JPH10309808A - Apparatus and method for detecting ink run-out for ink-jet recording, and recording medium having ink run-out detection program for ink-jet recording recorded therein - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correctly detect an ink run-out even when ink run-out detection sensors show a large difference of detection outputs. SOLUTION: The apparatus has an ink run-out detection sensor 18 for detecting a concentration of an inspection mark 19 which is formed by blowing ink drops to a recording paper 6. A detected value of the concentration from the ink run-out detection sensor 18 is compared with a preliminarily set threshold value, thereby detecting an ink run-out. In a set mode for the threshold value, the ink run-out detection sensor 18 detects concentrations of a white reference paper set at a concentration indicating an ink run-out state and a black reference paper set at a concentration indicating the presence of ink, and sets the threshold value between concentration detection values of the white reference paper and black reference paper on the basis of the detected values.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for detecting a lack of ink for ink-jet recording by detecting the density of a test mark formed by spraying ink droplets on recording paper, and an ink for ink-jet recording. The present invention relates to a recording medium on which a cutting detection program is recorded.

[0002]

2. Description of the Related Art A communication device such as a facsimile device and an information processing device such as a personal computer usually include a recording device capable of printing data consisting of characters and figures as visual information so that the data can be printed on paper. Have. Various recording methods such as an impact method, a heat-sensitive method, and an ink-jet method are adopted for this recording apparatus. In recent years, an ink-jet method which is excellent in quietness and can print on paper of various materials is adopted. Ink-jet recording apparatuses are frequently used.

In the above-described ink jet recording apparatus, an ink jet head having a large number of nozzles and a recording sheet are arranged to face each other, and ink is ejected from nozzles corresponding to print data while main scanning of the ink jet head is performed. Characters and figures are printed by spraying. Therefore, an ink jet recording apparatus that performs printing by such an operation can maintain a good initial print density until immediately before the entire amount of ink is consumed, and can perform good reading.
When the ink runs out, there is a problem that printing cannot be performed at all and reading becomes impossible. In particular, this problem is significant in a facsimile machine of a specification in which received data is recorded only by printout without being stored in a storage device.

[0004] Therefore, the ink jet recording apparatus is provided with an out-of-ink detection sensor composed of a reflection type optical sensor capable of detecting the density of the ink sprayed on the recording paper.
This sensor is used to detect ink exhaustion. That is, in the related art, a predetermined threshold value common to all apparatuses, which is a criterion for determining that the ink has run out, is set in advance, and before and after printing, ink is sprayed on the leading edge and the trailing edge of the recording paper to check the mark. Is formed, and the density of the inspection mark is detected by an ink-out detection sensor. Then, by comparing the density detection value of the inspection mark with the threshold value, it is determined whether the density detection value of the inspection mark is equal to or greater than the threshold value, thereby detecting ink exhaustion.

[0005]

However, in the configuration in which the out-of-ink state is detected by using a constant threshold value common to all the apparatuses as in the above-mentioned conventional apparatus, variations in the mounting state of the out-of-ink detection sensor and variations in the amount of emitted light, etc. If the detection output greatly differs between the ink-out detection sensors, the density detection value of the inspection mark fluctuates according to the detection output.
Since the threshold value is fixed, there is a problem in that the density detection value is always biased to one side of the threshold value and it is not possible to accurately detect the ink shortage regardless of the presence or absence of the ink shortage.

Therefore, the present invention provides an ink-out recording apparatus and method for ink-jet recording and an ink-out recording method capable of accurately detecting ink-out even if there is a large variation in detection output between the ink-out detection sensors. It is an object of the present invention to provide a recording medium on which an ink out detection program is recorded.

[0007]

According to a first aspect of the present invention, there is provided an image forming apparatus, comprising: density detecting means for detecting the density of an inspection mark formed by spraying ink droplets on a recording sheet; An ink-out-of-ink detecting device for ink-jet recording for detecting ink out by comparing a density detection value from a detection unit with a preset threshold value, wherein the density detection is performed in a threshold setting mode. Means for detecting the densities of the first density defining means indicating the out-of-ink state and the second density defining means indicating the ink-existing state; and detecting the density of the first density defining means based on the density detection value from the density detecting means. It is characterized in that it has a threshold value setting means for setting the threshold value between the detected value and the density detection value of the second density defining means.

Thus, if the ink output is detected using a fixed threshold value as in the prior art, if the detection output greatly differs between the density detecting means, the density detection value is always determined regardless of the presence or absence of the ink exhaustion. Is biased to one side of the threshold value, it may not be possible to accurately detect the ink-out condition. However, as described above, the threshold value between the density-detection value in the ink-out condition and the density detection value in the ink-in condition is increased. By setting the threshold value, a threshold value is set for each of the density detecting means. Therefore, it is possible to prevent such a problem that the detected density value is biased to one side of the threshold value.
Therefore, even if there is a large variation in the detection output between the density detecting means, it is possible to reliably detect the ink shortage.

According to a second aspect of the present invention, there is provided an ink jet recording apparatus for ink jet recording according to the first aspect, wherein the density detecting means is arranged to irradiate light and receive reflected light. It is a sensor. As a result, even if the reflection type optical sensor easily varies in the light amount, the distance to the sheet, and the irradiation angle to the sheet, an appropriate threshold value is set after the reflection type optical sensor is installed. Can be detected.

According to a third aspect of the present invention, there is provided an ink-jet recording ink out detecting apparatus according to the first or second aspect,
The first density defining means is a sheet of white reference,
It is characterized in that the density defining means is a sheet based on black, and the density detecting means detects the density on a transport path when printing on a recording sheet.

With this configuration, the density detection is performed in a state in which the recording paper conveyance path is conveying the white reference sheet and the black reference sheet. Therefore, each sheet can be detected under the same conditions as those for detecting the density of the inspection mark. Density detection can be performed. Accordingly, since the density of each sheet can be detected with high accuracy, a more appropriate threshold can be obtained by setting the threshold using the detection result.

According to a fourth aspect of the present invention, there is provided the ink jet recording apparatus for ink jet recording according to the first or second aspect,
The first density defining means and the second density defining means are a first density mark and a second density mark formed on the same sheet, and the threshold value setting means is provided with the first density mark and the second density mark. , Wherein each of the detected density values is obtained.

Thus, the density detection values of the first density mark and the second density mark can be obtained with one sheet of paper, so that these density detection values are more threshold than when they are obtained from each sheet. Value setting can be completed in a short time.

According to a fifth aspect of the present invention, there is provided the ink jet recording out-of-ink detecting apparatus according to any one of the first to fourth aspects, wherein the apparatus is mounted on a facsimile apparatus which performs recording by an ink jet system in which ink droplets are sprayed on recording paper. Features. Thus, even in a situation where there is no operator, such as at night or on holidays, it is possible to detect the ink shortage and take a measure against the ink shortage.

According to a sixth aspect of the present invention, an inspection mark is formed by spraying ink droplets on a sheet of paper, and a density detection value of the inspection mark is obtained by density detection means. An ink-out condition detecting method for ink-jet recording, which detects an out-of-ink condition by comparing a threshold value with a threshold value. The method is characterized by comprising a first step of obtaining each of the density detection means and a second step of setting the threshold value between the density detection values obtained in the first step.

By setting a threshold value between the density detection values of the first density defining means indicating the out-of-ink state and the second density defining means indicating the ink-existing state,
Even if the detection output greatly differs between the density detecting means, it is possible to reliably detect the ink shortage.
With this method, the threshold can be automatically set by a computer, and the threshold can be manually set by an operator.

According to a seventh aspect of the present invention, the density of the inspection mark formed by spraying ink droplets on the recording paper is detected by the density detecting means, and the density detection value from the density defining means is set to a predetermined threshold value. A recording medium on which an ink-out recording ink detection program for ink-jet recording for causing a computer to detect ink-out by comparing the value with a value is provided. The density detection means obtains the density detection values of the first density definition means indicating the ink state and the second density definition means indicating the ink present state, respectively, and sets the threshold value between these density detection values. .

Thus, by causing the computer to set a threshold value between the density detection values of the first density defining means indicating the out-of-ink state and the second density defining means indicating the ink-existing state, the detection output can be set between the density detecting means. Therefore, even if the values are greatly different from each other, an ink-out detecting device for ink-jet recording can be realized which can reliably detect the ink-out.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. The ink-out-of-ink detection device for inkjet recording according to the present embodiment is built in a facsimile machine as shown in FIG. The facsimile apparatus has an apparatus main body 1 having a lower cover 2 and an upper cover 3 serving as a housing, and a receiver 4 arranged on a side of the apparatus main body 1. As shown in FIG. 3, the apparatus main body 1 takes in the original 20 into the apparatus from above the upper cover 3 and then discharges the original through the opening 3a, and an image of the original 20 conveyed by the original feeder 21. And a paper storage case 5 provided on the rear upper surface of the upper cover 3.

A large number of recording papers 6 are accommodated in the paper storage case 5, and these recording papers 6 are pressed against a paper feed roller 7 arranged at the bottom of the paper storage case 5. Have been. The paper feed roller 7 feeds the recording paper 6 in the paper storage case 5 from the paper feed port 5a to the paper feeding device 8. The paper feeder 8 to which the recording paper 6 is fed detects a leading edge of the recording paper 6 by contacting the paper 6 with the paper guide 9 for regulating the traveling direction of the recording paper 6 and outputs an on / off signal. It has a paper feed sensor 11 and a paper feed roller 10 for feeding out the recording paper 6.

In the feeding direction of the paper feed roller 10,
A printing unit 30 that prints on the recording paper 6 is arranged. The printing unit 30 includes a platen 13 that supports the back surface of the recording paper 6 and an ink jet recording apparatus main body 12 that sprays ink droplets on the surface of the recording paper 6 to perform printing. As shown in FIG. 1, the inkjet recording apparatus main body 12 includes an inkjet head 31 that ejects ink droplets.
A carriage 32 joined to the inkjet head 31, guide members 34a and 34b for supporting the carriage 32 movably in the main scanning direction X, and a carriage 32 in the main scanning direction X along the guide members 34a and 34b. And a traveling mechanism 33 for reciprocating (main scanning).

The above-described ink-jet head 31 is shown in FIG.
As shown in FIG. 7, the nozzle 31b for ejecting ink droplets by driving the piezoelectric element has, for example, 64 channels.
Note that the inkjet head 31 may eject ink by a bubble method. These nozzles 31b are provided on a nozzle surface 31a facing the recording paper 6, and are arranged at regular intervals in a sub-scanning direction Y orthogonal to the main scanning direction X. Thereby, as shown in FIG. 1, in the printing unit 30, the main scanning of the inkjet head 31 by the inkjet recording apparatus main body 12 and the sub-scanning of the recording paper 6 by the paper feed roller 10 are repeated, so that the recording paper The printing of black dots by spraying ink droplets on the entire surface or a part of 6 is performed.

As shown in FIG. 3, a paper guide 14 for regulating the traveling direction of the printed recording paper 6 and a discharge of the recording paper 6 out of the machine are provided on the side of the recording paper 6 carried out from the printing section 12 as shown in FIG. The discharge rollers 15 are arranged in this order. Further, in the discharge direction of the discharge roller 15, a discharge sensor 16 that detects the recording paper 6 by contacting the recording paper 6 and outputs an on / off signal, and a reflection-type optical sensor that is used to detect an ink out condition are provided. And an out-of-ink detection sensor 18 are arranged in this order, and the out-of-ink detection sensor 18 outputs a detection output proportional to the amount of reflected light received when the recording paper 6 is irradiated with light. ing.

The out-of-ink detection sensor 18 is shown in FIG.
Is connected to the A / D conversion unit 42 of the control unit 40, and the A / D conversion unit 42 converts the detection output from the out-of-ink detection sensor 18 into a digital value and outputs the digital value as a density detection value. It is supposed to. A sensor that outputs an on / off signal, such as the paper feed sensor 11 and the paper ejection sensor 16 in FIG. 3 described above, is connected to the I / O unit 41a, and the I / O unit 41a transmits the on / off signal to the information. The signal is converted into a signal form suitable for processing and output.

The A / D conversion section 42 and the I / O section 41a
The control unit 40 including the I / O unit 41 enables transmission and reception of signals to and from the outside of the control unit 40 in the same manner as the I / O unit 41a.
b and a memory 44 for storing various data and programs
And a CP for executing various processing operations according to a program
U section 43. The memory 44 has an RA capable of temporarily storing print data, density detection value data, and the like.
M, R which fixedly stores control data and control program
It has an OM and an E ² PROM in which threshold data described later is rewritably held.

The I / O unit 41b of the control unit 40 includes:
Key input unit 45 arranged on the front side of upper cover 3 in FIG.
Are connected, and various data such as ten-key data, function data, and mode designation data are input from the key input section 45. Further, a display unit 46 and a head driving unit 47 are connected to the I / O unit 41b of the control unit 40.
When print data indicating a black dot is input from the control unit 40, a drive voltage is applied to a channel corresponding to the print data to eject ink droplets from the nozzle 31b in FIG. The display unit 46 is formed of a liquid crystal display, and displays a control result, control contents, and abnormal contents such as out of ink on a screen based on display data from the control unit 40.

In the above configuration, the operation of the out-of-ink detecting device will be described. As shown in FIG. 3, the image reading device 2
After assembling the facsimile apparatus by assembling the ink jet recording apparatus main body 12, the out-of-ink detection sensor 18, and the like at predetermined positions, when it is confirmed that each driving device operates normally, the power is turned on to the facsimile apparatus. The CPU 43 executes the control routine of FIG. CPU unit 4
3 executes the control routine, accepts selection of a processing mode from the key input unit 45 (S1), and determines the contents of the processing mode (S2).

If the selected processing mode is the threshold setting mode (S2, YES), the process waits until white reference paper having a density indicating an out-of-ink state is set in the paper storage case 5. When it is confirmed that the setting of the white reference sheet has been completed by inputting the set signal from the key input unit 45 (S3), the paper feed roller 7 and the like are driven to take the white reference sheet into the apparatus and convey it. (S4). Thereafter, the white reference paper passes through the printing unit 30 and is output from the paper ejection sensor 1.
When it is detected by step 6, the counting of the elapsed time is started. Then, after a lapse of a predetermined time period in which the white reference sheet is considered to have reached the detection position of the out-of-ink detection sensor 18,
The density detection value, which is the detection output from the out-of-ink detection sensor 18, is fetched and stored in the white storage area formed in the RAM of the memory 44 (S5).

Next, the apparatus waits until black reference paper having a density indicating the presence of ink is set in the paper storage case 5, and when it is confirmed that the black reference paper has been set (S10).
6), the black reference sheet is taken into the apparatus and transported (S)
7) The density detection value, which is the detection output from the out-of-ink detection sensor 18, is read and stored in the black storage area of the memory 44 by the same operation as S5 described above (S8). When the densities of the white reference sheet and the black reference sheet are detected in this way, an intermediate value between the two detected densities is obtained as a threshold value, written into the E ² PROM of the memory 44 (S9), and the threshold value is set. Exit the mode. As a result, as shown in FIG. 5, between the ink-out detection sensors 18 (detection device (1) and detection device (2)) due to variations in the mounting position, the mounting angle, the amount of emitted light, and the like of the ink-out detection sensor 18. Even if the detection output varies, the threshold value corresponding to the detection output of each ink-out detection sensor 18 is set individually.

Next, when the receiving mode is selected in S1, it is determined that the mode is not the threshold setting mode (S2, NO), and the receiving process is executed (S1).
0). That is, as shown in FIG. 7, it is determined whether or not print data has been received from the other party (S11). If it has not been received (S11, NO), the process is re-executed from S1 in FIG. S2 until a processing mode other than the mode is selected.
The determination of the processing mode and the reception processing of S10 are repeated.

Thereafter, if it is determined in S11 that the print data has been received (S11, YES), the received print data is sequentially stored in a print data storage area formed in the RAM in the memory 44. As shown in FIG. 3, one sheet of recording paper 6 is taken in from a paper storage case 5 by a paper feed roller 7 and conveyed to a predetermined position of a printing unit 30 via a paper feed device 8 and a paper feed roller 10. Wait. Thereafter, when the received data amount of the print data exceeds 64 lines (the 64th stage in the sub-scanning direction) corresponding to the number of channels of the inkjet head 31, the print data is stored while the inkjet head 31 is running. The data is read from the area and output to the head drive unit 47,
Performs printing for the band (line). When printing for one band is completed, the recording paper 6 is sent out by one band width, and then printing for the next band is performed (S12).

By alternately repeating the printing of one band and the feeding of the recording paper 6 of one band width as described above, when the printing of one page is completed, as shown in FIG. Inspection marks 19 are printed by spraying ink droplets on the portion so that, for example, rectangular black solid printing is performed (S13). Then, as shown in FIG. 3, when the trailing end of the recording paper 6 discharged by the discharge roller 15 is detected by the discharge sensor 16, counting of the elapsed time is started,
After a lapse of a predetermined period of time when it is considered that the inspection mark 19 has reached the detection position of the out-of-ink detection sensor 18, a density detection value, which is a detection output from the out-of-ink detection sensor 18, is fetched and formed in the RAM of the memory 44 in FIG. It is stored in the designated inspection mark storage area (S14).

When the detected density value is stored in the inspection mark recording area, the threshold value stored in the E ² PROM is read out in S9, and the detected density value of the inspection mark 19 is on the black side of the threshold value. Is determined (S1).
5). If it exists on the black side of the threshold (S15,
YES), it is determined that ink has not run out, and S11 is determined.
Is executed again, and it is determined whether or not subsequent print data has been received, and the printing process is continued or terminated. On the other hand, if it is not on the black side of the threshold value (S15, NO), it is determined that the ink has run out, and the fact that the ink has run out is displayed on the display unit 46 or the ink runs out. A warning sound is generated to notify the operator (S16).

As described above, the out-of-ink detection device of this embodiment is provided with the out-of-ink detection sensor 18 (density detecting means) for detecting the density of the inspection mark 19 formed by spraying ink droplets on the recording paper 6. Detects ink-out by comparing the density detection value from the ink-out detection sensor 18 with a preset threshold value. In the threshold setting mode, the ink-out detection sensor 18 The densities of white reference paper (first density defining means) set to a density indicating an out-of-ink state and black reference paper (second density defining means) set to a density indicating an ink present state are detected, respectively. Threshold setting means for setting a threshold between the density detection value of the white reference sheet and the density detection value of the black reference sheet based on the density detection value (S3 to S3 in FIG. 6).
S9).

In the present embodiment, an intermediate value between the density detection value of the white reference paper and the density detection value of the black reference paper is set as the threshold value. However, the present invention is not limited to this. A threshold value may be set between the two density detection values. Further, in the present embodiment, a case is described in which the present invention is applied to an ink jet recording apparatus that prints using black ink, but the present invention is not limited to this, and printing is performed using color inks such as red and green. It can also be applied to an ink jet recording apparatus. That is, a first density defining means corresponding to the color of the recording paper 6 and a second density defining means corresponding to the ink color of the color ink are prepared, and a threshold value is set between the detected density values of these density defining means. This makes it possible to apply the present invention to a color ink jet recording apparatus.

Thus, when ink shortage is detected using a fixed threshold value as in the prior art, if the detection output greatly differs between the ink shortage detection sensors 18, the density is always constant regardless of the presence or absence of the ink shortage. When the detected value is biased to one side of the threshold value, there may be a case where it is not possible to accurately detect the out-of-ink state. By setting a threshold value between the threshold value and the threshold value, it is possible to prevent such a problem that the detected density value is biased to one side of the threshold value. Therefore, even if there is a large variation in the detection output between the out-of-ink detection sensors 18, the out-of-ink state can be reliably detected.

In the present embodiment, the sensor 18 is constituted by a reflection-type optical sensor installed so that the ink-out detection sensor 18 emits light and receives reflected light. Accordingly, even if the reflection type optical sensor is liable to cause variations in the amount of emitted light, the distance to the recording sheet 6, and the irradiation angle on the sheet, an appropriate threshold value is set after the reflection type optical sensor is installed. Cuts can be reliably detected.

In the present embodiment, the recording paper 6
Is configured to convey white reference paper (first density defining means) and black reference paper (second density defining means) to a transport path when recording is performed, and to detect the density of these papers on the transport path. Have been.

Since the density detection is performed while the white reference sheet and the black reference sheet are transported along the transport path of the recording sheet 6, the density detection can be performed under the same conditions as those for detecting the density of the inspection mark 19. Can be. Therefore, the density of the white reference sheet and the black reference sheet can be detected with high accuracy, and a more appropriate threshold value can be obtained by setting the threshold value using the detection results.

In place of the above-mentioned white reference paper (first density defining means) and black reference paper (second density defining means), a first density mark (first density defining means) indicating no ink and ink present are provided. May be formed on the same sheet, and the density detection values of these marks may be obtained by the ink-out detection sensor 18, respectively. In this case, since the density detection values of the first density mark and the second density mark can be obtained with one sheet, the density detection values are obtained from the white reference sheet and the black reference sheet, respectively. Also, the setting of the threshold can be completed in a short time.

The out-of-ink detecting apparatus according to the present embodiment is mounted on a facsimile apparatus that performs recording by an ink jet method in which ink droplets are sprayed on recording paper 6. Thus, even in a situation where there is no operator, such as at night or on holidays, it is possible to detect the ink shortage and take a measure for the ink shortage (for example, proxy reception).

Further, in the present embodiment, the density detection values of the white reference paper (first density defining means) indicating the ink out condition and the black reference paper (second density defining means) indicating the ink out condition are detected by the ink out detection. A first step (S3 to S8 in FIG. 6) obtained by each of the sensors 18 and a second step (FIG. 6) for setting a threshold value between the density detection values obtained in the first step.
(S9) is carried out, the density detection value of the inspection mark 19 obtained by the ink-out detection sensor 18 is compared with a preset threshold value to detect the ink-out. It is designed to detect.

By setting the threshold value between the density detection value in the out-of-ink state and the density detection value indicating the ink-out state, the detection output greatly differs between the out-of-ink detection sensors 18. Also, it is possible to reliably detect the ink shortage. Then, according to this method, the threshold value can be automatically set by a computer programmed to calculate the threshold value while storing each concentration detection value in the memory,
The operator can manually set the threshold while checking the density detection value with an oscilloscope or the like.

In the present embodiment, the threshold value setting process (S3 to S9 in FIG. 6) is stored in the memory 44 in advance as a part of the control program. However, the present invention is not limited to this. An out-of-ink detection program for causing a computer to execute the threshold setting process may be recorded on a recording medium such as a magnetic tape, a magnetic disk, or an optical disk.

That is, when the computer is in the threshold value setting mode, the density detection of the white reference paper (first density defining means) indicating the out-of-ink state and the black reference paper (second density defining means) of the ink-present state is performed. Even when the threshold value setting process is performed by using a recording medium recording an ink shortage detection program for causing a value to be obtained by the ink shortage detection sensor 18 and setting a threshold value between these density detection values, respectively. good. In this case, the facsimile machine has a reading device,
If the computer can be connected to an information processing device such as a personal computer, by reading the out-of-ink detection program from the recording medium, the computer on the facsimile device side or the information processing device side can set the threshold value. Even if the output is largely different between the out-of-ink detection sensors 18, an out-of-ink detection device for ink jet recording that can reliably detect the out of ink can be realized.

[0046]

According to the first aspect of the present invention, there is provided a density detecting means for detecting the density of an inspection mark formed by spraying ink droplets on a recording sheet, and a density detection value set in advance by the density detecting means from the density detecting means. An ink out-of-ink detecting device for ink-jet recording, which detects an out-of-ink condition by comparing a threshold value with a threshold value. Means and the density of the second density defining means indicating the presence of ink, respectively, and based on the density detection values from the density detecting means, the density detected value of the first density defining means and the density detected value of the second density defining means are detected. And a threshold setting means for setting the threshold between the two.

As a result, when ink shortage is detected using a fixed threshold value as in the prior art, if the detection output greatly differs between the density detection means, the density detection value is always determined regardless of the presence or absence of the ink shortage. Is biased to one side of the threshold value, it may not be possible to accurately detect the ink-out condition. However, as described above, the threshold value between the density-detection value in the ink-out condition and the density detection value in the ink-in condition is increased. By setting the threshold value, a threshold value is set for each of the density detecting means. Therefore, it is possible to prevent such a problem that the detected density value is biased to one side of the threshold value.
Therefore, even if there is a large variation in the detection output between the density detecting means, it is possible to reliably detect the ink shortage.

According to a second aspect of the present invention, there is provided the ink-out detecting device for ink-jet recording according to the first aspect, wherein the density detecting means is arranged to irradiate the light and receive the reflected light. The configuration is a sensor. This allows
Even if it is a reflection-type optical sensor that tends to vary in the amount of light, the distance to the paper, and the irradiation angle on the paper, an appropriate threshold value is set after the reflection-type optical sensor is installed, so that it is possible to reliably detect the ink shortage. It has the effect of being able to do so.

According to a third aspect of the present invention, there is provided an ink jet recording ink out detecting apparatus according to the first or second aspect,
The first density defining means is a sheet of white reference,
The density defining means is a sheet based on black, and the density detecting means is configured to detect the density on a transport path when recording on a recording sheet.

Thus, the density is detected while the recording paper transport path is transporting the white reference paper and the black reference paper. Therefore, the density of each paper is detected under the same conditions as those for detecting the density of the inspection mark. Density detection can be performed. Accordingly, since the density of each sheet can be detected with high accuracy, setting the threshold value using the detection result has an effect that a more appropriate threshold value can be obtained.

According to a fourth aspect of the present invention, there is provided an ink jet recording ink out detecting apparatus according to the first or second aspect,
The first density defining means and the second density defining means are a first density mark and a second density mark formed on the same sheet, and the threshold value setting means is provided with the first density mark and the second density mark. , And the density detection values are obtained from the respective components. As a result, the density detection values of the first density mark and the second density mark can be obtained with one sheet of paper, so that the threshold value is set more than when these density detection values are obtained from each sheet. Can be completed in a short time.

According to a fifth aspect of the present invention, there is provided an ink-jet recording ink-out detecting apparatus according to any one of the first to fourth aspects, wherein the apparatus is mounted on a facsimile apparatus which performs recording by an ink-jet method in which ink droplets are sprayed on recording paper. is there. As a result, even in a situation where no operator is present, such as at night or on holidays, it is possible to detect an out-of-ink condition and take an action for the out-of-ink condition.

According to a sixth aspect of the present invention, an inspection mark is formed by spraying ink droplets on a sheet, and a density detection value of the inspection mark is obtained by density detection means. An ink-out condition detecting method for ink-jet recording, which detects an out-of-ink condition by comparing a threshold value with a threshold value. The apparatus has a first step of acquiring each of the density detection means and a second step of setting the threshold value between the density detection values obtained in the first step.

Thus, by setting a threshold value between the density detection values of the first density specifying means indicating the out-of-ink state and the second density specifying means indicating the out-of-ink state,
Even if the detection output greatly differs between the density detecting means, it is possible to reliably detect the ink shortage.
This method has an effect that the threshold value can be automatically set by the computer and the threshold value can be manually set by the operator.

According to a seventh aspect of the present invention, the density of the inspection mark formed by spraying ink droplets on the recording paper is detected by the density detecting means, and the density detection value from the density defining means is set to a predetermined threshold value. A recording medium on which an ink-out recording ink detection program for ink-jet recording for causing a computer to detect ink-out by comparing the value with a value is provided. The density detection values of the first density definition means indicating the state of the ink and the second density definition means indicating the ink presence state are obtained by the density detection means, respectively, and the threshold value is set between these density detection values.

By causing the computer to set a threshold value between the density detection values of the first density defining means indicating the out-of-ink state and the second density defining means indicating the ink-existing state, the detection output can be set between the density detecting means. Therefore, even if the difference is large, an effect of being able to realize an ink-out-of-ink detecting device for ink jet recording that can reliably detect the ink out is provided.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a control unit and a printing unit of an ink jet recording apparatus.

FIG. 2 is a perspective view of the facsimile machine.

FIG. 3 is a schematic configuration diagram of a facsimile machine.

FIG. 4 is a perspective view of an inkjet head.

FIG. 5 is an explanatory diagram showing a setting state of a threshold.

FIG. 6 is a flowchart of a control routine.

FIG. 7 is a flowchart of a reception processing routine.

[Explanation of symbols]

 REFERENCE SIGNS LIST 5 paper storage case 7 paper feed roller 8 paper feeder 9 paper guide 10 paper feed roller 11 paper feed sensor 12 ink jet recording apparatus body 13 platen 14 paper guide 15 discharge roller 16 paper discharge sensor 18 out-of-ink detection sensor 19 inspection mark 20 original 21 Document Feeding Device 22 Image Reading Device 31 Inkjet Head 31b Nozzle 32 Carriage 33 Traveling Mechanism

Claims (7)

[Claims] 1. A density detecting means for detecting the density of an inspection mark formed by spraying ink droplets on recording paper,
An ink-out-of-ink detection device for ink-jet recording that detects ink out by comparing a density detection value from the density detection unit with a preset threshold value, wherein the threshold value setting mode is The concentration detecting means is
Detecting the densities of the first density defining means indicating the out-of-ink state and the second density defining means indicating the ink-existing state, respectively, and detecting the density detected by the first density defining means based on the detected density value from the density detecting means. An ink-out-of-ink detecting apparatus for ink-jet recording, comprising a threshold value setting means for setting the threshold value between the detected density value of the second density defining means and the density detection value. 2. The apparatus according to claim 1, wherein said density detecting means is a reflection type optical sensor installed so as to irradiate light and receive reflected light. 3. The method according to claim 1, wherein the first density defining unit is a sheet based on white, the second density defining unit is a sheet based on black, and the density detecting unit is a conveyance path for performing recording on a recording sheet. 2. The method according to claim 1, wherein the detection of the density is performed on the above.
Or the ink-out detecting device for ink-jet recording according to 2. 4. The first density defining means and the second density defining means are a first density mark and a second density mark formed on the same sheet, and the threshold value setting means is a first density mark. 3. The apparatus according to claim 1, wherein the detected density value is obtained from each of a density mark and a second density mark. 5. The ink jet recording apparatus according to claim 1, wherein said ink jet recording ink depletion detecting apparatus is mounted on a facsimile apparatus which performs recording by an ink jet method in which ink droplets are sprayed on recording paper. Out of ink detector. 6. A test mark is formed by spraying ink droplets on a sheet, and a density detection value of the test mark is obtained by density detection means, and then the density detection value is compared with a preset threshold value. A method for detecting an ink shortage for ink-jet recording, wherein the density detection values of a first density defining means indicating an out-of-ink state and a second density defining means indicating an ink present state are detected by the density detecting means. A method for detecting ink shortage for ink-jet recording, comprising: a first step of obtaining each of them; and a second step of setting the threshold value between the detected density values obtained in the first step. 7. A density detection unit detects the density of an inspection mark formed by spraying ink droplets on recording paper,
A recording medium on which is recorded an ink-out-of-ink detection program for ink-jet recording, in which a computer detects ink depletion by comparing a density detection value from the density defining means with a preset threshold value, wherein the detection program The density detection means obtains, in the threshold setting mode, the density detection values of the first density definition means indicating the out-of-ink state and the second density definition means indicating the in-ink state, respectively. A recording medium on which an ink-out-of-ink detection program for inkjet recording is recorded, wherein the threshold value is set between density detection values.