JP2714515B2 - How to detect the remaining amount of paper tray - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting the remaining amount of a paper tray, and more particularly to a method for detecting the amount of paper in a paper tray such as a copier equipped with a vertically movable paper table using a reflection plate and a photosensor system. The present invention relates to an improvement in a method for detecting a remaining amount.

[0002]

2. Description of the Related Art A reflection plate having a continuous color gradation from dark to light, for example, from black to white, is used to detect the amount of remaining paper in a paper feed tray provided with a vertically movable paper table. Use in a copier, a facsimile, or the like in combination with a sensor system has been conventionally performed as needed and is a known means. Such a conventional paper feed tray is shown in a perspective view of FIG. As shown in FIG. 1, reference numeral 1 denotes a paper feed tray, which is provided with a vertically movable paper table 2, and a reflection type photosensor system 3 is provided at a side end of the paper table 2; It is opposed to the reflector 4 having a series of continuous color gradations from black to white on the lower end side. In FIG. 2, only the reflector 4 is shown in a front view so that the color tone of the reflector 4 can be easily understood. As shown in FIG.
Rises together with the paper table 2, so that the color tone of the reflection plate 4 changes continuously, so that the output of the photosensor system changes linearly, and the change in the paper amount can be detected from the color tone change. Becomes

That is, in FIG. 6, the color tone of the reflection plate and the remaining amount of paper in the paper table 2 correspond to each other, and when the paper is fully filled, the paper table 2 descends to the lower limit and faces each other. The color tone of the reflector is white (WH). On the other hand, when the paper table 2 is emptied after the paper is exhausted, the height rises to the upper limit, and the color tone of the opposing reflector becomes black (BL). At this intermediate stage, the position of the paper table 2 and the corresponding color tone are selected as dark gray (DG), gray (GR), and light gray (LG), and are determined as output signals in the respective photosensor systems 3. For example, based on these outputs,
It is possible to detect the remaining amount of paper in the inside. FIG. 7 is a circuit diagram showing the relationship between the reflection plate 4 and the reflection type photosensor system 3. The reflection type photosensor system 3 is a known means, and includes a light emitting diode D ₁ and a phototransistor Q _{1. The} light emitting diode D ₁ is connected to a power supply P on an anode side and grounded on a cathode side.
Power P is connected to the collector side of the phototransistor Q _1, it is intended for processing the output signal V _out like normal theoretical circuit from the emitter side.

[0004]

At first glance, the above-mentioned means seem to be able to detect the remaining amount of paper easily with fairly high accuracy. However, in practice, there is a problem in practical use, and the accuracy is not necessarily high. There are aspects that cannot be said to be detection means. That is, in the conventional method using the reflection type photosensor system 3,
Assuming that the output level of the sensor is always constant, no contamination or aging of the sensor surface is taken into account. However, in practice, such a situation always occurs, and if these are not taken into account, an error occurs in the detection result. FIG. 8 is a graph illustrating an example of occurrence of such erroneous detection. In the figure, the vertical axis shows the output voltage (V _out ) of the photosensor system 3 and the horizontal axis shows the elapsed time (t). At a certain reference time (t = 0), the remaining amount of paper and the reflection plate 4 are shown. Photo sensor system 3
In which various varied Request residual paper web amounts the relationship between the output voltage V _out of _the. For example, as shown in the figure, _Vout corresponding to black (BL), dark gray (DG), light gray (LG), and white (WH) at time t = 0 is obtained, and then, _Vout of BL and BG is determined. The values of V _out at the middle, the middle between BG and LG, and the middle between LG and WH are S ₁ , S ₂ , and S ₃ , respectively. These values are set as threshold levels (threshold levels). It is used as a guideline such as the level of the remaining amount of paper, so that paper should be supplied. This is necessary as management information especially when a large number of copies are continuously made.

However, the photosensor system 3 generally has deterioration due to aging, and the output voltage _Vout of the BL or the like generally changes with time from the time t = 0. The graph of FIG. 8 shows such a change with time, and these straight lines are not parallel to the time (t) axis. On the other hand, as for the threshold level is initially then be performed setting the S ₁ to S _3, it means that using this value always these lines are parallel to the time (t) axis. Therefore, as shown in FIG. 8, after a certain point in time t, the line of the output voltage and the line of the threshold level cross, and after that point, for example, in the case of FIG.
Actually, even though the BL level, that is, the paper table 2 has reached the upper limit and the paper has already been used up, it is detected as if there is a little paper remaining as far as the threshold level is concerned. Therefore, detection after the above time point is erroneous detection. Other causes that are not necessarily chronological are photosensor system 3
The output voltage may also fluctuate due to surface dirt or the like, which also leads to erroneous detection. Conventionally, in such a case, the threshold level is fixed, so that measures such as adjusting the sensor output with a volume or the like are required each time to cope with this, which is extremely complicated. Therefore, the object of the present invention is to detect the remaining amount of paper in the paper feed tray 1 provided with the elevating paper table 2 using the reflection plate 4 and the photosensor system 3. Provided a paper tray remaining amount detection method that automatically corrects sensor output fluctuations due to deterioration over time or surface contamination, etc., and detects the remaining amount of paper correctly. Is to do.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the gist of the invention is that the remaining amount of paper in a paper feed tray provided with an elevating paper table is provided. Sensor using a reflection plate having a continuous color gradation from dark to light and a reflection type photo sensor system, the photo sensor corresponding to the dark and light color tone of the reflection plate in response to paper replenishment This is a method for detecting the remaining amount of the paper feed tray by automatically dividing the threshold value level between the dark and light tones for the remaining amount of paper from the output level.

[0007]

According to the present invention, when the reflection type photo sensor system 3 and the reflection plate 4 having continuous color gradation are combined to detect the remaining amount of paper in the paper feed tray 1, the paper is filled to its full capacity. The lower limit position of the paper table 2, that is, the output signal of the photo sensor system 3 corresponding to the position of WH on the reflection plate 4, and the upper limit position of the paper table 2 when the paper table 2 is empty, that is, The output signal of the photo sensor system 3 corresponding to the position of BL is input to the central processing unit (CPU) by the reflection plate 4, and the upper and lower output levels stored are divided into several pieces by software to set the threshold level. And automatically set the threshold level in accordance with the output signal each time the output signal of WH changes over time when paper is replenished. Become In, it is possible to avoid erroneous detection of the remaining amount of paper.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit diagram showing an example of means for realizing the method of the present invention. In the figure, 3 has a light emitting diode or known reflective photosensor system equipped with a D ₁ and phototransistor Q _1, continuous color gradation of series from black (BL) to white (WH) The point facing the reflection plate 4 is the same as that of the conventional circuit diagram of FIG. 7 and the configuration of the paper feed tray 1 is the same as that of the conventional example of FIG. are intended to be input to the analog port 7 of the phototransistor output signal V _out from the emitter side of Q ₁ is controlled operating board unit (control PWB) Central provided 5 processing unit (CPU) 6 in the present invention .

As a method of detecting the remaining amount of paper by such means, first, the paper is filled to the full capacity of the paper table 2 and the paper table 2 is moved to the lower limit position, that is, white (WH) on the reflection plate 4. , The output signal V _out of the phototransistor Q ₁ at that time is input to the analog port 7 of the CPU 6 and stored, and then the paper in the paper table 2 is artificially removed for data collection. When the paper in the paper table 2 is emptied and the upper limit position, that is, the color tone of black (BL) at the reflection plate 4 is reached, and stores the output signal V _out of _the phototransistor to Q ₁ when the analog port 7 of the CPU 6. As a result, the sensor output levels at the upper limit (remaining paper amount 0) and the lower limit (paper Full) of the reflection type photosensor system 3 and the reflection plate 4 provided on the paper table 2 are stored in the CPU. Therefore, the remaining amount of paper between the level of the remaining paper amount 0 and Full is within an appropriate range in terms of software (for example, DG, GR,
If the threshold value level is determined by dividing the threshold value into steps such as LG and storing the threshold value level in the CPU, the threshold value becomes paper Full, and each time a new lower limit output signal is input, the lower limit output signal is automatically adjusted so as to correspond to that. By setting a program so as to correct the threshold level value, even if the photo sensor system 3 is deteriorated or stained, the level value is corrected in accordance with the deterioration, and the accurate remaining paper is always obtained. Amount detection becomes possible.

FIG. 2 is a graph showing the relationship between the sensor output voltage _Vout and the time aging t (time-dependent change) when the threshold value is corrected in this manner. In the graph of FIG. 2, the output voltage _Vout is black (BL), dark gray (DG), light gray (LG), and white (WH) for comparison with the case of FIG. ) Shows the same data, but the threshold level is automatically corrected, so that none of S _{1 to} S ₃ intersects the output voltage line. This means that by adopting the method of the present invention, even if the photosensor system 3 deteriorates due to aging, the threshold level is always correctly corrected, and the detection of the remaining amount of paper is always accurate.
It turns out that false detection does not occur.

The procedure of the above-described embodiment of the present invention will be described more specifically based on a flowchart.
First, FIG. 3 illustrates an example in which each output level is initially set. In this simulation, the paper table 2 is moved up and down in order to set a threshold level (threshold level) in the same manner as in the actual copying operation. Is performed. That is, at the start, step 1
The simulation is set in (S-1), and the paper feed tray 1 filled with the paper is mounted in the copying machine in step 2 (S-2). At this point, since the paper table 2 should be Full, it is possible (Yes) to be at the lower limit white (WH) position (Step 3 (S-3)), but has not reached the lower limit (Step 3 (S-3)). In the case of No), the paper feed tray 1 is pulled out again and the amount of paper is checked. If you have reached the lower white (WH) position,
This is set as step 4 (S-4), and the sensor output in this case is set to the lower limit, that is, C is set as the reference value for the sheet Full.
It is input to PU6 and stored.

Next, as described above, the sheet tray 2 is raised in step 5 (S-5) by artificially removing the sheet or using the copying machine as usual. In step 6 (S-6), the paper table 2
Is detected to have reached the upper limit black (BL) position (Yes), and if not reached (No), the paper table 2 is continuously raised. If the sheet table 2 has reached the black (BL) position, this is set as step 7 (S-7), and the sensor output in this case is set to the upper limit, that is, CP is set as the reference value for sheet 0.
Input to U6 and memorize it. After the upper and lower reference values are determined in this way, the threshold value level (threshold level) is set in step 8 (S-8) by dividing the reference value into several steps for each remaining amount of paper in an appropriate range. I do. When the setting is completed, the simulation is canceled in step 9 (S-9), and the entire initial setting ends here.

Next, based on the above initial settings, the threshold level (threshold level) is used at any time during continuous use of the copying machine.
Will be described with reference to the flowchart shown in FIG. First, after starting, step 11 (S-11)
Then, the power is turned on, and copying is started in step 12 (S-12). Copying ends immediately (Yes)
If so, this procedure ends here. However, if copying continues (No), the remaining amount of paper is checked in step 14 (S-14). If the paper is not exhausted (No), copying is continued, but if the paper is exhausted (Yes), since the paper table 2 has been raised to the upper limit black (BL) position, in step 15 (S-15) The sensor output at that time is input to the CPU 6 and stored. Next, replenishment of the sheet 2 is performed in step 16 (S-16). In this case, the sheet table 2 always descends to the lower limit white (WH) position.
At 17), the sensor output at that time is input to the CPU 6 and stored.

The upper and lower sensor outputs serve as sensor reference values until the next paper sheet runs out of the paper tray 2. The threshold value level is set at the time of the initial setting described in the flowchart of FIG. Each time a new upper / lower reference value is set, the program is configured to automatically correct the threshold level value so as to match the new reference value, thereby following the deterioration and dirt of the photosensor system 3. Since the correction is performed, the threshold level (threshold level) is set in step 18 (S-18). Thereafter, as the copying progresses, the paper table 2 rises (step 19 (S-19)), and if the number of sheets has not reached the upper limit, that is, if the remaining amount is 0 (No).
The copying operation is continued and the remaining amount has reached 0 (Ye).
s), wait from step 20 (S-20) (Re
ady) (step 21 (S-21)).
Then, in step 22 (S-22), if copying is to be continued (Yes), step 11 (S-11).
If it is determined that copying is no longer continued (No), the procedure is terminated.

Finally, an example of a specific display means of the remaining amount of paper detected as described above will be described. Now, the points of 3/4, 1/2, and 1/4 of the paper amount are adopted as the threshold value levels from the state where the paper amount is Full to the state of 0, and the output voltage at each position is adopted. V
_out is V _max from the paper amount Full (= 1) to 0,
There are five levels of S ₁ , S ₂ , S ₃ and V _min . In this case, S ₁ is at the sheet amount 3/4, S ₂ is in the paper amounts 1/2, also S ₃ are each threshold level in the paper amounts 1/4, these output V _out is the upper limit The value V _max and the lower limit value V
_{Since min} is obtained by the procedure of FIG. 3 or the like, it is obtained by calculation. That _{S 1 = (V max -V min} ) × 3/4 S 2 = (V max -V min) × 1/2 S 3 = (V max -V min) × 1/4

Therefore, as one of means for immediately recognizing the level of the remaining amount of paper at a glance, for example, a remaining amount indicator having a pilot lamp is provided in front of the control operation board unit (PWB) 5 in FIG. Is valid. That is, FIG. 5 schematically shows the relationship between the above-described five-stage sensor output voltage and the remaining amount of paper and the panel surface of the remaining amount indicator having the corresponding pilot lamps L _{1 to} L ₅ . Under such a configuration, when the sensor output is between V _{max and} S ₁ → L _{1 to} L ₄ are turned on. When the sensor output is between S _{1 and} S ₂ → L _{2 to} L ₄ are lit. When the sensor output is between _{S 2 ~S 3 → L 3 ~L} 4 lights. When the sensor output is between S ₃ ~V _min → L ₄ only lighting. When the sensor output of V _min → L ₅ only lighting. By setting the lighting method of the pilot lamp so as to obtain, the level of the remaining amount of paper can be immediately grasped only by glance at the lighting state of the pilot lamp.

[0017]

According to the present invention, when the photo sensor system detects the remaining amount of paper in a paper feed tray of a copier or the like having a lifting paper platform, the photo sensor system deteriorates due to aging, or Even if the sensor output fluctuates due to surface contamination etc., the sensor output of the threshold value level of the remaining paper level is automatically corrected in accordance with this, and it is possible to always correct and detect the remaining paper level, As in the related art, it is possible to avoid the trouble of adjusting the sensor output using a volume or the like each time, and the effect is unmeasurable.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an example of means for realizing the method of the present invention.

FIG. 2 is a graph showing the relationship between the sensor output voltage and the passage of time in the present invention.

FIG. 3 is a flowchart showing an example of means for initially setting an output level in the method of the present invention.

FIG. 4 is a flowchart showing a procedure of an example of correcting the output level during continuous use of the copying machine in the method of the present invention.

FIG. 5 is a diagram schematically illustrating an example of a relationship between a sensor output voltage and a remaining amount of paper in the method of the present invention, and an example of a panel surface of a remaining amount indicator provided corresponding thereto.

FIG. 6 is a perspective view showing a configuration of a conventional paper feed tray.

FIG. 7 is a circuit diagram showing a relationship between a conventional reflection plate and a reflection type photosensor system.

FIG. 8 is a graph showing the relationship between the sensor output voltage and the passage of time in the related art.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Paper feed tray 2 Paper board 3 Reflection type photo sensor system 4 Reflection plate 5 Control PWB 6 CPU 7 Analog port P Power supply Q ₁ Phototransistor D ₁ Light emitting diode

Claims (1)

(57) [Claims] When detecting the remaining amount of paper in a paper feed tray provided with an elevating paper table using a reflection plate having a continuous color gradation from dark to light and a reflection type photo sensor system,
The output level of the photosensor corresponding to the dark and light colors of the reflector is stored in response to the replenishment of the paper, and the threshold value level between the dark and light colors for the remaining amount of paper is automatically determined from the output level each time. A method for detecting the remaining amount of a sheet feed tray, wherein the method is divided into and determined.