JP2617125B2 - Method and apparatus for detecting duplicated paper feed - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for detecting the overlap of fed sheets suitable for use in a sheet-fed printing press.

[Conventional technology]

2. Description of the Related Art Conventionally, when a sheet (sheet) is fed to a sheet-fed printing press, an overlap of sheets to be fed is detected.

That is, when a sheet is supplied from a sheet feeding device to a sheet-fed printing press (hereinafter, simply referred to as a printing press), the front edge of the sheet is fed to a stopper provided at a leading end of the sheet feeding table on the printing press side. After the contact, the paper is supplied to the printing press. At this time, for the purpose of preventing two or more sheets of paper from being supplied simultaneously and simultaneously, a light projector is usually arranged on the back side near the front and back of the paper feed table and opposed to the light emitting part of the light projector. A through hole is formed in a predetermined portion of the sheet feeding table, and a light receiver is arranged on the upper surface side of the sheet feeding table opposite to the through hole. That is, the light emitted from the projector is projected in the thickness direction of the paper to be fed, the transmitted light from the fed paper is received by the light receiver, and the amount of received light obtained by converting the light into an electric signal is obtained. Is compared with a preset discrimination level, and based on the result of the comparison, the overlap of the paper sheets is detected.

Here, it is desired that the light emission amount of the light emitted from the light projector and the determination level be set to optimal values for the paper sheet. That is, the light emission amount and the output level have different characteristics between the case where the number of sheets supplied is one and the case where the number of sheets is two. For example, as shown in FIG. In some cases, the characteristic is I, and when there are two sheets, the characteristic is II. Here, the optimal value of the light emission amount is a light emission amount value at which the difference between the output level based on the characteristic I and the output level based on the characteristic II is maximized. This is 1/2 of the sum of the output level of the characteristic I and the output level of the characteristic II.

Conventionally, as a first method, a discrimination level is fixed and an output level obtained through a light receiver when one sheet of paper is fed and an output level obtained when two sheets are fed. On the other hand, the power supplied to the light projector is adjusted assuming that the discrimination level is located almost in the middle, thereby setting the amount of light emitted from the light projector. Further, as a second method, the power supply to the light projector is determined, the light emission amount of the emitted light is set to be constant, and the output level obtained via the light receiver when one sheet of paper is fed is determined by the following method. The discrimination level is set to a value that is located approximately in the middle of the output level obtained when sheets are printed.

[Problems to be solved by the invention]

However, printed materials printed by the sheet-fed printing press often use small lots and various types of paper. That is, the characteristics I and II shown in FIG. 5 differ depending on the paper quality (including paper thickness, color, etc.) of the paper used, and the optimum value of the light emission amount and the optimum value of the determination level are not constant. . For this reason, the first and second methods have a drawback that it is difficult to detect the overlap with high accuracy and stability on a wide range of paper quality, and that the adjustment largely depends on the experience of the operator.

[Means for solving the problem]

The present invention has been made to solve such a problem, and projects light emitted from a light projecting unit in a thickness direction of a sheet to be fed, and receives transmitted light from the fed sheet. Output level V according to the amount of received light
control level V _out for controlling the amount of light emitted from the light projecting means in detecting the overlap of the paper feed based on _in
Was a specified level value V _os, obtains a value V _ik of the output level V _in obtained as prescribed level value V _os as the paper quality data, the sheet feeding sheets stored in correspondence with the paper quality data in the case of one It reads out the optimum value V _od of the control level V _out corresponding to the emitted light amount value difference between the output level V ₂ in the case where the output level V ₁ and the two becomes approximately maximum, and is stored in correspondence with paper quality data reads the change value V _1-2 of the output level V _in which changes by overlapping paper feed paper when the optimum value V _od and that, after that the control level V _out and the optimum value V _od, the optimum value V _od
1 change value V _1-2 than the value V ₁ of the output level V _in obtained as
The value _VL is obtained by subtracting / 2, and the obtained value _VL is used as the determination level for detecting the overlap of the paper sheets.

[Action]

Therefore, according to the present invention, based on the value V _ik of the output level V _in the resulting control level V _out as prescribed level value V _os, an optimum value of the control level V _out corresponding to the paper quality of the paper feed paper
An optimum value V _L of V _od and the discrimination level is obtained.

〔Example〕

Hereinafter, a method and an apparatus for detecting duplicated paper feed according to the present invention will be described in detail.

FIG. 1 is a system configuration diagram showing an apparatus to which an embodiment of the present invention is applied. In the figure, 1 is a light projector, 2 is a light receiver, 3 is an amplifier for amplifying an output electric signal (analog signal) corresponding to the amount of light received by the light receiver 2 and 4 is an amplifier provided via the amplifier 3 a microprocessor (hereinafter, CPU) an electrical signal as an output level V _in is converted into a digital signal a / D converter for provision to 5,
Reference numeral 6 denotes a D / A converter that converts a control level (digital signal) _Vout output from the CPU 5 into an analog signal. Reference numeral 7 denotes an amplifier that amplifies the analog signal output from the D / A converter 6 and supplies the analog signal to the projector 1 as a power signal. It is.

The CPU 5 is connected to a key group 8 for giving an instruction from an operator, a detection timing generator 9 for generating a paper detection timing, and a monitor 10 for notifying the operator of processing information in the CPU 5. And CPU5 and this
A ROM 11 in which a program for operating the CPU 5 and a characteristic table to be described later are stored, and various kinds of information are stored and stored.
The RAM 12 to be edited constitutes a central processing unit.

The light emitter 1 and the light receiver 2 are arranged opposite to each other on a front contact portion of a paper feed table for a printing machine (not shown) as described in the conventional example. The amplifiers 3 and 7 are configured so that their amplification (gain) can be freely adjusted.

FIG. 2 is a flowchart showing the data registration processing performed by the CPU 5, and the processing operation will be described below with reference to this flowchart. That is, when an initial command for paper duplication detection processing, that is, a "registered data initialization command" is given via the key group 8, the CPU 5 initializes the registered data up to that time (step 201). Then, only one sheet of paper is sent to the front section, that is, one sheet of paper 13 is transported between the light emitter 1 and the light receiver 2, and a “data registration start command” is issued via the key group 8.
Gives the control level V _{out the} specified level value V _os
(Step 202). As a result, the light projector 1 emits light having a light emission amount corresponding to the specified level value _Vos . Thereafter, CPU 5 calculates a time the emission amount of light emission of the light projector 1 is stabilized, waits for elapse of the calculated time (step 203), the output level V _in corresponding to the received light amount of the light receiver 2 Import from A / D converter 4 (Step 20
Four). The value V _ik of the captured output level V _in the sheet 1
Is data means 3 of paper quality, the the optimum value V _od of the control level V _out of _the response to this value V _ik and paper 13 in order to ensure the optimum value of the amount of light emission, constant relationship. FIG. 3 is a characteristic diagram (V _ik −V _od characteristic table) showing an optimum value V _od of the control level V _out experimentally obtained using the value V _ik as paper quality data, and the V _ik −V _od characteristic table. Is stored in the ROM 11, the CPU 5 follows the V _ik −V _od characteristic table, and controls the control level V corresponding to the fetched value V _ik.
The optimum value _{Vod of out} is obtained and registered (step 205).

Next, the CPU 5 sets the control level V _out to its registered optimal value.
_Vod is set (step 206), and the amount of light emitted from the projector 1 is changed. Thereafter, CPU 5 again calculates the time that the emitted light amount of the emitted light of the light projector 1 is stabilized, waits for elapse of the calculated time (step 207), the output level V _in corresponding to the received light amount of the light receiver 2 (Step 208). The value V ₁ of the this captured output level V _in is determined as the output level V _in for one sheet of paper 13 when a control level V _out and the optimum value V _od. Here, the value V _ik obtained in step 204 and the control level V _out are optimized values.
Duplicate sheet 13 when formed into a V _od in the (2-ply) change value of the output level V _in which changes by (difference between the output level V _in the case of one and when two) V _1-2 is There is a certain relationship. Figure 4 is a characteristic diagram showing the change value V _1-2 of the output level V _in experimentally obtained values V _ik as paper quality data (V _ik -V _1-2
A characteristic table), the V _ik -V _1-2 characteristic table R
By storing the OM11, is CPU5 this Vik-V _1-2
According to the characteristic table, the value V obtained in step 204
obtains the change value V _1-2 corresponding to _ik, registers determine the discrimination level V _L by the following equation (step 209).

By the processing of V _L = V ₁ −V _1-2 · 1/2 or more, the optimum light emission amount and the optimum determination level for the paper 13 are determined, and the above processing is performed for each paper having different paper quality. By repeating this, the optimum light emission amount and the optimum discrimination level are determined for a wide range of paper quality sheets, and highly accurate and stable paper overlap detection is performed. Also, V _ik -V accordance _od characteristic table Motomari the optimum value V _od of the control level V _out, the change value V _1-2 in accordance with V _ik -V _1-2 characteristic table is obtained, being dependent on the experience of the operator Therefore, the adjustment to the optimum light emission amount and the optimum determination level is performed, and the adjustment work is greatly simplified.

In the above description, the “data registration start command” is given to the CPU 5 via the key group 8, but the “data registration start command” is automatically given at a predetermined timing by the detection timing generator 9 during the operation of the printing press. In this case, it is not necessary to manually transfer the sheet to the front section and provide a "data registration start command" via the key group 8, and the operator needs to execute the "registered data initial command". It is only necessary to execute the “modification instruction” as needed.

In mass production, variations in the characteristics of the light projector 1 and the light receiver 2 for each product become a problem. That is,
The relationship obtained by the actually used light projector 1 and light receiver 2 may greatly deviate from the relationship shown in FIG. 3 and FIG. 4, which is a large unstable factor in mass production. Therefore, a correction function (hereinafter, referred to as an ADJ function) is added to the present system for the purpose of constantly correcting the relationship obtained by the light projector 1 and the light receiver 2. In other words, “ADJ function start command”
Is input, CPU5 switches ADJ from the normal duplication detection mode.
The mode shifts to the function mode. In the ADJ function mode, the CPU 5 first sets the control level _Vout to the specified level value _Vos, and then takes _{in the} output level Vin at regular intervals. And, CPU5, the output level V _in captured to display whether the information specified range in either excess or deficiency on the monitor 10. If the operator adjusts the gains of the amplifiers 3 and 7 while watching the displayed values, the relationship obtained by the projector 1 and the light receiver 2 can be easily corrected to a constant value without using a measuring instrument or the like. This makes it possible to perform more stable duplication detection by this correction. Note that this adjustment
It only needs to be performed once when the apparatus is carried in.

Further, in the present embodiment, the overlap detection is performed on the paper to be fed to the printing press. However, the present invention is not limited to this. Can be implemented.

〔The invention's effect〕

According to the present invention described above, the control level V _out for controlling light emission amount of light emission of the light emitting means to the prescribed level value V _os, the value V of the output level V _in obtained as prescribed level value V _os seeking _ik as paper quality data, the difference between the output level V ₂ when the sheet feeding sheets stored in correspondence with the paper quality data is two and an output level V ₁ of the case of one becomes approximately maximum emission Optimal value V _od of control level V _out corresponding to light intensity value
Reads, and reads out the output level V _in the change value V _1-2 that varies with overlapping paper feed paper when the optimum value V _od stored in correspondence with the paper quality data, a control level V _out after having the optimum value V _od, by subtracting the half of the change value V _1-2 than the value V ₁ of the output level V _in obtained as the optimum value V _od value
Since V _L is obtained and the obtained value V _L is used as a determination level for detecting the overlap of the paper sheets, the optimum value V of the control level V _out according to the paper quality of the paper sheet based on the value V _ik is determined. _od and the optimum value _VL of the discrimination level are determined, and the optimum light emission amount and the optimum discrimination level are determined for a wide range of paper quality, and highly accurate and stable duplication detection of the paper is performed. Becomes In addition, the adjustment is made to the optimum light emission amount and the optimum determination level without depending on the experience of the operator, and the adjustment work is greatly simplified.

[Brief description of the drawings]

Figure 1 is a system configuration diagram showing an application to become the apparatus of one embodiment of the present invention, the flow chart FIG. 2 showing a data registration process performed by the CPU in the apparatus, FIG. 3 is a value V _ik as paper quality data characteristic diagram showing an optimum value V _od of the control level V _out experimentally determined, Figure 4 is a characteristic diagram showing a change value V _1-2 of the output level V _in experimentally obtained values V _ik as paper quality data FIG. 5 is a diagram showing the relationship between the amount of emitted light and the output level when the number of sheets supplied is one and two. 1 ... Emitter, 2 ... Receiver, 3,7 ... Amplifier, 5 ... C
PU, 8 ... key group, 9 ... detection timing generator, 10
… Monitor, 11… ROM, 12… RAM, 13… Paper paper.

Claims (2)

(57) [Claims] The light emitted from the light projecting means is projected in the thickness direction of the paper to be fed, and the light transmitted from the fed paper is received by the light receiving means. in duplicate detection method of the sheet feeding sheet for detecting the overlap of the sheet feeding sheet based on the output level V _in, the control level V _out to control the light emission amount of the emitting light of the light projecting means to the prescribed level value V _os, the value of the output level V _in obtained as prescribed level value V _os
V _ik is determined as the paper quality data, and the output level V _{1 for} the case of one sheet and the output level for the case of two sheets stored in correspondence with the paper quality data
It reads the control level V _out optimum value V _od of the difference between V ₂ corresponds to the light emission amount value which is substantially maximum, and, when said optimum value V _od stored in correspondence with the paper quality data of reading out the paper feed change value _1-2 of the output level V _in which changes by overlapping of the sheet, after which the control level V _ont was the optimum value V _od, the optimum value V the output level V obtained as _od obtains the value V _L by subtracting the half of the change value V _1-2 than the value V ₁ of the _in, that the calculated value V _L were set as the discrimination level for detecting a duplicate of the paper feed paper A method for detecting duplication of a sheet of paper. 2. The light emitted from the light projecting means is projected in the thickness direction of the sheet to be fed, and the light transmitted from the sheet is received by the light receiving means. in overlap detection apparatus of the feeding paper for detecting duplication of the paper feed paper on the basis of the output level V _in, the control level V _out to control the light emission amount of the emitting light of the light projecting means to the prescribed level value V _os, obtains a value V _ik of the output level V _in obtained as prescribed level value V _os as the paper quality data, the sheet feeding paper stored in correspondence with the paper quality data output level V ₁ of the case of one and 2 and the optimum value determining means for reading an optimum value V _od of the control level V _out a difference between the output level V ₂ in the case of sheets corresponds to a light emission amount value which is substantially maximum, is stored in correspondence with the paper quality data The optimal value V
the change value determination means for reading the change value V _1-2 of the output level V _in which changes by overlapping of the feed sheet when the _od, the control level V _out after having said optimal value V _od, the optimal calculated values V _L and than the value V ₁ of the said output level V _in obtained as the value V _od subtracting 1/2 of the change value V _1-2, the obtained value V _L
And a discrimination level determining means for setting a discrimination level for detecting the overlap of the paper sheets.