JP2509079Y2 - Automatic document feeder - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to an automatic document feeder, which prevents a reading error due to an erroneous set of the document surface, and particularly, in a copy mode, facsimile mode, fairing mode, etc. The present invention relates to an automatic document feeder suitable for a mode-selectable copying machine and a digital multifunction copying machine.

[Conventional technology]

Conventionally, there is one disclosed in Japanese Patent Laid-Open No. 63-109641 as a means for preventing a reading error due to an erroneous set on the original surface.

In this facsimile system, a part of the signal from the reading circuit is stored in the memory included in the all-white all-black judgment circuit, and the contents of the memory and the preset all-white and all-black reference values are set by the CPU. After the comparison with the value, if the result is all white or all black, the fact is displayed on the display unit.

[Problems to be solved by the device]

By the way, in the above-mentioned prior art, a memory for storing a part of the contents of the original is provided, and the original is read by the scanner once to determine the front and back of the original. Therefore, the memory is required, and the scanning time of the scanner is required. It took time.

Further, in a multifunctional digital copying machine capable of selecting a copy mode, a facsimile mode, a fairing mode, etc., the set surface of the document surface is different in each mode, so that it is promptly determined whether the document is set incorrectly. Is desired.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and an object thereof is to provide an automatic document feeder capable of identifying an erroneous set on a document surface and preventing a reading error.

[Means for solving the problem]

In order to achieve the above object, the present invention provides a first mode in which a manuscript is sent from the last page, and a second mode in which the manuscript is set so that the front and back sides of the manuscript are different from each other and the manuscript is sent from one page. Which is provided in the image forming apparatus capable of selecting the mode, and a table unit on which the originals are placed with the first page up or the last page up, and a call for calling the originals on the table unit one by one Means and a transport path for transporting the original called by the calling means, wherein the original on the table portion is sent to the reading means via the transport path in the middle of the transport path. A plurality of detecting means for detecting the image density of the surface of the original are provided at a position facing the surface of the original in the first mode, and the detecting means detects the image density of the surface of the original. To the detection means The document surface is provided with a discriminating unit for discriminating whether the face of the document facing is front or back, and a control unit for discriminating whether or not the discrimination result by the discriminating unit corresponds to the selected mode of the respective modes. The configuration is such that the selected mode operation is executed only when the selected mode is supported, and when the document surface does not correspond to the selected mode, the selected mode operation is stopped and the document is discharged. is there.

[Action]

By the above-mentioned means, since the identifying means is provided in the conveying path in front of the reading means, it is possible to identify the erroneous set on the document surface before the copying operation, the facsimile transmission operation, or the failing operation. Therefore, it is possible to identify the erroneous set in a short time without requiring a memory for storing a part of the content of the document and without entering each operation.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a vertical sectional view showing an outline of an automatic document feeder according to the present invention, FIG. 2 is an enlarged sectional view showing a separating portion of the automatic document feeder, and FIG. 3 is a multi-function equipped with the automatic document feeder. 4 is a perspective view showing an operating portion of the multi-function digital copying machine, FIG. 5 is a block diagram for controlling the automatic document feeder, and FIGS. Is a time chart showing a signal obtained by a reflection type sensor, FIGS. 8 and 9 are flow charts showing identification control, and FIGS. 10 (a) to 10 (c) are operating states in the faxsimile mode and the fairing mode. FIGS. 11A to 11E are explanatory views showing the operation state in the copy mode.

FIG. 6 shows a multifunctional digital copying machine. 1 is an automatic document feeder, 2 is a reading unit having a scanner for reading a document, and 3 is a signal from the reading unit 2 to a photosensitive drum 5 of a printer unit 4. It is a writing unit for writing. The printer unit 4 is provided with a paper feed cassette 6, a paper discharge tray 7, a conveyance roller 8, and the like. Recording paper passes from the paper feed cassette 6 through the photoconductor drum 5 by the conveyance roller 8 to the paper ejection tray. It has been transported to 7. Then, the information on the photosensitive drum 5 is transferred while the recording paper rolls on the photosensitive drum 5. This multi-function type digital copying machine can perform copying, facsimile, fairing, etc., and each of these functions can be selected by operating the mode button of the operating section shown in FIG. This mode button is a copy mode button 9, a fax mode button 10, and a file mode button 11.
Made of. Also, set the number of sheets 10 key 1
2. A copy start button 13 and the like are provided.

1 and 2 show an automatic document feeder 1. The automatic document feeder (ADF) 1 is on the main body of the copying machine, which comprises the reading section 2, the writing section 3 and the printer section 4, that is, It is installed on the contact glass 14 of the reading unit 2. This ADF1 is a manuscript table 15, pinch rollers 16,
It consists of a calling roller 17, a separation belt 18, a separation roller 19, a pulse generator 20, an endless conveyor belt 21, a stopper pawl 22, a reversing roller 23, a reversing switching pawl 24, a paper ejection roller 25, a document receiver 26, and the like. . Further, a document set detection device 27, an identification means, for example, an image density detection device 28, a registration width detection device 29, a paper discharge detection device 30, etc. are arranged on the conveyance path, and the pulse generator 20 has a length detection device 31. Is provided.

Fig. 5 shows a block diagram for controlling ADF1.
Is a main circuit, 33 is an operation unit, 34 is a display unit.
The above-mentioned mode buttons 9 to 11 and the like are arranged on the 33. Reference numeral 35 is a front / back side determination circuit, 36 is a reference value setting circuit, 37 is a document length detection circuit, and 38 is a white part time detection circuit. An original reading signal from the image density detecting device 28 is input to the original length detecting circuit 37 and the white portion time detecting circuit 38.

 The operation of the ADF1 configured as above will be described below.

In the normal copy mode, the document surface is set to the upper side and the sheet is fed from the last page (nth sheet) (Fig. 11 (a)). As a result, as shown in FIGS. 11 (b) and 11 (c), the first page is on the upper side and the front side is the front side when the sheet is discharged. As described above, set the original on the original table 15 and call it.
At 17 the original is pulled in and the separation belt 19 etc.
It is conveyed onto the contact glass 14 by means of 21 and stopped.
The surface of the original is on the lower side of this contact glass 14,
The sheet is read by the scanner of the reading unit 2, transferred to the recording paper by the printer unit 4, and the recording paper is discharged to the paper discharge tray 7 with the copy surface facing upward. Further, the original on the contact glass 14 is also conveyed by the conveyor belt 21, passes through the reversing roller 23, and is ejected on the original receiver 26 with the front side facing upward. Then, the originals on the original table 15 are sequentially conveyed and copied as described above.

Further, when the facsimile mode or the filing mode is selected, the document is set on the document table 15 so that the front side of the document faces downward and the document is fed from the first page (10th page).
Figure (a)). The lowermost original (first page) of the original on the original table 15 is drawn by the calling roller 17, and is conveyed onto the contact glass 14 by the conveyor belt 21 via the separating roller 19 and the like. Further, the conveyor belt 21 is operated to feed the document to the reversing roller 23, and the reversing switching claw 24 switches the document to the 10th position.
Invert and re-contact glass as shown in Figure (b)
14 Carry on and stop. At this time, the front surface of the document is oriented downward. Then, after the facsimile is transmitted, the fiber is sent, or the like, the conveyor belt 21 is operated to eject the document onto the document receiver 26 as shown in FIG. 10 (c). In this case, the originals on the original receiver 26 are sequentially discharged with the front side facing down and the first page at the bottom.

 Next, the operation of the image density detection device 28 will be described.

The image density detecting device 28 is composed of a reflection type sensor, is arranged on the conveying path between the separation roller 19 and the contact glass 14 as described above, and detects the image density of the document surface conveyed on the conveying path as described above. To detect. A plurality of the reflection type sensors are arranged at regular intervals over the entire width of the document.

Therefore, the original is placed on the original table so that the surface of the original (the surface on which the characters and the like are written) faces the image density detecting device 28 (in this embodiment, the original surface is on the upper side).
When the copy start button 13 is pressed after being set to 15, the document is conveyed, and the density of the document surface is detected by each sensor of the image density detecting device 28. FIG. 6 is a time chart showing a detection signal by the image density detecting device 28, in which the vertical axis represents the level of the detected value and the horizontal axis represents the document passage time t. Also, t _{a1 to} t _an is the image part (text part) t _{b1 to} t _bn is the non-image part (background part), the SH value is the threshold value, and this SH value depends on the background color of the document. I am trying to change it. This detection signal is input to the document length detection circuit 37 and the white portion (background portion) time detection circuit 38 shown in FIG.

It is to be noted that FIG. 7 shows a state in which the back surface of the document is detected by the image density detecting device 28.

 Next, a method of processing the detection signal will be described.

First, in the first method, a point of the detection signal that gives a value higher than the SH value is read as an image portion, and a point of a low value is read as a background portion. Further, a signal as shown in FIG. 6 is obtained from a certain number of sensors of the plurality of sensors of the image density detecting device 28, and the image portion points during the document passage time t are counted, Calculate the ratio of image points to the document passage time t,
If the calculated value is larger than a certain value (threshold value ₁ ), "table",
If it is small, it is determined as "back". This can be expressed by the following equation.

The second method is the time (t
_a1 , t _a2 …… t _an ) and the time of the bare part (t _b1 , t _b2 ……)
t _bn ), and the calculated value is a certain value (threshold ₂ )
If it is larger, it is determined to be "front", and if it is smaller, it is determined to be "back".
This can be expressed by the following equation.

The third method is to calculate the ratio of the sum of the time (t _an ) of the image part points or the ratio of the sum (t _bn ) of the background part per manuscript passage time t, and set these calculated values to a certain value. Determine the front and back sides by comparing with (threshold ₃ or threshold ₄ ). This can be expressed by the following equation.

Or In this way, the front side and the back side of the original are discriminated, and when the set surface of the original does not correspond to the mode selected by the mode button, for example, the copy mode, the copying is immediately stopped and the user is prevented from making an erroneous set of the original. Notify and prevent miscopy. That is, in the case of the ADF1 as described above, in the copy mode, it is set to enable the copy when the signal shown in FIG. 6 is obtained, and to stop the copy when the signal shown in FIG. 7 is obtained. In the facsimile mode and the fairing mode, it is set so that when the signal as shown in FIG. 7 is obtained, the transmission and the fairing are enabled, and when the signal as shown in FIG. 6 is obtained, the transmission and the fairing are stopped.

The control operation of the embodiment thus constructed will be described with reference to the flowcharts of FIGS. 8 and 9. 8th
FIG. 9 is a flow chart showing the overall control, and FIG. 9 is a flow chart showing the control in the copy mode.
In the flow charts of FIGS. 9 and 9, equations (7) and (8) of the above-described three methods, that is, the value of Σwhite time / document passing time are compared with a threshold value.

When the copy start button 13 is pressed, the ADF 1 is operated and it is discriminated whether it is the copy mode or the facsimile (or failing) mode (8-1). If the copy mode is selected in step (8-1), that is, if the copy mode button 9 is pressed to select the copy mode, the process proceeds to step (8-2). The processing in step (8-2) is shown in the flow chart of FIG. In FIG. 9, the detection signal detected by the document density detecting device 28 is processed as described above, the time of the white portion and the document passing time are counted (9-1), and the process proceeds to step (9-2). In step (9-2), it is determined whether Σwhite time / document passing time> threshold. If the answer is NO in step (9-2), the original surface detected by the original density detecting device 28 is a table and is correctly set, so the copy operation is performed as it is. On the other hand, if YES in step (9-2), the document side is the back side and it has been set by mistake. Therefore, the copying operation is stopped, "Document side confirmation" is displayed on the display unit, and ADF1 is displayed. The erroneously set original is ejected to the original receiver 26 (9-3). Then, the original is reset, and if reset is OK (9-4), the function is restored (9-5), and copying is performed.

If the facsimile mode is set in step (8-1) of FIG. 8, the process proceeds to step (8-3) to count the white part time and the document long time, and then proceeds to step (8-4). In step (8-4), it is determined whether Σwhite part time / document passing time> threshold. If YES in step (8-4), the document surface detected by the document density detecting device 28 is the back side and is correctly set. Therefore, the document is directly transmitted. On the other hand, if NO in step (8-4),
Since the document side is the front side and has been set incorrectly, the transmission operation is stopped, "Document side confirmation" is displayed on the display, and ADF1
Documents that have been erroneously set in the document receiver 26 are ejected (8
-5). Then, the original is reset, and if reset is OK (9-6), the function is restored (9-7), and the transmission is performed.

[Effect of device]

As described above, according to the present invention, the document surface is detected before the copy operation, facsimile transmission operation, or failing operation is performed by the detection unit located at the position facing the front surface of the original in the first mode. Since it is possible to identify whether the wrong mode is set for the selected mode, it is possible to identify the wrong set in a short time without entering each operation and prevent reading mistakes. The normal selected mode operation can be performed.

[Brief description of drawings]

The drawings are for explaining all the embodiments of the present invention,
FIG. 1 is a vertical sectional view showing an outline of an automatic document feeder according to the present invention, FIG. 2 is an enlarged sectional view showing a separating portion of the automatic document feeder, and FIG. 3 is a multi-function equipped with the automatic document feeder. 4 is a perspective view showing an operating portion of the multi-function digital copying machine, FIG. 5 is a block diagram for controlling the automatic document feeder, and FIGS. Is a time chart showing a signal obtained by a reflection type sensor, FIGS. 8 and 9 are flow charts showing identification control, and FIGS. FIGS. 11A to 11C are explanatory views showing the operation state in the copy mode. 1-Automatic document feeder, 28-Document density detector, 35
...... Front / back judgment circuit, 36 …… Reference value setting circuit, 37 …… Document length detection circuit, 38 …… White area time detection circuit.

Claims (1)

(57) [Scope of utility model registration request] 1. A first mode in which an original is fed from the last page, and an original is set by setting the front and back sides of the original differently.
The image forming apparatus is provided with an image forming apparatus capable of selecting a second mode of sending from a page, and a table section on which a document is placed with the first page up or the last page up, and the table section is provided on the table section. 1 for the original
An automatic document feeder including: a calling unit that calls the documents one by one; and a conveyance path that conveys the documents called by the calling unit, and the document on the table unit is fed to the reading unit through the conveyance path. A plurality of detecting means for detecting the image density of the document surface are provided in the entire width of the document at a position facing the surface of the document in the first mode on the conveyance path. Identification means for identifying whether the surface of the document facing the detection means is front or back based on the detection result, and it is determined whether the identification result by the identification means corresponds to the selected mode of the respective modes. A control unit is provided to execute the selected mode operation only when the document surface corresponds to the selected mode, and to execute the selected mode when the document surface does not correspond to the selected mode. An automatic document feeder, characterized in that the operation is stopped and the document is discharged.