JPH10315499A - APPARATUS AND METHOD FOR DETECTING OUT OF INK FOR INK JET RECORDING - Google Patents

Abstract

(57) [Problem] To accurately detect ink exhaustion even if there is a large variation in the performance of components of an ink exhaustion detection sensor. SOLUTION: An out-of-ink state is detected by comparing a density detection value of an inspection mark 19 formed by spraying an ink droplet onto a recording sheet 6 with a threshold value. An ink-out detection sensor 18 that detects the density of the inspection mark 19 and outputs a detection output corresponding to the input current as a density detection value
And a detection output section 51, a current changing section 52 capable of changing an input current, and detecting the density of the reference paper set to the reference density by the ink-out detection sensor 18 in the input current setting mode. And a control unit 40 for changing and setting the input current by the current changing unit 52 so that the detection output obtained from the detection output unit 51 approaches a predetermined target value.

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 generally use a recording device capable of printing data consisting of characters and figures as visual information on a recording sheet so as to record the data. have. This recording device has an impact method, a thermal method,
Various printing methods such as an ink jet method have been adopted, but in recent years, an ink jet recording apparatus employing an ink jet method which is excellent in quietness and can print on recording paper of various materials has been frequently used. ing.

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 ink exhaustion detection sensor comprising a reflection type optical sensor which detects the density of the ink sprayed on the recording paper and outputs a detection output corresponding to the input current. Is used to detect out of ink. That is, in the related art, a threshold value as a criterion for running out of ink is set in advance, and before and after printing, an ink is sprayed on the leading edge and the trailing edge of the recording paper to form an inspection mark. The density of the mark is detected by an out-of-ink detection sensor to which a constant input current is supplied. 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 above-described conventional configuration, the performance of components such as the light emitting diode in the out-of-ink detection sensor varies.
Even if a constant input current is supplied to the out-of-ink detection sensor and a test mark with a constant density is formed, when the density of the test mark is detected, the performance of component parts varies depending on the detection sensor. This causes a variation in the detected output. If the variation of the detection output is large, the density detection value obtained from the detection output is always biased to one side of the threshold value regardless of the presence or absence of the ink exhaustion, so that the ink exhaustion cannot be accurately detected. Problem. Such a problem also occurs due to a variation in the mounting state such as an angle and a distance with respect to the recording sheet when the out-of-ink detection sensor is mounted.

Therefore, according to the present invention, even if there is a large variation in the performance of the components of the ink-out detection sensor,
An object of the present invention is to provide an apparatus and method for detecting an ink-out condition for ink-jet recording, and a recording medium on which a program for detecting an ink-out condition for ink-jet recording is recorded.

[0007]

According to a first aspect of the present invention, a density detection value of an inspection mark formed by spraying ink droplets on a recording sheet is compared with a threshold value. An ink out-of-ink detecting device for ink jet recording for detecting ink out, wherein a density detecting means for detecting a density of the inspection mark and outputting a detection output corresponding to an input current as a density detection value, and wherein the input current can be changed. In the input current setting mode, the density of the reference density means set to the reference density is detected by the density detection means, and the detection output from the density detection means approaches a predetermined target value. And a current setting means for changing and setting the input current by the current changing means.

Accordingly, the input current is set by the current changing means so that the detection output when the density of the reference density means is detected becomes an input current approaching the target value. Variations in the detection output due to the variations can be suppressed. Therefore, since the density detection means of each device outputs a constant detection output for the density with ink and the density without ink,
It is possible to prevent a problem that the density detection value obtained from the detection output is always biased to one side of the threshold value, and it is possible to reliably detect an ink out condition.

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.

Thus, the light amount, the distance to the recording paper,
Even with a reflection-type optical sensor in which the irradiation angle to the recording paper tends to vary, an appropriate input current is set after the reflection-type optical sensor is installed.

According to a third 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 reference density unit is a reference sheet set to a predetermined density, and the density detection unit detects the density on a transport path when recording is performed on a recording sheet.

Thus, the density detection is performed while the reference paper having a predetermined density is being conveyed along the recording paper conveyance path, so that the density detection of the reference paper can be performed under the same conditions as those for detecting the density of the inspection mark. Therefore, since the density of the reference paper can be detected with high accuracy, the variation in the detection output of each density detecting means can be further suppressed by setting the input current using the detection result.

According to a fourth aspect of the present invention, in the ink jet recording apparatus for ink jet recording according to any one of the first to third aspects, the current changing means is capable of switching an input current to a plurality of stages. The current setting means selects an input current whose detection output from the concentration detecting means is closest to the target value from the input currents of the plurality of stages.

With this, an appropriate input current is selected from a plurality of input currents prepared in advance. For example, the input current to be changed by performing various arithmetic processing based on the detection output of the concentration detecting means , And the input current can be set efficiently without using complicated processing such as changing the input current to the input current or using a control circuit.

According to a fifth aspect of the present invention, there is provided the ink jet recording out-of-ink detecting device according to any one of the first to fourth aspects, wherein the current setting means is configured to perform the detection based on a detection output from the density detecting means. It is characterized by comprising a detecting means for detecting an abnormality of the concentration detecting means by judging whether the detection output is larger than a predetermined maximum value or smaller than a predetermined minimum value. .

[0016] This makes it possible to detect a sensor defect or a detection output adjustment unit defect in common with the process of setting the input current. Therefore, it is necessary to provide a dedicated process or device for detecting a sensor defect or the like. Cost can be reduced.

According to a sixth aspect of the present invention, the ink-out-of-ink detecting apparatus for ink-jet recording according to any one of the first to fifth aspects is mounted on a facsimile apparatus that performs recording by an ink-jet method in which ink is sprayed on recording paper. And

Thus, even in a situation where no operator exists, such as at night or on holidays, it is possible to detect a lack of ink and take a measure against the lack of ink.

According to a seventh aspect of the present invention, the density of an inspection mark formed by spraying ink droplets on a recording sheet is detected by a density detecting means, and a detection output corresponding to an input current outputted from the density detecting means is detected. An ink out-of-ink detection method for ink-jet recording, wherein the detected value is obtained as a detection value and the detected density value is compared with a threshold value, the reference density means being set to a reference density in an input current setting mode. Is detected by the density detecting means, and the input current is changed and set by the current changing means so that the detection output from the density detecting means approaches a predetermined target value.

Thus, if the detection output when the density of the reference density means is detected is set to an input current approaching the target value, the variation in the detection output due to the variation in the performance of the components between the density detection means is obtained. Can be suppressed. Therefore, since the density detecting means of each device outputs a constant detection output for each of the density with ink and the density without ink, the density detection value obtained from the detection output is always biased to one side of the threshold value. Problems can be prevented, and ink out can be reliably detected. With this method, the input current can be automatically set by a computer, and the input current can be set manually by an operator.

According to an eighth 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 detected output corresponding to the input current output from the density detecting means is detected by the density detecting means. A recording medium recording an ink-out-of-ink detection program for ink-jet recording, which is obtained as a detection value, and which detects a shortage of ink by a computer by comparing the density detection value with a threshold value,
The detection program causes the computer to detect the density of the reference density means set to the reference density by the density detection means in the input current setting mode, and the detection output from the density detection means is set to a predetermined target. The present invention is characterized in that the input current is changed and set by the current changing means so as to approach the value.

Thus, the variation in the detection output caused by the variation in the performance of the components between the density detecting means can be suppressed, and the density detecting means of each apparatus can maintain a constant level for the density with ink and the density without ink. By causing the computer to set the input current to the density detecting means so as to output the detection output, it is possible to realize an ink-out-of-ink detection device for ink-jet recording capable of reliably detecting ink out.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. The out-of-ink detection device for ink jet 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. 4, 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 sheets 6 are accommodated in the sheet accommodation case 5. The recording paper 6 is pressed against a paper feed roller 7 disposed at the bottom of the paper storage case 5, and the paper feed roller 7 feeds the recording paper 6 in the paper storage case 5 from a paper feed port 5 a. Paper is fed to the 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 similar to that 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. 4, a paper guide 14 for regulating the traveling direction of the printed recording paper 6 and a paper guide 14 for discharging the recording paper 6 out of the machine are provided on the discharge side of the recording paper 6 from the printing section 30. 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. Out of ink detection sensors 18 are arranged in this order.

The above-described ink-out detection sensor 18 is shown in FIG.
As shown in FIG. 7, a light emitting diode 18 connected to a DC power supply of, for example, 5 V and emitting light with a light emission amount corresponding to an input current.
a, and a phototransistor 18b that outputs a photocurrent proportional to the amount of received light. The out-of-ink detection sensor 18 is connected to the detection output adjustment unit 50,
The detection output adjusting unit 50 generates a detection output of a voltage proportional to the photocurrent of the phototransistor 18b.
1 and a current changing unit 52 that can change the input current of the light emitting diode 18a to an arbitrary current amount.

The detection output section 51 includes a detection transistor 51a in which a base terminal is connected to the collector terminal of the phototransistor 18b to form a Darlington circuit;
It has a detection resistor 51b connected between the collector terminal of the detection transistor 51a and the DC power supply. The detection output unit 51 amplifies the photocurrent from the phototransistor 18b in the detection transistor 51a, and outputs a voltage obtained by the amplified photocurrent and the detection resistor 51b as a detection output. on the other hand,
The current changing section 52 of the detection output adjusting section 50 has a first switch section 53 and a second switch section 54 connected in parallel to the cathode side of the light emitting diode 18a. Each switch unit 53/54 is connected to a current limiting resistor 53a / 54a for limiting an input current of the light emitting diode 18a, and a transistor which is turned on when a high level switch signal is input. 53b and 54b. Note that the current limiting resistor 53
a · 54a is set such that the resistance value of the current limiting resistor 53a is larger than the resistance value of the current limiting resistor 54a. Then, the current changing unit 52
3b / 54b ON (ON) state and OFF (OFF)
By combining the states, the current limiting resistor 53a
The resistance value of the resistor 54a can be switched in three stages, and the light-emitting diode 18a emits light with an input current corresponding to the resistance value.

As shown in FIG. 1, the detection output adjusting section 50 has a detection output section 51 and a current changing section 52 connected to an A / D conversion section 42 and an I / O section 41a of the control section 40, respectively. I have. The A / D conversion unit 42 detects the detection output unit 5
1 is converted into a digital value and output as a density detection value. Also, the I / O unit 41a
In addition to the current changing unit 52, a sensor that outputs an on / off signal, such as the paper feed sensor 11 and the paper discharge sensor 16 in FIG.

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 is an RA capable of temporarily storing print data, data of density detection values, and the like.
M, R which fixedly stores control data and control program
It has an OM and an E ² PROM which holds switch setting data to be described later in a rewritable manner. As shown in FIG. 6, the control program can select at least an input current setting mode and a reception processing mode. When the input current setting mode is selected, the control program An optimal input current is determined from among three levels of input currents to the out-of-ink detection sensor 18 so that the obtained density detection value of the reference paper approaches a predetermined target value.

Further, as shown in FIG.
A key input unit 45 disposed on the front side of the upper cover 3 in FIG. 3 is connected to the / O unit 41b, and various data such as ten-key data, function data, and mode designation data are transmitted from the key input unit 45. Is entered. Further, a display unit 46 and a head driving unit 47 are connected to the I / O unit 41b of the control unit 40, and the head driving unit 47 receives a print data indicating a black dot from the control unit 40. Then, 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.
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 input current setting mode (S2, YES), the process waits until the reference paper set to the reference density is set in the paper storage case 5. When it is confirmed that the setting of the reference sheet is completed by inputting the set signal from the key input unit 45 (S3), the sheet feeding roller 7 and the like are driven to take the reference sheet into the apparatus and convey it (S4). ). Thereafter, as shown in FIG. 2, a high-level switch signal is output to the transistor 53b of the first switch unit 53, and a low-level switch signal is output to the transistor 54b of the second switch unit 54. 1 switch unit 53
Is set to an ON state and the second switch unit 54 is set to an OFF state. The current limiting resistor 53a of the first switch unit 53 having a large resistance value
Is supplied to the light-emitting diode 18a and emits light of an amount corresponding to the input current, thereby enabling the ink-out detection sensor 18 to detect the density. . Further, the output form of the switch signal in such a setting state is stored as switch setting data in a switch setting storage area formed in the RAM of the memory 44 (S5).

Next, when the reference sheet passes through the printing unit 30 and is detected by the sheet ejection sensor 16, counting of the elapsed time is started. Then, after a lapse of a predetermined period of time when it is considered that the reference paper has reached the detection position of the out-of-ink detection sensor 18, a density detection value which is a detection output obtained from the out-of-ink detection sensor 18 via the detection output unit 51 is taken in. (S6), it is determined whether or not the detected density value is equal to or higher than the lower limit (S7). If the detected density value is less than the lower limit value (S7, NO), it is determined that the out-of-ink detection sensor 18 is abnormal, and a message indicating that the sensor is defective or the detection output adjustment unit 50 is defective is displayed on the display unit 46. Or an alarm sound is generated to notify the operator of a sensor failure or the like (S
8). Then, the reference sheet is discharged (S20), and this routine ends.

On the other hand, if the detected density value is equal to or higher than the lower limit value (S7, YES), it is determined whether the detected density value is equal to or higher than the target value (S9). When the detected density value is less than the target value (S9, NO), it is determined that the current setting state of the first and second switch sections 53 and 54 in the current changing section 52 is optimal, and the switch from the memory 44 is determined. after writing reads the configuration data to E ² PROM (S10), the standard sheet discharged (S20), and terminates this routine. As a result, in the subsequent operation, E ²
By setting the first switch unit 53 to the ON (ON) state and the second switch unit 54 to the OFF (OFF) state based on the switch setting data of the PROM, the current limit resistance 53a of the first switch unit 53 is set. Determined minimum (first
The detection of the density by the out-of-ink detection sensor 18 is performed using the input current in the (stage).

On the other hand, when the detected density value is equal to or higher than the target value (S9, YES), a low-level switch signal is output to the transistor 53b of the first switch section 53, and a high-level switch signal is output to the second switch section 53b. By outputting the signal to the transistor 54b of the switch unit 54, the first switch unit 53 is set to an off (OFF) state and the second switch unit 54 is set to an on (ON) state. And
An intermediate (second-stage) input current determined by the current limiting resistor 54a having a small resistance value of the second switch unit 54 is supplied to the light emitting diode 18a, and a light amount corresponding to the input current is emitted. Thereby, the density detection by the out-of-ink detection sensor 18 is enabled. The output form of the switch signal in such a setting state is stored as switch setting data in a switch setting storage area formed in the RAM of the memory 44 (S11).

Thereafter, a density detection value, which is a detection output obtained from the out-of-ink detection sensor 18 via the detection output unit 51, is fetched (S12), and it is determined whether or not this density detection value is equal to or more than the target value (S12). S13). If the detected density value is less than the target value (S13, NO), the current changing unit 5
It is determined that the setting states of the first and second switch units 53 and 54 in FIG. 2 are optimal, and the switch setting data is read out from the memory 44 and written into the E ² PROM (S
14) The reference sheet is discharged (S20), and this routine ends. As a result, in the subsequent operation, E ² PR
First switch unit 5 based on OM switch setting data
3 is set to an OFF (OFF) state and the second switch section 54 is set to an ON (ON) state, so that the intermediate (second-stage) input current determined by the current limiting resistor 54a of the second switch section 54 Is used to detect the density by the ink-out detection sensor 18.

On the other hand, when the detected density value is equal to or higher than the target value (S13, YES), the high-level switch signal is supplied to the transistors 53b and 54b of the switch units 53 and 54.
, The switches 53 and 54 are set to the ON state. Then, the maximum (third-stage) input current determined by the two current limiting resistors 53a and 54a connected in parallel is supplied to the light emitting diode 18a, and the amount of light corresponding to the input current is emitted, whereby the ink is discharged. The density detection by the cut-out detection sensor 18 is made possible. The output form of the switch signal in such a setting state is stored in the memory 4 as switch setting data.
4 is stored in the switch setting storage area formed in the RAM (S15).

Thereafter, a density detection value, which is a detection output obtained from the out-of-ink detection sensor 18 via the detection output unit 51, is fetched (S16), and it is determined whether or not the density detection value is less than the upper limit value (S16). S17). If the detected density value is equal to or higher than the upper limit value (S17, NO), the current changing unit 5
It is determined that the setting states of the first and second switch units 53 and 54 in FIG. 2 are optimal, and the switch setting data is read out from the memory 44 and written into the E ² PROM (S
18) The reference sheet is discharged (S20), and this routine ends. As a result, in the subsequent operation, E ² PR
By setting the first and second switch sections 53 and 54 to the ON state based on the OM switch setting data, the current is determined by the current limiting resistors 53a and 54a of both switch sections 53 and 54. The detection of the density by the out-of-ink detection sensor 18 is performed using the maximum (third stage) input current.

On the other hand, when the density detection value is equal to or higher than the upper limit value (S17, YES), it is determined that the out-of-ink detection sensor 18 is abnormal, and it is determined that the sensor is defective or the detection output adjusting unit 50 is defective. It is displayed on the display unit 46, or an alarm sound indicating that the sensor is defective or the like is generated to notify the operator (S19). Then, the reference sheet is discharged (S2
0), end this routine.

Next, in S1, when the reception mode is selected, it is determined that the input current setting mode is not set (S2, NO), and the reception process is executed (S3).
0). That is, as shown in FIG. 7, it is determined whether or not print data has been received from the other party (S31). If not (S31, NO), the process is re-executed from S1 in FIG. S2 until a processing mode other than the mode is selected.
Of the processing mode and the reception processing of S30 are repeated.

Thereafter, when it is determined in S31 that the print data has been received (S31, 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. 4, 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 the 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 (S32).

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 (S33). Then, the above-mentioned S10, S14, S1
8, the switch setting data stored in the E ² PROM is read out, and based on the switch setting data, a high-level or low-level switch signal is supplied to the current changing unit 52.
To the first and second switch units 53.
54 is set to an ON (ON) state or an OFF (OFF) state, and a predetermined input current is supplied to the out-of-ink detection sensor 18. Thereafter, as shown in FIG.
When the trailing end of the recording paper 6 discharged by the sensor is detected by the paper discharge sensor 16, counting of the elapsed time is started, and the inspection mark 19 is counted for a predetermined time considered to have reached the detection position of the out-of-ink detection sensor 18. After the lapse of time, the density detection value, which is a detection output from the out-of-ink detection sensor 18, is taken in and stored in an inspection mark storage area formed in the RAM of the memory 44, thereby detecting the density of the inspection mark (S34).

When the density detection value is stored in the inspection mark recording area, the threshold value previously stored in the memory 44 is read, and it is determined whether the density detection value of the inspection mark 19 is on the black side of the threshold value. A determination is made (S35). If it exists on the black side of the threshold value (S35, YES), it is determined that the ink has not run out and S31 is re-executed. Continue or terminate. On the other hand, if it is not on the black side of the threshold value (S35, 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 44 or the ink runs out. A warning sound is generated to notify the operator (S36).

As described above, the out-of-ink detecting device of the present embodiment compares the density detection value of the inspection mark 19 formed by spraying ink droplets on the recording paper 6 with the threshold value, as shown in FIG. The ink-out detection sensor 18 detects the density of the test mark 19 and outputs a detection output corresponding to the input current as a density detection value, and a detection output unit 51 (density detection means). ), A current changing section 52 (current changing means) capable of changing the input current, and detecting the density of the reference paper (reference density means) set to the reference density by the out-of-ink detection sensor 18 in the input current setting mode. The input current is changed by the current changing unit 52 so that the detection output obtained from the out-of-ink detection sensor 18 via the detection output unit 51 approaches a predetermined target value. Control unit constant to 40 have been configured to have a (current setting means).

In the present embodiment, the case where the present invention is applied to an ink jet recording apparatus for printing using black ink is described, but the present invention is not limited to this.
The present invention can also be applied to an ink jet recording apparatus that performs printing using color inks such as red and green.

Thus, if the current changing unit 52 is changed and set by the control unit 40 so that the detection output when detecting the density of the reference paper becomes an input current approaching the target value, the performance variation of the light emitting diode 18a and the like can be reduced. Variations in the detection output between the out-of-ink detection sensors 18 due to this can be suppressed. Accordingly, since the out-of-ink detection sensor 18 of each device outputs a constant detection output for each of the density with ink and the density without ink, the density detection value obtained from the detection output is always on one side of the threshold value. The problem of bias can be prevented, and ink out can be reliably detected.

Further, in the present embodiment, the out-of-ink detection sensor 18 is constituted by a reflection type optical sensor installed so as to irradiate light and receive reflected light. Thereby, even if the reflection type optical sensor is apt to cause variation in the light amount, the distance to the recording paper 6, and the irradiation angle to the recording paper 6,
Since an appropriate input current is set after the installation of the reflection type optical sensor, it is possible to reliably detect the ink shortage.

In the present embodiment, the reference paper set to a predetermined density is used, and the density is detected on the transport path when printing on the recording paper 6. Accordingly, the density detection is performed while the reference paper having the predetermined density is being conveyed to the conveyance path of the recording paper 6, so that the density detection of the paper can be performed under the same conditions as those for detecting the density of the inspection mark 19. By setting the input current using the detection result obtained by performing the density detection of the reference paper with high accuracy, each of the ink-out detection sensors 1
8 can further suppress the variation in the detection output.
Instead of using such a reference sheet, an inspection mark 19 having a predetermined density with adjusted dot density is formed on the recording sheet 6, and the input current is determined using the inspection mark 19. good.

In the present embodiment, the current changing unit 5
2, as shown in FIG. 2, the input current is changed in three stages (a plurality of stages) by the first switch unit 53 and the second switch unit 54.
The control unit 40 is configured to select an input current at which the detection output from the out-of-ink detection sensor 18 becomes closest to the target value from the three levels of input current. The number of switching stages of the input current is not limited to three, and can be set to an arbitrary number by connecting a plurality of circuit configurations such as the first switch unit 53 in parallel.

As a result, an appropriate input current is selected from a plurality of input currents prepared in advance. Therefore, the input current should be changed by performing various arithmetic processing based on the detection output of the out-of-ink detection sensor 18, for example. The input current can be set efficiently without complicated processing such as the case of obtaining the value of the input current and changing to the input current, or without using a control circuit.

In this embodiment, the control unit 40
Is based on the detection output from the out-of-ink detection sensor 18 and determines whether the detection output is larger than a predetermined maximum value or smaller than a predetermined minimum value. 6 or a detecting means for detecting an abnormality of the detection output adjusting section 50 (S in FIG. 6).
7, S17)). This makes it possible to detect a sensor failure in common with the process of setting the input current, so that there is no need to provide a dedicated process or device for detecting the sensor failure, and the cost can be reduced.

In this embodiment, the out-of-ink detecting device is mounted on a facsimile apparatus that performs recording by an ink jet system that sprays ink onto the 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 against the ink shortage.

As shown in FIG. 1, the ink-out detecting method according to the present embodiment is performed in the input current setting mode.
The out-of-ink detection sensor 18 detects the density of the reference paper (reference density means) set to the reference density, and the current changing unit 52 controls the detection output from the out-of-ink detection sensor 18 to approach a predetermined target value. To change and set the input current (S3 to S2 in FIG. 6).
0).

When the detection output when detecting the density of the reference paper is set to be an input current approaching the target value, the detection between the ink-out detection sensors 18 due to the variation in the performance of the light emitting diode 18a and the like. Output variations can be suppressed. Accordingly, since the out-of-ink detection sensor 18 of each device outputs a constant detection output for each of the density with ink and the density without ink, the density detection value obtained from the detection output is always on one side of the threshold value. The problem of bias can be prevented, and ink out can be reliably detected. With this method, the input current can be automatically set by a computer, and the input current can be set manually by an operator.

In the present embodiment, the input current setting process (S3 to S20 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 input current setting program for causing a computer to execute the current setting process may be recorded on a recording medium such as a magnetic tape, a magnetic disk, or an optical disk.

That is, in the input current setting mode, the computer causes the out-of-ink detection sensor 18 to detect the density of the reference paper set to the reference density, and the detection output from the out-of-ink detection sensor 18 is set to a predetermined target. The input current setting process may be performed by using a recording medium that stores an input current setting program for changing and setting the input current by the current changing unit 52 so as to approach the value. In this case, if the facsimile device has a reading device or is connectable to an information processing device such as a personal computer, the input current setting program is read from the recording medium, and the facsimile device side and the information are read. Since the input current can be set by the computer on the processing device side, it is possible to suppress the variation in the detection output between the out-of-ink detection sensors 18, and as a result, the ink jet recording that can reliably detect the out-of-ink condition Ink depletion detecting device can be realized.

[0059]

According to the first aspect of the present invention, an ink-out detecting apparatus for ink-jet recording detects an ink-out by comparing a density detection value of an inspection mark formed by spraying an ink droplet onto a recording sheet with a threshold value. A density detection unit that detects the density of the inspection mark and outputs a detection output according to an input current as a density detection value, a current change unit that can change the input current, and an input current setting mode. The density of the reference density means set to the reference density is detected by the density detection means, and the input current is changed and set by the current changing means so that the detection output from the density detection means approaches a predetermined target value. And a current setting unit that performs the operation.

With this, the input current is set by the current changing means so that the detection output when the density of the reference density means is detected becomes an input current approaching the target value. Variations in the detection output due to the variations can be suppressed. Therefore, since the density detection means of each device outputs a constant detection output for the density with ink and the density without ink,
It is possible to prevent a problem that the density detection value obtained from the detection output is always biased to one side of the threshold value, and it is possible to surely detect the out of ink.

According to a second aspect of the present invention, in the ink jet recording apparatus for ink jet recording according to the first aspect, the density detecting means is arranged to irradiate light and receive reflected light. The configuration is a sensor.

Thus, the light amount, the distance to the recording paper,
Even if the reflection-type optical sensor tends to vary the irradiation angle on the recording paper, an appropriate input current is set after the reflection-type optical sensor is installed, so that the ink out can be reliably detected. To play.

According to a third aspect of the present invention, there is provided the ink-out detecting apparatus for ink-jet recording according to the first or second aspect,
The reference density unit is a reference sheet set to a predetermined density, and the density detection unit is configured to detect the density on a transport path when recording on a recording sheet.

As a result, the density is detected while the reference paper having a predetermined density is being conveyed along the recording paper conveyance path, so that the density of the reference paper can be detected under the same conditions as those for detecting the density of the inspection mark. Accordingly, since the density of the reference paper can be detected with high accuracy, setting the input current using the detection result has the effect of further suppressing the variation in the detection output of each density detecting means. .

According to a fourth aspect of the present invention, in the ink jet recording out-of-ink detecting device according to any one of the first to third aspects, the current changing means can switch an input current to a plurality of stages. The current setting means is configured to select an input current whose detection output from the concentration detecting means is closest to the target value from the input currents in the plurality of stages.

As a result, an appropriate input current is selected from a plurality of input currents prepared in advance. For example, the input current to be changed by performing various arithmetic processing based on the detection output of the density detecting means. Is obtained, and the input current can be set efficiently without complicated processing such as a case where the input current is changed and the control circuit is not used.

According to a fifth aspect of the present invention, there is provided the ink-out recording apparatus for ink-jet recording according to any one of the first to fourth aspects, wherein the current setting means is configured to perform the detection based on a detection output from the density detection means. It is configured to include a detection unit that detects abnormality of the concentration detection unit by determining whether the detection output is larger than a predetermined maximum value or smaller than a predetermined minimum value.

As a result, a sensor failure or a detection output adjustment unit failure can be detected in common with the process of setting the input current, and it is necessary to provide a dedicated process or device for detecting a sensor failure or the like. Therefore, the effect that the cost can be reduced can be obtained.

According to a sixth aspect of the present invention, the ink-out-of-ink detecting apparatus for ink-jet recording according to any one of the first to fifth aspects is configured to be mounted on a facsimile apparatus that performs recording by an ink-jet method in which ink is sprayed on recording paper. .

Thus, even in a situation where there is no operator, 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 seventh aspect of the present invention, the density of an inspection mark formed by spraying ink droplets on a recording sheet is detected by a density detecting means, and a detection output corresponding to an input current output from the density detecting means is detected. An ink out-of-ink detection method for ink-jet recording, wherein the detected value is obtained as a detection value and the detected density value is compared with a threshold value, the reference density means being set to a reference density in an input current setting mode. Is detected by the density detecting means, and the input current is changed and set by the current changing means so that the detection output from the density detecting means approaches a predetermined target value.

When the detection output when the density of the reference density means is detected is set to an input current approaching the target value, the variation in the detection output due to the variation in the performance of the components between the density detection means is obtained. Can be suppressed. Therefore, since the density detecting means of each device outputs a constant detection output for each of the density with ink and the density without ink, the density detection value obtained from the detection output is always biased to one side of the threshold value. Problems can be prevented, and ink out can be reliably detected. Then, according to this method, there is an effect that the input current can be automatically set by the computer and the input current can be set manually by the operator.

According to an eighth aspect of the present invention, the density of a test mark formed by spraying ink droplets on a recording sheet is detected by a density detecting means, and a detection output corresponding to an input current output from the density detecting means is detected. A recording medium recording an ink-out-of-ink detection program for ink-jet recording, which is obtained as a detection value, and which detects a shortage of ink by a computer by comparing the density detection value with a threshold value,
The detection program causes the computer to detect the density of the reference density means set to the reference density by the density detection means in the input current setting mode, and the detection output from the density detection means is set to a predetermined target. The input current is changed and set by the current changing means so as to approach the value.

As a result, variations in the detection output due to variations in the performance of the components between the density detecting means are suppressed, and the density detecting means of each apparatus is provided with a constant value for the density with ink and the density without ink. By causing the computer to set the input current so that the detection output is output, an effect that the out-of-ink condition can be reliably detected is achieved.

[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 circuit diagram of a detection output adjustment unit.

FIG. 3 is a perspective view of the facsimile machine.

FIG. 4 is a schematic configuration diagram of a facsimile machine.

FIG. 5 is a perspective view of an inkjet head.

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 main body 13 platen 14 paper guide 15 discharge roller 16 paper discharge sensor 18 out-of-ink detection sensor 18a light emitting diode 18b photo Transistor 19 Inspection mark 20 Document 21 Document feeder 22 Image reading device 31 Inkjet head 31b Nozzle 32 Carriage 33 Travel mechanism 51 Detection output unit 52 Current change unit 53 First switch unit 54 Second switch unit

Claims (8)

[Claims] 1. An ink-out-of-ink detecting apparatus for ink-jet recording, which detects an out-of-ink state by comparing a density detection value of an inspection mark formed by spraying an ink droplet onto a recording sheet with a threshold value, wherein the inspection mark Density detecting means for detecting a density of the reference current and outputting a detection output corresponding to the input current as a density detection value; a current changing means capable of changing the input current; and a reference set to a reference density in the input current setting mode. Current setting means for detecting the density of the density means by the density detection means, and changing and setting the input current by the current change means so that the detection output from the density detection means approaches a predetermined target value. An out-of-ink detection device for ink jet recording, characterized in that: 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 2, wherein the reference density unit is a reference sheet set to a predetermined density, and the density detection unit detects the density on a transport path when recording on a recording sheet. Item 3. An ink-out recording device for ink-jet recording according to item 1 or 2. 4. The current changing means is capable of switching an input current to a plurality of levels, and the current setting means is configured to output a detection output from the concentration detecting means from the input currents of the plurality of levels to the target value. 4. The apparatus according to claim 1, wherein an input current closest to the above is selected. 5. The current setting means determines, based on a detection output from the concentration detection means, whether the detection output is larger than a preset maximum value or smaller than a predetermined minimum value. 5. The apparatus according to claim 1, further comprising a detecting unit configured to detect an abnormality of the density detecting unit. 6. An ink jet recording apparatus for ink jet recording according to claim 1, wherein said apparatus is installed in a facsimile apparatus for recording by an ink jet method in which ink is sprayed on recording paper. Out of ink detector. 7. A density detection unit detects the density of an inspection mark formed by spraying ink droplets on recording paper,
An ink outage detection method for ink jet recording, wherein a detection output corresponding to an input current output from the density detection means is obtained as a density detection value, and the density detection value is compared with a threshold value to detect ink depletion. In the input current setting mode, the density of the reference density means set to the reference density is detected by the density detection means, and the current is adjusted so that the detection output from the density detection means approaches a predetermined target value. A method for detecting ink shortage for ink-jet recording, characterized in that an input current is changed and set by changing means. 8. 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 program for ink-jet recording, in which a detection output corresponding to an input current output from the density detection means is obtained as a density detection value, and the density detection value is compared with a threshold value to detect out-of-ink by a computer. Wherein the detection program causes the computer to detect the density of the reference density means set to the reference density in the input current setting mode by the density detection means. Wherein the input current is changed and set by the current changing means so that the detected output of the ink becomes closer to a predetermined target value.