JP2003307976A - Medium detector, control method therefor, and image formation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a medium detector capable of entering an adjustment mode at an appropriate timing matched with using environment and conditions, etc., evading jamming without lowering the performance of a job as much as possible and improving reliability by an appropriate processing, and to provide its control method and an image formation device. <P>SOLUTION: By a microcomputer 8, the presence/absence of a medium is detected from the output of a light receiving element 2 when the light emitting element 1 of an optical sensor arranged inside the image formation device is made to emit light. At the time, the light quantity of the light emitting element 1 is controlled, the number of times of detecting the medium by the optical sensor is counted, and also the setting of the input voltage of the optical sensor is changed corresponding to the reduction value of an output voltage by the light quantity decline of the optical sensor. The number of detectable media is predicted from the reduction value of the output voltage of the optical sensor and the counted value, and the adjustment timing of changing the setting of the input voltage of the optical sensor is decided on the basis of the predicted number. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a medium detection device for detecting the presence / absence of a medium by an optical sensor, a control method therefor, and an image forming apparatus.

[0002]

2. Description of the Related Art FIG. 8 is a sectional view showing the overall construction of a general image forming apparatus, and here shows a schematic internal construction of an electrophotographic copying machine (laser printer).

In FIG. 1, reference numeral 100 denotes a main body of a copying machine (image forming apparatus), which has an automatic document feeder 101 for feeding a document to an exposure position on the upper part thereof, and a document table glass 102 as a document placing means. Has been done.

The original placed on the original table glass 102 is illuminated by a light source 104 in a scanner unit 103, and the reflected light passes through mirrors 105, 106, 107 and a lens 108 and a photoelectric conversion element 109 such as a CCD. And is converted into an image signal. Then, the laser light from the laser device 110 modulated by this image signal is applied to the photosensitive drum 113 via the polygon mirror 111 and the mirror 112, whereby the photosensitive drum 113 is exposed and a latent image is formed. Around the photosensitive drum 113, a primary charging device 114, a developing device 115, a toner image transfer portion 116 and a separation portion 117, and a cleaner 118 are arranged.

A medium (recording medium) 120 housed in a paper feed cassette 119 is placed below the copying machine main body 100. The medium 120 loaded in the paper feed cassette 119 is usually paper (paper), but there are some that can use a so-called OHP film for an overhead projector depending on the device.

Next, the copying operation will be described.

The media 12 loaded in the paper feed cassette 119
0 is sent out by the pickup roller 121,
The sheets are separated into one sheet by the separation sheet feeding rollers 122 and 123 and fed to the conveyance path 124. Then, the registration rollers 127 are conveyed by the respective conveyance rollers 125 and 126 to the registration rollers 127, and the registration rollers 127 operate when other conditions such as an optical system are satisfied.

On the other hand, the image formed on the photosensitive drum 113 is transferred onto the medium 120 by the transfer section 116 as described above, separated by the separating section 117 so as not to wind around the photosensitive drum 113, and sent to the conveying belt 128. Be done.
Then, it is conveyed to the fixing roller 129 and the pressure roller 130, where it is heat-fixed, and then the sheet discharge roller 1
It is discharged outside the machine by 31, 132.

When performing a double-sided copying operation, the flapper 133 does not discharge the sheet from the machine, but sends it to the double-sided conveying unit below. That is, the reversing roller 1
When 34 rotates and feeds the medium 120 in the A direction and reaches the reversing unit 135, the reversing roller 134 reversely rotates and conveys the medium 120 in the B direction. As a result, the medium 120 passes through the double-sided transport path 136 and passes through the registration roller 1
It is transported to 27.

Here, in the process in which the medium 120 passes through each of the above-mentioned transport paths, the sensors 141, 142,
Pass through 143, 144, 145, 146, 147.
Thus, by always detecting the current position of the medium 120, it is determined whether or not the medium 120 is normally conveyed, and the registration roller 127 and the flapper 133 are controlled.

Various sensors are used to detect the position of the medium 120. An example of a typical detection sensor will be described below.

FIG. 9 is a sectional view showing the structure of a conventional mechanical detection lever type detection sensor. In this sensor, the lever 51 is arranged so as to block the paper path, and when a part of the lever 51 is pushed by the leading end of the medium 120 passing through the paper path, the lever 51 rotates right in the figure, and near the lever 51. The configuration is such that a signal is emitted by blocking the luminous flux of the arranged photocoupler 52 (a signal generating portion is not shown).

Next, a recent optical sensor will be described. This optical sensor is roughly classified into two types, a reflection type optical sensor shown in FIG. 10 and a transmission type optical sensor shown in FIG.

The reflection type optical sensor shown in FIG.
A reflection sheet 31 is attached on the transport path, and when there is no medium 120, the light receiving element 2 receives the irradiation light of the light emitting element 1,
When the medium 120 is present, the presence or absence of the medium 120 is detected by blocking the irradiation light.

However, in the case of this reflection type optical sensor, the medium itself promotes reflection, which may cause erroneous detection as shown in FIG. 10 (b). For this reason, the accuracy of the medium carrying portion is required so that the medium position does not vary. Further, the diffused light of the light emitting element 1 may receive the light reflected by the medium 120 to cause erroneous detection. Therefore, in some cases, it is necessary to prevent the erroneous detection with a condenser lens or the like.

Further, in the transmission type optical sensor shown in FIG. 11, the light emitting element 1 and the light receiving element 2 are arranged to face each other with the medium conveying path interposed therebetween, and the irradiation light of the light emitting element 1 is crossed by the medium 120. The presence or absence of the medium 120 is detected. In this case, it is possible to prevent the medium itself from promoting reflection, but accuracy of the relative position between the light emitting side and the light receiving side is required.

Therefore, as a supplement to the above requirements, a refraction type optical sensor as shown in FIG. 12 has been put into practical use. In this optical sensor, the optical axes of the light emitting element 1 and the light receiving element 2 are refracted by a reflector such as a mirror or a prism so that the irradiation optical axis of the light emitting element 1 and the incident optical axis of the light receiving element 2 become parallel. It is configured in.

In the case of this configuration, the light emitting element 1 and the light receiving element 2
Even if the position shift occurs, the incident light and the reflected light are always parallel to each other, so that the allowable range of accuracy can be widened and the influence of medium reflection can be reduced.

That is, the optical sensor 10 shown in FIG.
(A), the light emitting element 1 and the light receiving element 2 are mounted in the sealed case 12 on the same substrate 11, and the light emitted from the light emitting element 1 is reflected by the reflecting surface 15 of the prism 14 as a reflector. , 16 is refracted twice at an incident angle of 45 degrees and returns to the light receiving element 2. Then, as shown in FIG. 12B, the medium 120 is provided between the lower transport guide 17 and the upper transport guide 18.
The irradiation light is blocked by the crossing, so that the presence or absence of the medium 120 can be detected.

Here, in the above-mentioned optical sensor system, the light emitting element has a higher brightness as a current is passed therethrough, and a large dynamic range depending on the presence or absence of the medium can be obtained, so that the reliability of the detection accuracy is improved. However, increasing the current value leads to a reduction in life. Also in the case of mechanical type, it can be said that it is optical type in terms of using a photo coupler, but in this case, by arranging the light emitting / receiving element at a short distance, and by shielding with a black member that does not affect the reflection, It is possible to reliably detect even a small amount of light. On the other hand, in the optical sensor method, since the medium itself to be shielded has a high transmittance and a high reflectance, it is required to secure a light amount that can be reliably discriminated.

Therefore, when the amount of light is set low, it is advantageous for the life, but since the dynamic range is narrowed, the influence of the medium and the influence of dirt become large, and there is a risk of false detection. There is. For this,
With the optical sensor method, adjustment must be performed at the initial stage.

Further, even if the initial adjustment is performed, the light emitting portion or the light receiving portion may be contaminated by the paper dust or the like at the time of passing the paper. Therefore, the interval according to the speed of the image forming apparatus and the light quantity reduction degree according to the specification / application is set. It is necessary to make adjustments at regular intervals so that the dynamic range can be kept constant by increasing the amount of light. By this sequence, it is possible to achieve both the securing of the dynamic range and the long-term maintenance-free maintenance of the optical sensor until just before reaching the unadjustable state.

A conventional adjustment method will be described with reference to FIG. FIG. 13 is a diagram showing an input / output characteristic at the time of adjustment in the conventional example, where Vin represents an applied voltage to the light emitting element of the optical sensor, and increasing the applied voltage also increases the light amount. Further, Vout indicates a value obtained by converting the light amount when the light receiving element of the optical sensor receives the irradiation light into a voltage.

The graph shown in FIG. 13 (a) is a factory adjustment mode that is performed during production in a factory.

When a predetermined voltage Vi1 is applied to the light emitting element and the value output from the light receiving element through the voltage conversion circuit is equal to or higher than the preset Vh, the adjustment is completed. Since A1 in FIG. 13A is already Vh or more when Vi1 is input, it is determined that the adjustment is unnecessary and the adjustment ends. Vh at this time
Is an output voltage that is determined to have no problem in determining the medium in consideration of a reduction in the amount of light, and is set in advance according to the characteristics of the image forming apparatus. Vs is a threshold voltage, and if Vs or more, the irradiation light is received as it is, so it is determined that there is no medium, and if Vs or less, it is determined that there is a medium because the irradiation light is interrupted.

Further, in the case of B1 in FIG. 13A, that is, when it is below Vh, Vin is increased from Vi1 until a voltage above Vh is obtained, and when it is above Vh, then Vin value of is set as the control voltage,
Finish the adjustment. In (a) of FIG. 13, the characteristic at the time of Vi1 is the point of B1, which is Vh or less, so the input voltage is increased, and when it is increased to Vi2, it exceeds Vh, so it is set to operate at the point of B2. To be done. FIG. 13 (a)
In the case where the characteristic at the time of inputting Vi1 is C1, even if the adjustment to increase Vin from Vi1 is performed until a voltage equal to or higher than Vh is reached, VinMAX which is the upper limit on the input side is reached, and Vh Never exceeds. In this case, it is treated as a defective product.

The graph shown in FIG. 13B is a user adjustment mode that is performed for each job or when the power is turned off / on.

When the user actually starts using the device, even if a voltage of Vi1 which is the initial setting value is applied, the amount of light decreases from the initial amount due to dirt such as paper dust and toner, as shown in FIG.
As shown in FIG. 3B, a level below Vh, that is, A1
To A2 output. When it further decreases and becomes equal to or lower than the threshold value Vs, it becomes impossible to determine the presence or absence of the medium, and the operation is stopped. Therefore, regular adjustments have to be made.

At this time, when the output of A2 is obtained as described above, Vin is increased from Vi1 as in the initial adjustment, and when it becomes Vh or more, the Vin value at that time is set and changed as the control voltage. , Adjustment is completed. In FIG. 13B, A3 is the operation point after adjustment. Figure 1
In the case of B3 of 3 (b), VinM which is the upper limit on the input side is VinM even if the adjustment to increase Vin from Vi2 is performed.
It never reaches AX and the output does not exceed Vh. In the case of B4 in (b) of FIG. 13, the adherence of dirt is already severe and the life of the device is approaching. Therefore, when Vs is reached, control becomes impossible.

However, if the adjustment is performed frequently for each job or the like, as shown in (c) of FIG. 13, the line becomes close to a straight line that always maintains Vh, and even if Vin increases to points D and E. If the light amount returns by cleaning due to service maintenance, the Vin value returns to the vicinity of the point A1. Then, the operation of increasing Vin due to dirt is repeated again, and eventually the Vin value returned by cleaning due to service maintenance due to element deterioration or the like gradually becomes closer to VinMAX, and the life of the element is completed.

[0031]

However, even if the above-mentioned adjustment is performed, there are variations in both the light emitting element and the light receiving element, and when considered as variations in the light amount, there are variations in the emission amount of the light emitting element. Since it is affected by both the variation in the amount of light received by the light receiving element, the variation is considerably large, and in order to achieve long-term maintenance-free operation, the variation in the amount of light due to the variation in both elements may cause a decrease in the maintenance interval or the life of the element. It will have a big impact.

Although the maximum rating of the element itself has been determined, the upper limit value for control has a margin from the maximum rating in consideration of the temperature rise during actual use and environmental factors, as described with reference to FIG. By the way, it is decided as VinMAX. Therefore, the larger the distance from point A1 to point F in FIG. 13C, the wider the control range and the longer maintenance can be realized. However, when the adjustment that requires a considerable amount of light is performed at the initial adjustment stage due to the above-mentioned variation, for example, when the point E in FIG. The difference becomes small and the light amount adjustment range becomes narrow.
For this reason, when slight stains due to aging occur or when the light amount decreases due to element deterioration, adjustment becomes impossible immediately, which causes erroneous detection, and maintenance is immediately required.

Further, even if the light quantity is lowered due to the installation adjustment error, the adjustment can be made by increasing the current value to increase the light quantity, so that the installation adjustment error is recovered, and VinMAX is the same as above. And the control range is narrowed. For this reason,
There has been a problem that a slight stain due to a change with time causes an erroneous detection.

As described above, in the case of an optical sensor, the amount of light is reduced due to stains due to aging, especially the accumulation of paper powder, which causes an indiscernible situation. Normally, however, such as power ON / OFF. By adjusting at the timing and raising the input voltage (increasing the emitted light amount) by the amount of the reduced light amount, it is possible to avoid the situation where the light cannot be easily discriminated.

However, particularly in a recent network environment as shown in FIG. 7, since the power is always on due to a large amount of copying at night, reception of a facsimile (fax), etc., adjustment at power on / off is required. There is a fear of not. Even if adjustment settings are made between jobs, jobs may continue due to the above-described network printing, FAX, copy, and other complex operations. As a workaround for this, there is a method of using a counter inside the main body to stop the operation for each predetermined number of sheets and forcibly enter the adjustment mode.

FIG. 14 shows the input / output characteristic (characteristic curve) in the forced adjustment mode.

In FIG. 14A, for example, A is initially set.
If the setting is made at the point of L, the amount of light decreases due to dirt such as paper dust even when the voltage of Via is applied, and the output drops to the voltage of Vo2. At this time, if the predetermined number has been reached, adjustment is performed. After adjusting to CL,
Adjustment is made again in DL, and EL is set.

However, the amount of paper powder varies depending on the type of paper and the environment. For example, if the type of paper is changed, the amount of paper powder increases rapidly and the amount of light decreases to FL. If the predetermined number is reached in FL, adjustment is performed and the input voltage is raised to GL. In the case of FIG. 14 (a), the environment is relatively low humidity with relatively little paper dust, and adjustment is performed even in a state where the light amount does not drop so much.

FIG. 14B shows a case where a high humidity environment is assumed, and the amount of light decreases from the AH point of the initial adjustment due to paper dust stains due to the passing of paper, and the adjustment is performed at the BH point when the predetermined number of sheets is reached. Is performed. At this time, the input voltage is Via
→ Vic and becomes CH point.

As can be seen from the graphs of FIGS. 14 (a) and 14 (b), the reduction amount of the light amount greatly differs depending on the difference in environmental conditions. However, if the light quantity becomes lower than VoA, a jam will be immediately caused, and thus the predetermined number of sheets should be set in advance so that the light quantity does not decrease to VoA under any environment. Further, when not only the environment but also various parameters such as the type of medium and the detection margin are taken into consideration, the predetermined number of sheets set in advance tends to be a small numerical value.

On the other hand, in an environment in which the conditions are relatively good as shown in FIG. 14 (a), adjustments are made more than necessary. That is, although a large number of sheets can be passed until the amount of light required to be adjusted, the operation is stopped for each predetermined number of sheets and the adjustment mode is forcibly entered, so that the job performance deteriorates. It will be.

The present invention has been made in view of the above problems, and it is possible to enter the adjustment mode at an appropriate timing according to the operating environment and conditions, without degrading the performance of the job as much as possible. Moreover, it is an object of the present invention to provide a medium detection device, a control method therefor, and an image forming device that can avoid jams and that have improved reliability by appropriate processing.

[0043]

A medium detecting device according to the present invention has an optical sensor composed of a light emitting element and a light receiving element, and detects the output of the light receiving element when the light emitting element of the optical sensor is made to emit light. A medium detection device for detecting the presence or absence of a medium, the control means adjusting the input voltage of the optical sensor to control the light amount of the light emitting element, and the counter means for counting the number of times the optical sensor detects the medium. Comparing means for comparing a predetermined set voltage with the output voltage of the optical sensor, calculating means for calculating an input voltage applied to the optical sensor according to the comparison result, and the optical system based on the set voltage. When the output voltage of the sensor is low, the output voltage of the optical sensor is lower than the output voltage of the optical sensor from the count value of the counter means until the output voltage of the optical sensor is reduced from the set voltage. It has a second calculating means for calculating a count value until the voltage is reduced to a constant voltage, and a judging means for judging whether or not the count value of the counter means has reached the calculated value of the second calculating means. The operation mode is changed according to the judgment result of the judgment means.

Further, there is provided a medium detecting device having an optical sensor comprising a light emitting element and a light receiving element, and detecting the presence or absence of a medium from the output of the light receiving element when the light emitting element of the optical sensor is caused to emit light. The optical sensor includes a control unit that adjusts the input voltage of the optical sensor to control the light amount of the light emitting element, and a counter unit that counts the number of times the optical sensor detects the medium. The setting of the input voltage of the optical sensor is changed in accordance with the reduction value of, and the number of media that can be detected is predicted from the reduction value of the output voltage of the optical sensor and the count value of the counter means, and the prediction is performed. The adjustment timing for changing the setting of the input voltage of the optical sensor is determined based on the number of sheets.

The optical sensor is a pair of photodetectors in which the irradiation optical axis of the light emitting element and the incident optical axis of the light receiving element are refracted by the reflecting means so as to be parallel on the same plane. It was done like this.

Further, the reflecting means is a prism.

Further, the reflecting means is a reflecting plate.

The medium is a recording medium used in the image forming apparatus.

Further, the image forming apparatus has a network connection means for communicating with an external device, and notifies the external device of information relating to medium detection through the network connection means.

The method of controlling the medium detecting device according to the present invention is as follows.
A method of controlling a medium detection device, comprising: an optical sensor including a light emitting element and a light receiving element, wherein the presence or absence of a medium is detected from the output of the light receiving element when the light emitting element of the optical sensor is caused to emit light. The light amount of the light emitting element is controlled by adjusting the input voltage of the optical sensor, the number of times the medium is detected by the optical sensor is counted, and a predetermined set voltage is compared with the output voltage of the optical sensor, and the comparison is made. The input voltage applied to the optical sensor is calculated according to the result, and when the output voltage of the optical sensor is lower than the set voltage, the count until the output voltage of the optical sensor is reduced from the set voltage From the value, a count value until the set voltage lower than the output voltage of the optical sensor is reduced is calculated, and it is determined whether or not the count value reaches the calculated value. It is obtained so as to change the operation mode according to results.

A method of controlling a medium detecting device having an optical sensor comprising a light emitting element and a light receiving element and detecting the presence or absence of a medium from the output of the light receiving element when the light emitting element of the optical sensor is made to emit light. There, the input voltage of the optical sensor is adjusted to control the light amount of the light emitting element, and the number of times of detection of the medium by the optical sensor is counted,
The number of media that can be detected from the reduced value of the output voltage of the optical sensor and the count value by changing the setting of the input voltage of the optical sensor according to the reduced value of the output voltage due to the decrease of the light amount of the optical sensor. And the adjustment timing for changing the setting of the input voltage of the optical sensor is determined based on the predicted number.

Further, the information relating to the medium detection is notified to the external device via the network connecting means.

An image forming apparatus according to the present invention includes the above-mentioned medium detecting device.

[0054]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will now be described in detail with reference to the drawings. It should be noted that the same reference numerals are given to the constituent elements common to the respective drawings for description.

FIG. 1 is a diagram showing a circuit configuration of a medium detecting device according to the present invention, which is used by being attached to the image forming apparatus shown in FIG.

In the figure, 1 is a light emitting element such as an LED (light emitting diode) on the light emitting side, and 2 is a light receiving element such as a PD (photodiode) on the light receiving side, and these constitute an optical sensor. . 3, 4 are operational amplifiers (operational amplifiers), 5 are comparators (comparators), 6 are D / A converters (digital-analog converters), 7 are A / Ds.
A converter (analog-digital converter) 8 is a microcomputer (microcomputer) that controls the whole.

The microcomputer 8 constitutes control means for detecting the presence or absence of the medium 120 from the output of the light receiving element 2 when the light emitting element 1 emits light, and adjusting the amount of light emitted from the light emitting element 1, and the control means. Then, a calculation unit is configured to calculate the remaining number of the medium 120, the presence / absence of which can be determined by the determination unit based on the result of adjusting the amount of light emitted from the light emitting element 1.

Specifically, the control means adjusts the voltage applied to the light emitting element 1 to adjust the amount of light emitted from the light emitting element 1, and the computing section optically adjusts by the control means. The number of media 120 passing through the sensor, the voltage applied to the light emitting element 1 before adjustment by the control means,
Based on the voltage applied to the light emitting element 1 after the adjustment by the control means, the remaining number of the medium 120 whose presence can be discriminated by the discrimination means is calculated.

Further, a counter means for counting the number of times the optical sensor detects the medium by the microcomputer 8, a comparison means for comparing a predetermined set voltage with the output voltage of the optical sensor, and the above-mentioned comparison result according to the comparison result. Calculation means for calculating an input voltage applied to the optical sensor, and counter means for decreasing the output voltage of the optical sensor from the set voltage when the output voltage of the optical sensor is lower than the set voltage. Second calculating means for calculating a count value from the count value until the set voltage is lower than the output voltage of the optical sensor, and the count value of the counter means reaches the calculated value of the second calculating means. And a determination unit that determines whether or not the operation mode is changed according to the determination result of the determination unit.

Further, the setting of the input voltage of the optical sensor is changed according to the reduced value of the output voltage due to the decrease of the light amount of the optical sensor, and the reduced value of the output voltage of the optical sensor and the count value of the counter means are used. The number of detectable media is predicted, and the adjustment timing for changing the setting of the input voltage of the optical sensor is determined based on the predicted number.

In FIG. 1, Q1 is a transistor for turning the light emitting element 1 on and off, and D1.
1, D2 are diodes, and R1 to R13 are resistors.

Next, the medium detecting operation of this embodiment will be described in detail with reference to FIG.

When a predetermined digital voltage signal is sent from the microcomputer 8 to the D / A converter 6, the D / A converter 6 converts the digital signal of the microcomputer 8 into a voltage. This voltage is converted into a constant current output for driving the light emitting element 1 by the operational amplifier 3, the transistor Q1 is turned on by this current, and the light emitting element 1 is lit with a predetermined current.

Here, the structure of the light emission / light reception / prism of the optical sensor in this embodiment is the same as that shown in FIG. 12, and the irradiation light from the light emitting element 1 returns to the light receiving element 2 via the prism 14. . The light receiving element 2 is composed of a phototransistor. When light of a predetermined wavelength is received, a current flows and a voltage is generated across the light receiving element 2. This voltage is amplified to a predetermined range width by the operational amplifier 4.

When the paper is being passed, the received light is blocked and no current flows through the light receiving element 2. Therefore, the operational amplifier 4
Output is 0V. If there is no paper, the irradiation light of the light emitting element 1 is received and an output voltage proportional to a predetermined light amount can be obtained. Therefore, the comparator 5 outputs the output of the operational amplifier 4 to the H level at the predetermined voltage set by the resistors R10 and R11.
The binary value of (high) / L (low) can be used and the presence or absence of paper can be determined by the microcomputer 8.

Further, the output of the operational amplifier 4 is divided into two systems and the like and is also sent to the A / D converter 7. As a result, the output of the operational amplifier 4 when the voltage signal is output to the D / A converter 6 during monitoring is monitored, and the output of the operational amplifier 4 that is most suitable for the determination in the comparator 5 is obtained to the D / A converter 6. Determine the output value of.

For example, if there is no paper, the light emitted from the light emitting element 1 is sent to the light receiving element 2 via the prism 14, and the light receiving element 2 generates a predetermined voltage equal to or higher than the slice level, and this voltage is applied to the comparator 5. At H level, microcomputer 8
Is output and it is determined that there is no paper. If you have paper,
Since the irradiation light is blocked by the medium 120, the light path to the light receiving element 2 is blocked, and the comparator 5 outputs the L level to the microcomputer 8 to determine that there is paper.

Although the present embodiment has the D / A converter 6 and the A / D converter 7, it goes without saying that a microcomputer having a built-in type may be used. Also, the presence / absence of the medium is judged by binarizing using the comparator 5.
You may make it judge from the output of the converter 7.

FIG. 2 is a view showing the external arrangement of the above-mentioned medium detecting device. (A) of the figure is a side view seen from the side, (b)
3A is a perspective view seen from the direction of arrow C in FIG. 3A, and FIG. 3C is a side view when the sealed case 12 is removed.

As shown in FIG. 2, a sealed case 12 is provided on the main body 10 of the medium detecting device.
The prism 14 shown in FIG. The sealed case 12 is made of synthetic resin or the like capable of blocking light and has a slit for transmitting light. In the sealed case 12, the light emitting element 1 and the light receiving element 2 are provided on the substrate 11 as shown in FIG.

The hermetically sealed case 12 itself has notches (not shown), and is lightly locked in such a manner that the protrusions sneak into the lower part of the substrate 11 when it is inserted to a predetermined position, and is mounted. There is. Also mounted on the body 10 is a connector 13 made of synthetic resin and a part of the circuit shown in FIG.

Further, as shown in FIG. 2, the hermetically sealed case 12 is attached to a position which is in contact with the lower conveyance guide 17 or is as close as possible to the lower conveyance guide 17. A prism 14 is attached to the upper conveyance guide 18, a reflecting surface 15 thereof faces the light emitting element 1 in the sealed case 12, and a reflecting surface 16 faces the light receiving element 2.

The reflecting surface 15 reflects the light emitted from the light emitting element 1 in the sealed case 12 inside the prism 14, and the reflecting surface 16 reflects the light reflected by the reflecting surface 15 (reflected light) again. It is sent to the light receiving element 2 in the sealed case 12. The irradiation light and the reflection light extend in a direction intersecting with the surface of the medium 120, and the reflection surfaces 15 and 16 have a structure inclined at a predetermined angle to reflect the irradiation light in a predetermined direction. Has become.

Although not particularly shown, the sealed case 12
By making the light emission transmitting portion of the convex lens shape, the irradiation light from the light emitting element 1 is refracted and condensed. in this case,
Since the light quantity can enter the light receiving element 2 without being attenuated,
It is valid.

FIG. 3 is a diagram showing input / output characteristics during adjustment. Next, the Vin-Vout characteristic curve will be described. Vin is a voltage applied to the light emitting element 1 of the sensor, and Vout is a value obtained by converting the amount of light when the light receiving element 2 of the sensor receives the irradiation light into a voltage.

When Vi1 is applied to the light emitting element 1, the light receiving element 2 outputs Vo1 via the voltage conversion circuit. Also,
When Vi2 having a relation of Vi2> Vi1 is applied, Vo2
Is output. Similarly, when the voltage is applied in the relationship of Vi (n + 1)> Vin, the increase of the input voltage directly increases the light amount, and the output also increases accordingly. However, the microcomputer 8, the A / D converter 7, etc. In order to protect the input of the control section, the voltage is prevented from exceeding a certain voltage by a diode clamp using the diode D2.

Next, the initial adjustment operation of the optical sensor used in this embodiment will be described with reference to the circuit diagram of FIG. 1, the input / output characteristic diagram of FIG. 3 and the flowchart of FIG. The control process shown in the flowchart of FIG. 4 and the flowchart of FIG. 5 described later is executed by the microcomputer 8 of FIG. 1 according to a program stored in advance.

In S101, when the light amount adjustment start command is input, the initial adjustment operation is executed. At this time, although not particularly shown, the input from the operation unit may be used, or the configuration may be such that it is automatically started when the power is turned on. First, after resetting the counter N to 1 in S102, a predetermined digital signal corresponding to Vi1 is output from the microcomputer 8 in S103 to cause the light emitting element 1 of the circuit of FIG. 1 to emit light.

Then, in S104, the value of the A / D converter 7, which has converted the amount of light received by the light receiving element 2 into a voltage value, is read. The value of Vi1 is a value defined by the light amount variation MAX. Therefore, if the VM has already reached the VM at Vi1 in S105, it is judged to be NG because it is too bright and there is a risk of erroneous detection due to medium reflection.
A message such as "Please replace parts" is displayed on the display unit (display means) provided in the image forming apparatus. When the exchange is completed in S113, the process returns to S102.

On the other hand, if the VM is not reached at Vi1 described above, the microcomputer 8 stores the input voltage value in the built-in storage unit in S106. That is, Vi in FIG.
The output value Vo1 when 1 is input is stored. This storage unit does not have to be included in the microcomputer 8 and may be an accessible external element. Then, the counter is incremented by 1 in S107, and the preset value is set to 1 in S108.
It is determined whether output / input has been performed 0 times.

In the present embodiment, as shown in FIG. 3A, it is set to 10 times up to Vi10. This number is obtained by dividing the signal output from the microcomputer 8 in advance within a certain range. , 8 divisions, 16 divisions can be set freely. However, the higher the number of times, the higher the accuracy, but it takes time. Further, since Vi10 is a MIN whose machine specification is acceptable, setting is performed according to the specification.

If the number of times has not reached 10 times in S108, the process returns from S102 to S103 again, and the microcomputer 8 outputs a predetermined digital signal. At this time, the previous input Vi
Input Vi2 which is increased from 1 by a predetermined amount. And
The voltage is applied in the relationship of Vi (N + 1)> ViN. Here, MIN Vi1 to MAX is obtained by the above 10 division.
Enter up to Vi10.

Next, when the routine from S103 to S108 is completed 10 times, the process proceeds to S109, and it is determined whether or not the preset voltage value is reached. The voltage value set here is the maximum value VM of Vout, and the medium 120
That is, the irradiation light that can fully recognize the presence or absence of light is received. Then, if it reaches the preset voltage value, it is determined to be OK, and Vo1 to Vo10 are determined in S110.
Is the Vin value when the amount of change becomes 0
At the point where Vo (n + 1) -Von = 0, the smallest Vin value is set as the control value, "OK display" is performed in S111, and the adjustment is completed.

In FIG. 3A, the saturation voltage VM is reached when Vi8 is input, and VM is always obtained even if a voltage of Vi8 or higher is applied. Since the amount of change is 0, Vi8 is applied. If it does, it will function sufficiently as a sensor. Therefore, Vi8 is set as a control value by factory adjustment.

On the other hand, if VM has not been reached in S109, that is, if the preset voltage value VM has not been reached as shown in FIG. 3B, it is judged as NG and S1
At 14, the NG display such as "Please check the parts and installation" is displayed on the display. At this time, the determination display is performed sequentially or collectively as soon as the adjustment is completed. And S11
When the confirmation or the action is performed in 5 and the repair is completed, the adjustment from S102 and S103 is started again.

Here, if the result in S105 is NG, the amount of light is too high, so it can be limited to a defective part.
In the case of NG, the light quantity on the light emitting side / light receiving side is insufficient, so there is a possibility of dirt attachment / attachment error / part defect. Then, both of them are returned to S102 after the treatment, and adjustment is performed.

The range from Vi1 to Vi10 is set according to the characteristics of the mounting location. For example, if the area is easily contaminated, the output M can be reduced by setting Vi10 to a lower value.
The adjustment range up to AX can be widened, and the maintenance interval can be extended.

Next, the main operation of this embodiment will be described with reference to the flowchart of FIG. 5 and the input / output characteristic diagram (Vin-Vout characteristic curve) of FIG.

When the user actually starts the use, the amount of light is lower than the initial amount even if the input voltage set as the initial setting value is applied due to dirt such as paper dust and toner.

That is, as shown in FIG. 6, as the lowest input voltage at which VM is obtained, ViN is set in the initial setting state.
Since 1 is set as the input voltage and VM is output in this state, it is at point A. However, as mentioned above,
When ViN1 is input due to a change over time, the voltage is reduced from A to B, that is, the output voltage is reduced from VM to VoN1.
When it further decreases and falls below the threshold value, it becomes impossible to determine the presence or absence of the medium 120, and the medium does not operate. Therefore, regular adjustments have to be made.

Therefore, in the present embodiment, the processing shown in the flowchart of FIG. 5 is performed. Here, in FIG. 6, it is assumed that the output is lowered from the previously set A to B due to dirt such as paper dust and toner, and the adjustment is performed at the point B.

When the power is turned on in S201, S2
Light intensity adjustment starts at 02. Then, in step S203, ViN is input to the sensor, and in step S204, the output VoN1 is read.

Subsequently, in S205, the number of sheets from the output voltage reduction value to the voltage at which it becomes impossible to determine the presence or absence of the medium 120 is calculated. At this time, when N sheets are passed, the VM is V
Since it has decreased to oN1, the prediction of the number n of VMs that decreases to VoA from that ratio is calculated as (VM-VoA) / (VM
-VoN1) * N = n.

For example, if the VM is 10V and the ViN1 is 9V and the number of sheets passed during this period is 10,000, it means that the light amount attenuation of 1V is caused by passing 10,000 sheets. If is 5V, 10,000 sheets x (10V
-5V) / (10V-1V) = 50,000 sheets, and when the number of sheets passed from the adjusted VM is n = 50,000 sheets, VoA is reached, and the medium 12
It can be predicted that the presence or absence of 0 cannot be determined.

The value of n is a target value for performing the next adjustment after the adjustment, which is stored in the storage unit (not shown) and is updated at the same time as it is calculated in S205.

Next, in S206, the setting of the input voltage value is changed by adjustment. At this time, since it is sufficient to increase the input applied voltage ViN by the ratio of the output VoN1 when the output voltage MAX is reduced by VM due to contamination, V
M ÷ VoN1 × ViN1 = ViN2, and the input voltage increases by the reduced ratio. V in this S206
If the relationship of inMAX> ViN2 is established, S20
7, the input applied voltage value is set to ViN2, and the output V
Make M available. As a result, in FIG.
It means that the setting has been changed from point to C point.

Further, in S206, VM ÷ VoN1 ×
When ViN1> VinMAX, the microcomputer 8
Will not be able to output more than VinMAX. Therefore, the input applied voltage value is set to VinMAX in S208, and the adjustment ends in S209.

Next, since the adjustment is completed in S207, the counter value N is reset to 1 in S210, and S
At 211, a standby state is entered.

Thereafter, the copy start in S212, S21
Copy end in 3, set the counter value in S214,
Counting up is performed for each copy until the counter values are compared in S215, the job is interrupted when the n value calculated in S205 is reached, and the process returns to S202 to start the light amount adjustment.

Then, in step S216, the contents of the above-mentioned light amount adjustment are notified to the external host computer by the communication means, and the processing is ended.

As described above, the predicted number of sheets until the presence / absence of the medium 120 cannot be determined is calculated, and the counter setting for determining the next adjustment timing is updated after the adjustment. Therefore, when the job cannot be continuously entered in the adjustment mode. , The adjustment mode is forcibly entered at an appropriate timing according to the usage environment and conditions, and the job performance is minimally affected.

Further, in the case of having a network means, it is possible to make a notification by remote control. FIG. 7 is a block diagram when connected to the network 20.
21f are image forming apparatuses of the present embodiment having a communication means with the host computer 22 which is an external apparatus, and 23 is a network server.

Then, the network connection means and the host computer 22 connected to the network connection means
With the above, by reporting the predicted value to the manager / service person via the network connection means, appropriate processing can be performed and a jam can be avoided.

As described above, in this embodiment, the adjustment mode can be entered at an appropriate timing according to the use environment and conditions, and the jam performance can be avoided without degrading the job performance as much as possible. Moreover, the reliability is improved by proper processing.

[0105]

As described above, according to the present invention, it is possible to enter the adjustment mode at an appropriate timing that suits the use environment and conditions, and to avoid jams without degrading job performance as much as possible. It can be avoided, and the reliability can be improved by appropriate processing.

[Brief description of drawings]

FIG. 1 is a diagram showing a circuit configuration of a medium detection device according to the present invention.

FIG. 2 is a diagram showing an external configuration of a medium detection device according to an embodiment.

FIG. 3 is a diagram showing input / output characteristics at the time of adjustment according to the embodiment.

FIG. 4 is a flowchart showing an operation at the time of adjustment of the embodiment.

FIG. 5 is a flowchart showing the main operation of the embodiment.

FIG. 6 is a diagram showing an input / output characteristic during a main operation of the embodiment.

FIG. 7 is a diagram showing a configuration connected to a network.

FIG. 8 is a sectional view showing the overall configuration of the image forming apparatus.

FIG. 9 is a cross-sectional view showing the configuration of a conventional mechanical detection sensor.

FIG. 10 is a cross-sectional view showing the configuration of a reflective photosensor.

FIG. 11 is a sectional view showing the structure of a transmissive optical sensor.

FIG. 12 is a cross-sectional view showing a configuration of a refraction type optical sensor.

FIG. 13 is a diagram showing input / output characteristics during adjustment in a conventional example.

FIG. 14 is a diagram showing input / output characteristics in a forced adjustment mode of a conventional example.

[Explanation of symbols]

1 Light emitting element 2 Light receiving element 3 operational amplifier (operational amplifier) 4 operational amplifier (operational amplifier) 5 comparator 6 D / A converter 7 A / D converter 8 Microcomputer 10 body 11 board 12 sealed case 14 Prism 20 networks 21a image forming apparatus 21b image forming apparatus 21c image forming apparatus 21d image forming apparatus 21e image forming apparatus 21f image forming apparatus 22 Host computer (external device) 100 Copier (image forming apparatus) body 113 photosensitive drum 120 media 141 sensor 142 sensor 143 sensor 144 sensor 145 sensor 146 sensor 147 sensor

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H04N 1/00 108 H04N 1/00 108H F term (reference) 2H027 DA45 DC07 DC09 DC18 DE02 DE07 ED16 HA03 HA13 HB09 2H072 AA32 AB07 BA03 BA12 BA20 CA01 CA02 CA05 CB09 3F048 AA01 AA02 AB01 BA05 BB03 BB08 BC04 BC08 BD07 BD08 CA05 CB03 CC01 DA06 DB11 DB16 DB19 DC13 DC14 5C062 AA05 AA13 AA35 AB08 AB32 AB38 AB42 AC11 AC34 AC66 AE08

Claims (11)

[Claims] 1. A medium detection device having an optical sensor including a light emitting element and a light receiving element, and detecting the presence or absence of a medium from the output of the light receiving element when the light emitting element of the optical sensor is caused to emit light. Control means for adjusting the input voltage of the optical sensor to control the light quantity of the light emitting element, counter means for counting the number of times of detection of the medium by the optical sensor, predetermined set voltage and output of the optical sensor Comparing means for comparing the voltages, calculating means for calculating an input voltage applied to the optical sensor according to the comparison result, and when the output voltage of the optical sensor is lower than the set voltage, from the set voltage From the count value of the counter means until the output voltage of the optical sensor is reduced, the count value until the set voltage lower than the output voltage of the optical sensor is calculated A second calculating means and a judging means for judging whether or not the count value of the counter means has reached the calculated value of the second calculating means, and operates according to the judgment result of the judging means. A medium detection device characterized by changing modes. 2. A medium detecting device having an optical sensor including a light emitting element and a light receiving element, and detecting the presence or absence of a medium from the output of the light receiving element when the light emitting element of the optical sensor is made to emit light. The optical sensor includes a control unit that adjusts the input voltage of the optical sensor to control the light amount of the light emitting element, and a counter unit that counts the number of times the optical sensor detects the medium. The setting of the input voltage of the optical sensor is changed in accordance with the reduction value of, and the number of media that can be detected is predicted from the reduction value of the output voltage of the optical sensor and the count value of the counter means, and the prediction is performed. A medium detection device, wherein an adjustment timing for changing the setting of the input voltage of the optical sensor is determined based on the number of sheets. 3. The optical sensor is a pair of photodetectors in which an irradiation optical axis of a light emitting element and an incident optical axis of a light receiving element are refracted by a reflecting means so as to be parallel on the same plane. The medium detection device according to claim 1 or 2, characterized in that. 4. The medium detecting device according to claim 3, wherein the reflecting means is a prism. 5. The medium detecting device according to claim 3, wherein the reflecting means is a reflecting plate. 6. The medium detecting device according to claim 1, wherein the medium is a recording medium used in an image forming apparatus. 7. The image forming apparatus according to claim 6, further comprising a network connection unit for communicating with an external device, and notifying information related to medium detection to the external device via the network connection unit. Media detection device. 8. A method of controlling a medium detecting device, comprising an optical sensor comprising a light emitting element and a light receiving element, and detecting the presence or absence of a medium from the output of the light receiving element when the light emitting element of the optical sensor is made to emit light. There, the input voltage of the optical sensor is adjusted to control the light amount of the light emitting element, and the number of times of detection of the medium by the optical sensor is counted, and a predetermined set voltage and the output voltage of the optical sensor are set. Compare, calculate the input voltage applied to the optical sensor according to the comparison result, when the output voltage of the optical sensor is lower than the set voltage, from the set voltage to the output voltage of the optical sensor From the count value until it is reduced, the count value until it is reduced to a set voltage lower than the output voltage of the optical sensor is calculated, and it is determined whether the count value has reached the calculated value. And, a control method of a medium detecting device is characterized in that so as to change the operation mode according to the determination result. 9. A method of controlling a medium detecting device, comprising an optical sensor comprising a light emitting element and a light receiving element, and detecting the presence or absence of a medium from the output of the light receiving element when the light emitting element of the optical sensor is made to emit light. There, the input voltage of the optical sensor is adjusted to control the light amount of the light emitting element, and the number of times of detection of the medium by the optical sensor is counted, and a reduction value of the output voltage due to a decrease in the light amount of the optical sensor. According to the setting of the input voltage of the optical sensor, predict the number of media that can be detected from the reduction value of the output voltage of the optical sensor and the count value, the optical type based on the predicted number A method for controlling a medium detection device, characterized in that adjustment timing for changing the setting of the input voltage of the sensor is determined. 10. The method for controlling a medium detecting device according to claim 1, wherein the information related to the medium detection is notified to an external device via a network connecting means. 11. An image forming apparatus comprising the medium detecting device according to claim 1.