JPS60127865A - Document information reader - Google Patents

Abstract

PURPOSE:To set automatically the reading range and also to attain the detection of the reading range and picture reading processing with one scanning by providing an illuminating light at the back side position of an original in opposition to the original scanning face. CONSTITUTION:The light from a lamp LPX or an LPY does not reach a mirror 2c because the light strikes the back side of the original 3 at the part where the original 3 exists, but the direct light from the lamp LPX or LPY transmits through a contact glass 1 at the part where no original exists and reaches an image sensor IMS through mirrors 2c, 2d, 2e and a lens 2f or the like. Thus, the light from the lamp LPX and LPY does not give any effect on the reading picture and is received by the IMS only when the scanning position is at the outside of the original existing range. Since the intensity of the said direct light is set larger than the intensity of the reflected light when the normal original 3 is scanned, the presence of the original 3 is discriminated by supervising an output signal level of the IMS.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an image reading device such as a facsimile machine or a copying machine, and in particular, the present invention relates to an image reading device such as a facsimile machine or a copying machine. The present invention relates to a calligraphic information reading device for reading.

[Prior Art] In this type of image reading device, if the size of the document is arbitrary, a large amount of waste will occur unless the image reading position is set only in the area where the document exists. For example, if a facsimile machine scans an A4 size document even though the M size is B5, approximately 1/3 of unnecessary information will be transmitted, and the transmission time will be 1.5 times the normal time. I end up.

If the reading size can be specified with a switch, wasteful reading can be eliminated by the operator operating the appropriate switches, but if there is an operational error, information may be dropped or useless reading may occur. Furthermore, even if the document size is specified appropriately, if the document is not positioned properly, the correspondence between the document surface and the reading surface may be misaligned, resulting in information being omitted or the like.

In order to eliminate such inconveniences, the position and size of the document may be automatically detected. This type of technology is well known in general facsimile machines, which scan original sheets while moving them.
An optical scanning system or an apparatus in which a book-shaped original is placed on a document table and the document table is scanned is rarely used because of various problems.

In a copying machine that digitally processes signals, the entire surface of the pressure plate that presses the original from the back is used as a reflecting mirror, and the pattern is recognized from the image sensor output signal by scanning it once before copying. There is a known device that reads the size and position of a document using a document. According to this, since the scanning range to be read is automatically set, operational errors do not occur. However, in this case, it is necessary to perform two scans for one copying process, so there is an inconvenience that the process takes time.

[Purpose The present invention automatically sets the reading range.

Further, the object is to detect a reading range and perform image reading processing in one scan.

[Configuration] If you decide to read all the parts where the original exists,
By determining the presence or absence of a document at each scanning position, the size of the document can be determined. In other words, if the presence or absence of a document is detected in a portion of the document reading surface in the main scanning direction and a portion in the sub-scanning direction, an appropriate document reading area can be determined by simple signal level discrimination.

Incidentally, in this type of device, the reading section can be used as an optical sensor, so if the document size is to be detected optically, it is preferable to use the reading section for detecting the document size in order to simplify the configuration. However, in this type of reading device, as shown in FIG. 1, the illumination lamp 2a illuminates the original 3 from an oblique direction, and the reflected light in a direction perpendicular to the original surface is guided to the image sensor IMS. Since light is scattered on a normal document surface, even if light is applied from an oblique direction, the light will travel in a direction perpendicular to the document. However, in the case of a mirror, the light travels so that the angle of incidence and angle of reflection are equal, so when the mirror part is scanned, the detection level becomes the black level. Therefore, when a mirror is installed on the pressure plate 4 to distinguish between document portions and non-document portions, the presence or absence of the document will be determined based on the black level of the signal from the image sensor. However, if there is a completely black part of the original, the signal level will be the same as when scanning a mirror part, so complex signal identification processing is required to distinguish the original area. shall be.

Therefore, if a reflector is provided on the pressure plate and a second light with its optical axis directed perpendicular to the pressure plate is provided for document detection in addition to the first light for image reading, it is possible to detect the original. Since the reflected light from the second illumination lamp is received by the photoelectric converter for image reading in areas where there is no light, if the light reflectance of the reflector is made sufficiently higher than that of the original, the photoelectric converter for image reading will receive the reflected light. The output level (self level) changes greatly depending on the presence or absence of a document, and the presence or absence of a document can be detected by simple level determination.

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 2a shows a schematic configuration of the image reading mechanism, and FIG. 2b shows a perspective view thereof.

This will be explained with reference to FIG. 2a. 3 is the contact glass on which the original 3 is placed. The optical scanning system 2 includes a first carriage 51 including an illumination lamp (halogen lamp) 2a, a reflection plate 2b, a first mirror 2c', a second mirror 2d, and a third mirror 2.
It consists of a second carriage 52 made of e.g., a lens 2f, a fourth mirror 2g, etc. In this example, the first mirror 2c'
is a half mirror. 2h is dustproof glass,
4 is a pressure plate that presses the original 3, and IMS is a one-dimensional CCD image sensor. The first carriage 51 and the second carriage 52 are driven in reciprocating scanning (sub-scanning) by a stepping motor M7 at a speed ratio of 2:l so that the optical path length from the original does not change during scanning. . ``This will be explained with reference to FIG. 2b. Stepping motor M7
A drive wire 61 coupled to an optical scanning system is wound around a pulley 6o fixed to the shaft of the camera. Drive wire 61
, one end 51 a fJ' et al., stud pulley 62
．． Drive pulley 63 coupled to second carriage 52 . Turn pulley 64. Bracket pulley 65. Pulley 60.
Bragg T-pulley 65, turn pulley 66, bracket 67 connected to first carriage 51, drive pulley 63
．． It is connected to the other end 61b passing through the tightener pulley 68 to form a closed loop.

The HPI shown in FIG. 2b includes a switch (photo sensor) that detects the home position of the scanner (optical scanning system);
RP1 is a limit switch that detects one forward scan end position of the scanner, and RP2 is a limit switch that detects another forward scan end position.

FIG. 3a shows the contact glass l viewed from above (the optical scanning system is omitted). In this example, the third a
In the figure, the lower left corner is the reference position when positioning the document 3. At the left end of the scanning range, a large number of lamps LPY are arranged in a row in the main scanning direction, and in the center of the main scanning direction, a large number of lamps LPY are arranged in a row in the sub-scanning direction.
PX is arranged in one column.

The lamps LPX and LPY are arranged below the first mirror 2c' of the optical scanning system at a position where it passes, as shown in FIG. 3b. Referring to FIG. 3b, the light emitted from the illumination lamp 2a is scattered on the surface of the document 3,
A part of the scattered light reaches the first mirror 2e' located in the direction perpendicular to the surface of the document, and is transmitted to the second mirror 2d, the third mirror 2e,
The light passes through the lens 2f etc. and reaches the image sensor IMS.

In the area where the document 3 is not present, the light emitted from the illumination lamp 2a does not reach the first mirror 2c'.

On the other hand, the light emitted from the lamp LPX or LPY passes through the first mirror 2c' from the back side, regardless of whether there is a document or not.
The light is reflected by the original 3 or the pressure plate 4, passes through the first mirror 20', the second mirror 2d, the third mirror 2e, the lens 2f, etc., and reaches the image sensor IMS. In this case, since the light reflectance of the pressure plate 4 is sufficiently higher than that of the original 3, the level of light received by the image sensor MS due to the light 1 emitted from the lamps LPX and LPY is determined at the position where the original 3 is located. There is a big difference between the position and the position without.

However, since the intensity of the light output by lamps LPX and LPY is very small compared to the illumination lamp 2a, the original 3
In the position where the lamps LPX and LPY exist, the intensity of the light received by the image sensor IMS hardly changes between the positions with and without the lamps LPX and LPY.
is located at the center of the image reading area, but this effect does not appear on the read image <a.

FIG. 4 shows the configuration of an electric circuit according to an embodiment.The explanation will be given with reference to FIG. 4. In this embodiment, the image sensor IM
S consists of a reading area AI made up of a photodiode array, a gate area A2, and a CCD shift register A3. The image sensor IMS includes a main scanning control circuit 11.
0, the read control pulse signal φ and two-phase shift pulse signals φA and φB are applied.

The output signal of the image sensor IMS is amplified by an amplifier AMP1 and applied to one end of analog comparators CPI and C20, respectively. Analog comparators CPI and C2
Reference voltages V r 1 and V r 2 of nine different levels are applied to the other input terminals of V r 1 and V r 2 respectively. Reference voltage Vrl
is set to a reference level that can distinguish between the black level and white level of an image, and the reference voltage Vr2 is set to a reference level that can be used to distinguish between the black level and white level of an image, and the reference voltage Vr2 is set to the level of emitted light when scanning an area where an original exists and the reflection level when scanning an area where an original does not exist. This is a reference level that can be used to distinguish between the light level and the light level.

The binary image signal vb obtained at the output terminal of the analog comparator CPI is converted into parallel data of a predetermined number of bits by a serial-in/parallel-out type shift register SR, and applied to the image memory IMM.

The sub-scanning motor M7 is controlled by the sub-scanning control circuit 120 via the motor driver 130. Main scanning control circuit 110
．． The image reading control circuit 1 controls the sub-scanning control circuit 120 and the like.
00 will do it. Image reading control circuit 100 identifies the size and position of the document by referring to binary signal Va from analog comparator CP2.

FIG. 5a shows an analog image signal V when main-scanning several lines near the left end of FIG. 3a, that is, the starting position of sub-scanning.
v, the binary signal Vn of the CP2 output terminal and the reference voltage V r
1, an example of V r 2 is shown. This will be explained with reference to FIGS. 3a and 5a. If the document 3 exists between the start point Y0 of main scanning and Ya in the middle of the main scanning, from the timing tyo to tya when reading that area,
The level of the analog image (ti- No. Vv changes up and down in the vicinity of the reference level Vrl depending on the image, but even when there is no image and the light reflection is the largest, the light reflectance of paper is relatively small, so It is below the reference level Vr2.

When time tya is exceeded, the scanning position deviates from document 3.

Light from the lamp LPY reaches the pressure plate 4 via the first mirror 2c' and the contact glass 1, is reflected on the lower surface of the pressure plate 4, and reaches the image sensor IMS via the optical scanning system. The level of the reflected light at this time is relatively high because the light is not scattered, and the level of the analog image signal Vv exceeds the reference level Vr2. Therefore, the analog comparator CP
The output level of No. 2 is a low level L when the document area is scanned, but is reversed to a high level H when the scanning position leaves the document area. The main scanning ends at time tym, and scanning of the next line is subsequently started.

Therefore, the image reading control circuit 100 uses the analog comparator CP
By looking at the output level 2, the width Y of the document can be determined. For example, in this example, the width Y of the original image to be read can be determined from the scanning speed and the time tya-tyo at which the output level of CF2 is set. The time is main scanning pulse φA or φB
The scanning speed can be obtained from the pulse period of the main scanning pulse.

FIG. 5b shows an example of various signal waveforms when several lines near the position Xa in the sub-scanning direction are main-scanned.

This will be explained with reference to FIG. 5b. While the original exists at the scanning position, the reflective surface of the pressure plate 4 is hidden by the original 3, so the image signal obtained by scanning each line is at the reference level Vrl.
The white level or black level is close to . When the scanning position reaches a scanning line that deviates from the original 3, the light emitted from the lamp LPX is reflected by the pressure plate 4 and reaches the image sensor IMS near timing txa in the middle of the main scanning Q period.

Since this light has a higher level than the light reflected from the white pixels during scanning of the document surface, the level of the analog image signal Vv exceeds the reference level Vr2 at this timing. Therefore, the output level of the analog comparator CP2 becomes high level H at a predetermined timing when the scanning position deviates from the end Xa of the document 3. That is, the image reading control circuit 100 can determine the length X of the document by monitoring the output level of the analog comparator CP2.

For example, the width Y can be determined by counting the number of main scanning lines from the end of determining the width Y (after the scanning position leaves the reflector 5a) until the level of the binary signal v8 becomes H. Ru. In the case of facsimile, control may be performed such that it is determined that the document is finished when the level of the binary signal va becomes H, and the transmission is terminated.

In the above embodiment, the lamp LPY for detecting the original size is placed at the center in the main scanning direction, but if the read image is affected by this light, it should be placed at the end, that is, near the main scanning start position. You may. Further, in the above embodiment, a large number of lamps LPY and LPX are arranged in the main scanning direction and the sub-scanning direction of the optical scanning system, but if a lamp is provided in the sub-scanning mechanism, for example, as the image reading progresses, the lamps LPY and LPX are arranged in the sub-scanning direction. Therefore, there is no need to arrange lamps in the sub-scanning direction.

[Effects] As described above, according to the present invention, it is possible to easily determine the presence or absence of a document while performing image reading, so there is no need for two scans, and moreover, the light receiving device (image sensor) can be used for both image reading and document size detection. The configuration can be shared by multiple users, so the configuration does not become complicated.

[Brief explanation of the drawing]

FIG. 1 is a front view showing the configuration of a conventional image reading device. FIGS. 2a and 2b are a front view and a perspective view, respectively, showing the configuration of a scanning mechanism according to an embodiment of the present invention. FIG. 3a is a plan view of the image reading device viewed from above the contact glass, and FIG. 3b is a front view schematically showing the scanning mechanism and optical path. FIG. 4 is a block diagram showing the electrical circuit configuration of the device of the embodiment. FIGS. 5a and 5b are timing charts showing various signal waveforms when scanning different positions, respectively. l: Contact glass (original table) 2: Optical scanning system 2a: Illumination light (first illumination light) 2b, 2c', 2d, 2a: Mirror 2f: Lens 3: Original 4: Pressure plate (reflection member) 51s 52: Carriage 100: Image reading control circuit (electronic control means) LPX, LP
Y: Lamp (second illumination light) IMS: Image sensor (
Light receiving device) M7: Stepping motor AMP: Amplifier CPI, CF2: Analog comparator Patent applicant Ricoh Co., Ltd. No. 38V Brown 1V Mu ¥3b ■ Ll-'X Procedural amendment (voluntary) February 16, 1988 1, Display of the case 1982 Patent Application No. 235962 2
, Title of the invention Calligraphy and painting information reading device 3, Relationship to the person making the amendment Patent applicant address 1-3-6 Nakamagome, Ota-ku, Tokyo Name (67
4) Ricoh Co., Ltd. Representative Hama 1) Hiro 4, Agent 103 Te 1.03864-6052
Address: 2-27-6-5 Higashi Nihonbashi, Chuo-ku, Tokyo, The entire text of the specification to be amended and Drawing 6, Contents of the amendment (a) The entire text of the specification is corrected as per the attached specification. (b) Correct figures 1, 3a and 3b of the drawings in accordance with the accompanying drawings. 7.Inventory specification of attached documents・・・・・・・・・・・・1 copy of drawings (
Figures 1, 3a, and 3b)... 1 Description 1. Title of the invention: Calligraphy and drawing information reading device 2. Claims (1) At least a partially transparent document table; Document and image information comprising a first illumination lamp disposed at a position facing the original, a light receiving device, an optical system that guides light from the original to the light receiving device, and a scanning mechanism that scans at least one of the document table and the optical system. In the reading device: It is placed at the back side of the original, facing the original scanning surface. a second illumination lamp having a length longer than a predetermined length in at least one direction of document scanning; and determining at least one of the position and size of the document according to the output level of the light receiving device of the optical system and the position of the scanning mechanism. What is claimed is: 1. A calligraphy information reading device, comprising: electronic control means for; (2) The document and image information reading device according to claim (1), wherein the second illumination light includes an illumination light that is long in the main scanning direction of document scanning and an illumination light that is long in the sub-scanning direction. 3) The document and image information reading device according to claim (2), wherein the illumination lamp, which is long in the main scanning direction of document scanning, is arranged near the sub-scanning start position. (4) The second illumination light is a plurality of point light sources arranged in a predetermined direction, and the calligraphy information reading device according to claim 1, (2), or (3) . 3. Detailed Description of the Invention ■Technical Field The present invention relates to an image reading device such as a facsimile machine or a copying machine, and in particular, the present invention relates to an image reading device such as a facsimile machine or a copying machine. read The present invention relates to a calligraphy information reading device. (2) Prior Art In this type of image reading device, if the size of the document is arbitrary, a large amount of waste will occur unless the image reading position is set only in the area where the document exists. For example, if a facsimile machine scans an A4 size document even though the original size is B5, approximately 1/3 of the useless information will be transmitted, and the transmission time will be 1.5 times longer than usual. . If the reading size can be specified with a switch, wasteful reading can be eliminated by the operator operating the appropriate switches, but if there is an operational error, information may be dropped or useless reading may occur. Furthermore, even if the document size is specified appropriately, if the document is not positioned properly, the correspondence between the document surface and the reading surface may be misaligned, resulting in information being omitted or the like. In order to eliminate such inconveniences, the position and size of the document may be automatically detected. This type of technology is well known in general facsimile machines, which scan original sheets while moving them.
An optical scanning system or an apparatus in which a book-shaped original is placed on a document table and the document table is scanned is rarely used because of various problems. In a copying machine that digitally processes signals, the entire surface of the pressure relief device that presses the document from the back is used as a reflecting mirror, and the document is scanned once before copying, and the document size is determined from the image sensor output signal at that time. A device is known that reads the position. According to this, since the scanning range to be read is automatically set, operational errors do not occur. however,
In this case, it is necessary to perform two scans for one copying process, so there is an inconvenience that the process takes a long time. ■Purpose The present invention automatically sets the reading range, and
The purpose is to detect the reading range and perform image reading processing in one scan. ■If you decide to read all the parts where the constituent manuscript exists,
The document size can be determined simply by determining the presence or absence of a document at each scanning position. In other words, if the presence or absence of a document is detected in a portion of the document reading surface in the main scanning direction and a portion in the sub-scanning direction, an appropriate document reading area can be determined by simple signal level discrimination. In this type of apparatus, the reading section can be used as an optical sensor, so if the document size is to be detected optically, it is preferable to use the reading section for detecting the document size in order to simplify the configuration. In other words, the presence or absence of a document may be determined by monitoring the output signal of the image reading section. In order to realize this, for example, it is conceivable to attach a reflecting mirror to the pressure plate as described above. However, in this type of reading device, as shown in FIG. 1, the illumination lamp 2a illuminates the original 3 from an oblique direction, and the reflected light in a direction perpendicular to the original surface is guided to the image sensor IMS. Since light is scattered on a normal document surface, even if light is applied from an oblique direction, the light will travel in a direction perpendicular to the document. However, in the case of a mirror, the light travels so that the angle of incidence and angle of reflection are equal, so when the mirror part is scanned, the detection level becomes the black level. Therefore, when a mirror is attached to the pressure plate 4 to distinguish between document portions and non-document portions, the presence or absence of the document is determined based on the black level of the signal from the image sensor. However, if there is a completely black part of the original, the signal level will be the same as when scanning a mirror part, so complex signal identification processing is required to distinguish the original area. shall be. Therefore, if a second illumination light is provided on the pressure plate itself for document detection, the light from the second illumination light will be blocked by the document in the part where the document is, but the light from the second illumination light will be blocked in the part where there is no document. The light from is received by a photoelectric converter for image reading,
The output level (white level) of the photoelectric converter for image reading is
It changes greatly depending on the presence or absence of a document, and the presence or absence of a document can be detected by a simple level judgment. Further, in this case, the light from the second illumination lamp does not appear on the read image. Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 2a shows a schematic configuration of the image reading mechanism, and FIG. 2b shows a perspective view thereof. This will be explained with reference to FIG. 2a. 1 is a contact 1-glass on which the original 3 is placed. The optical scanning system 2 includes an illumination lamp (halogen lamp) 2a, a reflection plate 2b, a first carriage 51 including a first mirror 20, a second mirror 2d, and a third mirror 2.
A second carriage 52 .e etc. It consists of a lens 2f, a fourth mirror 2g, etc. 2 b is a dustproof glass, 4 is a pressure plate for pressing the original 3, and IMS is a one-dimensional CCD image sensor. First carriage 51 and second carriage 5
2, so that the optical path length from the original does not change during scanning.
It is designed to be driven in a reciprocating manner (sub-scanning) by a stepping motor M7 at a speed ratio of 2:1. This will be explained with reference to FIG. 2b. Stepping motor M7
A drive wire 61 coupled to an optical scanning system is wound around a pulley 60 fixed to the shaft of the drive wire 61 . Drive wire 61
is a stud pulley 62. from one end 61a thereof. Drive pulley 63 coupled to second carriage 52 . Turn pulley 64. Bracket pulley 65. Pulley 60. Bracket 1 - pulley 65, turn pulley 66, first carriage 5
Bracket 67 and drive pulley 63. It is connected to the other end 61b passing through the tie 1 to the nap pulley 68 to form a closed loop. The HPI shown in FIG. 2b includes a switch (photo sensor) that detects the home position of the scanner (optical scanning system);
RP1 is a limit switch that detects the end position of one forward scan of the scanner, and RP2 is a limit switch that detects the end position of another forward scan. In FIG. 3a, the contact glass 1 is shown with the pressure plate 4 facing down.
Shown as viewed from the side. In this example, the lower left corner in FIG. 3a corresponds to the reference position for positioning the document 3. A light reflective member is attached to the surface (lower surface) of the pressure plate 4. At the left end of the scanning range, that is, at the sub-scanning start position, a large number of lamps LPY are arranged in a row in the main scanning direction, with their optical axes facing the contact 1 to glass 1 side. (near the reference position), a large number of lamps LPX are arranged in a row in the sub-scanning direction with their optical axes facing the contacts 1 to the glass 1 side. Referring to FIG. 3b, the light emitted from the illumination lamp 2a is scattered by the surface of the document 3, and a portion of the scattered light is directed to the first mirror 2c located perpendicular to the surface of the document. The light reaches the image sensor IMS through the second mirror 2d, third mirror 2e, lens 2f, etc. In the area where the document 3 is not present, the light emitted from the illumination lamp 2a does not reach the first mirror 2c. On the other hand, the light emitted from the lamp LPX or LPY hits the back surface of the original 3 in the area where the original 3 is present, and the first mirror 2c
lamp LPX is not reached, but in the area where there is no original
Or the direct light from LPY passes through the contact glass 1, and the first mirror 2c, the second mirror 2d, the third mirror 2e,
The light passes through the lens 2f etc. and reaches the image sensor IMS. Therefore, the light from the lamps LPX and LPY does not affect the read image, and is received by the image sensor IMS only when the scanning position is outside the document area. In this example,
Since the intensity of the direct light from the lamps LPX and LPY is set to be higher than the intensity of the reflected light when scanning a normal document, the presence or absence of the document can be determined by monitoring the output signal level of the image sensor IMS. can be determined. FIG. 4 shows the configuration of the electric circuit of the embodiment. This will be explained with reference to FIG. In this embodiment, the image sensor IM
S consists of a reading area AI made up of a photodiode array, a gate area A2, and a CCD shift 1-register A3. The image sensor IMS includes a main scanning control circuit 1.
10, a read control pulse signal φR and two-phase shift pulse signals φA and φB are applied. The output signal of the image sensor IMS is amplified by an amplifier AMP1 and applied to one end of analog comparators CPI and C20, respectively. Analog comparators CPl and C2
Reference voltages Vrl and Vr2 of different levels are applied to the other input terminals of 0. The reference voltage Vrl is set to a reference level that can distinguish between the black level and the white level of the image, and the reference voltage Vr2 is set to the level of reflected light when scanning the area where the original exists and the level of reflected light when scanning the area where the original does not exist. The reference level is set at which the level of reflected light (both white level) can be determined. The binary image signal vb obtained at the output terminal of the analog comparator CPI is converted into parallel data of a predetermined number of bits by a serial-in/parallel-out type shift register SR, and applied to the image memory IMM. The sub-scanning motor M7 is controlled by the sub-scanning control circuit 120 via the motor driver 3o. Main scanning control circuit 110
．． The image reading control circuit 1 controls the sub-scanning control circuit 120 and the like.
00 will do it. The image reading control circuit 100 identifies the size and position of the original by referring to the binary signal Va from the analog comparator CP2. FIG. 5a shows an analog image signal V when main-scanning several lines near the left end of FIG. 3a, that is, the starting position of sub-scanning.
v, binary signal Va at the output end of CP2 and reference voltage Vrl
, Vr2 is shown below. This will be explained with reference to FIGS. 3a and 5a. If the original f+Gi 3 exists between the starting point Y0 of the main scan and Ya in the middle of the main scanning, the level of the analog image (Flj % V v will depend on the image It changes up and down in the vicinity of the reference level Vrl, but even when there is no image and the light reflection is the largest, the light reflectance of paper is relatively small, so it is below the reference level Vr2. is removed from the document 3, and direct light from the lamp LPY provided on the pressure plate 4 passes through the contact glass 1 and reaches the image sensor IMS via the optical scanning system.The level of this direct light is higher than the light reflected from the document. is also large, and the level of the analog image signal Vv is
Exceeds reference level Vr2. Therefore, the analog comparator C
The output level of P2 is a low level L when the document area is scanned, but is reversed to a high level H when the scanning position leaves the document area. The main scanning ends at time tym, and scanning of the next line is subsequently started. Therefore, the image reading control circuit 100 uses the analog comparator CP
By looking at the output level 2, the width Y of the document can be determined. For example, in this example, the width Y of the document image to be read can be determined from the scanning speed and the time tya-ty0 at which the output level of C20 is set. The time is main scanning pulse φA or φB
The scanning speed can be obtained from the pulse period of the main scanning pulse. FIG. 5b shows an example of various signal waveforms when several lines near the position Xa in the sub-scanning direction are main-scanned. This will be explained with reference to FIG. 5b. While the original exists at the scanning position, the image signal obtained by scanning each line has a white level or black level close to the reference level Vrl. When the scanning position reaches a scanning line extending from the original 3, the lamp LP is turned on near the timing txa at the beginning of the main scanning cycle.
Direct light emitted from X passes through contact glass 1 and reaches image sensor IMS via an optical scanning system. Since this light has a higher level than the light reflected from the white pixels during scanning of the document surface, the level of the analog image signal Vv exceeds the reference level Vr2 at this timing. Therefore, the output level of the analog comparison 1cP2 becomes a high level H at a predetermined timing when the scanning position deviates from the end Xa of the document 3. That is, the image reading control circuit 100 can determine the length X of the g document by monitoring the output level of the analog comparator CP2. For example, the width Y can be determined by counting the number of main scanning lines from the end of determining the width Y until the level of the binary signal Va becomes H (after the scanning position leaves the reflecting mirror 5a). . In the case of facsimile, control may be performed such that it is determined that the document is finished when the level of the binary signal Va becomes H, and the transmission is ended. In the above embodiment, the lamp LPY for detecting the document size is arranged at the end in the main scanning direction, but it may be arranged at the center. In addition, in the embodiment, a lamp L for detecting the original size is used.
PX and LPY were constructed with many point light sources, but instead of these, hot cathode fluorescent tubes were used. Slow thermionic vacuum fluorescent lamps, long wall tungsten light bulbs, etc. may also be used. ■Effects As described above, according to the present invention, the presence or absence of a document can be easily determined while performing image reading, so two scans are not required, and the light receiving device (image sensor) can be used for both image reading and document size detection. Since it can be shared, the configuration does not become complicated. 4. Brief Description of the Drawings FIG. 1 is a front view showing the configuration of a conventional image reading device. FIGS. 2a and 2b are a front view and a perspective view, respectively, showing the configuration of a scanning mechanism according to an embodiment of the present invention. FIG. 3a is a plan view of the image reading device viewed from above the contact glass, and FIG. 3b is a front view schematically showing the scanning mechanism and optical path. FIG. 4 is a block diagram showing the electrical circuit configuration of the device of the embodiment. FIGS. 5a and 5b are timing charts showing various signal waveforms when scanning different positions, respectively. J Nikon Taku] - Glass (manuscript table) 2: Optical scanning system 2a: Illumination light (first illumination light) 2b, 2c, 2d, 2e: Mirror 2f: Lens 32 Original 4: Pressure plate 51, 52: Carriage 100: Image reading control circuit (electronic control means) LPX, LP
Y: Lamp (second illumination light) IMS: Image sensor (
(light receiving device) M7: Stepping motor AMr': Amplifier CPl, CF2: Analog comparator name 38A1SHIMUKARU3b■l□

Claims (2)

[Claims] (1) A document table that is at least partially transparent, a first illumination lamp placed opposite the document with the document table in between, a light receiving device, an optical system that guides light from the document to the light receiving device, and a document table. and a scanning mechanism that scans at least one of the optical system; and a scanning mechanism that scans at least one of the document scanning surface and the optical system; a reflective member; a second illumination lamp, which is placed opposite to the reflective member across the document table and positioned to illuminate at least a predetermined width of the document in the main scanning direction; What is claimed is: 1. A calligraphy information reading device comprising: electronic control means for determining the position of a document according to the position of a mechanism. (2) The document and image information according to claim (1), wherein the second illumination light is a plurality of point light sources arranged in a row in each of the main scanning direction and sub-scanning direction of document scanning. reading device.