JPH11109727A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of obtaining high image quality and improving handleability by automatically detecting whether a document is a book or not, automatically detecting the position or the width of a middle fold part when it is the book document and changing the image at the middle fold part to a middle erasion part. SOLUTION: This device is equipped with a photoreceptor drum 1 carrying the image of the document by exposing and scanning the document P on a document platen 10 by the exposure lamp 30 of a scanner 31, and an LED erasion sensor 25 which irradiates the area of the drum 1 equivalent to the middle fold part and changes it to the middle erasion part when the document is the book by making a sensor detect the document P before the exposure scanning by the lamp 30 provided on the scanner 31 and detect the existence of the middle fold part (q) of the document P and making a control circuit 50 judge whether it is the book document or a sheet document from the existence of the middle fold part (q) based on the detection signal of the sensor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic copying machine as an image forming apparatus, and more particularly to an improvement in a copying function for a thick book.

[0002]

2. Description of the Related Art When using an electronic copying machine as an image forming apparatus, there are many opportunities not only to copy ordinary thin-sheet documents but also to copy thick books such as dictionaries and encyclopedias.

In the case of copying a thin leaf document, the document is placed on a document table and covered with a platen cover or an automatic document feeder which also serves as a cover. The original closely adheres to the image, and a high-quality image can be reliably obtained.

However, when copying a thick book (hereinafter, referred to as a book document), the pages of the book document to be copied are set to the double-open state, and the facing pages are placed on the document table. Then, the cover is placed over the front and back and back covers of the book document, and the copy button is pressed.

A scanner provided with an exposure lamp as an exposure scanning means forms an original image (latent image) on a photosensitive drum as an image carrier by exposing and scanning an original surface. However, in the case of a book document, the throat (hereinafter, referred to as a “folded portion”) between two facing pages cannot be brought into close contact with the document table, and cannot be exposed and scanned.

That is, the light of the exposure lamp is recognized as an image without being reflected, and a black band is formed in the obtained copy image in the shape of the above-mentioned bent portion. Therefore, the image becomes very difficult to see, and a decrease in image quality is inevitable.

[0007]

In order to eliminate such a problem, some electronic copiers have a book copy mode. This has a function of forming a certain white band portion (hereinafter, referred to as a center eraser portion) in a portion which is considered to correspond to the above-described bent portion, and erases a black band.

However, the book copy mode must be set each time a user makes a copy of a book document, and the user tends to forget it. In addition, after setting and copying, it is necessary to release the setting, which is troublesome.

Further, since the thickness of the book document varies, the width of the center eraser also varies depending on the book document. Each time the user changes the book original, the user must reset the width of the center eraser, which is troublesome.

[0010] Even when copying the same book original,
Particularly in the case of a thick book document, the position of the folded portion varies depending on the position of the double-page spread to be copied. Therefore, the user must reset the position of the eraser every time the spread page to be copied is changed.

That is, the center-folded portion exists almost in the middle when copying the approximately center spread page of the book document, but the center-folded portion is copied when the front spread page or the back cover double page is copied. Are displaced to either side. If the settings are not reset each time, the required image is erased by the center eraser.

The present invention has been made in view of the above circumstances. It is an object of the present invention to automatically detect whether a document on a document table is a thin-sheet document or a book document. In the case of a book document, the position and width of the folded part are automatically detected, and the folded part image is changed to a centered part to provide an image forming apparatus that can obtain high image quality and improve usability. What you want to do.

[0013]

According to a first aspect of the present invention, there is provided an image forming apparatus, comprising: an original placing table on which an original is placed; and an exposure scan of the original on the original placing table. In an image forming apparatus including an exposure scanning unit and an image carrier that carries an original image that has been exposed and scanned by the exposure scanning unit, the image forming apparatus is mounted on the exposure scanning unit and before the exposure scanning by the exposure scanning unit. The original is detected as a book original based on the means for detecting the presence of the folded part of the original on the platen, and the presence or absence of the folded part based on the detection signal of this detecting means. Means for judging whether the original is a thin leaf original or not, and when this judging means judges the book original, the signal is received to irradiate the image carrier region corresponding to the center folded portion of the book original. Illumination changed to eraser Characterized in that and means.

According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the exposure scanning means includes a scanner on which an exposure lamp is arranged, and the detection means is arranged on the scanner, and moves together with the scanner to move the original surface. And a sensor for detecting presence or absence of reflected light.

According to a third aspect of the present invention, in the image forming apparatus according to the first aspect, the exposure scanning means includes a base frame and a lens cover, and the detection means is provided on the base frame and the lens cover along the exposure scanning direction. It is characterized by a plurality of fixed sensors arranged at predetermined intervals and illuminating the original surface to detect the presence or absence of reflected light.

According to a fourth aspect of the present invention, in the image forming apparatus according to the first aspect, when the output signal level value of the detection means drops to a predetermined width or more at a substantially central portion,
It is characterized in that the document on the document table is determined to be a book document.

[0017] Claim 5 is Claim 2 and Claim 3
In the image forming apparatus described in any one of the above, a plurality or a plurality of rows of the sensors are provided in a direction substantially orthogonal to an exposure scanning direction of the exposure scanning unit.

According to a sixth aspect of the present invention, in the image forming apparatus according to the fifth aspect, when the output signal level value of at least one of the sensors is reduced to a predetermined width or more at a substantially central portion, the document placing table is provided. It is characterized in that the upper manuscript is determined to be a book manuscript.

According to a seventh aspect of the present invention, in the image forming apparatus according to the fifth aspect, even when the output signal level values of both of the sensors have decreased by a predetermined width or more at the substantially central portion, the judging means determines the timing of the mutual decrease. If there is a deviation,
It is characterized in that it is determined that the document is a thin leaf document.

According to an eighth aspect of the present invention, in the image forming apparatus according to the fifth aspect, the document placing table presses the document against the document placing table, and the height of the cover varies with the thickness of the document. A means for detecting the height position of the lid is provided, and the determination means determines whether the document on the document table is a thin leaf document or a book document based on the detection signal of the lid height position detecting means. Is determined.

According to a ninth aspect of the present invention, in the image forming apparatus according to the first aspect, the document placing table is configured to automatically transport a document by a transport belt and to contact the transport belt of the automatic document feeder. Comprises a plurality of height detection means for detecting a partial height displacement, the determination means,
It is also characterized in that it is determined from the detection signal of the height detecting means of the automatic document feeder whether the document on the document table is a thin leaf document or a book document.

According to a tenth aspect, in the image forming apparatus according to the first aspect, the determining means determines that the original on the original placing table is a book original, and then places the book original at an angle. Or not.

According to an eleventh aspect of the present invention, in the image forming apparatus according to the tenth aspect, when the book original is placed at an angle on the original placing table, the book document is placed inside the folded portion of the book original as it is. It is characterized in that the irradiation means is controlled to change to the eraser.

According to a twelfth aspect of the present invention, in the image forming apparatus according to any one of the first to eleventh aspects, the irradiating means includes a plurality of LED erasing arrays arranged to face each other along the axial direction of the image carrier. It is characterized by being.

By adopting a means which satisfies the above-mentioned object, it is automatically detected whether the original on the original placing table is a thin original or a book original. The position and width thereof are automatically detected, and the center bent image is changed to a center erased portion.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described.
This will be described with reference to the drawings. FIG. 1 shows an electronic copying machine which is an image forming apparatus. In the copying machine main body S, a photosensitive drum 1 as an image carrier is arranged. This photosensitive drum 1
Are connected to a drive source (not shown).

Around the photosensitive drum 1, along the rotation direction, a charging charger 2, an exposing unit 4, a developing device 5, a transfer charger 6, a peeling charger 7, a cleaning device and a discharging lamp (not shown) are shown. Be placed.

On the upper surface of the copying machine main body S, there is provided a document table 10 made of a glass plate on which a document P is placed, and an optical system 8 is provided between the document table 10 and the exposure section 4. Are located.

At the bottom of the main body S of the copying machine, a plurality of cassettes 11 each containing sheets of different sizes are arranged. The pickup belt 12 is rolled on the uppermost sheet in the cassette 11 to form a sheet feeder 13.

An automatic duplex paper feeder 14 is disposed further above the uppermost cassette of the paper feeder 13. A large-capacity paper feeder 15 is disposed on the sides of the automatic duplex paper feeder 14 and the paper feeder 13, and a manual paper feeder 16 is disposed above the large-capacity paper feeder 15. .

A paper transporting device 17 is arranged on each paper feeding side of each of the cassettes 11 of the paper feeding device 13, the automatic duplex paper feeding device 14, the large capacity paper feeding device 15 and the manual paper feeding device 16. And a pair of registration rollers 1 disposed at the lower side of the developing device 5 with the paper fed from each device.
8. The transfer charger 6 is disposed on the sheet discharge side of the pair of registration rollers 18.

A transport belt 19 for transporting a sheet is disposed at a side portion of the peeling charger 7. A fixing device 20 is disposed at a transport end of the transport belt 19, and a paper discharge tray 21 is attached to a side portion of the copying machine main body.

FIG. 2 is an enlarged view of the vicinity of the photosensitive drum 1 in particular. Here, the peeling charger 7 and the charging charger 2
Between the cleaning device 23 and the static elimination lamp 24
Is shown.

Further, between the charging charger 2 and the exposing unit 4, an LED erasing array 25 constituting irradiation means to be described later and an LED erasing array cleaner (not shown) are arranged.

The LED erasing array 25 is conventionally provided depending on the model. A plurality of LED erasing arrays 25 are provided in one row in the longitudinal direction of the photosensitive drum 1, that is, in the front side and the rear side of the apparatus main body S. (62 pieces), and are arranged densely with each other.

Then, a plurality of designated LEDs are
By illuminating the erasing array 25 and partially irradiating the photosensitive drum 1, the surface potential of only the irradiated portion of the photosensitive drum 1 charged by the charging charger 2 is reduced, so that the portion is electrostatic latent This is the processing of a so-called middle eraser where no image is formed.

Explaining that, when a normal full-size copy is made, it is not turned on. For example, if the original to be copied has a character group and a frame surrounding the character group, and only the character group is needed as the image to be copied and the frame image is to be removed, a specific portion of the original can be specified. Good. The LED erasing array 25 is turned on for the corresponding one of the photosensitive drums, and partial erasing of the copy image in which the frame portion is replaced with a white belt portion becomes possible.

As shown in FIG. 3A, a sensor 40 as detection means, which will be described later, is mounted on the scanner 31 which is reciprocally driven by mounting the exposure lamp 30 in the optical system 8.

The sensor 40 is arranged on the upstream side of the exposure lamp 30 in the exposure scanning direction, which is the moving direction of the scanner 31, and the document placed on the document table 10 immediately before the exposure lamp 30 performs the exposure scanning. The light is projected to P and the reflected light is received to output a detection signal.

The sensor 40 is electrically connected to a control circuit 50 constituting a judgment means. This control circuit 50
Receives a detection signal of the sensor 40 and compares the signal with a predetermined value stored in advance.

From the result, the document P on the document table 10
Is a book original Pa or a thin original Pb. Then, if it is the book document Pa, the position and width of the center folded portion q are determined.

The control circuit 50 is electrically connected to the LED erasing array 25 and controls the lighting timing and the lighting time. That is, the surface potential is lowered by irradiating the photosensitive drum 1 corresponding to the above-mentioned bent portion q.

When the original is set on the original table 10 and the copy switch is turned on, the optical parts of the optical system 8 expose and scan the original surface, and the exposure unit 4 exposes the original image to the peripheral surface of the photosensitive drum 1. Is imaged.

The peripheral surface of the photosensitive drum 1 is charged by the charging charger 2 in advance, and the original image is formed as an electrostatic latent image. When the photoreceptor drum 1 rotates and the electrostatic latent image portion faces the developing device 5, the developer is supplied from here and the image is visualized.

Simultaneously with the start of copying, for example, a sheet of the designated size is supplied from the sheet feeding device 13 via the sheet conveying device 17. If the sheet feeding from the large-capacity sheet feeding device 15 is instructed, the sheet is naturally fed from this device 15.

The fed paper is sent between the photosensitive drum 1 and the transfer charger 6 at a time by a pair of registration rollers 18, and an image visualized by the transfer charger 6 is transferred to the paper. .

This sheet is peeled off from the photosensitive drum 1 by the action of the peeling charger 7 and is conveyed on the conveyor belt 19. Then, the image is guided to the fixing device 20 to fix the image, and the paper is discharged to the paper discharge tray 21.

The photosensitive drum 1 continues to rotate. The portion where the sheet has been peeled off by the peeling charger 7 is wiped and removed from the peripheral surface of the drum 1 in opposition to the cleaning device 23, the charge is removed by the charge removing lamp 24, and the sheet again faces the charging charger 2. Will be repeated.

Immediately before the original P is exposed and scanned by the optical system 8, the sensor 40 detects the presence or absence of the bent portion q of the original P as shown in FIG. Here, if it is a normal thin leaf document not shown here, naturally,
Is not detected, so that the copying operation as described above is repeatedly performed.

In the case of the book document Pa, an output waveform of the sensor 40 is formed as shown in FIG. That is, since the light output from the sensor 40 is reflected 100 and received at the leading end of the document surface, a predetermined signal level value is detected. That is, this portion is determined to be the original surface.

With the movement of the scanner 31, the sensor 4
As the 0 moves, the signal level value is kept constant as long as the original surface is detected. However, when the light from the sensor 40 reaches the bent portion q, the reflected light is almost absorbed, and the signal level value is extremely reduced.

This signal level value continues to be reduced for a predetermined length La, returns to the original signal level value, and continues for a certain period of time. Then, there is no reflected light at the end of the document surface, and the signal level value decreases again.

As described above, when the signal level value is L0 between the leading edge and the trailing edge of the document, and a waveform in which the signal level decreasing range La is equal to or larger than the predetermined width is formed substantially at the center thereof,
The control circuit 50 compares the information with the information stored in advance and determines that the document on the document table 10 is the book document Pa. At the same time, from the range of the decrease in signal level value and its position,
The position and width of the center bent portion q are automatically recognized.

The control circuit 50 controls the LED erase array 25 by accurately tracing the waveform. That is,
The timing of turning on and off the LED erasing array 25 is controlled so as to correspond to the position and width of the signal level decrease, and the processing of the center erasing section for erasing the center bent section q is automatically executed.

In this way, even for the book original Pa, the user does not need to select the book copy mode each time and does not need to set the width of the middle erasing part, and the middle erasing part processing is automatically performed. A copied image can be obtained, and the convenience is improved without the hassle.

In the above embodiment, the scanner 31 on which the exposure lamp 30 is mounted is provided with the sensor 40 and used as a movable sensor. However, the present invention is not limited to this.

For example, as shown in FIGS. 4A and 4B, a plurality of sensors 40a may be arranged at predetermined intervals along the traveling direction of the scanner 31. That is,
The sensor 40 a is mounted not only on the base frame 32 constituting the optical system 8 but also on the upper surface of the lens cover 33.

The detection timing of each sensor 40a is sequentially performed by the scanner 31 which is moved and is located immediately before the exposure lamp 30 performs exposure scanning.
Although it is a so-called fixed sensor 40a, it performs exactly the same detection action as the above-mentioned movable sensor 40.

Modifications will be described below with reference to FIG. In both cases, a mobile sensor, which is a sensor provided in the scanner, is shown and described as a detecting means, but there is no problem even if this is replaced with the fixed sensor 40a shown in FIG. And
The same parts as those in the above embodiment are denoted by the same reference numerals, and a new description will be omitted.

FIGS. 5A and 5B show a first sensor 41 and a second sensor 4 along the longitudinal direction of the scanner 31. FIG.
This is an example in which 2 are arranged at predetermined intervals. Originally, these sensors 41 and 42 are provided to detect the size (size) of the document P, but are used here as they are.

As shown in FIG. 7A, if the book document Pa1 is relatively large, the document surface exists on the detection locus of the first sensor 41 and the second sensor 42. Therefore, the output waveforms of the sensors 41 and 42 have exactly the same shape, and the signal level value is reduced at a predetermined width at a substantially central portion.
Is determined to be a book document Pa, and the position and width of the center eraser processing for the LED erase array 25 are automatically controlled.

As shown in FIG. 7B, if the book document Pa2 is relatively small, for example, only the first sensor 41 has a document surface on the detection locus, and the second sensor 42 has a document surface on the detection locus. Has no manuscript surface.

That is, only the output waveform of the first sensor 41 has a decrease in the signal level value with a predetermined width substantially at the center, and is not output by the second sensor 42. However, since a predetermined output waveform is formed on at least one of the sensors, here the first sensor 41, the control circuit 50 determines that the original is a book document, and determines the position of the middle eraser processing for the LED erase array 25 and Control width automatically.

FIG. 6 shows a document on the document table 10 on the assumption that the first sensor 41 and the second sensor 42 are arranged at a predetermined interval along the longitudinal direction of the scanner 31. For example, the output waveforms of the sensors 41 and 42 when the cutouts Pb1 and Pb2 of two newspapers are placed and copied are shown.

When one of the cutouts Pb1 is placed at an angle, the first sensor 41 and the second sensor 42
Are in a state where the signal level value is reduced substantially at the center, and are waveforms close to the pattern of FIG.

However, the control circuit 50 controls the first and second
The sensor outputs of the sensors 41 and 42 are compared and referred to. Here, since the reduction width of the signal level value of each of the sensors 41 and 42 is longer than a predetermined value, and the start timing is offset even if the timing of the reduction of the signal level value coincides, the original is a book original Pa. Instead, it is possible to prevent erroneous detection without determining that the document is a normal thin-sheet document Pa, and
A normal copying operation without turning on the D erase array 25 is performed.

FIG. 7 shows that the original P on the original table 10 is converted to a normal thin original Pb by another means different from the sensors 40 and 40a.
Or a book original Pa.

Here, the platen cover 26 is used as a lid for pressing the original P on the original placing table 10 and bringing the original surface into close contact with the original placing table 10. Alternatively, an automatic document feeder (called ADF or DF) may be used instead of the platen cover 26.

The rotation support 26 of the platen cover 26
a, a rod 27 extending into the apparatus main body S is integrally provided. On the other hand, a micro switch 43 as means for detecting the height position of the platen cover 27 is arranged at a predetermined position in the apparatus main body S.

As shown in FIG. 9A, when the original is a thin sheet, the position of the platen cover 26 does not change, and the end of the rod 27 has the micro switch 43 turned on. Since the detection signal of the micro switch 43 is ON, the control circuit 50 places the thin leaf document P on the document table 10.
It is determined that b exists.

As shown in FIG. 7B, the document table 10
If the upper document is thick, the cover 26 itself floats from the document table 10 with the platen cover 26 closed, and the rod 2
7 turns off when it is separated from the microswitch 43. The control circuit 50 determines that the document on the document table 10 is a book document Pa.

By combining the detection operation of the first sensor 41 and the second sensor 42 described above with reference to FIGS. 5 and 6 and the detection operation of the microswitch 43 described here, a plurality of positions ( It is needless to say that the detection is performed in (phase) and the detection accuracy is increased.

FIG. 8 is a flowchart showing a specific example. When the copy button is depressed by the user to instruct copying, the control circuit 50 determines in step 1 whether the platen cover 26 (or DF) is closed. This judgment is made by the micro switch 43
From the presence or absence of the detection signal.

If No, it means that the platen cover 26 is open, and the routine goes to Step 2. If Yes, it is closed, and the process proceeds to step 3 to determine that it is not a book copy, and proceeds to step 4 to perform a normal copy operation.

In step 2, it is determined whether the output of the first sensor 41 is divided into two. That is, the second sensor 42 is provided at the end of the scanner 31 in the longitudinal direction, and does not detect a small book document Pa2 as shown in FIG.
1 is provided substantially at the center of the scanner 31 in the longitudinal direction, and as shown in FIG.
1 as well as a small book document Pa2 shown in FIG.

If No in step 2, the process proceeds to step 4 via step 3. If Yes in step 2, the process proceeds to step 5 where the output K of the first sensor 41 is within ± 15% of L1 = L2 and 30% of L3 <L0.
Determine if:

That is, as shown in FIG.
In the output waveform of the sensor 41 of FIG.
It is determined whether or not the position 3 is located substantially at the center of L0 between the leading edge of the copy surface and the terminal and within a predetermined width.

If No, a normal copy operation from step 3 to step 4 is performed. If Yes, go to step 6. Here, the first and second sensors 41 and 42 are used.
Are the same, that is, the pattern of FIG. 5 (A), or the detection of only the first sensor, that is, FIG.
It is determined whether the pattern is (B).

If the answer is No in both cases, a normal copy operation is performed from step 3 to step 4. If one of them is Yes, the process proceeds to step 7 where it is finally determined that a book copy is made, and the above-described book copy operation is performed.

The user does not always place the book document Pa on the document table 10 in a correct state. With the control of the control circuit 50 for the LED erasing array 25 described above, the hollow portion q of the book document Pa placed at an angle cannot be processed.

Therefore, the control circuit 50 controls the document table 1
In addition to detecting the type of the original on top 0 and detecting the position and length of the folded portion q when it is determined that the original is the book original Pa, a function for determining whether or not the book original Pa is inclined is provided. Have.

FIGS. 9A and 9B show specific examples. That is, as shown in FIG. 2B, the control circuit 50 compares the output waveform of the first sensor 41 with the output waveform of the second sensor 42. At this time, the decrease width L3 of the signal level value
And L3 'are the same, but if the timings are different, it is determined that the book document Pa is placed in an inclined state.

FIG. 9A shows a flowchart in which the control circuit 50 determines whether or not the book document Pa is tilted. In other words, the steps from step 1 to step 5 when the copy button is depressed and starting from step 2 to step 5 are exactly the same as starting from step 1 and step 2 to step 5 in the flowchart described above with reference to FIG. Therefore, a new description is omitted here.

If Yes in step 5, step 8
The difference between L1 and L1 'is within 3%, and L2 and L1'
After satisfying all that the difference from 2 ′ is within 3% and the difference between L3 and L3 ′ is within 3%, L0 and L0 ′ are satisfied.
It is determined whether or not the difference is within 10%.

If No, the process proceeds to step 3 via step 2, and a normal copy operation is performed. If Yes, the process proceeds to step 9 where it is determined that the book (book document Pa) is inclined.

At this time, on an operation panel (not shown),
For example, a message such as "Please correct the inclination of the document" is displayed. Since the user recognizes the inclination of the book document Pa and corrects it correctly, the book copy is made promptly.

FIG. 10A shows a document table 10 having an automatic document feeder 26A as a lid. here,
Document feed belt 28 constituting automatic document feeder 26A
A plurality of rollers 43 are arranged at a predetermined interval along the feeding direction of the belt 28 inside.

Each roller 43 is elastically pressed and pressed against the back surface of the document feed belt 28 by a pressing spring 44 to be brought into rolling contact with the roller. A microswitch 45 is attached to each roller 43 so that the floating of the roller 43 is detected.

When the book document Pa is placed on the document table 10, the document document feed belt 28 of the automatic document feeder 26A serving as a cover presses the book document Pa. At this time, if the document is a thin document, the position of each roller 43 does not fluctuate, and therefore, the microswitch 45 does not detect the floating of the roller 43.

As shown in FIG. 9B, the book original Pa
In this case, the original document feed belt 28 presses the front cover, the back cover, and the back portion, and the book document Pa portion where the document feed belt 28 in which the roller 43 is in contact with the feed belt 28 comes into contact has an uneven shape. The roller 43 partially floats, and the microswitch 45 detects this. The control circuit 50 includes an automatic document feeder 26A
When there is a detection signal from the microswitch 45 disposed therein, the document on the document table 10 is determined to be a book document Pa.

The result may be added to the flowcharts described with reference to FIGS. 8A and 9A. That is, it is finally determined that the document is a book document, and then execution of book copy is determined. Alternatively, the mode directly shifts to the book copy mode. In any case,
More accurate detection becomes possible.

FIGS. 11A and 11B show examples in which the width of the center folded portion q varies depending on the type (thickness, binding method, etc.) of the book original. Is performed.

That is, as shown in FIG. 9A, in the case of a relatively thin book original Paa, the range of decrease in the signal level value output from the sensor 40 is relatively narrow, whereas B) As shown in FIG.
In the case of aa, the range in which the signal level value decreases is relatively long, so the range of the predetermined value stored in advance in the control circuit 50 is long.

FIGS. 12A and 12B are examples showing that the position of the center folded portion q is different depending on the type (thickness, binding method, etc.) of the book document. Detection is performed.

That is, especially in the case of a thick book document Paa, and when the spread page to be copied is almost at the center of the book document as shown in FIG. The position where the level decreases is formed substantially uniformly from the center.

However, as shown in FIG. 13B, when the facing pages to be copied are biased toward either the front cover or the back cover of the book document, the detection signal level in the output waveform of the sensor 40 decreases. The position is shifted to one side from the center.

As described above, the control circuit 50 reliably recognizes the actual position and width of the bent portion q. Therefore, it is sufficient to perform the hollow portion processing on this portion, and a high-quality copy can always be provided.

This type of mode may be selectable by a serviceman's operation as needed, and the position and width of the hollow portion may be automatically set by switching the user.

As shown in FIG. 13, when the control circuit 50 determines that the book document Pa is placed at an angle, the control circuit 50 controls the LED erasing array 25 to light up with a time difference. Thus, the process of obtaining the hollow portion Z can be performed without correcting the inclination of the book document Pa.

[0100]

As described above, according to the present invention, it is automatically detected whether or not the original on the original placing table is a book original, and if the original is a book original, the position and width of the folded portion are determined. By automatically detecting and changing the image of the bent part into a center-erased part, it is possible to obtain high image quality, improve usability, and improve reliability.

Further, the LED erasing array conventionally used as the irradiating means can be used as it is, and only the setting of the detecting means and the control circuit is required, so that the adverse effect on the cost can be suppressed very slightly.

[Brief description of the drawings]

FIG. 1 is a schematic front view of an electronic copying machine as an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a front view of a part of the electronic copying machine around the photosensitive drum according to the embodiment;

FIG. 3 is a schematic configuration of a detection unit, a determination unit, and an irradiation unit, and an output waveform diagram of the detection unit according to the embodiment;

FIG. 4 is a partial perspective view of an electronic copying machine and a configuration diagram of a detecting unit according to another embodiment.

FIG. 5 is a diagram showing output waveforms of a plurality of sensors for book documents of different sizes according to another embodiment.

FIG. 6 is an output waveform diagram of a plurality of sensors for two thin-sheet documents according to the embodiment;

FIG. 7 is a configuration diagram of a detection unit for detecting a different type of original according to another embodiment.

FIG. 8 is a flowchart of a determination circuit for determining the type of a document according to the embodiment, and an output waveform diagram of a detection unit.

FIG. 9 is a flowchart of a determination circuit for determining the type of a document and determining the inclination of the document according to still another embodiment, and an output waveform diagram of a detection unit.

FIG. 10 is a configuration diagram of a detecting unit according to still another embodiment for detecting different types of originals.

FIG. 11 is an output waveform diagram of a detection unit for book originals having different thicknesses.

FIG. 12 is an output waveform diagram of a detection unit based on a difference in copy position in the same book document.

13A and 13B are an output waveform diagram of a detection unit for a book document placed obliquely on a document mounting table, and a control explanatory diagram of an irradiation unit.

[Explanation of symbols]

 P: manuscript, 10: manuscript mounting table, 31: scanner, 1: photoconductor drum, 40: (movement) sensor, Pa: book manuscript, Pb: thin manuscript, 50: control circuit, 25: LED erasing scanner, q: bent part, Z: eraser part, 32: base frame, 33: lens cover, 40a (fixed) sensor, 26: platen cover, 43: micro switch, 26A: automatic document feeder, 28: original Conveyor belt.

Claims (12)

[Claims] An original mounting table for mounting an original, an exposure scanning means for exposing and scanning the original on the original mounting table, and an image carrier for carrying an original image exposed and scanned by the exposure scanning means. In the image forming apparatus provided with the image forming apparatus, the document is placed on the exposure scanning unit, detects the document on the document table before the exposure scanning by the exposure scanning unit, and detects a throat (hereinafter referred to as a center fold) between spread pages of the document. And the presence or absence of the above-described folded portion based on the detection signal of the detection means, and determines whether the original is a thick book (hereinafter referred to as a book original) or a thin leaf. Means for judging whether the original is an original or not. When the judging means judges the book original, the signal is received to irradiate the image carrier area corresponding to the center folded portion of the book original and a white band (hereinafter referred to as a , Called the middle eraser) An image forming apparatus comprising irradiating means, that provided with the that. 2. The exposure scanning means comprises a scanner having an exposure lamp disposed thereon, and the detection means is a sensor which is disposed on the scanner and moves together with the scanner to irradiate a document surface and detect the presence or absence of reflected light. The image forming apparatus according to claim 1, wherein: 3. The exposure scanning means includes a base frame and a lens cover, and the detection means is disposed on the base frame and the lens cover at a predetermined interval along the exposure scanning direction. 2. The image forming apparatus according to claim 1, wherein the plurality of fixed sensors detect the presence or absence of reflected light by irradiation. 4. When the output signal level value of the detecting means drops to a predetermined width or more at a substantially central portion between the leading edge of the document and the terminal, the determining means determines whether the document on the document table is a book document. The image forming apparatus according to claim 1, wherein the image forming apparatus determines that the condition is true. 5. An image according to claim 2, wherein said sensor is provided in a plurality or a plurality of rows in a direction substantially orthogonal to an exposure scanning direction of said exposure scanning means. Forming equipment. 6. When the output signal level value of the sensor on at least one side decreases to a predetermined width or more at a substantially central portion between the leading edge of the document and the terminal, the determining means determines whether the level of the output signal is higher than a predetermined value. 6. The image forming apparatus according to claim 5, wherein it is determined that the original is a book original. 7. When the output signal level values of the sensors on both sides decrease by a predetermined width or more at a substantially central portion between the leading edge of the document and the terminal, the judging means shifts each other at the timing of decrease. 6. The image forming apparatus according to claim 5, wherein if there is a document, the document is determined to be a thin leaf document. 8. The document placing table has a cover that presses the document against the document placing table, the height of which varies depending on the thickness of the document, and a means for detecting the height of the cover. 6. The apparatus according to claim 5, wherein the determining means determines whether the document on the document table is a thin-sheet document or a book document based on a detection signal of the lid height position detecting means.
The image forming apparatus as described in the above. 9. An automatic document feeder for automatically transporting an original by a transport belt and a plurality of automatic document feeders for detecting a partial height displacement by contacting the transport belt of the automatic document feeder. Height detecting means, wherein the determining means determines from the detection signal of the height detecting means of the automatic document feeder whether the document on the document table is a thin leaf document or a book document. The image forming apparatus according to claim 1, wherein: 10. The method according to claim 1, wherein the determining means determines that the original on the original placing table is a book original and determines whether the book original is placed at an angle. Item 2. The image forming apparatus according to Item 1. 11. The illuminating means controls the irradiating means so that when the book document is placed on the document table at an angle, the book document is changed from the center folded portion to the central eraser portion as it is. The image forming apparatus according to claim 10, wherein: 12. The image forming apparatus according to claim 1, wherein said irradiating means is a plurality of LED erasing arrays arranged to face each other along the axial direction of said image carrier. Image forming device.