position of the recording head 101, a recovery unit 120 is provided. The recovery system unit 120 includes four caps 121 arranged corresponding to the nozzle rows of each color of the recording head 101, and a pump unit (not shown) connected to each cap by a tube or the like. The cap 121 can be moved up and down in accordance with the movement of the carriage 103 when the carriage 103 approaches, so that the cap 103 comes into close contact with the nozzle row of each color of the recording head 101 when the carriage 103 is at the home position. Is configured. This capping prevents thickening or sticking due to evaporation of the ink in the nozzles, and prevents occurrence of ejection failure.

When the ink tank is replaced or a recording head discharge failure occurs, the pump unit is operated under the capping state to generate a negative pressure. Can suck out and guide new ink.

Further, the recovery system unit is provided with a wiper blade 122 for wiping and cleaning the leading end of the recording head 101 at a position between the cap 121 and the recording paper transport section.

The cap 121 and the wiper blade 1
22, a photo interrupter 123 is provided, and the ink tank 102 is connected to a recording head described later.
This is for detecting that the remaining amount of ink in the ink tank is low by irradiating the bottom surface of the absorber portion with light, and by scanning the carriage 103, the light reflectance of the ink tank of each color can be measured. It is configured as follows.

FIG. 11 illustrates the recording head 101 on the carriage 103.

In the carriage 103, K, C, M, Y
Recording heads and ink tank 1 for ejecting ink
02K, 102C, 102M, and 102Y are mounted. Each of the four print heads has 64 nozzles, and each nozzle discharges about 40 ng of ink droplets per discharge. Each of the four ink tanks is configured to be detachable from the carriage 103, and a new ink tank can be replaced for each color when the ink runs out.

A recording head fixing lever 104 is for positioning and fixing the recording head 101 to the carriage 103, and a boss 103b of the carriage 103 and a hole 104a of the recording head fixing lever 104 are rotatably fitted. The recording head 101 can be replaced by opening and closing the lever.

FIG. 12 is a diagram for explaining the ink tank 102. The ink tank 102 has a portion where the ink is absorbed by the absorber 122 by the partition 121 and a portion where the ink is not absorbed by the absorber ( Raw ink)
123. Also, the ink tank 102
Is provided with a supply port 124 for supplying ink to the recording head 101 and an atmosphere communication port 125. If the ink tank used in this embodiment is used, for example, when printing an image of 10% duty for each color per A4 size page, it is possible to print about 160 A4 pages.

FIG. 13 is an electric control block diagram of the above-described ink jet printer.

Reference numeral 301 denotes a system controller for controlling the entire apparatus, which includes a microprocessor and other storage elements (ROM, storage elements used when the microprocessor performs processing, such as a ROM). RAM) etc. are arranged.

Reference numeral 302 denotes a driver for driving the recording head in the main scanning direction. Similarly, reference numeral 303 denotes a driver for moving the recording material in the sub scanning direction.

Reference numerals 304 and 305 denote motors corresponding to the driver, which operate by receiving information such as speed and moving distance from the driver.

Reference numeral 306 denotes a host computer,
This is a device for transferring information to be recorded to the recording device of the present invention.

Reference numeral 307 denotes the host computer 30
6 is a reception buffer for temporarily storing data from the system controller 6, and stores data until data is read from the system controller 301.

Reference numeral 308 denotes a frame memory for expanding data to be recorded into image data, and has a memory size necessary for recording. In this embodiment, a frame memory capable of storing one recording sheet will be described, but the present invention is not limited to the size of the frame memory.

Reference numeral 309 denotes a storage element for temporarily storing data to be printed, and the storage capacity varies depending on the number of nozzles of the print head.

Reference numeral 310 denotes a recording control unit for appropriately controlling the recording head according to a command from the system controller, and for controlling the recording speed, the number of recording data, and the like. Here, the recording head 312Bk,
The number of ink droplets ejected by 312C, 312M, and 312Y and the number of suctions performed to recover the print head are counted, and the amount of ink consumed for each color is converted into the number of ink droplets (number of pulses).

Reference numeral 311 denotes a print head driver for ejecting Bk, C, M, and Y inks, which is controlled by a signal from the print control unit 310. In the figure, the recording head is set to 312 Bk, 312 Bk for each color.
C, 312M, and 312Y.

Reference numeral 313 denotes a detection unit for measuring the light reflectance of the bottom surface of the ink tank by the photo interrupter 123 and obtaining an output value. The detection unit 313 detects the ink tank of each color according to a command from the system controller 301.

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

FIG. 14 is a diagram for explaining an operation flow for detecting the remaining amount of ink in the ink tank 102.

First, Step S1 is a step of counting the amount of ink consumed for each color by converting it into the number of pulses from the ejection of ink droplets for image formation and the idle ejection and suction performed to recover the recording head. It is. In this embodiment, suction 1
Counted as 3 × 10 ⁶ pulses per time.

Step S2 is a step for judging whether or not the number of pulses counted in step S1 has reached a predetermined number. In this embodiment, the number of pulses is set to 15 × 10 ⁶ . If the number of pulses has not reached the predetermined number, the counting is continued.
At 3, the light reflectance (output value) of the absorber on the bottom surface of the ink tank 102 is measured. In this embodiment, the output is measured at the time of returning to the first home position of the carriage 103 immediately after reaching the predetermined number of pulses. Therefore, when recording is performed when the predetermined number of pulses is reached, It was set to be performed before the scanning of the next line was completed after the scanning.

The output value is measured at the end of the page after the arrival of the predetermined pulse.
It can be performed at the time of idle discharge for the first recovery after the arrival of the predetermined pulse.

Step S4 is a step of comparing the output value obtained in step S3 with the previous output value, and determines whether the output value has increased by α or more from the previous output value. If it has not risen by more than α, the process returns to step S1 to continue counting the number of pulses and obtain the output value. If it has risen by more than α, the process goes to step S5 to determine that the remaining amount of the ink tank 102 is running low. Inform.

After turning on a warning lamp (not shown), the recording scan is interrupted in step S6.

In this embodiment, when the above α is set to 0.20 and several new ink tanks are mounted and an image with a duty of 10% is continuously recorded, about 130 to 1
On the 55th page, the warning lamp was turned on.

The displayed warning lamp can be turned off by, for example, pressing a warning lamp release switch (not shown) provided in the printer.

As described above, according to the present embodiment,
To compare with the previous output value and detect if there is a change of more than a predetermined value from the previous output value, the output of the photointerrupter Even if there is, it is possible to always accurately detect that the remaining amount of the ink tank is low.

(Embodiment 2) In this embodiment, the determination method of the remaining amount detection in the first embodiment is made different, and when a new ink tank is replaced after the warning lamp for the remaining amount of ink is turned on, the present embodiment is automatically performed. The light is turned off.

FIG. 15 is an operation flow for explaining a method of detecting the remaining amount of ink in this embodiment.

The difference from the first embodiment lies in steps S12 and S14 and thereafter.

Step S11 is the same as step S1 of the first embodiment.
Step 12 is to set the predetermined consumption amount to 5
Step S of Example 1 except that the pulse is set to × 10 ⁶ pulses.
Step S13 is the same as step S3 of the first embodiment.

Step S14 is a step of calculating the past three output change amounts from the present output value. In order to obtain the past three output change amounts, the present output value and the stored last three output values are required.

Further, in step S15, step S
It is determined whether or not the output change amount in the past three times obtained in 14 has increased by β or more. If the output change amount has not increased by α or more, the process returns to step S11. Display is performed in step S16.

This embodiment is different from the first embodiment in that, as described above, the setting of the predetermined amount of consumption in step S12 is set smaller than that of the first embodiment, and the total value of the past output change is compared with the predetermined value. It is a point to do. That is, in the present embodiment, there is an advantage that an error in remaining amount detection hardly occurs because the interval for acquiring the output value is short. However, if the setting of the predetermined number of pulses is extremely small, the number of times of obtaining the output value increases, which undesirably lowers the throughput.

Next, the case where the printer user replaces the ink tank with a new ink tank after the warning lamp is turned on when the remaining amount of the ink tank is low will be described.

When replacing the ink tank, a normal recovery operation is performed in order to prevent the problems described below.

That is, as a result of continuing to use the ink tank having a small remaining amount, the ink runs out and the ink is not supplied to the nozzles of the recording head, resulting in non-ejection of ink. Even if the ink tank is replaced with a new one in this state, no new ink is supplied to the nozzles unless the recovery operation is performed.

When the ink tank having a small remaining amount is replaced with a new ink tank before non-discharge occurs, ink remains in the nozzles. However, when the ink tank is replaced, there is a possibility that air may enter from the supply port of the print head, and normal printing can be performed for a while after the ink tank is replaced. May be disturbed, and as a result, non-ejection may occur.

In order to prevent such a problem, a normal recovery operation is performed when the ink tank is replaced. In this embodiment,
By paying attention to the recovery operation performed at the time of replacing the ink tank described above, the warning lamp is automatically turned off when the new ink tank is replaced.

FIG. 16 is an operation flow for explaining the turning off of the warning lamp.

In step S21, the output value P1 is set before the recovery operation.
Is measured, and a recovery operation is performed in step S22. The recovery operation here includes suction for guiding ink from the ink tank to the nozzle portion of the recording head, wiping by a blade or the like performed after suction, and idle discharge performed after wiping.

After the end of the recovery operation, the output value P2 is measured again in step S23.

Further, in step S24, step S2
1 and the difference between the output values measured in step S23 (P2-
It is determined whether or not P1) is smaller than a predetermined value β. If it is smaller, the process proceeds to step S25. If not, the recovery operation ends and returns to the original state, and the counting of the ink consumption is continued.

In step S25, all output values obtained before the recovery operation are reset and discarded. The reason will be described later.

In step S26, it is determined whether or not the warning lamp was lit before the recovery operation. If so, the display is turned off in step S27, the recovery operation is terminated, and the light is not lit. If it has, the recovery operation is terminated and the operation returns to the original state.

Next, the reason for resetting the output value in step S5 will be described.

First, when the warning lamp is lit and the ink tank is replaced with a new ink tank and the recovery operation is performed, the output value obtained before the recovery operation is unnecessary because the ink tank is a new ink tank. .

When the warning lamp is not lit and the ink tank is replaced with another ink tank and the recovery operation is performed, the output value may change due to variations in manufacturing of the ink tank. For example, assuming that the ink tank A is replaced with the ink tank B when the number of printed sheets is Y as shown in FIG. 17, the output value of the ink tank B is larger than the output value of the ink tank A. The output rise from the output value acquired by the ink tank A is large. As a result, when the ink tank B is replaced, there is a problem that the warning lamp is turned on even though the ink is sufficient.

Therefore, if the output value before the recovery operation is reset, such a problem can be prevented from occurring.

Also, when a normal recovery operation is performed other than when the ink tank is replaced, if there is no output change of a predetermined value or more before and after the recovery operation, it is considered that there is sufficient ink, and the output before the recovery operation is determined. You can reset the value.

For the reasons described above, if the output value change before and after the recovery operation in all cases is equal to or less than the predetermined value, the output value up to that time is reset, so that the remaining ink amount without malfunction can be detected. At the same time, the warning lamp can be automatically turned off.

Finally, in this embodiment, the value of α is set to 0.2.
When 0 and β were set to 0.09 and images with a duty of each color of 10% were continuously recorded, the warning lamp was turned on at about pages 135 to 150. When the ink tank was replaced with a new ink tank and the recovery operation was performed, the warning lamp was turned off.

(Embodiment 3) The ink jet printer of FIG. 18 is similar to the ink jet printer of Embodiment 1, except that a carriage position lever 130 is attached to the carriage 103 so that the position of the carriage can be changed to two positions. Is different from the first embodiment.

FIG. 19 is a schematic cross-sectional view of the carriage 103 showing a state in which the sheet interval position is changed by operating the sheet interval position lever 130 shown in FIG.

FIG. 19A shows a state in which the sheet interval position is normal, that is, ordinary plain paper, coated paper, OHP paper, or the like.
It is used when obtaining an image on a recording material such as a film.
When the sheet position lever 130 is tilted in the direction of arrow c from this state, as shown in FIG.
The inter-sheet position changing member 131 protrudes from the bottom of the conveyance roller 106 with respect to the conveyance roller 106, the carriage 103 moves upward with the guide shaft 105 as a fulcrum, and the distance from the recording material increases. The carriage position in FIG. 19B is called a thick paper position, and is used when an image is obtained on a thicker than normal paper or a special film having a thicker thickness.

FIG. 20 shows the operation flow of this embodiment. Steps S31 to S33 are the same as steps S1 to S3 of the first embodiment, and the steps after step S34 are different from those of the first embodiment.

That is, in step S34, it is determined whether the position of the carriage 103 is at the normal position or the cardboard position. If it is in the normal position, the process proceeds to steps S36 to S39, and the same processing as steps S4 to S6 of the first embodiment is performed.

On the other hand, if the card is in the thick paper position, the flow advances to step S35, and a value obtained by multiplying the output value obtained in step S33 by 1.5 is used as a new output value, and the flow advances to steps S36 to S39.

As described above, the output value at the thick paper position
By multiplying by 1.5, the output value at the thick paper position can be corrected and treated as the output value at the normal position. Become.

The recognition of the carriage position in step S4 can be performed as follows.

For example, it can be recognized by a paper interval position input switch (not shown) provided in the ink jet printer, or can be recognized by setting from a printer driver. Further, by mechanically detecting that the user of the printer has switched the paper gap position lever 130, the input by the paper gap position input switch and the input by the printer driver can be omitted. is there.

Further, since the carriage 103 is moved up and down by the sheet interval lever 130, the sheet interval position can be automatically detected by measuring the light reflectance from a predetermined position on the back surface of the carriage by the photo interrupter 123. Becomes possible.

(Embodiment 4) The embodiment 4 is a further development of the embodiment 3 with higher precision, and is used instead of uniformly correcting the output value according to the carriage position. The correction is performed for each ink tank. This makes it possible to accurately detect the remaining amount even if there is a variation in the production of the ink tank.

FIG. 21 shows a flow for calculating the correction coefficient of the sheet interval position. In step S41, it is determined whether the carriage is currently in the normal position or the thick sheet position. As the recognizing means, the same method as that described in the third embodiment can be used.

Next, in step S42, the output value R1 is measured after printing at the recognized carriage position is completed.

In the step S43, it is determined whether or not the carriage position for printing the next page has been changed.
If there is no change, there is no need to correct the output value, so recording is performed as it is, and the process returns to step S42 to measure the output value R1 after recording is completed. At this time, R1 is updated.

On the other hand, if there is a change in the carriage position in step S43, the output value R2 is measured before recording is started in step S44, and the flow advances to step S45.

In step S45, correction coefficient = output value at normal position / output value at cardboard position is calculated.

The calculated correction value is used in step S35 in FIG. 20 instead of the uniform correction coefficient 1.5.

According to the above-described method, the correction coefficient can be calculated for each ink tank used, so that the remaining amount of ink can be detected with higher accuracy.

(Embodiment 5) In this embodiment, the turning off of the warning lamp in the embodiment 2 is made more reliable.

That is, in the second embodiment, when a new ink tank is replaced, the amount of change in the output value before and after the recovery operation is detected, and the warning lamp is turned off according to the result. When the ink tank is replaced with a new ink tank, the warning lamp is automatically turned off even when the recovery operation is not performed.

FIG. 22 is a diagram for explaining the operation after the warning lamp is turned on because the remaining amount of ink is low in this embodiment. The operation before the warning lamp is turned on is the same as that of the second embodiment. Description is omitted because there is.

In step S51, the ink consumption of each color is counted continuously even after the warning lamp is displayed.

If the predetermined consumption has been reached in step S52, the process proceeds to step S53, where the output value is measured.

In step S54, it is determined whether or not the increase in the output value obtained in step S53 is twice or less consecutively. If it is not more than γ, the process proceeds to step S56, and the warning lamp is turned off.

Here, as a measure to be taken when the recovery operation is not performed despite replacement with a new ink tank, if the output value does not increase, the absorber in the ink tank has sufficient ink, and Assume the tank has been replaced. The reason why the output value is checked twice consecutively is that erroneous detection may occur only with one output value. It may be seen three or more times, but in that case, the time until the warning lamp is turned off becomes long.

On the other hand, if the output rise is not less than γ twice in succession in step S54, the process proceeds to step S55, and the current output value rises by δ or more compared to the previous output value, or falls. Determine whether it has been done. If there is a change of δ or more, the process proceeds to step S56, and the warning lamp is turned off.

Here, if the output value rises or falls by more than a predetermined value, it is regarded that another ink tank has been replaced.

In this embodiment, γ is 0.07 and δ is 0.1
5 was set, the ink tank was replaced immediately after the warning lamp was turned on, and recording was continued without performing the recovery operation. After a while, the warning lamp was turned off.

As described above, in this embodiment, even if the recovery operation is not performed when the ink tank is replaced, it is detected that the output value has not changed, or that the output value has changed abruptly. Thus, the warning lamp can be automatically turned off.

(Embodiment 6) The present embodiment is intended to solve the problem that the reflected light amount varies in a plurality of detections due to the variation in the stop position of the carriage. That is, it is possible to solve the problem that the reproducibility of the amount of reflected light to be detected is not very good regardless of the amount of remaining ink. In the above-described embodiment, the output value is a value obtained by one measurement, but in the present embodiment, (1) the average value of the past obtained data and the current obtained data is used as the current output value. ,
Alternatively, (2) the n-th output value is an average value of the values acquired repeatedly m times.

Here, when the average value of the past obtained data and the current obtained data is used as the current output value, for example, the obtained value is used as the output value in the first time, but the output value is used in the second time. Is an output value of an average of the first output value and the second acquisition value, and an average of the first and second output values and the third acquisition value is the third output value. At the n-th time, the average of the (n-2) th, (n-1) -th output values and the n-th acquired value is set as the output value.

If the n-th output value is an average value of values acquired repeatedly m times, for example, the carriage is scanned three times, and the average of the acquired values of each color three times is used as the output value. . In this case, the throughput decreases,
High-precision detection is possible.

(Other Embodiments) In the first to sixth embodiments, the description has been given of the case where the four color ink tanks can obtain substantially the same output value. The output value may be different for each color according to. In this case, the reference value for detecting the remaining amount of ink may be different for each color.

For example, α, β,
The values of γ and δ may be set for each color. In this case, all four values may be different for each color, or β and γ may not be different for each color because the set values are usually small, and only α and δ may be different. You may.

Although the present invention has been described in detail with reference to the embodiments, the present invention is not limited to the embodiments.

(Other Basic Configuration Examples) As described above, in the configuration of the first basic configuration example for explaining the principle of the present invention, accurate detection is performed due to the non-uniformity of the density of the absorber 7a. May be difficult. FIG. 24 shows another basic configuration example of the present invention in which another measure is taken against the non-uniformity of the density of the absorber 7a in the first basic configuration example.

In FIG. 24, the same components as those in FIG. 6 are denoted by the same reference numerals. Reference numeral 6 'denotes a photo interrupter arranged as a second ink sensor, which is the same as the photo interrupter 6. In this example, the photo interrupter 6 is also referred to as a first photo interrupter for convenience of explanation.

In the first basic example, the remaining amount of ink is determined only from the output of the photo interrupter 6, but in this basic configuration example, the average value of the outputs of the first photo interrupter 6 and the second photo interrupter 6 'is determined. Is used to detect that the amount of remaining ink has decreased. This average value may be a simple average or a weighted average. In this basic example, the second photo-interrupter 6 'is closer to the supply port 24 than the first photo-interrupter 6, so that an output change occurs after the remaining recordable number becomes smaller. Therefore, which weight is to be determined more depends on the remaining number of sheets to be detected.

As described above, by providing sensors for detecting the remaining amount of ink at a plurality of points and using the average value of the measured values at the plurality of detection points, even if the density of the absorber 7a is non-uniform, the effect is not affected. Thus, the remaining amount can be detected with high accuracy.

Similarly, as means for reducing the variation in the detected value due to the influence of the non-uniformity of the density of the absorber 7a, FIG.
It is also conceivable to make the photointerrupter 6 movable as described in, and to detect the remaining amount of ink at a plurality of points in the ink tank.

Further, the present invention is not limited to the example in which the photointerrupter 6 is configured to be movable, and a plurality of points may be measured while the carriage 1 is moved while the photointerrupter 6 is fixed. However, in this case, if the ink tank 7 does not have a certain thickness in the moving direction of the carriage 1, the effect achieved by increasing the number of detection points is small.

In this basic configuration example, the remaining amount of ink is detected at a plurality of points while the photointerrupter 6 and the carriage 1 are relatively moved, and the average value of the measured values of the plurality of detection points is used. Thus, even if the density of the absorber 7a is non-uniform as described above, the influence can be reduced, and the remaining amount can be detected with high accuracy.

In the above-described first basic configuration example, when the output of the photo interrupter 6 exceeds a predetermined threshold value, a warning or a stop of the recording operation is performed.

In the present basic configuration example, when the output of the sensor exceeds the threshold value, no warning or stop of the recording operation is performed, and instead, a display corresponding to the output of the photo interrupter 6 is performed.
That is, a display that changes proportionally or monotonically with the output of the photo interrupter 6 is performed.

As apparent from FIG. 8, the ink tank 7
The output of the photointerrupter 6 changes continuously as the remaining ink amount in the inside decreases. Therefore, by displaying the remaining amount corresponding to the output change, it is possible to continuously perform display substantially corresponding to the remaining recordable number. By doing so, more detailed ink remaining amount information can be given to the user.

FIG. 25 shows an example in which the remaining amount of ink in the ink tank 7 is displayed on the display panel. The display in the display panel may be such that the level of the digital meter changes in accordance with the remaining recordable number as shown in FIG. 25, or alternatively, the remaining recordable number may be displayed by a number.
Further, as the display panel, generally used display devices such as those using liquid crystal may be used.

The present invention is not limited to the display means that can be visually recognized, but may be a method of guiding the remaining recordable number by voice or a method of changing the length and the number of times of the buzzer sound according to the remaining recordable number.

With the above configuration, the photo interrupter 6
, It is possible to inform the user of detailed ink remaining amount information. According to this basic configuration example, when the remaining amount of ink in the ink tank 7 is reduced, the user can know the detailed remaining ink amount, and can perform maintenance such as replacement of the ink tank at an appropriate time. .

In the first basic configuration example described above, the ink tank 7 has both the absorber 7a and the raw ink storage 7c. However, the present invention is not limited to this configuration.
The present invention is also applied to an ink tank having a configuration as shown in FIG.

In the ink tank shown in FIG. 26, an absorber 7a is arranged over the whole area inside the ink tank 7.

In FIG. 26, as in FIG. 2, 24 is a supply port, 28 is an air communication port, and 6 is a photo interrupter as a photo interrupter. Photo interrupter 6
Is arranged to detect a change in the reflectance of the bottom surface of the absorber 7a as in the first embodiment.

According to the present invention, when the ink tank 7 is not provided, the reflected light of the photo interrupter 6 is eliminated, so that the output level is much lower than the output level when there is sufficient ink.

In the present basic configuration example, the presence or absence of the ink tank 7 is determined by the photo interrupter 6 using the configuration of the ink remaining amount detection shown in the first basic configuration example.

Using the photo interrupter 6, the presence or absence of the ink tank 7 can be detected from the difference in detection level between when the ink tank 7 is mounted and when it is not mounted.

Further, in this embodiment, the presence or absence of the ink tank of each color in the case of a color printer can be individually detected, and recording is not performed when the ink tank is not mounted.

Therefore, according to the above configuration, the presence / absence of the ink tank can be detected without providing a special configuration for detecting the presence / absence of the ink tank. It is possible to detect the remaining amount and the presence or absence of the ink tank.

The present invention provides an excellent effect particularly in a recording apparatus using an ink jet recording head for performing recording by forming a flying liquid by utilizing thermal energy among ink jet recording methods. is there.

The typical structure and principle are described in, for example, US Pat. Nos. 4,723,129 and 4,740.
It is preferable to use the basic principle disclosed in the specification of Japanese Patent No. 796. This method is a so-called on-demand type,
Although it can be applied to any type of continuous type, in particular, in the case of the on-demand type, it can be applied to a sheet holding liquid (ink) or an electrothermal converter arranged corresponding to the liquid path. By applying at least one drive signal corresponding to recording information and giving a rapid temperature rise exceeding nucleate boiling, heat energy is generated in the electrothermal transducer, and film boiling occurs on the heat acting surface of the recording head. Liquid (ink) corresponding to the drive signal
This is effective because air bubbles in the interior can be formed. By discharging the liquid (ink) through the discharge opening by the growth and contraction of the bubble, at least one droplet is formed. When the drive signal is formed into a pulse shape, the growth and shrinkage of the bubble are performed immediately and appropriately, so that the ejection of a liquid (ink) having particularly excellent responsiveness can be achieved, which is more preferable. As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. Further, if the conditions described in US Pat. No. 4,313,124 relating to the temperature rise rate of the heat acting surface are adopted, more excellent recording can be performed.

The configuration of the recording head may include a combination of a discharge port, a liquid path, and an electrothermal converter (a linear liquid flow path or a right-angle liquid flow path) as disclosed in the above-mentioned respective specifications. U.S. Pat. No. 4,558,333 and U.S. Pat.
A configuration using the specification of Japanese Patent No. 59600 is also included in the present invention. In addition, Japanese Unexamined Patent Application Publication No. 59-123670 discloses a configuration in which a common slit is used as a discharge portion of an electrothermal transducer for a plurality of electrothermal transducers, and an aperture for absorbing a pressure wave of thermal energy is provided. The effect of the present invention is effective even if the configuration is based on JP-A-59-138461, which discloses a configuration corresponding to a discharge unit. That is, according to the present invention, recording can be reliably and efficiently performed regardless of the form of the recording head.

Further, the present invention can be effectively applied to a full-line type recording head having a length corresponding to the maximum width of a recording medium on which a recording apparatus can record. Such a recording head may have a configuration that satisfies the length by a combination of a plurality of recording heads, or a configuration as one integrally formed recording head.

In addition, even in the case of the serial type as described above, a recording head fixed to the apparatus main body or an electric connection with the apparatus main body or ink from the apparatus main body by being attached to the apparatus main body. The present invention is also effective when a replaceable chip-type recording head that can be supplied or a cartridge-type recording head in which an ink tank is provided integrally with the recording head itself is used.

It is preferable to add a recording head ejection recovery means, a preliminary auxiliary means, and the like as the configuration of the recording apparatus of the present invention since the effects of the present invention can be further stabilized. If these are specifically mentioned, the recording head is heated using capping means, cleaning means, pressurizing or suction means, an electrothermal transducer, another heating element or a combination thereof. Pre-heating means for performing the pre-heating and pre-discharging means for performing the discharging other than the recording can be used.

Also, as for the type and number of the recording heads to be mounted, two or more recording heads may be provided corresponding to a plurality of inks having different recording colors and densities. That is, for example, the printing mode of the printing apparatus is not limited to a printing mode of only a mainstream color such as black, but may be any of integrally forming a printing head or a combination of a plurality of printing heads. The present invention is also very effective for an apparatus provided with at least one of the recording modes of full color by color mixture.

In addition, the form of the ink jet recording apparatus of the present invention is not only used as an image output terminal of an information processing apparatus such as a computer, but also for a copying apparatus combined with a reader or the like, and a facsimile apparatus having a transmission / reception function. It may take a form.

[0226]

As described above, according to the present invention, it is possible to accurately detect the remaining amount of ink in an ink tank containing an ink absorber. In addition, since it is a method of detecting from the variation of the light reflectance of the ink absorber, even if there is a variation in the output of the sensor, a variation due to the mounting accuracy, or a variation in the manufacturing such as the reflectance of the ink tank, the remaining ink is not affected. The quantity can always be detected with the same accuracy.

Also, after replacing a new ink tank, a warning lamp or the like for notifying that the ink remaining amount is low can be automatically stopped without bothering the user. Is improved.

[Brief description of the drawings]

FIG. 1 is a side view of a carriage according to a first basic configuration example of the present invention.

FIG. 2 is a side view of a carriage showing a tank mounted state of the first basic configuration example of the present invention.

FIG. 3 is a schematic view of a carriage according to a first basic configuration example of the present invention as viewed from a bottom side.

FIG. 4 is a schematic view of an entire apparatus according to a first basic configuration example of the present invention.

FIG. 5 is a diagram illustrating a configuration of an ink sensor used in a first basic configuration example of the present invention.

FIG. 6 is a diagram illustrating the principle of detecting the remaining amount of ink according to the present invention.

FIG. 7 is a diagram illustrating the principle of detecting the remaining amount of ink according to the present invention.

FIG. 8 is a diagram illustrating an output of the photointerrupter according to the first basic configuration example of the present invention.

FIG. 9 is a diagram illustrating a change in light reflectance due to a decrease in ink.

FIG. 10 is a schematic view of the ink jet printer used in the first embodiment.

FIG. 11 is a schematic diagram of a recording head, an ink tank, and a carriage used in the first embodiment.

FIG. 12 is a schematic diagram of a recording head, an ink tank, and a carriage used in the first embodiment.

FIG. 13 is an electrical control block diagram of the inkjet printer according to the first embodiment.

FIG. 14 is a diagram illustrating an operation flow according to the first embodiment.

FIG. 15 is a diagram illustrating an operation flow according to the second embodiment.

FIG. 16 is a diagram illustrating an operation flow for turning off a warning lamp in the second embodiment.

FIG. 17 is a diagram illustrating output characteristics of different ink tanks.

FIG. 18 is a schematic view of an ink jet printer used in Example 3.

FIG. 19 is a diagram illustrating a relationship between a sheet interval position and a carriage position.

FIG. 20 is a diagram illustrating an operation flow according to the third embodiment.

FIG. 21 is a diagram illustrating an operation flow according to the fourth embodiment.

FIG. 22 is a diagram illustrating an operation flow according to the fifth embodiment.

FIG. 23 is a diagram showing actual output characteristics of the ink tank used in each of the embodiments.

FIG. 24 is a diagram illustrating a configuration of an ink sensor according to a second basic configuration example of the present invention.

FIG. 25 is a diagram showing a display of a detection result of the remaining amount of ink of the present invention.

FIG. 26 is a diagram illustrating a configuration of a carriage and an ink sensor in another basic configuration of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Carriage 6 Photo interrupter 7 Ink tank 7a Absorber 21 Recording head

──────────────────────────────────────────────────続 き Continuing on the front page (72) Fumiyuki Mikami, Inventor 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Masafumi Kamata 3- 30-2, Shimomaruko, Ota-ku, Tokyo Within Canon Inc. (72) Inventor Takayuki Ninomiya 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Hitoshi Nishikori 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Masaya Uetsuki 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Kazuhiko Morimura 3-30-2, Shimomaruko 3-chome, Ota-ku, Tokyo Canon Inc. (56 References JP-A-63-115756 (JP, A) JP-A-4-38435 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41J 2/173 G01F 23/28

Claims (17)

(57) [Claims] 1. An ink tank containing an ink absorber, a recording head for discharging and attaching ink supplied from the ink tank to a recording material to form an image, and a wall of the ink tank. A method for detecting the amount of remaining ink in an ink jet recording apparatus, comprising: a detection unit for detecting a change in light reflectance at a boundary between a wall surface of the ink tank and the ink absorber. A detection step of detecting the amount of light reflection at the timing and outputting the acquired data; an output result of an n-th (n ≧ 2, an integer);
And a comparison step of comparing the output result up to the (n-1) th or the (n-1) th time.
A method for detecting the remaining amount of ink in the ink tank is low. 2. An ink tank having a built-in ink absorber, a recording head for discharging and attaching ink supplied from the ink tank onto a recording material to form an image, and the ink tank and the recording medium. A carriage for mounting a head, and detection means for detecting a change in light reflectance at a boundary between the wall surface of the ink tank and the ink absorber through a wall surface of the ink tank mounted on the carriage. A plurality of positions corresponding to the thickness of the recording material
An ink remaining amount detecting method for an ink jet recording apparatus , comprising: means for moving the carriage up and down at a position , wherein the detecting means detects the amount of light reflection at a predetermined timing and outputs data acquired. And performing a predetermined calculation in accordance with the position of the carriage with respect to the detected amount of light reflection ,
The detecting means and the ink which differ according to the position of the ridge.
The greater the distance from the tank, the greater the amount of light reflection.
An n-th (n ≧ 2, integer) output result obtained through the operation step and an (n−1) -th or (n−1) -th output result And a comparing step of comparing the value with a predetermined value α in the comparing step.
A method for detecting the remaining amount of ink in the ink tank is low. 3. The computing step comprises detecting a light reflectance R1 at the end of each page of the recording material, and prior to recording a subsequent page.
When there is a change in the carriage position continues
Before starting recording on a page , the light reflectance R2 is detected, a correction coefficient corresponding to the ink tank in use is calculated from R1 and R2, and the correction coefficient is used in accordance with the carriage position. 3. The method according to claim 2, wherein the correction of the output value is performed by the calculation step . 4. The method according to claim 1, wherein the predetermined timing is when the ink consumption calculated from the number of ejections of ink ejected from the recording head and the number of suctions for recovery of the recording head reaches a predetermined amount. 4. The method according to claim 1 , wherein the predetermined amount has been reached.
Ink remaining amount detection method. 5. A light reflectance is detected before and after all recovery operations of a recording head in the ink jet recording apparatus,
5. The method according to claim 1, wherein when the difference between the light reflectances before and after the recovery operation is equal to or less than a predetermined value .beta., All output results of the light reflectance detected before the recovery are reset .
Ink remaining amount detection method described in. When 6. accounted known that the ink level is low before the recovery operation, the time of the reset, to claim 5, characterized in that stops that notify the ink remaining amount is less Ink remaining amount detection method described . 7. Using a detection means for detecting the light reflection amount, by detecting the light reflectance from the carriage, 2 through claim, characterized in that detecting the positions of the plurality of carriages 5. The method for detecting the remaining amount of ink according to any one of 4 . 8. The ink remaining amount detecting method according to claim 1, wherein an output value of the detecting step is an average value of past acquired data and current acquired data. Output value of wherein said detection step, characterized in that the average of repeated m times the acquired data according to claim
3. The ink remaining amount detecting method according to 1 or 2 . Wherein said recording head, according to claim 1 to 9, characterized in that the energy generating element formed of a electrothermal transducer for generating thermal energy to cause film boiling in the ink is to discharge ink <br/> The method for detecting the amount of remaining ink according to any one of <1> to <3>. 11. of claims 1 to 10, wherein said recording head is detachable from the recording apparatus main body
An ink remaining amount detection method according to any one of the above . 12. An ink jet recording apparatus comprising: an ink tank containing an ink absorber; and a recording head for discharging and attaching ink supplied from the ink tank to a recording material to form an image. An ink remaining amount detecting device, which detects a change in light reflectance at a boundary portion between the wall surface of the ink tank and the ink absorber through a wall surface of the ink tank at a predetermined timing, and outputs data obtained. Means, the output result of the n-th (n ≧ 2, integer), and (n−1)
Comparing means for comparing the output result up to the (n) th or the (n-1) th time; and when the comparing means has changed by a predetermined value α or more,
Detecting means for notifying that the remaining amount of ink in the ink tank is low. 13. An ink tank containing an ink absorber, a recording head for discharging and attaching ink supplied from the ink tank onto a recording material to form an image, and the ink tank and the recording medium. A carriage for mounting a head, and a plurality of carriages corresponding to the thickness of the recording material.
An ink remaining amount detecting device for an ink jet recording apparatus , comprising: means for moving the carriage up and down at a position. Detecting means for detecting a change in the light reflectance at the boundary at a predetermined timing and outputting the acquired data; and performing a predetermined calculation on the detected light reflectance according to the position of the carriage. Means , said cap
The detecting means and the ink which differ according to the position of the ridge.
The greater the distance from the tank, the greater the amount of light reflection.
That the arithmetic means for performing arithmetic, the n-th obtained through the calculation means (n ≧ 2, an integer) output and the (n-1) th or the (n-1) output of up-time And a comparing means for comparing with a predetermined value α or more in the comparing means.
Detecting means for notifying that the remaining amount of ink in the ink tank is low. 14. The remaining ink amount detecting device according to claim 12 , wherein said detecting means outputs an average value of past acquired data and current acquired data. 15. The detecting means according to claim 1, characterized in that outputs an average value of the acquired data repeated m times
14. The ink remaining amount detecting device according to 2 or 13 . 16. The recording head according to claim 12 or 15, characterized in that the energy generating element formed of a electrothermal transducer for generating thermal energy to cause film boiling in the ink is to discharge ink Written in one of
Remaining ink amount detection device of the mounting. 17. The recording apparatus according to claim 12, wherein the recording head is detachable from a recording apparatus main body.
An ink remaining amount detecting device according to any one of the above .