JPH08112909A - Ink jet recording device - Google Patents

Abstract

(57) [Abstract] [Purpose] Along with the ink remaining amount detection function to detect the ink remaining amount in the ink tank containing the negative pressure generating member such as absorber and foam material with high accuracy, It is an object of the present invention to provide an inkjet recording apparatus having a unit that also has a detection function. A detection light of the photo interrupter 6 is transmitted through a part of a wall surface of an ink tank made of a transparent plastic or the like that is transparent to the detection light of the photo interrupter 6, and a boundary between the wall surface and the ink absorber 7a. The change in light reflectance of the part is detected. The remaining amount of ink is detected based on the difference in reflectance between the presence and absence of ink in the detection portion. The ink remaining amount detecting means detects the distance between the carriage and the paper.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink end detection device for detecting the exhaustion of ink in an ink storage container or the like in an ink jet recording device for ejecting ink for recording, or for detecting the remaining amount of ink. The present invention relates to a remaining amount state detection device that operates.

In particular, the present invention relates to an ink remaining amount state detecting device and method for detecting the remaining amount state of ink contained in an ink storage container composed of a plurality of containing members capable of communicating ink in different states. It is about.

[0003]

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

An ink jet type recording apparatus (ink jet recording apparatus) discharges ink from a recording means (recording head) onto a recording medium for recording, and has the following advantages. It is easy to make the recording means compact,
High-definition images can be recorded at high speed, plain paper can be recorded without requiring special processing, running costs are low, and because it is a non-impact method, there is less noise and more It is easy to record color images using colored inks.

In particular, an ink jet type recording means (recording head) for ejecting ink by utilizing thermal energy is an electrothermal converter or electrode formed on a substrate through a semiconductor manufacturing process such as etching, vapor deposition and sputtering. By forming the liquid passage wall, the top plate, etc., it is possible to easily manufacture a liquid discharge device having a high-density liquid passage arrangement (ejection port arrangement), and to further reduce the size.

In the ink jet recording apparatus, an ink storage device such as an ink tank for storing ink to be supplied to the recording head is mounted on a carriage together with the recording head and when it is mounted on a predetermined fixed portion of the inkjet recording apparatus. There are some cases. 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 print head and the storage device can be relatively short. Therefore, it can be said that the configuration in which the ink storage device is mounted on the carriage is suitable for downsizing the inkjet recording device and simplifying the configuration.

In the structure in which both the recording head and the ink storage device (ink tank) are mounted on the carriage, the recording head and the ink tank are integrally formed, or the recording head and the ink tank are separated. There is a configuration that can be installed.

In the former structure in which the recording head and the ink tank are integrally formed, when the ink in the ink tank is exhausted, the cartridge in which the ink tank and the recording head are integrated is replaced with a new cartridge. Therefore, since it is easy to handle, it is becoming popular in recent years.
Since the expensive head is replaced every time the ink runs out, the running cost increases.

Further, in the latter configuration in which the recording head and the ink tank are separably mounted, only the ink tank that stores the ink is replaced when the ink runs out, and the head itself has reached the end of its life. You can replace it 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 times the expensive head is replaced is less than the number of times the ink tank is replaced,
Running costs can be reduced. However, in the configuration in which the recording head and the ink tank are detachably mounted, it is necessary to elaborately manufacture the connecting portion between the ink tank and the recording head so that ink does not leak.

Further, in the recording apparatus using the ink jet system, it is possible to satisfactorily supply the ink corresponding to the amount of ink ejected from the recording head at the time of recording, and at the time of non-recording, the ink leaks from the ejection port. There is a need for an ink supply system that does not have such problems.

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

In addition to the above-mentioned problems, when the ink containing portion is of a replaceable type, the ink containing portion can be smoothly attached and detached, and at that time, there is no ink leakage and the ink can be reliably transferred to the recording head. Supply is required.

One form of an ink container as an ink containing portion used in the above-mentioned 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 foam material is arranged almost entirely in an ink container and which is provided with a plurality of ink ejection orifices.

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

However, in the first conventional example, since the foam is required almost entirely in the ink containing portion, the filling amount of the ink is limited and the amount of the ink not used in the foam and remaining is large. There is a problem that the efficiency of ink use is poor.

Japanese Unexamined Patent Publication No. 6-40043 has been proposed as a technique for increasing the ink filling amount in such a structure in which a foam material is arranged as a negative pressure generating member in the ink storage means. According to the present application, by using the ink storage container in which the negative pressure generating member accommodating portion and the ink accommodating portion for accommodating the ink are separated, almost all the ink can be used except the ink adhering to the wall surface in the ink accommodating portion. A large capacity of the ink storage container is achieved. Further, the contained negative pressure generating member can prevent ink from leaking from the recording head and maintain 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 to accurately detect the amount of ink remaining in the ink storage means, and the ink. It is necessary to provide a configuration for appropriately detecting the time when there is no problem.

When there is no more ink in the ink storage means during recording, the ejection means for ejecting ink from the recording head will generate energy for ejection in the absence of ink. In particular, a so-called bubble jet method of providing a thermal energy generating means such as an electrothermal conversion element as an ejecting means, applying thermal energy to the ink, and ejecting the ink by utilizing the pressure generated by the state change of the ink due to heat In an inkjet recording device,
Driving the thermal energy generating means in the absence of ink not only unnecessarily raises the temperature of the recording head, but also causes damage to the recording head itself.

Further, in an ink jet recording apparatus of the type which ejects ink using a mechanical pressure generating means such as a piezo element as the ejecting means, the ejecting means is driven in the absence of ink to eject the ink. Pressure will continue to be generated in the absence of a load, resulting in deterioration of the ejection means and deterioration of durability.

Conventionally, as a structure for detecting the exhaustion of ink (ink end) in an ink storage container of an ink jet recording apparatus, Japanese Patent Laid-Open No. 54-133733.
Japanese Patent Publication No. 1-174, which discloses a configuration for detecting a light-transmitting state of an ink tank using an optical element as disclosed in Japanese Patent Publication No.
No. 65, a configuration for detecting by conduction of electrode members, and an estimation based on the amount of ink used by counting the number of ejection pulses as disclosed in JP-A-59-194853. A configuration (hereinafter referred to as a dot count method) and the like are known.

[0022]

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

For example, among the above-mentioned prior arts, the one that detects the light-transmitting state of the ink tank by using an optical element and the one that detects by the conduction of the electrode member have a negative pressure generating member due to the structure of the ink storage container. It is difficult to detect that the stored ink tank is out of ink. In addition, even if the remaining amount of ink in only the ink storage portion is detected in the configuration in which the negative pressure generation member storage portion and the ink storage portion are separated, a considerable amount of ink still remains in the negative pressure generation member storage portion. Can only be applied to the warning that the has decreased to some extent.

Further, in the structure 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, the desired negative pressure cannot be obtained and the ink supply is adversely affected. Could be.

Further, in the dot counting method, a large error occurs because the amount of discharge per one discharge of each device varies, the amount of initial injection into the ink tank varies, and the amount of use varies depending on the usage environment. This error may reach nearly half of the total ink amount when considering all the errors for each device and the influence of the environment, etc., and as a result, a warning that the remaining amount is low or a stop of the recording device is issued. In order to surely perform before the ink is exhausted, there is no choice but to leave almost half of the ink. As for the timing of issuing the warning or stopping, if the ink is left too much like this, there is no sense of remaining amount detection, or waste of ink will occur. If the dot count method is used to accurately detect the remaining amount, the cost becomes very high. Further, with the increase in capacity of the ink storage container, it becomes more difficult to accurately detect the remaining amount of ink.

In addition to the above-described detection of the remaining ink amount, in a printer device having a plurality of detection mechanisms such as the distance between the carriage and the paper, the internal mechanism becomes complicated and the cost increases. Especially in a printer device with a simple configuration,
It was very difficult to provide a plurality of detection mechanisms as described above. However, if a sensor as such a detection mechanism is not attached, recording failure may occur or a serious failure may occur in the printer device. Therefore, it is necessary to develop an inexpensive sensor device.

In view of the drawback of the ink remaining amount detecting function in the ink tank containing the negative pressure generating member such as the absorber and the foaming material as described above, the present invention detects with a high accuracy and a desired ink remaining amount. While realizing the ink remaining amount detection function,
Another object of the present invention is to provide an inkjet recording apparatus having a unit that also has a function of detecting the distance between the carriage and the paper.

[0028]

For the above purpose, the present invention comprises 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 part of the wall surface of the ink tank. The remaining amount of ink is detected based on the difference in reflectance between when there is ink and when there is no ink.

In order to achieve the above object, the invention according to claim 1 supplies ink to the head from an ink tank containing an ink absorber so that ink droplets are ejected from a nozzle at the tip of the head onto a recording medium. In an ink jet recording apparatus for ejecting and recording, a state of remaining ink in the ink tank is detected based on a light reflection amount at a boundary between the wall and the ink absorber through a part of the wall of the ink tank. In addition, it also serves as means for detecting the distance between the nozzle of the head and the recording medium.

Here, the invention according to claim 2 is the same as claim 1.
In the inkjet recording apparatus described above, the detection unit may include a light emitting unit and a light receiving unit that receives reflected light of the light from the light emitting unit.

According to a third aspect of the present invention, in the ink jet recording apparatus according to the second aspect, the head is mounted on a carriage that moves in parallel with the surface of the recording medium, and the carriage is provided by the detecting means. It may have a reflection part that reflects the light.

According to a fourth aspect of the present invention, in the ink jet recording apparatus according to the third aspect, the carriage is
A switching unit that changes the distance between the head and the recording medium according to the thickness of the recording medium is provided, and the distance between the reflecting unit and the detection unit changes in response to the switching of the switching unit. You may do it.

The invention according to claim 5 is the invention according to claim 3 or 4.
In the ink jet recording apparatus described in the item [1], the ink tank may be detachably mounted on the carriage, and the carriage may be provided with a unit for transmitting light from the detection unit to a wall surface of the ink tank.

According to a sixth aspect of the invention, in the ink jet recording apparatus according to the fifth aspect, the transmitting means may be a hole provided on the bottom surface of the carriage.

[0035]

[Basic Configuration Example] A basic configuration example on which the present invention is based will be described below in detail with reference to the drawings.

(First Basic Configuration Example) FIG. 4 is a schematic diagram of a configuration in which the basic configuration example which is the premise of the present invention is applied to the ink tank and the ink jet recording apparatus proposed in the above-mentioned JP-A-6-40043. It is a perspective view.

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

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

3 is provided in parallel with the guide shaft 2,
A support shaft that maintains the posture of the carriage 1 that is rotatably provided around the guide shaft 2,
Reference numeral 14 is a carriage motor for scanning the carriage 1 along the guide shaft 2, and reference numeral 15 is a timing belt for transmitting the driving force of the carriage motor 14 to the carriage 1. Reference numeral 16 is a transmissive photointerrupter provided in the scanning area of the carriage 1 to set a reference position for scanning the carriage 1.

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

FIG. 1 is a side view of the carriage 1, FIG. 2 is a view showing a state in which an ink tank is mounted in FIG. 1, and FIG. 3 is a view of the carriage shown in FIG. 1 seen from the direction of arrow A in FIG. It is a figure which shows a state.

The positional relationship between the carriage 1 and the photo interrupter 6 and the principle of detection by the photo interrupter 6 will be described with reference to FIG. 1, FIG. 2 and FIG.

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

In FIG. 2, 21 is the nozzle 2 at the tip of the nozzle.
2 is a recording head for ejecting ink to perform recording. Reference numeral 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 portion between the absorber in the ink tank and the outer wall 7e of the ink tank, 7c is a state where ink is not mixed with other members in the ink tank (hereinafter,
An ink storage portion (hereinafter, also referred to as raw ink storage portion) 7d that stores raw ink and a boundary portion between the raw ink inside 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. Again 24
Is a supply port for supplying ink to the recording head 21,
Reference numeral 8 is an atmosphere communication port for performing gas-liquid exchange accompanying ink consumption.

The head 21 and the ink tank 7 are integrally mounted on the carriage 1, and the shafts 2 and 3 are slid to scan in the vertical direction in the drawing.

FIG. 5 is a plan view of the substrate on which the photo interrupter 6 is mounted. 6c shows a light emitting portion and 6d shows a light receiving portion. Further, in FIG. 1, reference numeral 6a denotes light emitted by the light emitting section 6c, and an optical path (hereinafter, also referred to as return optical path) reflected and returned by 6b is shown. The light receiving section 6d shown in FIG. To be done. This optical path may be a reflecting surface in the plane of FIG. 1 as shown in FIG. 1 or may be a plane perpendicular to the plane of FIG. 1 as a reflecting surface. However, when the posture of the carriage 1 is largely changed by the operation of the paper position switching lever 5 described above, it is better to set the reflection surface in the direction perpendicular to the paper surface of FIG.
Less likely to be affected by posture differences. Further, in FIG. 1, this optical path is drawn as a mere straight line in order not to complicate the drawing, but in reality, it is a light beam having a certain spread.

The photo interrupter 6 is installed so as to irradiate the absorber 7a in the ink tank 7 with detection light to a position 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 that the photo interrupter 6 is arranged so that the boundary 7b between the wall surface of the ink tank 7 and the absorber 7a is located near the focal position of the photo interrupter 6. When the photo interrupter 6 deviates from the focus position, the spread of the detection light becomes large, and the light reflected / scattered at the edge of the hole 1b of the carriage 1 reduces the S / N of the detection. .

In this basic configuration example, a color ink jet recording apparatus configured to be capable of ejecting a plurality of inks of different colors as shown in FIG. 4 will be described as an example. A plurality of inks of different colors are housed in corresponding ink tanks and mounted on the carriage. Therefore, the absorber 7a
The ink absorbed in is one of the four colors normally used in color printers: black, cyan, magenta, and yellow. The ink sequentially flows from the absorber 7a through the supply port 24 and the flow path 30 in the recording head 21, and then heat energy is applied by a heat generating means (hereinafter also referred to as a heater) 31 provided in the nozzle 22 as an ejecting means to rapidly The ink is foamed by applying sufficient thermal energy and ejected from the ejection port at the tip of the nozzle 22. Recording is performed by the ink thus ejected adhering to a medium such as paper.

As described above, the photo interrupter 6 is one in which the LED, which is the light emitting element 6c of the light source, and the light receiving element 6d are integrated. This LED is an infrared light that is transparent to any of the four color inks described above.
d also has sufficient sensitivity to the wavelength of the LED.

The photo interrupter 6 is installed separately from the carriage 1, and irradiates the bottom surface of the absorber 7a with infrared light through the hole 1b formed in the carriage 1 and the wall 7e of the transparent ink tank 7 and reflects the infrared light. The received light is detected by the light receiving element 6d. By installing the photo interrupter 6 which is the detection system separately from the carriage in this way, a power supply line and a signal line from the recording apparatus main body to the carriage, which is a movable part, are not necessary, and the structure is simple. It is possible to achieve low cost by achieving high efficiency.

FIG. 6 is an enlarged view of the lower surface of the absorber 7a where the photo interrupter 6 is irradiated with light when the ink tank 7 has a sufficient amount of ink, and FIG. 7 is an enlarged view when the ink is exhausted at the same position. It is a figure. FIG. 8 is a graph showing changes in the output of the light receiving section 6d of the photo interrupter 6 depending on the remaining ink amount.

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

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

[0054]

[Equation 1]

In this basic configuration example, assuming that the light from the light emitting portion 6c of the photo interrupter 6 is incident on the ink tank 7 at an angle close to vertical, it can be regarded as cos θ = 1, and the above amplitude reflection is performed. Squared to describe in terms of energy reflectivity instead of rate,

[0056]

[Equation 2]

It becomes

First, when there is sufficient ink in the ink tank 7, the gap between the wall surface 7e of the ink tank 7 and the absorber 7a is filled with ink as shown in FIG. Ink tank 7
Since the absorber 7a is made of plastic and has a refractive index of about 1.5, and the ink has a refractive index of about 1.4, 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, as the ink is consumed, air is forced into the gap between the wall surface 7e of the ink tank 7 and the absorber 7a as shown in FIG. 7 through the atmosphere communication port 28 in FIG. The reflectance on the inner wall 7e of the tank 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 about 40 times. (However, in reality, the boundary portion 7 such as reflected light from the outer bottom surface of the ink tank 7
Due to the influence of light other than the reflected light of c and electric noise, the output difference up to that point is not detected. ) Here, even if the photo interrupter 6 performs detection at the boundary portion 7d between the ink tank 7 and the raw ink storage portion 7c, a difference in reflectance occurs, but
In comparison with that case, there are the following differences in the number of reflective elements.

[0060]

[Table 1]

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

Further, as shown in FIG. 7, the air that has entered between the absorber 7a and the ink tank 7 often exists as a large number of fine bubbles while passing through the absorber 7a. The amount of reflected light is further increased by adding a scattering effect.

These reflectances are cos θ =
Although it is a value in the case of 1, there is a considerable difference in reflectance in the other cases as well, with and without ink. In either case, a large output difference is generated in the light receiving portion 6d of the photo interrupter 6 according to the reflectance difference, and therefore the presence or absence of ink in the ink tank 7 can be detected by this output difference.

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

In FIG. 8, the horizontal axis represents the remaining number of printable sheets until ink is exhausted and ejection failure occurs, and the vertical axis represents the output of the photo interrupter 6. Based on this output change curve, when a predetermined threshold level is exceeded (in FIG. 8, the remaining amount of about 15 sheets that can be recorded is set as the threshold value), the ink amount in the ink tank 7 becomes low. Determine that Then, it is possible to inform the user that the ink remaining amount is low by turning on the warning display LED or the like on the display panel of the main body of the inkjet recording apparatus.

The number of remaining sheets when it is displayed that the remaining amount of ink 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 sheets remaining in FIG. 8). On the other hand, the number of printable sheets when the output rises can be changed by changing the detection position of the photo interrupter 6. In this way, the warning can be issued with the desired remaining number of sheets.

Alternatively, in order to surely prevent the recording failure, the recording operation may be stopped instead of issuing the warning or simultaneously with the warning. In this case, there is an effect that a stronger warning is given by temporarily stopping.

As described in detail above, according to this basic configuration example, the reflected light of the light emitted from the light emitting section 6c is received by the light receiving section with respect to the ink tank 7 in which the absorber 7a is arranged as the negative pressure generating member. 6d, and it is possible to detect that the remaining amount of ink in the ink tank 7 is less than a predetermined amount based on the output level.

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 reflected light amount of the light emitted by the light emitting section 6c. As a result, it is possible to accurately detect a decrease in the amount of ink remaining in the ink tank 7 in which the absorber 7a is arranged.

Further, this basic configuration example is applied to the color printer as described above, and four ink tanks 7 are arranged side by side corresponding to four colors of color. Therefore, by moving the carriage 1, the ink tanks of the respective colors are sequentially opposed to the photo interrupter 6, and the ink remaining amount of each ink tank is detected. Since it is necessary to individually track the output change in each color, it has a corresponding memory means. In this case, it is desirable to display that the remaining ink level is low for each of the four colors, but only one of the colors has simply decreased due to the complexity of the display panel of the inkjet recording device body. May be displayed.

According to the above-mentioned structure, the ink remaining amount of each of the four color ink tanks can be accurately detected by one detection system with respect to the ink tank incorporating the ink absorber of the color ink jet recording apparatus.

In this basic configuration example, detection is performed from the bottom surface of the ink tank 7. However, 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 top surface.

However, for the following reasons, the ink tank 7
It is desirable to detect from the bottom of the.

In the absorber 7a, the density distribution is not generally uniform, and when the ink runs out, the ink runs out in spots. Therefore, even if ink remains in the surrounding area, the ink can be used up only at the place where the photo interrupter 6 happens to detect it, or vice versa, and the remaining recording at that time is possible even at the same output level. The number of sheets may vary, and in the worst case, the ink may run out without warning.

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

(Second Basic Configuration Example) As described above, in the configuration shown in the first basic configuration example, it may be difficult to perform accurate detection due to the non-uniformity of the density of the absorber 7a. FIG. 9 shows another example of the second basic configuration of the present invention in which the nonuniformity of the density of the absorber 7a described in the first basic configuration example is taken.

In FIG. 9, the same components as those in FIG. 6 are designated by the same reference numerals. Reference numeral 6'denotes a photo interrupter arranged as the second ink sensor, which is the same as the photo interrupter 6. In this basic configuration example,
The photo interrupter 6 is also referred to as a first photo interrupter for convenience of description.

In the first basic configuration example, the ink remaining amount is determined only from the output of the photo interrupter 6, but in this basic configuration example, the average output of the first photo interrupter 6 and the second photo interrupter 6'is averaged. The value is used to detect that the remaining amount of ink has decreased. This average value may be a simple average or a weighted average. In this basic configuration example, the second photo interrupter 6'is the first photo interrupter 6 '.
Since it is closer to the supply port 24, the output change occurs after the remaining recordable number becomes smaller. Therefore, which one is more weighted is determined by the remaining number of sheets to be detected.

As described above, the sensors for detecting the remaining amount of ink are provided at a plurality of points, and the average value of the measured values at the plurality of detection points is used. Therefore, the remaining amount can be reduced, and the remaining amount can be detected with high accuracy.

Similarly, as a means for reducing the variation of 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 photo interrupter 6 described in 1) movable and detect the remaining amount of ink at a plurality of points in the ink tank 7.

In addition, the photo interrupter 6 is not limited to the movable structure, but the photo interrupter 6 may be fixed and a plurality of points may be measured while moving the carriage 1. 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 relatively moving the photo interrupter 6 and the carriage 1, and the average value of the measured values at a plurality of detection points is used. As a result, even if the density of the absorber 7a is non-uniform as described above, the influence thereof can be reduced, and the remaining amount can be detected with high accuracy.

(Third Basic Configuration Example) In the first basic configuration example described above, when the output of the photo interrupter 6 exceeds a predetermined threshold value, a warning or a recording operation is stopped.

In this basic configuration example, when the output of the sensor exceeds the threshold value, the warning or the recording operation is not stopped, but instead the display corresponding to the output of the photo interrupter 6,
That is, a display that is proportional to or monotonically changes with the output of the photo interrupter 6 is performed.

As is clear from FIG. 8, the ink tank 7
The output of the photo interrupter 6 continuously changes as the remaining ink amount in the inside decreases. Therefore, by performing the remaining amount display corresponding to this output change, the display substantially corresponding to the remaining recordable number can be continuously performed. By doing so, more detailed ink remaining amount information can be given to the user.

FIG. 10 shows an example in which the remaining amount of ink in the ink tank 7 is displayed on the display panel. The display on the display panel may be such that the level of the digital meter changes according to the remaining recordable number as shown in FIG. 10 or that the remaining recordable number is displayed numerically.
In addition, as the display panel, a commonly used display device may be used, including those using liquid crystal.

Further, not limited to the visually recognizable display means, it is also possible to use a voice guidance of the remaining recordable number, or a method of changing the length and the number of buzzer sounds according to the remaining recordable number.

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

(Fourth Basic Configuration Example) In the first basic configuration example described above, the ink tank 7 has both the absorber portion 7a and the raw ink storage portion 7c, but the present invention has this configuration. However, the present invention is not limited to the ink tank having the configuration shown in FIG.

In the ink tank shown in FIG. 11, the absorber 7a is arranged over the entire inside of the ink tank 7.

In FIG. 11, similarly to FIG. 2, 24 is a supply port, 28 is an atmosphere communication port, and 6 is a photo interrupter as a photo interrupter. Photo interrupter 6
Is arranged to detect the reflectance change of the bottom surface of the absorber 7a as in the basic configuration example 1.

(Fifth basic configuration example) According to the present invention, since the reflected light of the photo interrupter 6 disappears when the ink tank 7 is not provided, the output level is much lower than the output level when there is sufficient ink. It becomes an output.

In this basic configuration example, the configuration of the remaining ink amount detection shown in the basic configuration example 1 is used, and the presence or absence of the ink tank 7 is determined by the photo interrupter 6.

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

Further, in this basic configuration example, 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, and the ink in the ink tank can be simply structured without increasing the cost. It is possible to detect the remaining amount and the presence or absence of the ink tank.

[0097]

Embodiments of the present invention will be described below with reference to the drawings.

The present invention is based on each of the basic configuration examples described above, and is characterized in that the photo interrupter 6 is used as a head-to-paper interval sensor.

That is, in this embodiment, the reflection portion 1a for reflecting the light from the photo interrupter 6 is provided on the bottom portion of the carriage 1 in FIG. The state of the paper position switching lever 5 shown in FIG. 1 indicates a thin paper position. Here, a case where thick paper is used as a recording medium will be briefly described below.

First, the paper position switching lever 5 provided on the carriage 1 is moved around the shaft 5a by the arrow X in FIG.
When rotated in the direction, the bottom surface portion 5b of the switching lever 5 slides on the top surface 4a of the carriage support plate 4. The carriage support plate 4 is pushed down in the direction of arrow B in FIG. 1 due to the difference in the distance of the bottom surface 5b of the switching lever 5 from the shaft 5a, and the carriage 1 including the switching lever 5 is moved relative to the support shaft 3 accordingly. Be pushed up.
As a result of this pushing up, FIG.
The distance between the head (not shown) and the paper as the recording medium is longer than in the thin paper position. This thick paper position is a position selected when an image is formed on a thicker film or a special film thicker than normal paper.

In the thick paper position and the thin paper position,
The output of the photo interrupter 6 is different. FIG.
FIG. 4 is a characteristic diagram showing a relationship between an output voltage of a photo interrupter and a photo interrupter-object distance. FIG.
From this, it is clear that the output voltage is large at the thin paper position and is small at the thick paper position.

However, there are variations in the photo interrupter exhibiting such output versus distance characteristics. This variation will be described with reference to FIG. When the photo interrupters A and B are prepared, the output is X when the threshold value for thin paper / thick paper determination is first obtained according to the characteristics of A (shown by the solid line). However, in the characteristic of B (shown by the broken line), the output voltage at the thin paper position is also lower than X, so it is regarded as thick paper. Further, it is necessary to set the threshold value of B to Y. Therefore, it is necessary to set the threshold value according to the characteristics of the photo interrupter.

Therefore, in the present embodiment, the photo interrupter 6 is arranged at a position facing the reflecting portion 1a of the carriage 1 when stopped at the capping position, and the reflected light is detected at this capping position to detect the sensitivity. Calibrate. Thereby, the output of the photo interrupter 6 can be made constant.

Next, the sequence of distance characteristic calibration and sensitivity calibration of the photo interrupter in this embodiment will be described with reference to FIG.

First, the carriage 1 is stopped at the capping position, and the paper position switching lever 5 shown in FIG.
After setting to the thin paper position, the distance characteristic calibration of the photo interrupter 6 is performed (S1).

Next, similarly to S1, sensitivity calibration of the photo interrupter 6 is performed at the capping position (S2).

Here, the capping is released (S3),
The bright voltage Von is measured, and the output voltage Vd at the thin paper position is calculated from the difference from Voff (S4).

Next, if the output voltage Vd at the thin paper position satisfies Vd1 <Vd <Vd2 (S5), the switching lever 5 is set to the thick paper position at S6, and the operation stands by until the switch is pressed next time. If the above inequality is not satisfied, it is out of the sensitivity adjustment range and the process returns to S1. Carriage reflectance error, tilt, etc. are included outside this sensitivity adjustment range.
In this embodiment, Vd1 is set to 1.7V, and Vd
2 was set to 3.2V.

Next, if the switch is pressed in S6, the bright voltage Von is measured, and the output voltage Vu at the thick paper position is calculated from the difference from Voff (S7).

Next, if the output voltage Vu at the thick paper position satisfies Vu1 <Vu <Vu2 (S8), the process proceeds to the linearity determination (S9). If the above inequality is not satisfied, the sensitivity is out of the range and the process returns to S1. Linearity (Vu-Vcal)

[0111]

(3) (Vd-Vcal) A <(Vu-Vcal) <
If (Vd-Vcal) B is not satisfied, the process returns to S1 as a linearity error. Here, in this embodiment, A is 0.25 and B is 0.
It was set to 55.

If the linearity (Vu-Vcal) satisfies the above inequality, the inter-sheet threshold value Vth1 can be calculated by the equation Vth1 = (V
d + Vu) / 2 and store the calculated value. In this example, Vth1 was 2.2V.

After the series of sequences is completed, the process returns to S1.

As described above, in this embodiment, since the photo interrupter 6 for detecting the remaining amount of ink is also used as the head-to-paper interval sensor, cost reduction and space saving can be achieved.

The present invention brings excellent effects especially in a recording apparatus using an inkjet recording head for recording by forming flying droplets by utilizing thermal energy among the inkjet recording methods.

Regarding its typical structure and principle, see, for example, US Pat. Nos. 4,723,129 and 4740.
What is done using the basic principles disclosed in 796 is preferred. This method is a so-called on-demand type,
It can be applied to any of the continuous type, but especially in the case of the on-demand type, it can be applied to the sheet holding the liquid (ink) or the electrothermal converter arranged corresponding to the liquid path. By applying at least one drive signal that corresponds to the recorded information and gives a rapid temperature rise exceeding nucleate boiling, heat energy is generated in the electrothermal converter, and film boiling occurs on the heat acting surface of the recording head. Liquid (ink) that is generated and eventually responds to this drive signal as a single unit
It is effective because bubbles can be formed inside. The liquid (ink) is ejected through the ejection openings by the growth and contraction of the bubbles to form at least one droplet. It is more preferable to make this drive signal into a pulse shape because bubbles can be immediately and appropriately grown and contracted, so that liquid (ink) ejection with excellent responsiveness can be achieved. As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. If the conditions described in US Pat. No. 4,313,124 of the invention relating to the rate of temperature rise on the heat acting surface are adopted, more excellent recording can be performed.

As the constitution of the recording head, other than the combination constitution (straight liquid passage or right-angled liquid passage) of the ejection port, the liquid passage and the electrothermal converter as disclosed in the above-mentioned respective specifications. U.S. Pat. No. 4,558,333 and U.S. Pat. No. 44, which disclose a configuration in which a heat acting portion is arranged in a bending region.
The structure using the specification of No. 59600 is also included in the present invention. In addition, Japanese Unexamined Patent Publication No. 59-123670 discloses a configuration in which a common slit is used as a discharge portion of the electrothermal converter for a plurality of electrothermal converters, and an opening for absorbing a pressure wave of thermal energy is provided. The effect of the present invention is effective even if the configuration corresponding to the ejection portion is disclosed in JP-A-59-138461. That is, according to the present invention, recording can be surely 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 which can be recorded by the recording apparatus. 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 recording head integrally formed.

In addition, even in the case of the serial type as in the above example, the recording head fixed to the main body of the apparatus or the ink jet from the main body of the apparatus is electrically connected to the main body of the apparatus by mounting the recording head. 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 integrally provided in the recording head itself is used.

Further, as the constitution of the recording apparatus of the present invention, it is preferable to add ejection recovery means of the recording head, preliminary auxiliary means, etc. because the effects of the present invention can be further stabilized. Specifically, heating is performed by using a capping unit, a cleaning unit, a pressure or suction unit for the recording head, an electrothermal converter or a heating element other than this, or a combination thereof. Examples thereof include a preliminary heating unit for performing the discharge and a preliminary discharge unit for performing discharge different from the recording.

Regarding the type and number of recording heads 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 recording mode of the recording apparatus is not limited to the recording mode of only the mainstream color such as black, but it may be either the recording head is integrally formed or a plurality of combinations may be used. The present invention is also extremely effective for an apparatus provided with at least one of full-color recording modes by color mixing.

In addition, as the form of the ink jet recording apparatus of the present invention, other than the one used as an image output terminal of information processing equipment such as a computer, a copying apparatus combined with a reader or the like, and a facsimile apparatus having a transmitting / receiving function can be used. It may be a form or the like.

[0123]

As described above, according to the present invention,
A part of the wall surface of the ink tank, and a means for detecting a change in light reflectance at the boundary between the wall surface and the ink absorber,
By detecting the remaining amount of ink based on the difference in reflectance between when there is ink and when there is no ink, the remaining ink amount can be displayed with high accuracy and at the desired remaining ink amount even in an ink tank that contains an absorber. It is possible to realize a detection function, and at the same time, by the above-mentioned light reflectance change detecting means,
The paper distance can be detected. Therefore, by also serving as the detecting means, cost reduction and space saving can be achieved. Further, it is also possible to adjust registration registration (ejection timing) of bidirectional scanning by software. Furthermore, the presence or absence of the ink tank can be detected with the same configuration.

[Brief description of drawings]

FIG. 1 is a side view of a carriage of a basic configuration example that is a premise of the present invention.

FIG. 2 is a side view of a carriage showing a tank mounting state of a basic configuration example which is a premise of the present invention.

FIG. 3 is a schematic view of a carriage of one basic configuration example, which is a premise of the present invention, viewed from the bottom side.

FIG. 4 is a schematic diagram of an entire apparatus of a basic configuration example that is a premise of the present invention.

FIG. 5 is a diagram showing a configuration of an ink sensor used in a basic configuration example which is a premise of the present invention.

FIG. 6 is a diagram illustrating the principle of remaining ink amount detection of the present invention.

FIG. 7 is a diagram illustrating the principle of the remaining ink amount detection of the present invention.

FIG. 8 is a diagram for explaining output of a photo interrupter of a basic configuration example that is a premise of the present invention.

FIG. 9 is a diagram showing a configuration of an ink sensor of one basic configuration example which is a premise of the present invention.

FIG. 10 is a diagram showing a display of an ink remaining amount detection result of a basic configuration example which is a premise of the present invention.

FIG. 11 is a diagram showing a configuration of a carriage and an ink sensor in one basic configuration example which is a premise of the present invention.

FIG. 12 is a diagram showing output versus distance characteristics of a photo interrupter used in the present invention.

FIG. 13 is a diagram for explaining the necessity of output-distance characteristic calibration for the photo interrupter used in the present invention.

FIG. 14 is a diagram showing a calibration sequence for a photo interrupter used in the present invention.

[Explanation of symbols]

 1 Carriage 6 Photointerrupter 7 Ink Tank 7a Absorber 21 Recording Head

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical indication location G01F 23/28 J (72) Inventor Toshiharu Inui 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (72) Inventor Masaya Uetsuki 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Fumiyuki Mikami 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. Inside the company (72) Inventor Yasuhiro Unozawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Makoto Torikoshi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (6)

[Claims] 1. An ink jet recording apparatus for performing recording by supplying ink from an ink tank containing an ink absorber to a head and ejecting ink droplets from a nozzle at the tip of the head onto a recording medium. The remaining amount of ink in the ink tank is detected based on the amount of light reflection at the boundary between the wall surface and the ink absorber through a part of the wall surface of the head nozzle and the recording medium. An inkjet recording apparatus, which also functions as a means for detecting a distance. 2. The ink jet recording apparatus according to claim 1, wherein the detecting means includes a light emitting portion and a light receiving portion that receives reflected light from the light emitting portion. 3. The ink jet recording apparatus according to claim 2, wherein the head is mounted on a carriage that moves parallel to the surface of the recording medium, and the carriage reflects the light from the detecting means. An inkjet recording apparatus having a section. 4. The inkjet recording apparatus according to claim 3, wherein the carriage includes a switching unit that changes a distance between the head and the recording medium according to a thickness of the recording medium. An ink jet recording apparatus, wherein a distance between the reflecting portion and the detecting means changes in response to switching of the means. 5. The ink jet recording apparatus according to claim 3 or 4, wherein the ink tank is removably mounted on the carriage, and light from the detection means is attached to the wall of the ink tank. An ink jet recording apparatus, which is provided with a means for transmitting light. 6. The ink jet recording apparatus according to claim 5, wherein the transmitting means is a hole provided on the bottom surface of the carriage.