JPH0825650A - Ink jet recording device - Google Patents

Abstract

PURPOSE:To provide an ink jet recording device which can read a recording paper by proper sensivity and make longer the life of a photoelectric sensor by controlling the electric current amount flowing on the luminous side of the photoelectric sensor in the case the sensitivity adjustment of the photoelectric sensor is carried out for the ink jet recording device. CONSTITUTION:The output level of reaction light received by a light accepting section 9b is sampled by a CPU by the given times, and the electric current amount supplied to the luminous section 9b is set and changed based on the average value of sampled output level.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus, and more particularly to recording an ink end mark for determining ink shortage on a recording paper and optically reading the ink end mark to determine ink shortage. The present invention relates to an inkjet recording device.

[0002]

2. Description of the Related Art Generally, a thermal printer, an ink jet recording apparatus, etc. are used as a means for printing on recording paper. With thermal recording paper used in thermal printers, when the roll-shaped thermal recording paper reaches a certain length before it runs out, the recording paper will be black-printed at a predetermined location in advance, and this black print density (black density) Is detected by the detection means, it is possible to determine whether the thermal recording paper is out of paper.

As a concrete method for determining the paper-out condition, a threshold value which sets a boundary between the black density and the white density (density of the paper itself which is not printed) is provided, and the density value detected by a photoelectric sensor or the like. And the threshold value are compared. The paper used for thermal recording paper, etc. is almost determined according to the type of recording device, and the white density or black density of the recording paper can be easily estimated, so the threshold value is the value of black density or white density. Either one of the values is used as a reference value and is stored in advance as a fixed value in the apparatus, and the presence / absence of paper is determined based on the magnitude relationship between the threshold value and the detected density value.

On the other hand, as a device for printing marks on recording paper to detect ink shortage, a "data processing device" described in Japanese Patent Application Laid-Open No. 2-221814 has been reported. This one conveys recording paper and prints a mark at a predetermined position before the end of one page with a print head. When the recording paper is conveyed and the reading position of the photoelectric sensor and the position where the mark is printed coincide with each other, it is determined whether or not the mark is detected. If no mark is detected, it is determined that the ink has run out, the conveyance is stopped, and the print data in the memory is transferred to and stored in the large capacity memory.
This prevents the waste of printing blank recording paper,
In addition, it has an advantage that data loss can be prevented.

As another apparatus for detecting ink shortage, an "ink jet recording apparatus" is described in Japanese Patent Application No. 5-196598 of the prior application. This is designed to adjust the output level of the photoelectric sensor based on the output level appearing on the light receiving side of the photoelectric sensor when light is applied to the non-printed portion of the recording paper, so that even the photoelectric sensor with poor sensitivity can operate normally. It has the advantage of being readable. Specifically, the light emitting side of the photoelectric sensor irradiates the non-printed portion of the recording paper with light, and the light receiving side of the photoelectric sensor receives the reflected light from the recording paper. Next, the current flowing according to the amount of received light is converted into a voltage, and the A / D converter converts the analog value into a digital value. Next, the voltage value converted into a digital value is sampled based on a predetermined sampling frequency. After repeating sampling a specified number of times,
The average value α of the sampled voltage values is calculated, and the voltage ratio (α /
β) is calculated. Based on the calculated voltage ratio (α / β), the output level on the light receiving side is adjusted to an output level at which the non-printed portion and the printed portion of the recording paper can be normally discriminated. In this way, the output level of the photoelectric sensor (light receiving side) is changed to the voltage ratio (α /
Since it is adjusted based on β), the performance of the A / D converter can be fully brought out, the reading performance variation due to the difference in sensitivity of the photoelectric sensor can be absorbed, and the output level can be adjusted. Has the advantage that it can be automated.

[0006]

However, in the above-mentioned "data processing device", the ink out condition is determined by the presence / absence of the mark, but the sensitivity of the photoelectric sensor is not taken into consideration. In the case of a device that uses a photoelectric sensor with uneven sensitivity and is equipped with a photoelectric sensor with poor sensitivity, the reflected light from the recording paper cannot be accurately read, and accurate ink exhaustion determination cannot be performed. There was a problem that it was not done.
In order to solve such problems, in the case of a device equipped with a photoelectric sensor with uneven sensitivity, a semi-fixed resistor is connected to the light receiving side of the photoelectric sensor and the output level of the photoelectric sensor is checked. However, there is known a technique of artificially adjusting the sensitivity of the photoelectric sensor by adjusting a semi-fixed resistor, etc. However, in such a configuration, the characteristic of the photoelectric sensor is well known in order to adjust the sensitivity. Must be adjusted and adjustment is not easy. Furthermore, if there is a possibility that the photoelectric sensor has a cause of abnormality, the output level of the photoelectric sensor must be measured each time, which makes adjustment more difficult.

Further, in order to solve the first problem, if a photoelectric sensor having no variation in sensitivity is used, the reflected light from the recording paper can be accurately read, but the cost increases. was there. On the other hand, in the "ink jet recording apparatus", the output level of the photoelectric sensor on the light receiving side is adjusted. Therefore, when the amount of light irradiated on the recording paper is extremely insufficient, Even if the output level is adjusted, there is a problem that the recording paper cannot be read accurately because the absolute amount of light reflected from the recording paper is insufficient. Further, since the light emitting side of the photoelectric sensor is constantly supplied with a constant amount of electric power, the light emitting side of the photoelectric sensor always consumes electric power, which increases the power consumption of the ink jet recording apparatus. There is a problem that the life of the sensor is shortened.

Therefore, an object of the present invention is to provide an ink jet recording apparatus having a photoelectric sensor capable of reading recording paper with appropriate sensitivity and having a long life. According to the second aspect of the invention, the electric current is supplied to the light emitting portion only when the ink end mark is sampled, so that the power consumption of the photoelectric sensor can be suppressed and the life of the photoelectric sensor can be extended. An object is to provide an inkjet recording device.

According to a third aspect of the present invention, an ink jet recording apparatus capable of storing the output level of the photoelectric sensor in a memory in time series and printing the value in time series so that the state can be easily grasped. Is intended to provide. According to the invention of claim 4, the maximum value, the minimum value and the threshold value of the output level of the photoelectric sensor are stored, and each value is printed when necessary, so that the state can be easily grasped. The purpose is to provide a device.

[0010]

According to the first aspect of the present invention,
In order to solve the above problems, a current supplied to an ink jet recording apparatus that irradiates an ink end mark printed on recording paper with light and detects the presence or absence of ink in an ink cartridge based on the output level of the reflected light. A light emitting unit that emits light according to the amount, a light receiving unit that receives reflected light from the recording paper, a sampling unit that samples the output level of the reflected light received by the light receiving unit a predetermined number of times, and a sampling unit that samples the output level. And a control unit that sets / changes the amount of current supplied to the light emitting unit based on the average value of the output levels.

In order to solve the above-mentioned problems, the invention according to claim 2 is the invention according to claim 1, wherein the ink end mark printed on the recording paper conveyed in a predetermined direction reaches a first predetermined position. In this case, it is characterized by having a current control unit that supplies current to the light emitting unit and stops supplying current to the light emitting unit when the ink end mark reaches the second predetermined position.

In order to solve the above-mentioned problems, the invention according to claim 3 is the output level storage section for storing the output level of the reflected light sampled by the sampling section in time series in the invention according to claim 1 or 2. And a printing unit for printing the sampling values stored in the output level storage unit on the recording paper in time series.

In order to solve the above-mentioned problems, the invention according to claim 4 is characterized in that, in the invention according to claim 1 or 2, the density of the ink end mark recorded on the recording paper and the threshold value between the white background portion of the recording paper are determined. A threshold value storage unit for storing,
A detection unit that detects the maximum value and the minimum value of the output level of the reflected light sampled by the sampling unit,
An output value storage unit that stores the maximum value and the minimum value detected by the detection unit, and a printing unit that prints the threshold value storage unit and the threshold value, the maximum value, and the minimum value stored in the output value storage unit. It is characterized by having.

[0014]

According to the present invention, the output level of the reflected light received by the light receiving section is sampled a predetermined number of times, and the amount of current supplied to the light emitting section is set based on the average value of the sampled output levels. / It is supposed to be changed. Therefore, the amount of light emitted from the light receiving unit onto the recording paper is corrected to an appropriate amount, the recording paper is read with an appropriate sensitivity, and the photoelectric sensor has a long life.

According to the second aspect of the invention, when the ink end mark printed on the recording paper conveyed in the predetermined direction reaches the first predetermined position, a current is supplied to the light emitting portion and the ink end is supplied. When the mark reaches the second predetermined position, the current supply to the light emitting unit is stopped. Therefore, the current is supplied to the light emitting unit only when the ink end mark is sampled,
The power consumption of the photoelectric sensor is suppressed and the photoelectric sensor has a long life.

According to the third aspect of the present invention, the output level of the reflected light sampled is stored in time series, and the stored sampling values are printed in time series on the recording paper. The state of the inkjet recording device can be easily grasped. According to the fourth aspect of the invention, the density of the ink end mark recorded on the recording paper, the threshold value with the white background of the recording paper, and the maximum and minimum values of the output level of the reflected light sampled are printed. Therefore, the state of the inkjet recording device can be easily grasped.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. (Embodiment 1) First, a system configuration diagram of an ink jet recording apparatus will be described. FIG. 1 is a system configuration diagram of an ink jet recording apparatus common to the inventions described in claims 1 to 4.

As shown in FIG. 1, a CPU (Central Proc
The essing unit) section 1 is a ROM (Read Only) not shown.
Based on a program and various data stored in the memory), each part of the inkjet recording device is mainly controlled. The memory unit 2 includes a ROM and a RAM (Random Access Me
mory) or SRAM (Static Random Access Memor)
y), a ROM stores a threshold value used for determining the ink exhaustion described later and control of the switch unit 13, and the RAM or SRAM sets the switch unit 13 and the ink density detection unit 5 described later. The output value is stored. The display unit 3 is composed of a liquid crystal display panel, and when the ink is depleted, various displays are performed to warn the ink depletion. The display unit 3 may be configured with a buzzer, an LED, or the like that emits a warning sound for this warning.

The ink jet recording apparatus 4 includes a CPU section 1
Data such as characters and symbols are printed by ejecting ink liquid onto the recording paper based on the command from the Print (ink end mark). The recording paper motor unit 6 conveys the recording paper in the forward direction or the reverse direction based on a command from the CPU unit 1. Also,
The head motor unit 7 moves the head unit 8 left and right based on a command from the CPU unit 1 to the print position of the recording paper. The head unit 8 is moved to the print position by the head motor unit 7 and prints characters, symbols, and ink shortage determination marks based on a command from the CPU unit 1.

The ink density detector 5 irradiates the recording paper with light based on a command from the CPU 1, receives the reflected light from the recording paper, and is represented by a digital value according to the amount of the reflected light. Output voltage value. The photoelectric sensor 9 is arranged at a position where the ink exhaustion determination mark can be detected, irradiates the recording paper with light by passing a current through the light emitting portion 9a, and receives the reflected light from the recording paper at the light receiving portion 9b. . The light emission amount of the light emitting unit 9a is determined according to the amount of current, and the light receiving unit 9b converts it into a current according to the amount of received light. Current-voltage conversion resistance unit (hereinafter, also referred to as I / V conversion resistance unit)
Reference numeral 10 converts the current (I) flowing through the light receiving section 9b into a voltage (V) according to the reflected light from the recording paper, and supplies the voltage to the A / D converter section 11. The A / D converter unit 11 has
It has a voltage separation capability β, and A / D converts the voltage supplied from the I / V conversion resistor unit 10 from an analog value to a digital value at a sampling frequency based on an external clock (not shown). The transistor 12 is turned on / off based on a command from the CPU unit 1, and controls whether or not to supply a current to the light emitting unit 9 a of the photoelectric sensor 9. The switch unit 13 turns on and off SW1 and SW2 based on a command from the CPU unit 1, and controls the amount of current flowing to the light emitting unit 9a. The current limiting resistor 14 has resistors Ra, Rb, and Rc connected in parallel, and controls the amount of current flowing to the light emitting unit 9a together with the switch unit 13. The resistance value and the number of resistors of the current limiting resistor 14 are
In consideration of the external environment, the light emitting unit 9a is arbitrarily set within a range not exceeding the rating. Further, instead of connecting the resistors in parallel and changing the combined resistance by the switch unit 13, the resistance value may be changed by using a volume or the like. Further, VCC15 and GND16 are power supply voltages that apply a constant voltage to the ink density detection device 5.

In this embodiment, in the invention described in claim 1, the light emitting portion 9a constitutes a light emitting portion, and the light receiving portion 9b constitutes a light receiving portion. Further, the CPU 1, the current / voltage conversion resistance unit 10 and the A / D converter unit 11 form a sampling unit, and the CPU 1, the switch unit 13 and the current limiting resistance 14 form a control unit. FIG. 2 is a diagram showing marks printed on recording paper by the inkjet recording apparatus of the present invention and sampling directions of the marks.

In FIG. 2, the recording paper 20 is printed on the recording paper 20 by the ink jet recording device 4 and the ink exhaustion determination mark 21.
Will be described as being printed. First, recording paper 2
When sampling 0, the recording paper 20 is conveyed in the recording paper conveyance direction 22. Next, when the sampling start position of the recording paper 20 reaches the reading position of the photoelectric sensor 9,
The CPU unit 1 turns on the transistor 12 to operate the photoelectric sensor 9. Next, the CPU unit 1 samples the output level of the photoelectric sensor 9 based on the sampling frequency. Since the recording paper 20 is conveyed in the recording paper conveyance direction 22, the direction in which the recording paper 20 is sampled is indicated by the arrow 2
As indicated by 3, sampling is performed in the + l direction from the sampling start position.

FIG. 3 is a diagram showing a connection state of the switch section of the ink jet recording apparatus of the present invention. In FIG.
When the connection state is the a state, SW1 of the switch unit
And SW2 are both off,
If the state is b, SW1 of the switch unit is off, S
W2 is in the on state, and when in the c state, both SW1 and SW2 are in the on state.

FIG. 4 is a diagram showing the output level of the photoelectric sensor in each connection state when the connection state of the switch section is defined as in FIG. 3 and the same object is sampled.
Since the combined resistance value of the current limiting resistance unit 14 connected to the light emitting unit 9a differs depending on each connection state, a difference occurs in the amount of current flowing through the light emitting unit 9a, and the amount of light emitted from the light emitting unit 9a, and Differences occur in the amount of light reflected from the recording paper. In addition, as shown in FIG. 4, a low output level is shown at a position where the position of the ink out judgment mark printed by the inkjet recording device 4 is sampled.

FIG. 5 is a diagram showing the relationship between the connection state of the switch section and the voltage ratio of the ink jet recording apparatus of the present invention. In FIG. 5, the voltage ratio (α / β) is the voltage separation ability β
Voltage ratio (α / β) between the average value α of the voltage values (digital values) A / D converted by the A / D converter of the above and the voltage separability β
Is. The connection state represents the connection state of SW1 and SW2 of the switch unit based on FIG.

FIG. 6 is a diagram showing a threshold value table. In FIG. 6, the average value γ is the average of the voltage values when the reflected light from the non-printed portion of the recording paper is quantized. The threshold value is a reference value for determining the non-printed portion and the printed portion of the recording paper. FIG. 7 is a flowchart showing the operation of setting the output level and the threshold value of the photoelectric sensor of the inkjet recording apparatus according to the first embodiment.

The flow chart will be described below with reference to the system configuration diagram shown in FIG. The flowchart corresponds to the invention of claim 1. First, the connection state of the switch unit 13 and the threshold value setting mode are entered (step S1). When the process 1 is entered, the CPU unit 1
Sets the connection state of the switch unit 13 to the a state. Next, the ink density detection unit 5 converts the reflected light from the non-printed portion of the recording paper into a voltage value represented by a digital value, and the CPU unit 1 samples the voltage a prescribed number of times (process S2). Then
The CPU unit 1 uses the average value α (A / A of the sampled voltage values
The average value of the digital values after D conversion) is calculated, and the voltage ratio (α / β) to the resolution β of the A / D converter unit 11 is compared and determined with the predetermined range shown in FIG. 5 (process S3). CPU
The unit 1 sets the connection state of the switch unit 13 based on the determination result (processes S4 to S6).

That is, when the calculated voltage ratio (α / β) is within the predetermined range 1/2 <α / β ≦ 1, the connection state of the switch unit 13 is maintained in the a state. Voltage ratio (α /
β) is in the predetermined range 1/4 <α / β ≤ 1/2,
The connection state is changed to the b state. When the voltage ratio (α / β) is within the predetermined range α / β ≤ 1/4, the connection state is changed to the c state.

After the CPU section 1 sets the connection state of the switch section 13, the ink density detecting section 5 again converts the reflected light from the non-printed portion of the recording paper into a voltage, and the CPU section 1 samples the voltage a prescribed number of times. Yes (process S7). Next, CP
The U unit 1 calculates the average value γ of the sampled voltage values (the average value of the digital values after A / D conversion) (process S8) and stores it in the memory unit 2 as a threshold value table as shown in FIG. A threshold value suitable for the average value γ is selected from the threshold values thus obtained (process S9). Next, the connection state of the switch unit 13 and the selected threshold value are stored in the memory unit 2 (process S10).

The connection state and the threshold value stored in the memory unit 2 in the process S10 are not changed unless the above process is executed again. Further, by changing the connection state according to the voltage ratio (α / β) between the average value α of the voltage values sampled in this way and the voltage separation capability β of the A / D converter unit 11, the photoelectric sensor 9 Since the amount of light emitted from the light emitting section 9a can be adjusted appropriately, the output level of the light receiving section 9b can be maintained at approximately 1/2 <α / β ≦ 1.
The performance of the A / D converter unit 11 can be sufficiently brought out.

As described above, in this embodiment, the output level of the reflected light received by the light receiving section 9b is sampled a predetermined number of times by the CPU 1, and the amount of current supplied to the light emitting section 9b is based on the average value of the sampled output levels. The set/
Since it is changed, the amount of light emitted from the light receiving portion 9b to the recording paper can be corrected to an appropriate amount, the recording paper can be read with an appropriate sensitivity, and the photoelectric sensor has a long life. Can be (Example 2) In this example (corresponding to claim 2), C
The PU1 and the transistor 12 form a current control unit.

FIG. 8 is a flow chart showing the operation selection of the light emitting portion of the photoelectric sensor of the ink jet recording apparatus according to the second embodiment. The flowchart will be described below with reference to the system configuration diagram shown in FIG. First, the CPU unit 1 turns on the transistor 12 after the ink jet recording device 4 prints the ink-out determination mark so that a current flows through the light emitting unit 9a of the photoelectric sensor 9 (process S2).
1). Next, when the ink exhaustion determination mark printed on the recording paper reaches the detection position of the photoelectric sensor 9, the ink density detection unit 5 converts the reflected light from the recording paper into a voltage, and the CPU
Part 1 performs the first sampling. The voltage value sampled for the first time is stored in the memory unit 2 as white data or black data (process S22).

Next, in order to grasp the current number of times of sampling, 1 is added to the number of times of sampling and the nth sampling is performed (step S23). Next, it is determined whether or not the voltage value sampled at the nth time is larger than the white data (process S24). When it is determined that the sampled voltage value is smaller than the white data, it is determined whether the sampled voltage value is smaller than the black data (process S25). If it is determined in step S24 that the sampled voltage value is larger than the white data, the sampled voltage value is stored in the memory unit 2 as white data, and it is determined in step S25 that the sampled voltage value is smaller than the black data. If so, the sampled voltage value is stored in the memory unit 2 as black data (step S26).

On the other hand, if it is determined in step S25 that the sampled voltage value is larger than the black data, or if step S26 is completed, it is determined whether sampling is completed a specified number of times. The sampling is repeated until (process S27). When the sampling is repeated up to the specified number of times, the transistor 12 is turned off to prevent current from flowing through the light emitting section 9a of the photoelectric sensor 9 (step S28), and the white data stored in the memory section 2 is stored. The difference between the black data is obtained, and it is determined whether or not the difference is equal to or more than the threshold value (process S29).
When it is determined that the difference is greater than or equal to the threshold value, the processing of this time is ended, and when it is determined that the difference is less than the threshold value, the display unit 3 is operated and the message of "ink shortage" is output. Then, an alarm is issued (process S30), and the current process is terminated.

As described above, in this embodiment, when the ink end mark printed on the recording paper conveyed in the predetermined direction reaches the first predetermined position, the current is supplied to the light emitting portion 9a and the ink end is reached. When the mark reaches the second predetermined position, the current supply to the light emitting unit 9a is stopped, so that the current can be supplied to the light emitting unit 9a only when the ink end mark is sampled. The power consumption of the photoelectric sensor 9 can be suppressed and the photoelectric sensor 9 can have a long life. (Embodiment 3) In this embodiment (corresponding to claims 3 and 4), the memory unit 2 constitutes an output level storage unit, a threshold value storage unit and an output value storage unit, and the CPU 1 and the head unit 8 are a printing unit. Are configured. Is configured.

FIG. 9 is a flowchart showing the recording operation of the photoelectric sensor sensitivity of the ink jet recording apparatus according to the third embodiment. The flowchart will be described below with reference to the system configuration diagram shown in FIG. First, the operator selects the check mode of the inkjet recording apparatus from an operation input unit (not shown) (step S41). Next, the inkjet recording device 4 prints an ink-out determination mark at a predetermined position on the recording paper, and performs a pre-processing operation for discharging the paper (processing S42). Next, the CPU unit 1 turns on the transistor 12 to allow a current to flow in the light emitting unit 9a of the photoelectric sensor 9 (step S43), and the ink density detecting unit 5 displays the reflected light from the recording paper as a digital value. To a voltage value, and the CPU unit 1 performs the first sampling.
The voltage value sampled for the first time is stored in the memory unit 2 as white data or black data (process S4).
4). Next, in order to grasp the current number of times of sampling, 1 is added to the number of times of sampling and the nth sampling is performed (process S45). The sampled voltage values are stored in the memory unit 2 in time series (process S4).
6). Next, it is determined whether or not the voltage value sampled at the nth time is larger than the white data (process S47). When it is determined that the sampled voltage value is smaller than the white data, it is determined whether the sampled voltage value is larger than the black data (process S48). If it is determined in step S47 that the sampled voltage value is larger than the white data, the sampled voltage value is stored in the memory unit 2 as white data, and it is determined in step S48 that the sampled voltage value is smaller than the black data. If so, the sampled voltage value is stored in the memory unit 2 as black data (step S49).

On the other hand, if it is judged in the process S48 that the black data is smaller than the sampled voltage value, or if the process S49 is ended, it is judged whether or not the sampling is ended a specified number of times, and the specified number of times is reached. Sampling is repeated (process S50). When the sampling is repeated up to the specified number of times, the transistor 12 is turned off to prevent current from flowing through the light emitting unit 9a of the photoelectric sensor 9 (step S51), and then the maximum value stored in the memory unit 2 is stored. The minimum value and the threshold value of the inkjet recording apparatus are printed on the recording paper (process S52), and the voltage values stored in the memory unit 2 are printed in time series on the recording paper (process S53).

FIG. 10 is a diagram showing an embodiment of a graph or the like printed in the flow chart shown in FIG. As described above, in this embodiment, the output levels of the sampled reflected light are stored in time series, and when the output request from the operator is made, the stored sampling values are printed in time series on the recording paper in a graph format. In addition to this, the density of the ink end mark recorded on the recording paper, the threshold value with the white background of the recording paper, and the maximum and minimum output levels of the reflected light sampled are also printed at the same time. Therefore, the state of the inkjet recording device 4 can be easily grasped.

In the first embodiment, when the connection state of the SW is set to the C state, the relationship between the connection state of the switch section of the ink jet recording apparatus and the voltage ratio is as shown in FIG. become. In FIG. 11, the voltage ratio (α /
β) is the average value α of the voltage values (digital values) A / D converted by the A / D converter of the voltage separability β and the voltage separability β
And the voltage ratio (α / β). The connection status is shown in Fig. 3.
3 shows the connection state of SW1 and SW2 of the switch section based on the above.

[0040]

According to the first aspect of the present invention, the output level of the reflected light received by the light receiving section is sampled a predetermined number of times and is supplied to the light emitting section based on the average value of the sampled output levels. Since the amount of current is set / changed, it is possible to correct the amount of light emitted from the light receiving section onto the recording paper to an appropriate amount, and to read the recording paper with an appropriate sensitivity, and to use the photoelectric sensor. It can have a long life.

According to the second aspect of the invention, when the ink end mark printed on the recording paper conveyed in the predetermined direction reaches the first predetermined position, the current is supplied to the light emitting portion and the ink is discharged. When the end mark reaches the second predetermined position, the current supply to the light emitting unit is stopped, so that the current can be supplied to the light emitting unit only when the ink end mark is sampled. The power consumption of the photoelectric sensor can be suppressed and the photoelectric sensor can have a long life.

According to the third aspect of the invention, the output level of the sampled reflected light is stored in time series, and the stored sampling value is printed in time series on the recording paper. The state of the recording device can be easily grasped. According to the invention of claim 4, the density of the ink end mark recorded on the recording paper, the threshold value with the white background of the recording paper, and the maximum and minimum values of the output level of the reflected light sampled are printed. Therefore, it is possible to easily grasp the state of the inkjet recording device.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of an inkjet recording apparatus of an inkjet recording apparatus that is an embodiment of the present invention.

FIG. 2 is a diagram showing marks printed on a recording paper by the inkjet recording device and sampling directions of the marks.

FIG. 3 is a diagram showing a connection state of a switch unit of the inkjet recording apparatus.

FIG. 4 is a diagram showing output levels of photoelectric sensors in respective connected states when the same object is sampled.

FIG. 5 is a diagram showing a relationship between a connection state of a switch section of the inkjet recording apparatus and a voltage ratio.

FIG. 6 is a diagram showing a threshold value table.

FIG. 7 is a flowchart showing an operation of setting an output level and a threshold value of a photoelectric sensor of the inkjet recording apparatus.

FIG. 8 is a flowchart showing an operation selection of a light emitting section of a photoelectric sensor of the inkjet recording apparatus.

FIG. 9 is a flowchart showing a recording operation of photoelectric sensor sensitivity of the inkjet recording apparatus.

FIG. 10 is a diagram showing an example of the printed graph and the like.

FIG. 11 is a diagram showing a relationship between a connection state of a switch section of the inkjet recording apparatus and a voltage ratio.

[Explanation of symbols]

 1 CPU part 2 memory part 3 display part 4 inkjet recording device 5 ink density detection part 6 recording paper motor part 7 head motor part 8 head part 9 photoelectric sensor 9a light emitting part 9b light receiving part 10 current-voltage conversion resistance part (I / V conversion) Resistor part) 11 A / D converter part 12 Transistor 13 Switch part 14 Current limiting resistance part 15 VCC 16 GND 20 Recording paper 21 Ink out judgment mark 22 Recording paper conveyance direction 23 Sampling direction

Claims (4)

[Claims] 1. An ink jet recording apparatus for irradiating an ink end mark printed on a recording paper with light and detecting the presence or absence of ink in an ink cartridge based on the output level of the reflected light. A light emitting unit that emits corresponding light, a light receiving unit that receives the reflected light from the recording paper, a sampling unit that samples the output level of the reflected light received by the light receiving unit a predetermined number of times, and a sampling unit that samples the output level. An inkjet recording apparatus comprising: a control unit that sets / changes an amount of current supplied to the light emitting unit based on an average value of output levels. 2. When the ink end mark printed on the recording paper conveyed in a predetermined direction reaches a first predetermined position,
2. A current control unit for supplying current to the light emitting unit and for stopping supplying current to the light emitting unit when the ink end mark reaches the second predetermined position. Inkjet recording device. 3. An output level storage unit for storing the output level of the reflected light sampled by the sampling unit in time series, and a print for printing the sampling values stored in the output level storage unit on a recording paper in time series. The inkjet recording apparatus according to claim 1 or 2, further comprising: 4. A threshold value storage section for storing a density value of an ink end mark recorded on a recording sheet and a threshold value for a white background portion of the recording sheet, and a maximum output level of reflected light sampled by the sampling section. And a detection unit that detects the minimum value, an output value storage unit that stores the maximum value and the minimum value detected by the detection unit, a threshold value storage unit and a threshold value stored in the output value storage unit,
The inkjet recording apparatus according to claim 1 or 2, further comprising: a printing unit that prints a maximum value and a minimum value.