JPH07112851A - Device for detecting folding of sheet - Google Patents

Abstract

PURPOSE:To facilitate the detection of presence of a folded sheet running on a processing device by detecting folding of a sheet in synchronization with the feed of the sheet in a sheet feed part of the sheet processing device with the use of timing detecting means and feed value detecting means. CONSTITUTION:A folding detecting device comprises four folding detecting means 1 to 4 are adapted to detect detection marks or the like put a sheet at corners thereof, timing detecting means 2 for detecting the timing of feeding a sheet, means 4 for detecting a feed value of sheets, determining means 4 receiving output signals from the folding detecting means, the timing detecting means and the feed value detecting means, signal input means 5 for converting these signals into digital data, computing and processing means 6 for determining the presence of a folded sheet in accordance with the digital data, and signal output means 7 for delivering an output signal 8 to, for example, a control device in a printer, in accordance with the result of the determination. Accordingly, the printer is stopped if the folding of the sheet is determined.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing machine such as an offset printing machine, a paper processing machine such as an embossing machine, a folding machine, or a folding of a sheet corner that occurs when sheets are loaded or unloaded in an inspection process, a transportation process, or the like. The present invention relates to a paper fold detection device that detects paper.

[0002]

2. Description of the Related Art The printing paper used in a sheet-fed printing machine is usually packaged in units of about 100 to 1,000 sheets, and when printing, the operator of the printing machine unpacks the packaging and the feeder of the printing machine. It is piled up on the elevator of the department and piled up to the size of about 1,000 to 10,000 sheets. Further, the printed matter that has been printed is taken out from the paper discharge unit of the printing machine for further printing, or proceeds to a paper processing machine or other steps, and at that time, paper loading / unloading work is also performed. As a result of the paper being handled by such loading and unloading work, the paper may be folded. In particular, folding is likely to occur at the corners of the paper.

If the sheet is processed in the next step while such folding is caused, a processing failure occurs. In that case, it may be sufficient to remove defective products in the inspection process, but printing may have to be redone. For example, if a serial number is printed on a cash voucher or the like, removing a defective product will leave a series of serial numbers open.
You must reprint and replenish so that there is no empty space.

As a conventional method for inspecting the folding of the sheet corners, a method of counting the number of stacked sheets by a sheet counting device is used. This sheet counting device counts the corners of the stacked sheets while feeding them one by one.
If the results of counting the two corners have the same count value, it is determined that the corner of the sheet is not folded.

[0005]

According to this conventional method, when the same number of sheet corners are folded at the four corners of the sheet, the result of counting the four corners of the sheet becomes the same count value. Therefore, strictly speaking, there is a possibility of making a judgment error. Also, when it is determined that there is a fold of the paper corner, it is not easy to find and remove the fold paper from the stacked paper, and inspect each one in a visual inspection process by a person,
It was necessary to go through a process with a heavy work load. Further, it may not be necessary to simply remove the folded paper, and it may be necessary to redo printing or the like as described above. Therefore, the problem to be solved by the present invention is to inspect whether there is a fold in the sheet corner immediately before processing the sheet with a serial number printing machine or the like, and if there is a fold in the sheet corner, process the sheet. An object of the present invention is to provide a folding inspection device that can remove the paper without performing the operation.

[0006]

The above object can be achieved by the present invention described below. That is, at least fold detection means for detecting the folding of the paper, timing detection means for detecting the feeding timing of the paper, feed amount detection means for detecting the feeding amount of the paper, and folding from the output of the folding detection means. This is achieved by a paper fold detection device having a determination means for determining the presence or absence of

[0007]

According to the paper folding detecting apparatus of the present invention, it has the timing detecting means and the feed amount detecting means, and detects the folding of the paper synchronized with the feeding of the paper in the paper feeding section (feeder section) of the paper processing apparatus. Therefore, it is possible to detect whether or not the paper sheet traveling on the processing device is folded.

[0008]

EXAMPLES Next, preferred embodiments of the present invention will be described with reference to examples. FIG. 1 is a block diagram of a paper fold detection device of the present invention. In FIG. 1, reference numeral 1 denotes a fold detecting means for detecting a fold of a sheet, and four fold detecting means (1) to (4) are provided so that four corners of the sheet can be detected.
It is composed of (4). Reference numeral 2 is a timing detection means for detecting the paper feed timing, and 3 is a feed amount detection means for detecting the paper feed amount. Each of the folding detecting means 1, the timing detecting means 2, and the feed amount detecting means 3 are connected to the determining means 4 shown in FIG.

The determination means 4 is further composed of signal input means 5 in detail, operation processing means 6 and signal output means 7. The signals output from the folding detection unit 1, the timing detection unit 2, and the feed amount detection unit 3 are input to the determination unit 4 by the signal input unit 5. The signal taken into the judging means 4 is converted into digital data of a unified format by the signal inputting means 5 even if the form is different (contact signal, current signal, etc.) by each means. The digital data is subjected to calculation in the calculation processing means 6, and it is judged whether or not there is a paper break, and the judgment result is output from the signal output means 7 as an output signal 8 shown. The output signal 8 is connected to the control device of the printing press so as to operate in parallel with, for example, a stop switch of the printing press, and is configured and used to stop the printing press when it is determined that there is a paper break.

FIG. 2 is a diagram in which the sheet folding detecting device of the present invention is installed in a sheet-fed offset printing machine, and in particular, the layout of sensors is shown. In FIG. 2, 9 is a sheet, 10 is an elevator, and has a function of lifting the uppermost portion of the stacked sheets 9 to a predetermined height. Reference numeral 11 is a soccer, which sucks the uppermost sheet 9 by a vacuum suction device and has a function of feeding the sheet 9 toward the printing unit of the printing machine. The fed paper 9 is a roll 12 which is continuously driven.
Then, it is sandwiched between the rollers 13 that press and roll the roll 12, and it is further transferred. Immediately in front of the roll 12 and the roller 13, there is a contact mechanism called a front aligning piece (not shown), which works so as to set the timing for feeding the paper 9 to the roll 12 and the roller 13. Then, the sheets 9 that are sequentially sent out are stacked and transported while being offset and overlapped. Further, the roll 12 is driven by the drive roll 15 via the belt 14, and the paper 9 is placed on the belt 14 and is transported on the feeder board 16.
Such a sheet feeding device is called a stream feeder.

In FIG. 2, 17 is a swing and 18 is a swing.
Is a plate cylinder, 19 is a blanket cylinder, and 20 is an impression cylinder. The sheet 9 to be transferred hits an abutting mechanism called a front pad (not shown) located immediately before the swing 17 so that the position in the transfer direction (vertical direction) is regulated and stopped, and further a moving mechanism called a needle (not shown) The position in the left-right direction is restricted. In this state, the sheet 9 is gripped by the claws of the swing 17 and is carried to the impression cylinder 20, and is gripped by the claws of the impression cylinder 20 and wound around the impression cylinder 20 for printing.

Further, in FIG. 2, reference numeral 21 is a timing plate, which is a metal disk mounted on the shaft of the impression cylinder 20, and a concave portion or a convex portion is formed on a part of the outer periphery of the impression cylinder to form an impression cylinder. The rotation angle of 20 can be detected by the timing detection means 2. Further, reference numeral 1 is a fold detection means, which is installed near the roller 13 on the belt 14 which holds the sheet 9. This is to reduce the detection error due to floating of the paper. Of course, the installation position of the folding detection unit is adjusted to the position where the folding occurs, and within that restriction, the installation position can be selected and the mounting position of the roller 13 can be changed.

FIG. 3 is a view of FIG. 2 seen from above. In FIG. 3, a gear 22 is fixed to the shaft of the drive roll 15. The gear 22 is driven by the main drive unit of the main body of the printing machine, and is configured so that timing with printing can be taken. Reference numeral 23 is a frame of the feeder section of the printing press. Reference numeral 24 is a ball, which is on the belt 14 and has a role of suppressing the flapping of the paper. Reference numeral 3 is a feed amount detecting means attached to the shaft of the roll 12.

As the folding detecting means 1 that can be used in the present invention, an optical detector having a light emitting and receiving device such as an optical fiber sensor for detecting the difference in optical reflectance between the front and back of the paper 1 and a feeder board. A non-contact type capacitance detector for detecting that the height of the sheet 9 on the sheet 16 is different at the folded portion, or a change in the height of the sheet 9 is converted into a change of the roller 13 for pressing the sheet 9, and It may be any type of detector such as an eddy current type detector that detects a non-contact type change, a differential transformer type detector that detects a transition type, a potentiometer type detector, and the like.

Among them, an optical fiber sensor is particularly preferable, and it is easy to handle, can be installed in a narrow place, is inexpensive, and is reliable. Even when the difference in reflectance between the front surface and the back surface of the sheet 9 is small, it can be usually detected from the change in the reflection angle due to folding. However, as a method for further increasing the reliability, for example, as shown in FIG. 6, a detection mark is printed on the corner of the paper, and the reflectance of this detection mark and the reflectance of the back surface of the paper 9 are combined. The difference can be large.

The difference in optical reflectance between when a fold is generated and when it is normal is determined by the installation position of the detection means, the size of the fold, the presence or absence of printing, the difference between the front and back sides of the paper, and the overlapped position below. It consists of various factors such as the reflectance at the detection position of the paper to be used, but the change in the paper reflectance is normal when there is no fold and the change when the fold occurs compared to that Is usually extremely large, and can be detected from the magnitude of the change.

By the way, in the case of a normal printed matter, a color patch for color tone management, a register mark for alignment of multicolor overprinting, a peripheral portion of the paper, etc. Is included in the center). Peripheral portions and the like of these sheets are removed by cutting or the like in the printed matter as the final product. Therefore, the above-described detection mark can be treated in the same manner as these color patches and register marks, and can be printed on a portion near the corner of the paper and not left on the printed matter of the final product.

As described above, since the peripheral portion of the sheet is removed by cutting or the like, even if there is a slight fold that is removed, the product is not defective and it is necessary to detect this with the sheet fold detection device. There is no sex. On the other hand, it is desirable to detect with high sensitivity a fold that causes a product defect. Therefore, the preferable position and size of the detection mark are set. The position of the detection mark is a position that is removed by cutting or the like, and a position closer to the periphery of the cutting is more preferable than a position closer to the periphery of the sheet. The size of the detection mark is preferably larger than the detection area of the optical detection means. The reason is that the position on the detection mark, which is detected due to a paper transport error or the like, changes within the error range each time it is detected, but is not easily affected by the error. In this case, it is obvious that a small detection area is advantageous for highly sensitively detecting a fold that causes a product defect, and an optical sensor having a small detection area is suitable as the detection means. Further, the color and density of the detection mark are set in consideration of the large difference in reflectance from the back surface of the paper.

The timing detecting means 2 that can be used in the present invention may be any detector as long as it can detect the concave portion (or convex portion) of the timing plate 21. For example, an optical detector having a light emitting / receiving device, a timing plate 2
Capacitance type detector, eddy current type detector or non-contact type differential transformer type detector, potentiometer type detection which detects that the height of 1 is different in concave (or convex) by non-contact type Any type of detector may be used. Of these, particularly preferred are eddy current detectors that are non-contact, durable, and resistant to oil stains and the like.

The folding detecting means 1 and the timing detecting means 2 are usually composed of a sensor head section and a sensor amplifying section. The sensor amplifying section amplifies the output of the sensor head section and compares the set value with the magnitude. The comparison result is output as a digital signal. The set value is usually determined by turning the dial attached to the sensor amplifying section to determine its rotation angle.

As the feed amount detecting means 3 which can be used in the present invention, a rotary encoder can be used. A rotary encoder mainly outputs a code data corresponding to a rotation angle for measuring a rotation angle, and one rotation mainly for measuring a rotation amount is equally divided into a predetermined number of pulses per rotation, for example, Fifty
There is a type that outputs 0 to 10000 pulses. In the present invention, both can be used, but the former needs to decode the code data, but the latter is more suitable because it can be converted into the feed amount by only counting the number of pulses without decoding. Further, a mechanism having the same function can be made and used without being a so-called rotary encoder.

In the present embodiment, the rotary encoder is attached to the rotary shaft of the roll 12 as described above, but it is also attached to a portion driven in synchronization with the main drive shaft of another printing press. be able to. In addition to the pulse output described above, the normal rotary encoder has a pulse output terminal that outputs one pulse when the rotary shaft of the rotary encoder rotates and passes a predetermined angle. When such a rotary encoder is attached to the rotary shaft of the impression cylinder 20, the output of the one pulse can be used as the timing detection pulse. With such a configuration, the timing detecting unit 2 and the feed amount detecting unit 3 can be formed by one rotary encoder.

Usually, a rotary encoder comprises a detector attached to the rotary shaft and an amplifier which amplifies the signal output by the detector, shapes the waveform, and outputs the amplified signal. To count more,
Some have a calculation function of converting the count value and outputting or displaying it. Although any type can be used in the present invention, the simplest example of using a rotary encoder of the type which outputs a pulse is shown.

Now, the operation of the paper break detecting device of the present invention having the above-mentioned structure will be described. FIG. 4 is a timing chart showing the output of each detecting means of the paper fold detection device of the present invention and the process of paper fold detection. In FIG. 4, the timing detecting means 2 outputs a pulse at a fixed mechanical operation position only once in the cycle each time the printing machine prints on the individual sheets 1. In FIG. 4, a shows the pulse waveform. In this example, this output is negative logic, indicating that the pulse is low in a predetermined mechanical operating position. Among the edges of this pulse waveform a, by capturing the trailing edge of the pulse shown in FIG. 4, "a predetermined mechanical operation position is detected",
That is, the timing is detected.

In FIG. 4, b is a pulse waveform output from the feed amount detecting means 3. When the trailing edge of the pulse indicated by is captured, the trailing edge of the pulse waveform b at the first trailing edge is captured, and this portion is set as the starting point for pulse counting. That is, the counting device is cleared at this falling portion and the count value becomes zero, and the count value becomes 1 at the trailing edge of the next pulse.
Then, the count value becomes count 2 at the trailing edge of the next pulse, and the count value is incremented each time the trailing edge of the pulse is captured.

In FIG. 4, c, d, e and f are pulse waveforms output from the folding detecting means (1), (2), (3) and (4). This output is a negative logic, and when it is high, there is no folding, and when it is low, there is a folding, which is formally shown. The form is shown because Low means a necessary condition with a fold.

The levels of the pulse waveform c and the pulse waveform d are captured at the trailing edge of the pulse waveform b where the count value is the count n. The count value becomes the count n when the installation positions of the folding detection means (1) and the folding detection means (2) coincide with the positions of the left and right corners of the front (top) of the fed sheet. And n is a value set to do so. Similarly, the pulse waveform b whose count value is the count m
The levels of the pulse waveform e and the pulse waveform f are captured at the trailing edge indicated by. The count value becomes the count m at the timing when the installation positions of the folding detection unit (3) and the folding detection unit (4) coincide with the positions of the left and right corners of the rear (ground) of the sheet, m is a value set to do so. Here is the position of the corner
It is assumed to include the entire periphery of four corners (strictly speaking, points) of the sheet 1 capable of detecting a corner break.

The pulse waveform c captured in this way,
d, e, and f are shown in FIG. In FIG.
,,, the level of each pulse waveform is High
Therefore, this indicates that the paper 1 has no paper fold. In each pulse waveform, at a portion other than ,, in FIG.
Or High can be seen, but since these are not the timings for catching the level, the paper break detection apparatus of the present invention operates so as to be ignored. The fold detection means becomes High not only when the fold is not detected,
This is because there is disturbance or the like when the print pattern on the paper 9 is detected or the detection mark at the corner of the paper which should not be detected is detected. One of the features of the present invention is to eliminate the erroneous determination caused by such a situation.

In FIG. 4, g, h, i, and j are pulse waveforms output by the folding detection means (1), (2), (3), and (4). It is a pulse waveform when inspected by the paper folding inspection apparatus of the invention. As shown in the timing of capturing the level in FIG. 4, the pulse waveform i
Since the level of is low, it indicates that there is a fold in the right corner of the rear (ground) of the sheet 1. As described above, when low is detected even at one place in the pulse waveforms g, h, i, and j at the timing of capturing the level, it is determined that the sheet has a sheet break, and the determination result is output by the sheet break detection device. .

Next, the operation of the judging means 4 will be described with reference to the flow chart of the paper break detection process shown in FIG. This processing is mainly performed by the arithmetic processing means 6 of the determination means 4.
First, in step S1, it is determined whether the timing detection unit 2 has detected the feed timing of the sheet 1.
If the feed timing is not detected, the monitoring state continues until the feed timing is detected. Then, the timing detection unit 2 detects the feed timing, outputs the detection result, and when the determination unit 4 receives it, the counter of the determination unit 4 is cleared and the count value is set to zero in the next step S2. The counter of the determination means 4 counts the pulses corresponding to the feed amount of the paper 1 output by the feed amount detection means 3.

The count value is obtained in step S3.
It is compared with a preset value n. And step S5
Fold detection means 1 when the count value becomes n in
The data of (1) and (2) are taken into the judging means 4.
Similarly, the count value is compared with a preset value m in step S4. Then, the folding detection means 1 when the count value becomes m in step S6
(3) The data of the detection means 1 (4) is taken into the determination means 4.

The above-mentioned four data taken into the judging means 4 are High or Low. High in this example
Means no folding, and Low means folding. Since there should be no fold at one place, if there is at least one Low, the determination means 4 determines in step S7 that there is a fold. If not,
That is, when it is determined that there is no folding, the process returns to step S1. If the result of the determination in step S7 is that there is a fold, the process proceeds to step S8, and the determination unit 4 outputs the paper fold detection.

The output of the paper break detection output by the judging means 4 can be used as a signal for stopping the printing press and for displaying an alarm (buzzer, lamp, etc.). Then, the operator of the printing press receives an alarm, and the paper 2
And restart printing machine operation. At that time, the determination unit 4 restarts the paper fold detection process from step S1.

The determination means 4 as described above can be configured by hardware logic, but can also be configured by programming of a programmable sequence controller. In general, the hardware logic is capable of high-speed processing even by programming, and in this case there is almost no need to consider the influence of the processing speed. On the other hand, even in the case of programming, there is no problem if the detection accuracy of the feed amount detection means 3 is not set higher than necessary and the number of pulses per feed amount is reduced.

Next, in the paper break detecting device of the present invention,
A method of setting the above n and m will be described. FIG. 6 is a diagram of a test sheet used when setting n and m.
The test sheet is referred to as a sheet to be inspected for detecting a sheet break. In FIG. 6, reference numeral 24 is a detection mark, and 25 is a test paper. When an optical detector is used as the folding detecting means 1 in the present invention, the detection mark 24 may be, for example, a square patch having a color of black and a size of about 2 × 2 cm, which is attached to a blank sheet of paper. A test sheet 25 can be obtained by attaching the sheet. Further, when the folding detection unit 1 that detects the thickness of the paper such as the capacitance type detector is used, the detection mark 24 has a size 2 made of the same material as the paper regardless of the color. The test paper 25 can be made by sticking a square patch or the like having a size of about 2 cm to the paper or a plurality of sheets.

When an optical detector is used as the folding detecting means 1 in the present invention, not only the detection mark 24 is put on the test paper 25, but also the detection mark (product) may be put on the paper as a product. It has already been described that the detection mark (product) can be put on the paper 9 as a product when there is no such product. Detection mark for testing 2
The difference between 4 and the detection mark (product) for the product depends on the purpose. The detection mark 24 is a parameter n,
The detection mark 24 for setting the value of m
Is to determine the timing at which the determination unit 4 reads the data detected by the folding detection unit 1. Further, the detection mark (product) is to increase the change in the detection value of the fold detection means 1 due to the detection mark (product) being hidden by the fold, thereby enhancing the sensitivity, reliability and the like. However, it is not necessary to distinguish between the two detection marks in the paper fold detection device of the present invention, and if there is a paper on which the detection marks are printed, then that is the test paper 2.
It can be used as 5.

A processing procedure for setting the values of n and m using the test paper 25 will be described with reference to FIG. These processes are performed by the determination means 4. The paper fold detection apparatus of the present invention has a normal operation mode and a setting mode for setting parameters such as n and m. First, step S1
1, the paper break detection device of the present invention is set to the setting mode. Next, in step S12, the upside-down detection mark 24
The detection mark 24 on the side of the middle side is detected. Before that, the test paper 25 is inserted between the blank papers and placed on the feeder of the printing machine. When the printing machine is operated, a blank sheet is sent in the beginning, but finally, the test sheet 25 comes and the test sheet 25 is sent.

In the example of this embodiment, the top side detection mark 24 is the paper break detecting means 1 (1), although it depends on the structure of the feeder section of the sheet-fed offset printing machine and the installation position of the paper break detecting means 1. It is detected by (2). At that time, in the determination means 4, the pulse output from the feed amount detection means 3 is
The timing when the timing detecting means detects the timing is counted as a starting point, and the detection mark 24 from the blank sheet to the right
N11 is the count value when detecting the
Assuming that the count value when the blank sheet is detected from 4 is N12, those values are stored.

Since the installation positions of the left and right paper breakage detecting means 1 and the positions of the left and right detection marks 24 are normally arranged symmetrically, the parameter n is usually one, but it is deviated from the symmetrical arrangement. When n is large, the normal parameter n is divided into two, that is, n2 and n1. In that case, the count value when the left detection mark 24 is detected from the blank sheet is N2.
1. N22 is also stored as a count value when a blank sheet is detected from the left detection mark 24.

Next, in step S13, the value of n is set. The value of n is set to the value calculated by the following formula. n = INT ((N11 + N12) / 2), n = INT ((N21 + N22) / 2), or n = INT ((N11 + N12 + N21)
+ N22) / 4) And when the deviation from the symmetrical arrangement is large, the right is n1 = INT ((N11 + N12) /
2), the left is n2 = INT ((N21 + N22) /
2) Here, INT () means the value of the integer part of the numerical value in ().

Next, in step S14, the detection mark on the ground side is detected. In this example, as described above, after the top side detection mark 24 is detected by the paper break detection means 1 (1) and (2), the ground side detection mark 24 is detected as the paper break detection means 1 (3) and (4). ) Is detected. At that time, in the determination means 4, the pulse output from the feed amount detection means 3 is
The timing when the timing detection means detects the timing is counted as a starting point, and the detection marks 2 on the left and right from the blank
4 is detected by M21, M11, and the count value when a blank sheet is detected by the left and right detection marks 24 is M.
22 and M12, those values are stored.

In the next step S15, the parameter m
Is set. Similar to the case of the parameter n described above, the values calculated by the following formulas are set for the parameters m, m1, and m2. m = INT ((M11 + M12) / 2), m = INT ((M21 + M22) / 2), or m = INT ((M11 + M12 + M21)
+ M22) / 4), and when the deviation from the contrasting arrangement is large, on the right, m1 = INT ((M11 + M12) /
2), on the left is m2 = INT ((M21 + M22) /
2)

Although the present invention has been described with reference to the examples, the present invention can be carried out in various modes within the scope of the gist thereof. For example, although four folding detection means are used in the above-described embodiment, the number may be two depending on the paper feeder method. That is, the corners of the right and left sheets can be detected by the folding detection means (1) and the corners of the left side can be detected by the detection means (1). It has already been described that the timing detecting means and the feed amount detecting means can be replaced with one detecting means (for example, a rotary encoder) having both means. Further, in the present embodiment, an example in which the paper folding detection device of the present invention is installed in the sheet-fed offset printing machine is shown, but it is easy to install it in another processing machine, a conveyance device, or the like from the description of the present embodiment. Is. Needless to say, the present invention includes various embodiments as described above.

[0044]

According to the paper fold detection apparatus of the present invention, the paper fold is provided with the timing detection means and the feed amount detection means, and the paper feed section (feeder section) of the paper processing apparatus is synchronized with the paper feed. Since the jamming is detected, it is possible to detect whether or not the running paper is folded. Further, when a sheet having a fold is detected, the feeding of the sheet is stopped so that it can be removed by an operator before the sheet is processed by the processing device. The defect due to folding is eliminated. Further, since the parameter can be set only by detecting the paper having the detection mark, the handleability is excellent.

[Brief description of drawings]

FIG. 1 is a block diagram of a paper fold detection device of the present invention.

FIG. 2 is a diagram in which the sheet breakage detection device of the present invention is installed in a sheet-fed offset printing machine, and in particular, the layout of sensors is shown.

FIG. 3 is a view of FIG. 2 seen from above.

FIG. 4 is a timing chart showing the output of each detection unit of the paper fold detection device of the present invention and the process of paper fold detection.

FIG. 5 is a flowchart of a paper break detection process in the determination means 4 of the present invention.

FIG. 6 is a diagram of a test sheet used when setting parameters n and m.

FIG. 7 is a diagram showing a processing procedure for setting parameters n and m using a test sheet.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Folding detection means 2 Timing detection means 3 Feed amount detection means 4 Judgment means 5 Signal input means 6 Arithmetic processing means 7 Signal output means 8 Output signal 9 Paper 10 Elevator 11 Soccer 12 roll 13 Roller 14 Belt 15 Drive roll 16 Feeder board 17 swing 18 plate cylinder 19 blanket cylinder 20 impression cylinder 21 timing plate 22 gear 23 frame 24 ball

Claims (4)

[Claims] 1. At least a folding detection unit for detecting a folding of a sheet, a timing detection unit for detecting a feeding timing of the sheet, a feed amount detecting unit for detecting a feeding amount of the sheet, and an output of the folding detection unit. A paper fold detection device having a determination means for determining whether or not a fold has occurred. 2. The paper fold detection apparatus according to claim 1, wherein the fold detection means has a detector for detecting the optical reflectance of the paper as a constituent element. 3. The paper folding detecting apparatus according to claim 1, wherein a detection mark is provided at a corner of the sheet, and the presence or absence of folding is detected by detecting the detection mark. 4. The paper folding detecting apparatus according to claim 1, wherein a detection mark is provided at a corner of the paper, and the detection mark is detected so that the parameter of the judging means can be set. .