JPH06219599A - Detector of moving medium - Google Patents

Abstract

PURPOSE:To promote the speediness and exactitude of detection by detecting the extent of output voltage in a photointerrupter with a hinge contacting with a moving medium, calculating the actual gradient of an output voltage curve, and comparing it with the setting gradient, then checking the detection operation. CONSTITUTION:When a contact piece is rotated as far as more than a certain angle with a hinge as the center by contact of a moving medium, an output voltage is generated out of a photointerrupter 10. This output voltage is converted into digital data by an analog-to-digital converter 15 at every setting time. In addition, two gradient calculating means 21 and 22 calculate the actual gradient of an output voltage curve with both the digital data at the last time and this time. Hereat these detection operation checking means 21 and 22 compare the calculated actual gradient with the preset setting gradient, and when the actual gradient has cane to more than the setting one, they confirm that the photointerrupter 10 has entered the detection operation. Subsequently, in the case where the actual gradient calculated by these gradient calculating means 21 and 22 has cane to zero, the detection definitive means 21 and 22 detect and confirm that the moving medium arrives at the specified position or runs past.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moving medium detecting device. In particular, it is used to detect the presence / absence of a moving medium that is a transparent printing target used in a printer.

[0002]

2. Description of the Related Art In many cases, it is necessary to detect whether or not a moving medium has reached a predetermined position or has finished passing. As an example of this, a method of detecting a moving medium in a printer is shown in FIG.

In FIG. 6, reference numeral 1 forms a printing portion together with a platen 4 which includes a printing head and is arranged oppositely. The print target medium (moving medium P) is moved in the X direction by the transfer rollers 2 and 3. In such a printer, the moving medium P
In order to detect the cue and the print length at the start of printing, the front end and the rear end of the moving medium P are detected by the detection devices (5, 6) arranged at predetermined positions.

When the moving medium P is an opaque sheet, the reflection type optical detectors 5 and 6 shown by the solid lines in FIG. 6 are used. Alternatively, as shown by a dotted line, a transmissive optical detector in which the light receiver 7 is arranged so as to face is used. However, for example, when printing on a transparent moving medium P for creating a projection material used in an overhead projector, it cannot be accurately detected because of the dynamic range of the detectors 5 and 6.

Therefore, for the transparent moving medium P, the opaque marks M, M shown in FIG. However, this method has a problem that the print effective area Ap is narrowed due to the marks M, M, and the positions where the optical detectors 5, 6 (7, 7) are arranged with respect to the moving marks M, M. It is annoying because it has to be accurate.

Thus, the present applicant has proposed a detection device constructed by using a hinged limit switch 10S shown in FIG. 8 in place of the reflection type or transmission type optical detector. In this limit switch 10S with a hinge, the contact piece 14S rotates about the hinge 13S when the moving medium P abuts, and as a result, the detection piece 12S integrated with the contact piece 14S.
Is configured to turn on the limit switch 11S. In addition, a chattering prevention circuit is provided for more accurate detection.

That is, as shown in FIG. 5 (B), it is confirmed whether or not the limit switch 11S is in the ON state at every set time T, and the detection is confirmed on the condition that the limit switch 11S is in the ON state twice in a row. There is. Therefore, if the time when the leading end or the trailing end of the moving medium P actually reaches the predetermined position or the passage end is set to t1, it is possible to reliably detect with a time delay of at most 2T from the time t1.

[0008]

However, it has been pointed out that the detection device using the hinged limit switch 10S has a large time delay (2T). That is, due to its structure, the set time (sampling time) T
Is about 10 ms. However, when the transfer rollers 2 and 3 are driven by a stepping motor of, for example, 500 μs / step angle in the case where it is used in a printer that requires higher printing speed and higher accuracy, for example, from time t1 to 2T (20 ms). This is because, if the moving medium P is detected with a time delay of, the moving medium P is moved in the X direction by four step angles.

It is an object of the present invention to provide a moving medium detecting device capable of high-speed and accurate detection.

[0010]

SUMMARY OF THE INVENTION A moving medium detecting apparatus according to the present invention includes a hinged photo arranged so that a contact piece rotatable about a hinge can be brought into contact with a moving medium transported in a predetermined direction. An interrupter, an A / D converter that converts the output voltage of the photo interrupter into digital data at every set time, and a slope that calculates the actual slope of the output voltage curve using the converted previous digital data and current digital data. Detecting operation confirmation for comparing the calculating means with the calculated actual inclination and the preset inclination set to confirm that the photointerrupter has entered the detecting operation on condition that the actual inclination is equal to or larger than the preset inclination Means and the moving medium on the condition that the actual inclination calculated by the inclination calculating means after the detecting operation is confirmed by the detecting operation confirming means becomes zero. Detection determining means for determining that it has detected an a detection device of the moving medium consisting comprises a.

[0011]

According to the present invention having the above-mentioned structure, when the contact piece is rotated by a certain angle about the hinge due to the contact of the moving medium, the output voltage is generated from the photo interrupter. Output voltage is hunting, but A / D every set time
Converted to digital data by a converter. Further, the slope calculating means calculates the actual slope of the output voltage curve using both the previous digital data and the current digital data.

Here, the detection operation confirming means compares the calculated actual inclination with a preset setting inclination, and the photointerrupter enters the detection operation on condition that the actual inclination is equal to or larger than the set inclination. Check. When the actual inclination calculated by the inclination calculating means becomes zero (0) after the detection operation is confirmed, the detection confirming means detects and confirms that the moving medium has reached the predetermined position or has finished passing.

Therefore, the analog-digital conversion cycle, that is, the set time in the A / D converter is set to, for example, 10
If it is set to 0 μs, reliable detection can be performed with a time delay of 100 μs or less at the longest. Moreover, even if the set time is made very small, the detection operation confirmation is formed by comparing the actual inclination of the output voltage curve with the set inclination, so that the contact piece is temporarily rotated during the rotation. Even if there is a state where the inclination is actually zero, false detection is not performed.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIGS. 1 and 2, this detection apparatus includes a hinged photo interrupter 10, an A / D converter 15, an inclination calculation means (21, 22), and a detection operation confirmation means (21, 2).
2) and the detection confirming means (21, 22) are provided so that chattering can be prevented, time delay is small, and accurate high-speed detection can be performed. The hinged photo interrupter 10 is assumed to be used in the same printer as the conventional example (FIG. 8), and a pair (10, 10) is provided at each predetermined position on the upstream side and the downstream side of the printing section (1, 4). It consists of 10).

First, the photo interrupter 1 with each hinge
As shown in FIG. 2, the reference numeral 0 designates a contact piece 14 which rotates around a hinge 13, a shield piece 12 integrated with the contact piece 14, and a photocoupler 1.
It consists of 1. The contact piece 14 is shaped so that jamming does not occur. As shown in FIG. 1, each photocoupler 11 is composed of a light emitting element 11D and a light receiving element 11R, and is normally light-isolated by a shielding piece 12 and optically coupled when a contact piece 14 is rotated by a predetermined angle or more. It is formed with one.
Therefore, as shown in FIG. 5A, the output voltage is generated after the time t0 when the moving medium P starts to contact the contact piece 14. However, hunting appears because it is not in the sure detection state. Then, after the time t1, the output voltage becomes a constant predetermined voltage V when it is reliably detected.

Next, the A / D converter 15 converts analog data (output voltage) input from each photo interrupter 10 (11R) into digital data.
The conversion cycle (set time t) shown in FIG. 5A is set to 100 μs in this embodiment. The converted digital data Di-1 and Di are R by the CPU 21.
It is stored in AM23. In addition, this A / D converter 1
5 is shared by each photo interrupter 10.

More specifically, the conversion operation is performed by an A / D interrupt every set time t. The converted digital data, that is, the HEX value, is 00HEX when the moving medium P is not detected as shown in FIG. 3, and is E0HEX when the moving medium P is completely detected because the resistance voltage is divided (FIG. 1). The block selection is performed by the decoder 16. Note that FIG.
The interrupt status in FIG. 4 indicates a status I1 indicating that the upstream hinged photo interrupter 10 is detected, and the downstream hinged photo interrupter 10 is detected.
There are two types of status I2, which indicates that the detection is performed.

By the way, the drive control unit 2 shown in FIG.
Reference numeral 0 includes a CPU 21, a ROM 22, a RAM 23, a keyboard (not shown) and the like, and drives and controls the entire printer. For example, a stepping motor (STM) 26 for rotationally driving the transfer rollers 2 and 3 is connected via a driver 25 and is controlled to be driven in an appropriate amount at an appropriate time. In addition, the above A
The / D converter 15 and the decoder 16 are also connected to the bus.

Here, the inclination calculating means is used when the interrupt status (I1 or I2) is set (see FIG. 4).
ST11) of the previous digital data Di-1 and the current digital data Di-1 converted and stored in the RAM 23.
Is used to calculate the actual slope Ki (K12, K23, K34, K45, K46) of the output voltage curve enlarged and displayed in FIG. 3, which is formed from the CPU 21 and the ROM 22 and is executed in ST12 and 13 of FIG. . Incidentally, since the set time t is constant, the actual slope between the time axis and the time axis in FIG. 3 is obtained as the difference [Di− (Di−1)]. That is, K23 shown by the dotted line is obtained. The actual inclination Ki calculated in this manner is also temporarily stored in the RAM 23 (ST1
2, 13). The set slope k is stored in the ROM 22 as fixed data in advance. However, it can also be implemented by variably inputting it using a keyboard or the like and storing it in the RAM 23.

Next, the detection operation confirming means compares the calculated actual inclination Ki with the set inclination k (ST14 in FIG. 4), and when Ki ≧ k (YES in ST14), the photo interrupter 10 detects the photointerrupter 10. It is a means for confirming that the operation has started, and comprises a CPU 21 and a ROM 22, and ST14, 15
Run on. Upon confirmation, the CPU 21 sets a status to that effect in the RAM 23 (ST15).

That is, the detection operation is confirmed to prevent chattering. However, the set time t shown in FIG.
Is 1/100 of the set time T in the conventional example [(B)]
However, in order to detect at high speed, it is not possible to adopt the method that is required to be in the ON state twice in a row as in the conventional example.
This is because the time t at which actual reliable detection is possible in FIG.
This is because the detection may be confirmed even during the output fluctuation period before 1.

Therefore, in the present invention, the detection operation is confirmed when the rate of change (actual slope Ki) of the output voltage of each photo interrupter 10 becomes equal to or greater than the empirically selected value (set slope k). That is, a method of confirming immediately before the output voltage becomes constant prevents erroneous detection due to chattering.

Therefore, the detection confirming means confirms the detection operation (YES in ST16) and the actual inclination Ki calculated by the inclination calculating means (21, 22) thereafter is zero (0), that is, the output voltage is On condition that it became constant,
The detection of the front end and the rear end of the moving medium P is confirmed. Specifically, it is formed of the CPU 21 and the ROM 22, and is executed in YES in ST17 and ST18. The status of the detection confirmation is set in the RAM 23. At this time, ST
The detection operation confirmation status set in 15 is erased.

In the embodiment having such a structure, the detection operation of the hinged photo interrupter 10 arranged on the upstream side shown in FIG. 2 is performed as follows. The drive control unit 20 rotationally drives the stepping motor 26,
The tip of the moving medium P transferred in the X direction in FIG.
Suppose that it touches 4. In FIG. 5A, the contact is made at time t0.

Then, since the contact piece 14 (shielding piece 12) rotates about the hinge 13, the photocoupler 11 (11) is rotated.
The output voltage is generated from R). This output voltage is in the hunting state until time t1 as shown in FIGS. When the A / D interrupt occurs after the set time t has elapsed, the A / D converter 15 converts the output voltage into digital data Di (ST10 in FIG. 4). If the interrupt statuses I1 and I2 are not set (OFF),
The digital data Di is stored in the RAM 23 (S
T19).

Here, if the interrupt status I1 is set, the inclination calculating means (21, 22) operates to calculate the actual inclination Ki (ST12). Subsequently, the detection operation confirming means (21, 22) compares the calculated actual inclination Ki with the preset inclination k (ST1).
4). Ki <k at the beginning (NO judgment in ST14), and the detection operation has not been confirmed yet (ST16).
No.), the current digital data (Di) is used as the previous digital data (Di-1) for the RAM2.
3 is stored (ST19). And it is returned.

After that, if YES is determined in ST14, the detecting operation confirming means (21, 22) confirms the detecting operation (ST15). That is, the A / D converter 15
Although the output voltage of 1 is in the hunting state, it is predicted that the hinged photo interrupter 10 will surely detect the moving medium P soon.

Thus, the detection operation was confirmed (S
When the actual inclination Ki calculated by the inclination calculating means (21, 22) becomes zero (0) after (YES in T16) (YES in ST17), the detection confirming means (21, 22) causes the moving medium P to move.
Is determined to be the predetermined position (ST18).

According to this embodiment, however, the photo interrupter 10 with hinge, the A / D converter 15, the inclination calculating means (21, 22) and the detecting operation confirming means (21, 2).
2) and the detection confirmation means (21, 22) are provided, and the actual slope Ki of the output voltage of the A / D converter 15 is compared with the preset slope k to set the actual slope Ki.
The condition is that the above is satisfied, and after that, the actual slope Ki
Since the detection of the moving medium P is determined when is zero (0), erroneous detection during hunting is prevented regardless of whether the moving medium P is transparent or opaque. At the same time, the moving medium P can be detected reliably and quickly at the predetermined position.

Further, the detection operation state of the photo interrupter 10 can be confirmed at every conversion period (t) of the A / D converter 15, and the actual inclination Ki can be used to prevent hunting and give advance notice of reliable detection. Therefore, if the set time t is set to, for example, 100 μs, the detection can be confirmed with a time delay of 100 μs at the longest from the reliable detection time t1 due to the physical engagement between the photo interrupter 10 and the moving medium P. Therefore, the conventional example (Fig. 8)
It is possible to detect at least 100 times faster than the above case.

Further, since the set time t and the set slope k can be variably set, it is possible to operate in accordance with various conditions such as the characteristics of the photo interrupter 10 and the shape of the contact piece 14, and the applicability is wide.

Further, the set time t can be converted at a high speed of 100.
Since it can be set to μs or less, it is sufficient to provide one A / D converter 15 for both font interrupters 10 and 10, and the cost can be reduced.

[0033]

According to the present invention, a photo interrupter with a hinge, an A / D converter, a slope calculating means, a detection operation confirming means, and a detection confirming means are provided, and the actual slope of the output voltage of the A / D converter is preset. It is configured to determine the detection of the moving medium when the actual inclination becomes equal to or more than the set inclination and the actual inclination becomes zero (0) after that by comparing the set inclination that has been set. Whether the moving medium is transparent or opaque, the moving medium P can be reliably and quickly detected at a predetermined position while preventing erroneous detection during hunting.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a diagram for explaining a transfer direction of a moving medium and an arrangement positional relationship of photo interrupters.

FIG. 3 is a diagram for explaining the relationship between converted digital data and its actual inclination in the same manner.

FIG. 4 is likewise a flowchart for explaining the operation.

FIG. 5 is also a diagram for explaining the relationship between the output voltage waveform and the set time in comparison with the conventional example.

FIG. 6 is a diagram for explaining a conventional example (reflection type).

FIG. 7 is also a diagram for explaining the problem.

FIG. 8 is a diagram for explaining a conventional example (limit switch type with hinge).

[Explanation of symbols]

1 Printing Section 2, 3 Transfer Roller 4 Platen 5, 6 Reflection Type Detection Device 7 Transmission Type Detection Device 10S Limit Switch with Hinge 10 Photointerrupter with Hinge 11 Photocoupler 12 Blocking Piece 13 Hinge 14 Contact Piece 15 A / D Converter 16 Decoder 20 Drive control board 21 CPU (tilt calculation means, detection operation confirmation means, detection confirmation means) 22 ROM (tilt calculation means, detection operation confirmation means, detection confirmation means) 23 RAM P Moving medium t Set time Di-1 Previous digital Data Di Current digital data Ki Actual slope k Set slope

Claims (1)

[Claims] 1. A photo interrupter with a hinge, in which a contact piece rotatable about a hinge is arranged so as to be in contact with a moving medium transported in a predetermined direction, and an output voltage of the photo interrupter is digitalized every set time. An A / D converter for converting into data, a slope calculating means for calculating the actual slope of the output voltage curve using the converted previous digital data and this time digital data, and the calculated actual slope and preset settings. The detection operation confirming means for confirming that the photointerrupter has started the detection operation on the condition that the actual inclination is equal to or larger than the set inclination and the detection operation is confirmed by the detection operation confirming means. A detection confirming means for confirming that the moving medium is detected on condition that the actual inclination calculated by the inclination calculating means becomes zero. Detecting device that transfer medium.