JP2003205603A - Ink jet printer and method for calculating residual ink amount of ink jet printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink jet printer capable of obtaining reliability in indicating a residual ink amount by accurately recognizing the residual ink amount in an ink cartridge, and conducting a suitable warning operation in response to the residual ink amount and a good image forming operation. <P>SOLUTION: A method for calculating the residual ink amount of the ink jet printer comprises the steps of acquiring a total pixel counted value obtained based on a total ink amount in the ink cartridge and an unconsumed pixel counted value obtained by subtracting the consumed pixel counted value from the total pixel counted value, and obtaining the residual ink amount by a ratio of the unconsumed pixel counted value to the total pixel counted value. In this case, the method further comprises the steps of deciding a correction coefficient based on an area coverage and correcting the consumed pixel counted value according to the correction coefficient. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet printer that forms an image by ejecting ink droplets toward a recording medium (recording paper) and the remaining ink amount in an ink cartridge mounted in this ink jet printer. It relates to the calculation method. In particular, the present invention relates to an improvement for accurately recognizing the remaining ink amount.

[0002]

2. Description of the Related Art Conventionally, as an image forming operation in an ink jet printer, first, one of a plurality of sheets stored in a sheet cassette is sent to a conveying path, and the sheet is image-formed through the conveying path. Supply to the department.
Then, in the image forming section, a predetermined image is formed by ejecting ink droplets on the surface of the paper, and then the paper is ejected to a paper ejection tray.

Further, in the image forming section, a carriage carrying an ink cartridge is arranged, and while the carriage is performing a scanning operation, the image forming operation is performed by the ink supplied from the ink cartridge to the ink head. It has become.

In this type of ink jet printer, it is necessary to replace the ink cartridge when the ink remaining in the ink cartridge becomes low or the ink cartridge becomes empty. For this reason, conventionally, an inkjet printer has been provided with means for recognizing the amount of ink remaining in the ink cartridge.

An example of a conventional method for recognizing the remaining amount of ink in the ink cartridge will be described below.
First, the "total pixel count value" is previously recognized based on the size of the ink cartridge (the initial storage amount of ink) and the like. This "total pixel count value" is the number of pixels that can be ejected according to the initial storage amount of ink (the amount of ink stored in a new ink cartridge).
After that, as the image forming operation is performed, the number of printed pixels is integrated as a “consumed pixel count value”. Then, the "remaining amount of ink (remaining amount ratio when the initial storage amount of ink is 100)" is calculated by the following equation (3).

Ink remaining amount [%] = {(total pixel count value) − (consumed pixel count value)} / (total pixel count value) × 100 (3) Further, the above “total pixel count value” is as follows. Formula (4)
Required by.

Total pixel count value [dot] = (initial storage amount of ink [pl]) / (ink usage amount per pixel [pl / dot]) (4) Further, with the above equation (3) only There is a possibility that sufficient accuracy cannot be obtained by calculating the ink remaining amount. Therefore, an ink level sensor capable of optically detecting the ink level in the ink cartridge is also used. This ink level sensor detects the time when the remaining ink amount reaches 25%, for example, by optical means.
Then, when it is detected that the remaining ink amount has reached 25%, the user is warned that the remaining ink amount has become small.

As described above, when the calculation of the remaining ink amount by the pixel count and the detection of the remaining ink amount by the ink level sensor are used together, the former calculation operation can be corrected by the latter detection operation. That is, even when it is recognized that the remaining ink amount is less than 25% by the calculation operation of the remaining ink amount based on the pixel count, the remaining ink amount is 25% by the ink level sensor.
The remaining ink level is displayed until it is detected that
We try not to display less than 5%. In other words, even if it is recognized that the remaining ink amount is below 25% due to an error in the calculation of the remaining ink amount based on the pixel count, the ink level sensor detects that the remaining ink amount has reached 25%. Until that is done, "25%" is kept displayed as the remaining ink amount display.

Then, when it is detected by the ink level sensor that the remaining amount of ink has reached 25%, the calculation operation of the remaining amount of ink by pixel count is restarted by the following equation (5).

Ink remaining amount [%] = {(Ejectable pixel count value when remaining amount 25% is detected)-(Consumed pixel count value after remaining amount 25% is detected)} / (At remaining amount 25% is detected Ejectable pixel count value of x) (5) Further, the above "ejectable pixel count value at the time when the remaining amount 25% is detected" is obtained by the following equation (6).

Ejectable pixel count value [dot] at the time of remaining amount 25% detection = (ink remaining amount [pl] at the time of remaining amount 25% detection) / (ink usage amount per pixel [pl / dot] ) (6) In this way, after the remaining amount of 25% is detected, the remaining amount of ink is calculated by the equation (5), and when the remaining amount of ink reaches several%, a cartridge replacement warning is issued to the user and the image is displayed. Disables the forming operation. As a result, the user is prompted to replace the ink cartridge, and unnecessary image forming operation is not executed.

Further, when an ink ejection operation that does not contribute to image formation is performed by a prime operation or a spit operation, which is a maintenance operation for avoiding clogging of an ink nozzle, the ink used for that operation is performed. The amount is converted into the number of pixels, and the value is added to the consumed pixel count value.

[0013]

In the above-mentioned conventional method, the remaining ink amount is calculated by the above equations on the assumption that the amount of ink consumed per pixel is constant.

However, in reality, the amount of ink consumed per pixel varies depending on the environmental conditions and the execution status of the image forming operation.

Therefore, when the method in which the calculation of the remaining ink amount by the pixel count and the detection of the remaining ink amount by the ink level sensor are used together, the actual remaining ink amount is larger than the calculated value. In some cases, the ink remaining amount display of "25%" may be continued for a long time. On the contrary, when the actual ink remaining amount is smaller than the calculated value, the ink remaining amount display is, for example, “40”.
In some cases, the display state of "%" suddenly switches to the display state of "25%".

FIG. 9 is a diagram showing a temporal change of the remaining ink amount display in this case. In reality, as shown by the solid line in FIG. 9, even though the remaining ink amount is decreasing, when the actual remaining ink amount is larger than the calculated value, as shown by the broken line in the figure, Since the ink remaining amount is calculated, the state of 25% is displayed as the ink remaining amount for a long time (time T in the figure: the remaining amount 2 by the pixel count).
It is continued for a period of time from the calculation of 5% to the detection operation of the ink level sensor). Conversely, if the actual ink level is less than the calculated value,
The remaining ink amount is to be calculated as indicated by the alternate long and short dash line in the figure, and the remaining ink amount display is, for example, 40% suddenly (at the same time as the ink level sensor detection operation). In some cases, the display state may be switched to the% display state (switching operation at timing A).

In such a situation, the user feels uncomfortable with the remaining ink amount display, and cannot sufficiently obtain the reliability of this display. Not only that, if such a calculation error occurs when the remaining ink amount is 25% or less, an ink replacement warning may be issued to the user or the image forming operation may be performed even though the remaining ink amount is sufficient. May be disabled. Further, there is a possibility that the image forming operation is executed even though there is no remaining ink amount, a faint printed matter is produced, and the paper is wastefully consumed.

Note that Japanese Patent Laid-Open No. 9-11490 and Japanese Patent Laid-Open No. 9-156123 disclose techniques related to this type of ink level recognition. In the former publication, the amount of ink required to print the data in the print buffer is predicted, and by comparing this amount of ink with the current remaining amount of ink, it is possible to determine whether or not ink will run out on the way. There is disclosed a technical idea that enables judgment before printing. On the other hand, in the latter publication, the ink consumption amount based on the consumed pixel count value and the ink amount used in the maintenance process are subtracted from the initial ink amount in the same manner as described using the above equation (3). The technical idea of calculating the remaining amount is disclosed.

Even in the technologies disclosed in these publications, if the amount of ink consumed per pixel varies depending on the environmental condition or the execution condition of the image forming operation, the accurate remaining ink amount is determined. It cannot be recognized, and the reliability of the remaining ink amount display cannot be sufficiently obtained as in the above case. In addition, it may not be possible to perform an appropriate warning operation or a good image forming operation according to the remaining amount of ink.

The present invention has been made in view of the above points, and an object of the present invention is to accurately recognize the remaining amount of ink in the ink cartridge, thereby sufficiently ensuring the reliability of the remaining ink amount display. It is possible to obtain an appropriate warning operation and an appropriate image forming operation according to the remaining amount of ink.

[0021]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention considers a factor that causes variations in the ink consumption amount, and corrects the ink consumption amount based on this factor. The remaining ink amount is calculated based on this correction value. Factors that cause variations in the ink consumption include the execution status of image forming operations such as area coverage, and environmental conditions such as ink head temperature.

-Solution Means-Specifically, it is premised on an ink jet printer in which an ink cartridge is mounted and an image is formed on a recording medium by ink supplied from the ink cartridge. For this inkjet printer, subtract the total pixel count value obtained based on the total ink amount in the ink cartridge at the start of the ink remaining amount recognition operation, and the consumed pixel count value correlated with the consumed ink amount from the total pixel count value. And an unconsumed pixel count value obtained by obtaining the unconsumed pixel count value, and the remaining ink amount recognition means for determining the remaining ink amount by the ratio of the unconsumed pixel count value to the total pixel count value. Then, the remaining ink amount recognizing means is configured to correct the consumed pixel count value by a correction coefficient determined in accordance with the environmental condition or the execution condition of the image forming operation. In this case, the consumed pixel count value is the sum of the pixel count value of the ink ejected for image formation and the pixel count value obtained by converting the ink amount consumed for the maintenance operation into the number of pixels. Then, the ink remaining amount recognition means is configured to correct the pixel count value of the ink ejected for forming the image by the correction coefficient.

The following is a configuration for realizing the technical idea by detecting the consumed ink amount. In other words, it is premised on an inkjet printer that is equipped with an ink cartridge and that forms an image on a recording medium with the ink supplied from the ink cartridge. For this inkjet printer, the total amount of ink in the ink cartridge at the start of the remaining ink amount recognition operation and the unconsumed ink amount obtained by subtracting the consumed ink amount from this total ink amount are acquired, and the total ink amount is calculated. Ink remaining amount recognizing means for determining the ink remaining amount based on the ratio of the amount of ink not consumed is provided. Then, the remaining ink amount recognizing means is configured to correct the consumed ink amount by a correction coefficient determined according to the environmental condition or the execution condition of the image forming operation. In this case, the ink consumption amount is the sum of the ink consumption amount ejected for image formation and the ink amount consumed for the maintenance operation. Then, the remaining ink amount recognition means is configured to correct the consumed ink amount ejected for forming the image by a correction coefficient.

It should be noted that the method of calculating the remaining ink amount, which is executed by the ink jet printer having each of the above configurations, is also within the technical idea of the present invention.

Even if the ink consumption amount varies depending on the environmental condition or the execution condition of the image forming operation by these specific matters, the remaining ink amount in the ink cartridge should be recognized in consideration of it. Is possible.
Therefore, it is possible to accurately recognize the remaining ink amount by reducing the error in recognizing the remaining ink amount, and it is possible to sufficiently obtain the reliability of the remaining ink amount display. The start of the remaining ink amount recognition operation is, for example, the time when the ink cartridge is replaced with a new one.

A specific example of the method for determining the correction coefficient will be described below. First, when the ink remaining amount recognizing unit is configured to determine the correction coefficient according to the area coverage on the recording medium, α = 1 + area coverage [%] / 100 (1) (α: correction coefficient) I try to find the coefficient.

When the ink remaining amount recognizing means is configured to determine the correction coefficient according to the temperature of the ink head, α = 1 + {(ink head temperature [° C] -15) / 40} (2) The correction coefficient is calculated by (α: correction coefficient).

According to these, the correction coefficient can be determined by a simple calculation formula, and the ink remaining amount calculation operation can be simplified.

Further, when the correction coefficient is determined by the correction coefficient table provided in advance, the operation of calculating the correction coefficient becomes unnecessary and the ink remaining amount recognition operation can be speeded up. it can.

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. In this embodiment, a case where the present invention is applied to a color inkjet printer will be described.

(First Embodiment) First, the first embodiment will be described. FIG. 1 is an external view of an inkjet printer according to this embodiment. The inkjet printer includes a main body portion 1, a lid portion 2, a paper feed cassette 4, and a paper discharge tray 12.

FIG. 2 is a schematic view showing the internal structure of the color ink jet printer. A manual paper feed unit 3 is provided on the back side of the main body unit 1, and the paper feed cassette 4 is provided below the main body unit 1, and the recording paper P is placed on the manual paper feed unit 3 and the paper feed cassette 4. Has been done. Then, when a print request is made based on image information from a computer or the like connected via a cable (not shown), the pickup rollers 5, 6 arranged on the paper discharge side of the manual paper feed unit 3 and the paper feed cassette 4 are made. Rotates. By rotating the pickup rollers 5 and 6, one recording sheet P is conveyed to the sheet feeding section. Pickup roller 5,
The recording paper P transported by 6 is transported by the rotating paper feed roller 7 and passes through the paper transport path, and the transport roller (which aligns the leading edge of this image information with the leading edge of the sheet based on the image information ( PS roller) 9, transport auxiliary roller 1
The image forming unit is reached via 0.

In the image forming section, a carriage 11 on which an ink cartridge and an ink head are mounted, and a platen 14 opposed to the carriage 11 are arranged. The carriage 11 is configured to scan in a direction orthogonal to the conveyance direction of the recording paper P (direction orthogonal to the paper surface in FIG. 2). The ink cartridge is provided for each color (for example, black, magenta, yellow, and cyan), and the ink cartridge of each color is connected to an ink head having nozzles corresponding to a predetermined resolution. With this ink head, ink is ejected from the nozzles onto the recording paper P according to the image information. The transport speed of the recording paper P during image formation is determined by the resolution of the inkjet printer and the cycle of ink ejection timing, and the recording paper P is continuously transported.
An image corresponding to the image information is formed on the recording paper P by continuously performing such processing in the image forming unit.

The recording paper P on which an image is formed in the image forming section is discharged onto the paper discharge tray 12 by the paper discharge roller 16 and the star roller 17, and is provided to the user as a printed matter.

The operation of each unit described above is controlled by the control unit. The controller will be described below.

FIG. 3 is a block diagram showing the configuration of the control unit of the present inkjet printer. The control unit includes a print drive unit 20. The print drive unit 20 drives a plurality of piezoelectric elements provided on the black head 21 and each color head 22 by distinguishing them for each ink color, and is a so-called application-specific integrated circuit (ASIC). It is configured as a one-chip CPU having a hard logic circuit. A ROM 23 and a DRAM 24 are connected to the print driving unit 20 via a data bus.

Each head 21, 22 is stored in the ROM 23.
Or a control program for image recording control for recording color images by controlling the drivers 25a and 26a for driving the drive motors 25 and 26 in the X and Y coordinate directions (the sheet conveying direction and the carriage scanning direction). A maintenance control control program for driving the maintenance motor 27 to perform maintenance processing such as prime processing and spit operation, a control program for ink remaining amount management control in the ink cartridge, and the like are stored. Also, this RO
M23 stores ink amount data of a new ink cartridge for each ink color, and ink consumption amount data consumed by one prime process and one spit operation.

The DRAM 24 is provided with an image data memory for storing the received image data, an ink remaining amount memory for storing the ink remaining amount for each ink color, and other various memories and buffers necessary for image recording. ing. Here, at least the ink remaining amount memory is always backed up by a secondary battery or the like, and is configured to retain the stored contents even when the power switch is turned off.

Further, the print drive unit 20 is connected to the host computer PC via a connection cable, and is provided with a communication interface (not shown) capable of receiving image recording data transmitted from the host computer PC. .

Further, various sensors are connected to the print drive unit 20, and detection signals from these sensors are input. In FIG. 3, 30 is Y
A Y-axis sensor unit that detects the carriage position in the coordinate direction, 31 is a maintenance sensor that detects the carriage position during maintenance processing, 32 is a carriage sensor that detects that the ink cartridge has been replaced, and 33 is ink residue in the ink cartridge. An ink level sensor that detects the amount, and an ink brand sensor 34 that detects whether or not a predetermined ink cartridge is mounted on the carriage.

Next, a structure for recognizing the remaining ink amount, which is a feature of this embodiment, will be described. The print drive unit 20 is provided with an ink remaining amount recognition unit 40 as an ink remaining amount recognition means. The remaining ink amount recognition unit 40 is also provided with a pixel counter 41. The pixel counter 41 recognizes the number of pixels (ink droplets) ejected on the recording paper P along with the execution of the image forming operation based on the image information, and integrates the number of pixels for each ink cartridge. It goes.

The ink remaining amount detecting unit 40 is a "total pixel count value" obtained based on the total amount of ink in the ink cartridge at the start of the ink remaining amount recognition operation.
And the “unconsumed pixel count value” obtained by subtracting the “consumed pixel count value” that correlates with the consumed ink amount from the “total pixel count value”, and Pixel count value "
The remaining amount of ink is calculated by the ratio.
In other words, the ink cartridge stored when a new ink cartridge is converted into the pixel count value (“total pixel count value” above) is used when the ink is consumed in the image forming operation or the like. The ink amount remaining inside is converted into a pixel count value (the above-mentioned "unconsumed pixel count value") is expressed as a percentage, and is calculated as the ink remaining amount.

Then, the ink remaining amount detecting unit 40
The feature is that the "consumed pixel count value" is corrected by a correction coefficient determined according to the execution status of the image forming operation.

Specifically, the "consumed pixel count value" is defined as "a pixel count value of ink ejected for image formation (hereinafter, also referred to as" print pixel count value ") and" maintenance operation Pixel count value obtained by converting the amount of ink consumed for that purpose into the number of pixels (hereinafter, also referred to as “value obtained by replacing other amount of ink consumption with the number of pixels”) ”. Then, a correction coefficient is determined based on the area coverage on the recording paper P, and the "pixel count value of ink ejected for image formation" is corrected by this correction coefficient. The area coverage is a percentage of the ink ejection area per unit area on the recording paper P, and is proportional to the number of pixels ejected from the same ink nozzle per unit time.

The formula for calculating the remaining ink amount used in the remaining ink amount recognizing operation by the remaining ink amount detecting unit 40 is shown below.

Ink remaining amount [%] = {(total pixel count value) − (consumed pixel count value)} / (total pixel count value) × 100 (3) Here, consumed pixel count value = (corrected (Print pixel count value) + (value in which other ink consumption amount is replaced by the pixel number) (7) The "value in which other ink consumption amount is replaced by the pixel number" here means prime processing, spit operation, etc. This is a pixel count value when the ink amount consumed by is converted into the number of pixels.

The "corrected print pixel count value" is calculated by the following equation (8).

Corrected print pixel count value = (print pixel count value) × α (8) This α is a correction coefficient, and this correction coefficient is a value according to the above area coverage and is expressed by the following equation (1). Determined by

Α = 1 + area coverage [%] / 100 (1) The remaining ink amount detection unit 40 executes the arithmetic operation according to the above equations for each ink cartridge,
The amount of ink remaining in each ink cartridge is required.

Next, the operation of calculating the remaining ink amount by the remaining ink amount recognizing unit 40 will be described with reference to the flowchart of FIG.

When the operation of calculating the remaining ink amount is started, first, in step ST1, it is determined whether or not the ink cartridge has been replaced. That is, it is determined by the detection operation of the carriage sensor 32 whether the ink cartridge is replaced with a new one. Where YE
If it is determined to be S, the process proceeds to step ST2 and the pixel count value of the pixel counter 41 is reset to "0".

On the other hand, it is determined NO in step ST1,
When the printing operation is performed in step ST3, in step ST4, the pixel counter 41 determines the number of pixels (ink droplets) ejected on the recording paper P along with the execution of the printing operation for each ink cartridge. Accumulate. Specifically, the pixel number of ink for each color is recognized based on the image information, and this pixel number is integrated as a pixel count value for each ink cartridge. Further, in step ST5, the area coverage is calculated from the image information when the printing operation is executed. Then, in step ST6, the correction coefficient is determined by the above equation (1), and the "corrected print pixel count value" is calculated by the equation (8). The operations of steps ST1 to ST6 are repeated each time the printing operation is executed. The “corrected print pixel count value” calculated by this operation is updated by the DRAM 2 each time it is updated.
4 is written and stored.

On the other hand, a situation in which the printing operation is not being executed (when NO is determined in step ST3)
In the case where the prime processing or the spit operation is performed, the following operation is performed. First, when the prime process is executed, YES is determined in step ST7, the prime process is executed in step ST8, and then in step ST9, the ink amount consumed for the prime process is converted into the number of pixels. The pixel count value is added to the pixel count value of the pixel counter 41. For example, this pixel count value is obtained based on the execution time of the prime processing. Similarly, when the spit operation is executed, YES in step ST10.
And the spit operation is executed in step ST11, the pixel count value obtained by converting the ink amount consumed for this spit operation into the number of pixels is added to the pixel count value of the pixel counter 41 in step ST12. .

As described above, the printing operation, the prime processing,
In the situation where the pixel count value of the pixel counter 41 is accumulated by the spit operation, step S
At T13, it is determined whether or not there is an instruction to acquire the remaining ink amount. This command for obtaining the remaining ink amount is issued from the host computer PC or by operating an operation button provided on the inkjet printer.

When there is an instruction to obtain the remaining ink amount, the process proceeds to step ST14, the remaining ink amount is calculated for each ink cartridge by the above equation (3), and the remaining amount data is stored in the host computer. It is transmitted to a PC or displayed on a display unit provided in an inkjet printer. As a result, the user recognizes the amount of ink remaining in each ink cartridge.

As described above, in the present embodiment, when recognizing the ink remaining amount of the ink cartridge, the "corrected print pixel count value" is obtained by the correction coefficient obtained according to the area coverage, and this is obtained. The remaining ink amount is calculated based on this. This area coverage is proportional to the number of pixels ejected from the same ink nozzle per unit time. That is, the larger the area coverage, the larger the number of pixels ejected from the same ink nozzle per unit time. And
The larger the number of pixels, the larger the amount of ink consumed per pixel tends to be. This is because when the time interval between the timing of ejecting one pixel and the timing of ejecting the next one pixel is short, ink drips or the head temperature rises and the ink viscosity decreases. This is because a large amount of ink is consumed due to the influence of the above.

By thus calculating the ink remaining amount in consideration of the area coverage, it becomes possible to accurately recognize the ink remaining amount by reducing the recognition error of the ink remaining amount in the ink cartridge. The reliability of the quantity display can be sufficiently obtained. Therefore, when the warning operation is issued according to the remaining ink amount, it is possible to obtain a good transmission timing. Also, when performing control to disable the image forming operation when the ink level is exhausted,
The operation can be executed at an appropriate timing.

Further, conventionally, an ink level sensor capable of optically detecting the ink level in the ink cartridge has been used together in order to obtain sufficient accuracy in recognizing the remaining amount of ink. That is, the operation of calculating the remaining ink amount by pixel count is corrected by the operation of detecting the remaining ink amount by the ink level sensor. According to the ink remaining amount calculation operation of the present embodiment, it is possible to perform accurate ink remaining amount recognition without using this ink level sensor together, and to simplify the configuration for this ink remaining amount recognition. You can also

(Second Embodiment) Next, a second embodiment will be described. In the first embodiment, the remaining ink amount in the ink cartridge is calculated based on the print pixel count value accumulated by the pixel counter. In this embodiment, instead, the remaining ink amount is obtained based on the consumed ink amount (consumed ink count value) accumulated by the consumed ink amount counter (counter that integrates the consumed ink amount). Since other configurations are similar to those of the first embodiment, only the ink remaining amount recognition operation will be described here.

FIG. 5 is a flow chart showing the operation of calculating the remaining ink amount by the remaining ink amount detecting unit 40 in this embodiment. Steps that perform the same operations as those in the flowchart shown in FIG. 4 will be assigned the same step numbers and description thereof will be omitted. Hereinafter, only steps for performing an operation different from the flowchart shown in FIG. 4 will be described.

If YES is determined in step ST1, the process proceeds to step ST22, and the ink consumption amount of the ink consumption amount counter is reset to "0".

When the printing operation is performed in step ST3, after passing through steps ST4 and ST5, the process proceeds to step ST26, and the correction coefficient (calculated by the equation (1)) determined based on the area coverage is used. The "corrected print ink amount" is calculated.

When the prime process is executed, the amount of ink consumed for this prime process is added to the consumed ink amount of the consumed ink amount counter in step ST29. Similarly, when the spit operation is executed, the amount of ink consumed for this spit operation is added to the consumed ink amount of the consumed ink amount counter in step ST32.

Then, in the situation where the ink consumption amount of the ink consumption counter is integrated by the printing operation, the prime processing, and the spit operation, if there is an instruction to acquire the remaining ink amount in step ST13, the process proceeds to step ST34. Then, the remaining ink amount of each ink cartridge is calculated by subtracting the consumed ink amount accumulated in the consumed ink amount counter from the total ink amount of the new ink cartridge, and the remaining amount data is stored in the host computer PC. Or display it on the display unit provided in the inkjet printer. As a result, the user recognizes the amount of ink remaining in each ink cartridge.

As described above, also in this embodiment, since the ink remaining amount is calculated in consideration of the area coverage, it becomes possible to accurately recognize the ink remaining amount in the ink cartridge, and the ink remaining amount is displayed. It is possible to obtain sufficient reliability.

(Third Embodiment) Next, a third embodiment will be described. In the first embodiment, the correction coefficient is calculated as a value according to the area coverage, and the "corrected print pixel count value" is calculated based on this correction coefficient. In this embodiment, instead of this, the temperature of the ink head is detected and the correction coefficient is determined according to the temperature of the ink head. Specifically, the correction coefficient α is determined by the following equation (2).

Α = 1 + {(ink head temperature [° C.] − 15) / 40} (2) The correction coefficient α obtained by this equation (2) is applied to the above equation (8) to “correct it”. "Printed pixel count value" is calculated and applied to the equations (7) and (3) to calculate the remaining ink amount.

Since other configurations are the same as those of the first embodiment, only the ink remaining amount recognition operation will be described here.

FIG. 6 is a flow chart showing the operation of calculating the remaining ink amount by the remaining ink amount detecting unit 40 in this embodiment. Steps that perform the same operations as those in the flowchart shown in FIG. 4 will be assigned the same step numbers and description thereof will be omitted. In the flowchart shown in FIG. 6, the operations of steps ST5 'and ST6' are different from those of the flowchart shown in FIG. That is, in this step ST5 ′, a temperature detection signal from a head temperature sensor (not shown) arranged in the vicinity of the ink head is acquired, and in step ST6 ′, the correction coefficient is determined by the above equation (2), Then, the "corrected print pixel count value" is calculated. Other operations are similar to those of the first embodiment.

(Fourth Embodiment) Next, a fourth embodiment will be described. In the second embodiment, the correction coefficient is calculated as a value according to the area coverage, and the "corrected print ink amount" is calculated based on this correction coefficient.
In the present embodiment, instead of this, as in the case of the third embodiment, the temperature of the ink head is detected and the correction coefficient is determined according to the temperature of the ink head. Specifically, similarly to the above, the correction coefficient α is determined by the above equation (2), the “corrected print ink amount” is calculated based on this, and the ink remaining amount is calculated. There is.

Since the other construction is the same as that of the second embodiment, only the ink remaining amount recognition operation will be described here.

FIG. 7 is a flow chart showing the operation of calculating the remaining ink amount by the remaining ink amount detecting unit 40 in this embodiment. Steps that perform the same operations as those in the flowchart shown in FIG. 5 are assigned the same step numbers and explanations thereof are omitted. In the flowchart shown in FIG. 7, the operations of step ST5 ′ and step ST26 ′ are different from those of the flowchart shown in FIG. 5 described above. That is, in this step ST5 ′, a temperature detection signal from a head temperature sensor (not shown) arranged close to the ink head is acquired, and in step ST26 ′, the “corrected print ink amount” is calculated based on the correction coefficient α. To calculate. Other operations are similar to those of the second embodiment.

(Modification) In each of the above-described embodiments, the remaining ink amount is recognized only by calculating the remaining ink amount using the pixel counter or the consumed ink amount counter. In this modification, the recognition of the remaining ink amount and the recognition of the remaining ink amount by the ink level sensor that optically detects the ink level in the ink cartridge are used together.

In the case of this example, as shown in FIG. 8, an ink level detecting window 13a is formed in the ink cartridge 13A, and an ink level sensor 33 is provided at a position facing the window 13a. In FIG. 8, the state in which the ink level sensor 33 is provided in one color ink cartridge 13A is shown as a representative, but the ink level sensors are similarly provided in the other ink cartridges 13B to 13D. The ink level sensor 33 detects the time when the remaining amount of ink reaches 25%, for example, by an optical means. Reference numeral 34 in FIG. 8 is an ink brand sensor for detecting whether or not a predetermined ink cartridge 13 is mounted on the carriage 11. Each arrow in FIG. 8 indicates a light beam for detecting an ink level or an ink brand.

In this example, the operation of calculating the remaining ink amount using the pixel counter or the consumed ink amount counter is corrected by the ink amount detecting operation of the ink level sensor 33. That is, even when it is recognized that the remaining ink amount is less than 25% by the calculation operation of the remaining ink amount using the pixel counter or the consumed ink amount counter, the remaining ink amount is set to 25% by the ink level sensor 33. Until it is detected, the remaining ink amount is not displayed below 25%. In other words, even if it is recognized that the remaining ink amount is below 25% due to an error in the calculation of the remaining ink amount using the pixel counter or the consumed ink amount counter, the remaining ink amount is detected by the ink level sensor 33. Until it is detected that 25% has been reached, 25% is continuously displayed as the remaining ink amount display.

When the ink level sensor 33 detects that the remaining amount of ink is 25%,
The calculation operation of the remaining ink amount using the pixel counter or the consumed ink amount counter is restarted.

According to this example, it is possible to accurately recognize the remaining ink amount as in the case of the effects of the above-described embodiments. Therefore, the remaining ink amount is calculated using the pixel counter or the consumed ink amount counter. In the operation, the timing when the remaining ink amount becomes 25% and the timing when the remaining ink amount is detected by the ink level sensor 33 can be substantially matched. Therefore, the display state of the ink remaining amount "25%" is continued for a long time, or the ink remaining amount display is, for example, "40%".
It is possible to avoid a sense of incongruity in which the display state of "%" suddenly switches to the display state of "25%".

Even when the remaining ink amount is 25% or less, it is possible to accurately calculate the remaining ink amount using the pixel counter or the consumed ink amount counter. Therefore, it is possible to avoid problems such as issuing an ink replacement warning to the user and disabling the image forming operation even though the ink remaining amount is sufficient. Further, it is possible to avoid the problem that the image forming operation is executed even when there is no ink remaining amount, a faint printed matter is produced, and the paper is wastefully consumed.

-Other Embodiments- In the above-described embodiments, the case where the present invention is applied to the color ink jet printer has been described. The present invention is not limited to this, and can also be applied to a monochrome type inkjet printer.

Further, in each of the embodiments, the correction coefficient is calculated by a mathematical expression. However, the correction coefficient table is stored in the ROM 23 in advance, and the correction coefficient table is stored in accordance with the area coverage and the ink head temperature. May be determined. In this case, the operation for calculating the correction coefficient becomes unnecessary, and the speed of the remaining ink amount recognition operation can be increased.

[0081]

As described above, the present invention recognizes a factor that causes variations in the amount of ink consumed per pixel, and based on this, corrects the amount of ink consumed per pixel, The remaining ink amount is calculated based on this correction value. For this reason, it is possible to reduce the error in recognizing the remaining ink amount in the ink cartridge and to accurately recognize the remaining amount, and it is possible to obtain sufficient reliability of the remaining ink amount display. As a result, when the warning operation is issued according to the remaining amount of ink, it is possible to obtain a good transmission timing. Further, in the case of performing the control for disabling the image forming operation when the ink level is exhausted, the operation can be executed at an appropriate timing.

In particular, when the correction coefficient is determined by the correction coefficient table provided in advance, the operation for calculating the correction coefficient becomes unnecessary, and the speed of the remaining ink amount recognition operation is increased. be able to.

[Brief description of drawings]

FIG. 1 is a perspective view showing an appearance of a color inkjet printer according to an embodiment.

FIG. 2 is a schematic diagram showing an internal structure of an inkjet printer.

FIG. 3 is a block diagram showing a configuration of a control unit of the inkjet printer.

FIG. 4 is a flowchart showing an ink remaining amount calculation operation according to the first embodiment.

FIG. 5 is a flowchart showing an ink remaining amount calculation operation according to the second embodiment.

FIG. 6 is a flowchart showing an ink remaining amount calculation operation according to a third embodiment.

FIG. 7 is a flowchart showing an ink remaining amount calculation operation according to the fourth embodiment.

FIG. 8 is a perspective view of an ink cartridge peripheral portion showing an arrangement position of an ink level sensor.

FIG. 9 is a diagram for explaining a detection error in the conventional ink remaining amount detection operation.

[Explanation of symbols]

13 Ink Cartridge 40 Ink Remaining Amount Recognition Unit (Ink Remaining Amount Recognition Unit) P Recording Paper (Recording Medium)

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiroyuki Ishikura             22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka             Inside the company F-term (reference) 2C056 EA29 EB07 EB20 EB30 EB50                       EB59 EC26

Claims (11)

[Claims] 1. In an ink jet printer which is equipped with an ink cartridge and which forms an image on a recording medium with ink supplied from the ink cartridge, based on the total amount of ink in the ink cartridge at the start of the ink remaining amount recognition operation. Obtain the total pixel count value obtained and the unconsumed pixel count value obtained by subtracting the consumed pixel count value related to the ink consumption amount from the total pixel count value, and the unconsumed pixel count value with respect to the total pixel count value Is provided with an ink remaining amount recognizing unit that obtains an ink remaining amount according to the ratio of the ink remaining amount, and the ink remaining amount recognizing unit uses the correction coefficient determined according to the environmental condition or the execution state of the image forming operation, An interface characterized by being configured to make corrections. Jet printer. 2. The inkjet printer according to claim 1, wherein the consumed pixel count value is a pixel count value of ink ejected for image formation and an ink amount consumed for maintenance operation converted into the number of pixels. Ink remaining amount recognizing means is configured to correct the pixel count value of the ink ejected for image formation by a correction coefficient. . 3. In an ink jet printer which is equipped with an ink cartridge and which forms an image on a recording medium by the ink supplied from the ink cartridge, the total amount of ink in the ink cartridge at the start of the remaining ink amount recognition operation, and An ink remaining amount recognizing unit that obtains the unconsumed ink amount obtained by subtracting the consumed ink amount from the total ink amount and obtains the ink remaining amount by the ratio of the unconsumed ink amount to the total ink amount is provided. The ink jet printer is characterized in that the remaining amount recognition means is configured to correct the consumed ink amount by a correction coefficient determined according to an environmental condition or an execution condition of an image forming operation. 4. The ink jet printer according to claim 3, wherein the ink consumption amount is the sum of the ink consumption amount ejected for image formation and the ink amount consumed for maintenance operation. The ink jet printer characterized in that the remaining amount recognizing means is configured to correct the consumed ink amount ejected for the image formation by a correction coefficient. 5. The ink jet printer according to any one of claims 1 to 4, wherein the ink remaining amount recognition means is configured to determine the correction coefficient according to the area coverage on the recording medium. Inkjet printer characterized by. 6. The ink jet printer according to claim 5, wherein the ink remaining amount recognition means is configured to determine the correction coefficient by α = 1 + area coverage [%] / 100 (1) (α: correction coefficient). An inkjet printer characterized in that 7. The ink jet printer according to any one of claims 1 to 4, wherein the ink remaining amount recognition means is configured to determine the correction coefficient according to the temperature of the ink head. And inkjet printer. 8. The ink jet printer according to claim 7, wherein the ink remaining amount recognition means corrects by α = 1 + {(ink head temperature [° C.]-15) / 40} (2) (α: correction coefficient) An inkjet printer characterized in that it is configured to determine a coefficient. 9. The ink jet printer according to any one of claims 1 to 4, wherein the ink remaining amount recognition means is configured to determine a correction coefficient by a correction coefficient table provided in advance. Characteristic inkjet printer. 10. A method for calculating the remaining amount of ink in an ink jet printer, in which an ink cartridge is mounted, and an image is formed on a recording medium by the ink supplied from the ink cartridge, the ink cartridge at the time of starting the remaining ink amount recognition operation. The total pixel count value obtained based on the total ink amount in the ink and the unconsumed pixel count value obtained by subtracting the consumed pixel count value related to the consumed ink amount from the total pixel count value are acquired, When determining the remaining ink amount by the ratio of the unconsumed pixel count value to the pixel count value, the consumed pixel count value is corrected by a correction coefficient determined according to the environmental condition or the execution status of the image forming operation. Ink remaining amount calculation method for inkjet printer 11. A method for calculating the remaining ink amount in an ink jet printer, in which an ink cartridge is mounted, and an image is formed on a recording medium by the ink supplied from the ink cartridge, the ink cartridge at the time of starting the remaining ink amount recognition operation. The total amount of ink in the ink and the amount of unconsumed ink obtained by subtracting the amount of consumed ink from this total amount of ink are acquired, and the ink remaining amount is calculated by the ratio of the amount of unconsumed ink to the total amount of ink An ink remaining amount calculation method for an inkjet printer, characterized in that the consumption ink amount is corrected by a correction coefficient determined according to a state or an execution state of an image forming operation.