JPS6341842A - Image processor - Google Patents

Abstract

PURPOSE:To accurately detect the existence or size of an original by forming the original covering surface of a carrying belt as a mirror surface. CONSTITUTION:In case of covering an original set up on an original platen glass 2 from upper side with the carrying belt 103, the side of the belt 103 opposed to the back of the original, i.e. an original covering surface 103a, is formed as mirror surface. A part of light radiated from a light source 4 is reflected at random by an original image surface 20a as light beams A and the other is transmitted through the inside of the original 20. The transmitted light is regularly reflected by the mirror surface of the original covering surface 103a and the reflected light is transmitted through the inside of the original 20 again, reflected at random at the time of outgoing from the original image surface 20a and a part of the reflected light becomes light B. The light beams A, B are unitedly received by a solid image pickup element 9. Consequently, the existence and size of the original can be accurately detected independently of the format and colors of the original.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention uses an image processing bag, and in particular, a document feeder and an optical sensor that detects various optical information such as the presence or absence of a document to be read and its size. The present invention relates to an image processing apparatus including a document detection means for electrically processing a document.

(Conventional Technique #) In general, in an image processing apparatus equipped with this type of document feeding means, the size of the document is detected, for example, in Japanese Patent Laid-Open No. 54-103
As disclosed in No. 5, a sensor or the like is provided on the document conveyance path, and the determination is made based on the document passage time. With this type of detection method, if the original is used only as a pressure plate without using the original feeding means, for example, the original is irregularly shaped, the original is very thin or thick, and if the original is not used for book copying. When doing so, the size of the 'IX document cannot be detected because the document does not pass through the document conveyance path.

Another method is an optical method, in which light is irradiated onto the area where the document is placed, the reflected light from the image surface of the document is received by an optical sensor, and an output is generated according to the incident intensity. One example is a method of extracting a signal and determining the presence or absence of a document or +fX document size.

By the way, when the size of the document to be covered by the conveyance belt of the document feeding means is small.

A part of the document cover surface of the document transport belt that faces the back side of the document, that is, the document cover surface in an area that is outside the size of the document, may also be recorded as an image, so that part may be recorded as a white image. In order to record the document as a document, the cover surface of the document is made white.

However, in the above case, if the background color of the document is white like the document cover surface, the light reflected from the image surface of the document and the light reflected from the document cover surface of the document transport belt are different. Since they are detected by the optical sensor at almost the same level, it is extremely difficult to determine the presence or absence of a document or the size of the document from the difference in these reflected lights.

Therefore, above! ! There have also been proposals to make the X-document covering surface black, or to open the IXX feeding device so as not to cover the back surface of the document when detecting the presence or absence of the document and its size. In this way, the reflected light from the area protruding from the M-transfer image plane will not be incident on the optical sensor, so a clear difference will occur in the light level, and the presence or absence of the document and its size can be determined.

However, in this case, the following situation arises. In general, the original image is projected onto a photoreceptor or taken 1! When reading with an element, a document is irradiated with light, and the reflected light is imaged on a photoreceptor or an image pickup element through an optical system. At this time, part of the light irradiated onto the original is diffusely reflected on the surface of the original, and the other part is transmitted through the original and exits from the back surface of the original. The ratio of the reflected light to the transmitted light varies depending on the material, thickness, etc. of the original. If there is another paper behind the original (for example, in the case of a book) or if there is a document cover member with a white original cover surface, the light that has passed through the original will be absorbed by the other paper or cover surface. It is reflected by the surface, a portion of which passes through the document again, and is projected onto the photoreceptor or image sensor through the optical system, contributing to exposure of the photoreceptor or to the reading of the image. Therefore, in a general image forming or processing apparatus, the white level of the original is set at a level including the light transmitted through the rX original and returned as described above. However, as mentioned above, when the document cover surface is made black or the fXX feeding device is opened to detect the document, the light that passes through the document becomes a black original TQM! Since the light is absorbed by the surface or diffused into the air, it is no longer used as light for exposing the photoreceptor or for reading. Therefore, in the above case, the light intensity level for the white color of the document material will be lower than in the case of using a document conveyance belt having a white document covering surface. For example, in the case of a manuscript made of high-quality paper that is normally used for general office work, there is a lot of light that passes through the manuscript and does not return, so that the background of the resulting recorded image may be considerably obscured.

In addition, tracing paper (7) J' used for drawings etc.
In the case of an accompanied by difficulties.

Therefore, the only method currently in practical use is to color the document transport belt in a color for which the photoreceptor or image sensor has extremely high color sensitivity (in other words, a color that would be interpreted as white), and vice versa. Some devices attempt to determine the presence or absence of a document using an optical sensor that is separate from the image sensor and has low color sensitivity. Then, to the optical sensor, the color of the document covering surface appears darker than the white color of the document background, and the difference between the two becomes clear.

(Problem to be solved by the invention) However, in the case of such conventional examples, the color of the document background is not necessarily white, and there are many cases of colored backgrounds, and in such cases, the above-mentioned In addition, in the conventional example described above, an optical sensor for detecting the presence or absence of a document and its size is combined with an image sensor that reads the document image and converts it into an electrical signal. There was also the problem that it could not be applied. Here, the document conveyance belt is required to have n-document conveyance properties, that is, to have a high surface friction coefficient.

However, in a document conveying belt whose photoreceptor or image sensor is colored in a color with very high color sensitivity, an optical sensor is used to detect the presence or absence and size of a document, regardless of the form and color of the document. There is a problem in that it is not possible to accurately detect the presence or absence of a document or the size of the document.

Therefore, the present invention has been made to solve the above-mentioned problems of the conventional example, and its purpose is to provide an image processing device that can accurately detect the presence or absence of a document and its size. It is in.

(Means for Solving the Problems) In order to achieve the above object, the present invention includes a document feeder that feeds the document to a reading position by a conveyor belt, and an image surface of the document that is irradiated. In this image processing device, the image processing device includes a light source that detects light reflected from the light source and an image sensor that detects reflected light from the light source and converts it into an electrical signal.The image processing device is configured such that the surface of the conveyor belt on the side that covers the original is made into a mirror surface.

(Function) In the present invention having the above configuration, the surface of the conveyor belt on the side that covers the document is made into a mirror surface, so that the presence or absence of the document and the size of the document can be accurately detected.

(Example) The present invention will be explained below based on the illustrated example. 1st
The figure is a schematic diagram of an image processing device equipped with a document feeder 2'4cn equipped with a document conveyor belt, which is a feature of the present invention. In the figure, 100 is a document feeder as a document feeder; The manuscript feeder;! Reference numeral 1100 feeds the document set on the paper feed tray 101 to a predetermined reading position n, and discharges the document onto the upper surface of the cover 106 after processing. Here, the document is conveyed by rotating a conveyor belt 103 wound around a driving roller 102 and a driven roller 104 in the direction of the arrow. It is pressed in the pressing direction.

A document table glass 2 is attached to the top surface of the image reading section 1, on which a document to be read is placed. Inside the image reading unit l, there is a light source 4 that irradiates light onto the image surface of the memorandum manuscript while moving in the sub-scanning direction shown by the arrow, and a light source 4 that irradiates light onto the image surface, etc. of the memorandum manuscript, and the light emitted from the light source 4 is reflected by the image surface, etc. The light is received through mirror 5゜6.7 and lens 8.
i: A solid-state image sensor 9 that converts into an air signal is provided.

Further, the image recorder Q unit IO includes a semiconductor laser 11 for emitting a laser beam according to an image signal received from the image reading Ff&l, and a semiconductor laser 11 for scanning and exposing the surface of the photoreceptor by changing the traveling direction of the laser beam while rotating. The laser beam reflected by the rotating polygon fi 12 is guided onto the photosensitive drum 14 via the mirror 13, and is transferred onto recording paper through various known electrophotographic processes. , visualized.

Note that an unillustrated 'fX document ratio detection device is provided between the solid-state image sensor 9 and the semiconductor laser 11, and a control circuit (not shown) causes the light source 4 to move in front of the image surface and the document cover surface. The document detection device δ detects the signal obtained by scanning, and detects the presence, size, or position of the document a. After selecting the recording paper size and projection magnification based on the information obtained in the pre-scan, the main scan is performed in order to read and record document image information.

Next, the conveyor belt 103, which is the most characteristic feature of the present invention, will be explained. The conveyor belt 103 is the document feeder lOO
When the original placed on the original platen glass 2t is covered, the surface of the conveyor belt 103 opposite to the first surface of the original, that is, the front surface of the original, is mirrored (or has a specular reflectance of 60 or less). 90% semi-mirror surface).

Therefore, the principle of how the light from the light source described above is reflected and detected on the mirrored (or semi-mirror) document covering surface as described above will be explained based on FIGS. 2 to 5. .

FIG. 2 shows the principle of light reflection in the area where the conveyor belt 103 covers the original 20. A part of the light emitted from the light source 4 is diffusely reflected on the original image surface 20a and becomes light ray A, and the rest is The inside of the document 20 is transmitted through. The transmitted light is
Since the rX draft covering surface 103a is a mirror surface (or semi-mirror surface), 100% (or 60 to 90%) of light is regularly reflected on that surface.

The reflected light passes through the interior of the yX document 20 again, and is diffusely reflected when exiting from the document image surface 20a, and a portion of it becomes light ray B. The light beams A and B are received together by the solid-state image sensor 9 via a mirror or lens (not shown). Here, when the document 20 is semitransparent paper such as tracing paper, if the document covering surface is black as in the conventional example described above, light will be absorbed by that surface and the amount of light received by the solid-state image sensor will be reduced. However, in the present invention, the document cover surface is mirror-finished (or semi-mirror-finished).
Therefore, by adding the light ray B to the light ray A, a sufficient amount of light is obtained, and the level is detected as being closer to white, so that the background of the recorded image does not become blackish.

FIG. 3 shows the principle of light reflection in an area below the conveyor belt 103 where there is no document. In this case, the light emitted from the light source 4 is directly reflected almost specularly by the detection cover surface 103a; Almost no light reaches the image sensor 9. Then, it will be detected as a level close to black.

Therefore, for the reasons shown in FIGS. 2 and 3 above,
For example, as shown in FIG. 4, an original 20 having a width W is placed on the upper surface of the original platen glass 2, and a conveyor bell) 1
When pre-scanning is performed in a state covered by 03, the signal received by the solid-state image sensor 9 and detected by the a-document detection device (not shown) is as shown in FIG. That is, the signal obtained by main scanning along the C line is detected as almost white level in the portion of the radial W of the JI2 draft 20, except for the portion where the image is drawn, as shown in Fig. 5 (Ca). The peripheral portion of the document 20 is detected as a black level. Further, all signals obtained by main scanning along the D line where the original 20 does not exist are detected as a black level, as shown in FIG. 5(b).

As described above, the reflected light from the original image surface 20a or the original cover surface 103a in FIG. There is no problem that the color cannot be distinguished from the color of the cover surface of the document, and the rXX2O3 boundary is clearly distinguished and detected between the white level and the black level. Therefore, as will be described in detail later, by detecting, as the edge of the document 20, the point where the black level signal changes to the self-level signal during the scanning process by the document detection device (not shown), the jXX2O3 size and position can be determined. t can be found.

Next, the reason why the document covering surface 103a is made to have a regular reflectance of 60 to 90% will be described. If the original cover surface 103
If a is a mirror surface with a high specular reflectance of 90 to 100%, the reflected light from the tracing paper will become closer to the white level, as described above, for the same reason that the original covering surface 103a If there is dirt such as a fingerprint, the light will be reflected diffusely, causing a tendency for the light to wander and be mistakenly recognized as a white level.Furthermore, this will be easily noticeable in terms of appearance.
In the case of a semi-mirror surface of 90% to 90%, the above problems are almost eliminated for the following reasons.

That is, FIG. 6 shows the specular reflectance of the original covering surface 103a when the original covering surface 103a is scanned and read using tracing paper as the original 20, and the original covering surface 103a is free from dirt such as fingerprints on the original covering surface 103a. FIG.

Here, a comparison will be made between a case where the specular reflectance of the document covering surface 103a is 95% and a case where the specular reflectance is 70%. Then, the difference between the reading level for dirt and the original covering surface 103a is m in the case of 95%, and n( in the case of 70%).
m>n), and it is clear that the latter makes stains less noticeable. In addition, the reading level for translucent paper such as tracing paper decreases as the specular reflectance decreases, but since the change is minute, the S/N
The decrease in ratio is almost negligible. Therefore, according to the results of experiments that took into account 131 problems of conspicuousness of dirt and reduction of S/N ratio, a regular reflectance of 60 to 90% is good.

Furthermore, a means for forming the document cover 103a of the conveyor belt 103 into a mirror surface or a semi-mirror surface having a regular reflectance of 60 to 90% will be described. Here, since it is a necessary condition for the conveyor belt lO3 to convey the document well, the surface on the conveying side, that is! ! It is necessary that the X document covering surface 103a has a high friction coefficient. As shown in FIG. 9(a), the conveyor belt 103 has a core body 103b having a high reflectance, and a cover member 103c having a high transmittance and a high friction coefficient is superposed on the outside of the core body 103b to form a two-layer structure. By making it a structure,
In addition to increasing the friction coefficient of the document transport surface, the document cover surface 1
It is possible to make 03a a mirror surface or a semi-mirror surface. In addition, as shown in FIG. 9(b), the conveyor bell) 103 has fine powder 103d of a highly reflective material on the cover member 103c.
A similar residue to that shown in FIG. 9(a) can also be obtained by mixing.

In addition, in FIGS. 9(a) and (h), the cover member 10
By applying a matte finish to the outer surface of 3c, it is possible to cover the original 1.
Freely selecting the specular reflectance of 03a is a circular movement and is effective against suction of the original due to static electricity generated during transport, so that the original transport performance is further improved. Furthermore,
If a metal wire or a metal plate is used for the core 103b of the conveyor belt 103 and urethane rubber is used for the cover member 103c, a mirror or semi-mirror surface is formed, and since the core is metal, it has a static neutralizing effect.) fX document conveyance is improved. Furthermore, the core body 103b may be made of silver dyed fabric.

On the other hand, FIG. 1θ shows another example of the conveyor belt in this embodiment.
3c and a cover member 113d as a second cover member with high transmittance and high friction coefficient are sequentially superposed to form a three-layer structure, so that the friction coefficient of the document transport surface is high and the document cover surface 113a is mirror-finished. Alternatively, it is possible to make it semi-mirrored.

In addition, in FIG. 10, by applying a satin finish to the outside of the cover member 113d, it is possible to freely select the specular reflectance of the document cover 103a, and it is also possible to freely select the specular reflectance of the document cover 103a. Since it is also effective for suction, document conveyance performance is further improved. Furthermore, by hairline processing the high reflectance cover member 113c,
Appropriate selection of specular reflectance results in rotation. At this time, if the line direction matches the sub-scanning direction, good results with less diffusely reflected light from the hairline surface can be obtained. Furthermore, the conveyor belt 113
The same effect can be obtained by using a sheet-like elastic member, for example, a polyester film, as the core body 113b, vapor-depositing aluminum for the cover member 113c, and using urethane rubber for the cover member 113d. The core body 113b may be made of silver dyed fabric.

As described above, in any of the methods shown in FIGS. 9 and 10, it is possible to obtain a conveyor belt that has a mirror surface or specular reflection*60 to 90% and has good document conveyance properties.

Next, the document detecting means performed during pre-scanning as described above, particularly pt> for detecting the document position t, will be explained below.

In Fig. 7, a document 2 is placed on the document table glass 2 of the image reading section l.
Basically it shows the state in which 0 is placed, Gi 2? Although the position is fixed, it can also fall diagonally as shown in the picture. in this case,
From the reference point SP on the document platen glass 2, the main scanning direction is X and the sub-scanning direction is Y, the time base m 20 and the four corner coordinates P,
(X+, Y,).

P7 (X2, Y2), P3 (X3
, Y3) and P4 (X4.Y4) are detected by pre-scanning the optical system, thereby J! ' This is to determine the size and position of the X document. Note that the document cover surface 103a is mirror-finished or semi-mirror-finished as described above so that the image data outside the combed area of the document 20 is always black data. In pre-scanning, main scanning and sub-scanning are performed to cover the entire glass area, followed by scanning for image reading and image recording.

FIG. 8 is a circuit diagram of a document detection device for detecting Moeki coordinates. Based on this, the circuit processing will be sequentially explained below. The image data (VIDEO) that has been binarized as a white image or black image by the previous scanning is shifted or transferred to the register 30.
Input in bits. When the 8-bit input is completed, the gate circuit 31 checks whether all of the 8-bit data is a self-portrait, and if yes, sends a 1 to the signal line 32.
Output.

F/F when the first 8-bit white appears after scanning the original
33 is set. This F/F33 is reset in advance by VSYNC (image leading edge signal), and the next VS
Leave it set until YNC comes. When the F/F 33 is set, the main scanning counter 3 at that time is stored in the latch 34.
A value of 5 is loaded. This is the XS target value XI of point P1
At the same time, the value of the sub-scanning counter 37 at that time is loaded into the latch 36. This becomes the Y-locus Pl value Y1 of the point PI. Therefore, the coordinates of point P1 (xl.

Y+) is found.

Also, each time 1 is output to the signal line 32, the main scanning counter 3
Load the value of 5 into latch 38. This value is immediately stored in latch 39 (until the next 8-bit data enters shifter register 30). When the value of the main scanning counter 35 when the first 8-bit white appears is loaded into the latch 39, it is compared in magnitude with the data in the latch 40 (which is set to 0'' at the time of VSYNC) by the comparator 41. If the data in latch 39 is greater, comparator 41 outputs a signal that indicates the data in latch 38 (which is greater than the data in latch 39).
9) is loaded into latch 40. Also, at this time, the value of the sub-scanning counter 37 is loaded into the latch 42. In this operation, the next 8 bits are shifted to shift register 3.
It is processed until it reaches 0. If the data comparison operation of the latch 39 and the latch 40 is performed for the entire image area in this way, the maximum value of the document area in the X direction will remain in the latch 40, and the coordinate in the Y direction at this time will remain in the latch 42. . Therefore, the coordinates (X2.Y2) of point P2 are found.

F/F43 is an F/F that is set when 8-bit white appears for the first time in each main scanning line.
It is reset by NC, and the first 8 bits are set to white and held until the next H3YNC. When the F/F 43 reaches 7-2, the value of the main scanning counter 35 is set in the latch 44, and is loaded into the latch 45 until the next H3YNC. Then, the latch 46 and the comparator 47 compare the magnitude. The maximum f1 in the X direction is preset in the latch 46 at the time VSYNC occurs. If the data in latch 46 is greater than the data in latch 45, comparator 47 signals and the data in latch 44 (which is equal to the data in latch 45) is loaded into latch 46.

If this operation is performed to compare 0 or more between H3YNC and the next H3YNC for the entire image area, the minimum value of the document coordinates in the X direction will remain in the latch 46. This is point P3, X'F! The value is x3. At the same time, I1 of the sub-scanning counter 37 is loaded into the latch 48 by the output signal from the comparator 47. This becomes the Y coordinate value Y3 of point P3. Therefore, point P(X3.
Y3) is found.

The channels 49 and 50 are loaded with the values of the main scanning counter 35 and the sub-scanning counter 37 each time 8-bit white appears in the entire image area.

Therefore, when the document pre-scanning is completed, the count value at the time when 8-bit white appears last remains in latches 49 and 50. As a result, point P4 (X4.Y4) is found.

The following eight latches (34, 36, 40°42.46
, 48, 49.50) data lines are connected to CPU (not shown).
The CPU reads this data when surface scanning is completed. Of these data, the points (X+, Y+), (X2
,Y+).

(X+, Y4) and (X2, Y4) The Marel area surrounded by Te is determined as a document area. Based on this, processes such as determining the image reading scanning stroke and selecting a paper feed cassette of a desired size are performed when scanning the document for image recording.

Therefore, when the document feeder of the above embodiment is used,
Even if the original is set at the reading position t in a skewed manner, the above operation can perform good processing.

(Effects of the Invention) The image processing device according to the present invention has the above-described configuration and operation, and since the surface of the conveyor belt on the side that covers the document is mirror-finished, the image processing device according to the present invention can handle the document regardless of the shape and color of the document. The presence or absence of the document and the size of the document can be detected accurately, the self level or the black level can be easily set, and there is no risk of malfunction.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an example of an image processing apparatus to which an A-document conveying belt is applied, which is a feature of the present invention, and FIGS. 2 and 3 are principles of light reflection on the document conveying belt, which is a feature of the present invention. FIG. 4 is a schematic diagram showing the state in which the original is placed, FIGS. 5(a) and (b) are waveform diagrams showing signals detected by the original detection device, and FIG. Figure 7 is a diagram showing the relationship between reflectance and reading level! ! A schematic diagram showing a state in which a document is placed on the glass of the X81 machine. FIG. 8 is a circuit diagram of a document detection device for detecting the document position. FIG. 9 (a)
, (b) is a cross-sectional view of the document conveying belt, and FIG. 10 is 1'X
FIG. 7 is a sectional view showing another example of the document conveyance belt. Explanation of symbols 1...Image reading section 2...Original platen glass 4,
...Light source 5,6.7...Mirror 9...
・Solid-state image sensor 10... Image recording section 11...
Semiconductor laser 12...Rotating polygon mirror 13...Mirror 14...Photosensitive drum 100...Document feeder (rXX feeding L stage) 103...Transport belt 103a...P! X-document covering surface 103b... Core body 103c... Covering member 113... Conveyance belt 113a... Original covering surface 113b... Core body

Claims (12)

[Claims] (1) An image that includes a document feeder that feeds the document to a reading position by a conveyor belt, a light source that illuminates the image surface of the document, and an image sensor that detects reflected light from the light source and converts it into an electrical signal. An image processing apparatus characterized in that a surface of the conveyor belt on the side that covers the document is a mirror surface. (2) The image processing apparatus according to claim 1, wherein the surface of the conveyor belt that covers the document is a mirror surface with a regular reflectance of 60 to 90%. (3) The conveyor belt has a two-layer structure by polymerizing a cover member with high transmittance and high friction coefficient on the outside of a core body with high reflectance. The image processing device according to item 2. (4) The image processing device according to claim 3, wherein the cover member has a satin finish on its outer surface. (5) The image processing apparatus according to claim 3, wherein the cover member is formed by mixing fine powder of a high reflectance substance. (6) The image processing apparatus according to claim 3, wherein the core body is made of metal, and the cover member is made of urethane rubber. (7) The image processing device according to claim 3, wherein the core is made of silver-dyed fabric. (8) The conveyor belt is characterized in that it has a three-layer structure by sequentially polymerizing a first cover member with a high reflectance and a second cover member with a high transmittance and a high coefficient of friction on the outside of the core body. An image processing device according to claim 1 or 2. (9) The image processing apparatus according to claim 8, wherein the second cover member has a satin finish on its outer surface. (10) The image processing device according to claim 8, wherein the first cover member is hairline-processed in the sub-scanning direction. (11) The image according to claim 8, wherein the core body is made of a sheet-like elastic member, the first cover member is made of an aluminum vapor-deposited member, and the second cover member is made of urethane rubber. Processing equipment. (12) The image processing apparatus according to claim 8, wherein the core is made of dyed cloth.