JPH11215321A - Image reader with original feeding mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the deviation problem of an image position by providing a original detection means for detecting the tip of a sent original, independently of a means reading the image of an original face for a read part carriage. SOLUTION: A read carriage 7 is constituted of a lamp 10, a mirror 9, a reflecting board 11 and a timing sensor 12. Especially, the timing sensor 12 is provided of the read part carriage 7 similarly as the mirror 9. Thus, the original can be detected on the up-stream side of the read position of the original on automatic original feeding device (ADF) platen glass 39 and at a position which is considerably close to ADF platen glass 39. The tip part of the original, which is sent from an original feeding tray to a read transportation roller 36 and is led on ADF platen glass 39, can be detected immediately prior to the reading start of the original. Timing when the original just reaches the read position and that when CCD just starts reading can be adjusted easily, and the occurrence of hourly deviation can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention can read an image on a document surface of a document placed on a reading glass, for example, by moving a reading unit carriage, and further stops the reading unit carriage at a predetermined standby position. An image reading device capable of reading an image on the original surface of the original sent by the original feeding device by feeding the original,
In particular, the present invention relates to a technique for optimizing timing control in reading an image on a document surface in the latter reading operation.

[0002]

2. Description of the Related Art In an image reading apparatus used for an image forming apparatus such as a copying apparatus or a facsimile apparatus,
The original is placed on the reading glass such that the reading surface faces the reading glass, and the reading unit carriage of the image reading device moves the home scanning from the home position in the sub-scanning direction while scanning the image on the reading surface of the original in the main scanning direction. And read. Also,
If an automatic document feeder (automatic document feeder, hereinafter referred to as "ADF") is attached, the document sent out by the ADF with the reading unit carriage stopped at a predetermined standby position. Are sequentially scanned by main scanning and read.

In the case of the former reading operation, the reading unit carriage located at the home position starts moving in the sub-scanning direction with the original placed at a predetermined position on the reading glass. The main scanning start timing may be triggered by a movement start signal of the reading unit carriage. Then, the reading unit carriage ends scanning at a predetermined position in accordance with the size of the document, and returns to the home position again.

However, in the image reading operation when the ADF is used, since the original is sent out by the ADF in a state where the reading unit carriage is stopped at a predetermined standby position, the control unit of the image reading apparatus performs image reading scanning. In order to take a start timing, it is necessary to detect the leading end of the sent original.

In the prior art, in order to take such a timing, a document detecting means for detecting the leading edge of a document is provided in a document conveying path in the ADF, and the document is detected after passing through the detection position of the document detecting means. Measuring the elapsed time or the number of rotations of the original feed motor, or detecting a change in the light receiving level of this CCD using only the CCD installed in the reading unit carriage or the image reading device and finally receiving the image data. Thus, the detection of the transmission of the original has been performed.

As another example of the prior art for more reliably detecting the transmission of an original by the ADF, a sensor is installed at a predetermined position in the ADF corresponding to an image reading window of a reading unit carriage to detect an original to be transferred. That is being done.

Japanese Utility Model Publication No. 7-20993 discloses an example of such a conventional document reading apparatus. In the prior art, as shown in FIG. 16, a sensor 23 for detecting a document is provided with a document feed roller 17 in an ADF located above a scanning unit including a lamp 4 and a mirror 5 in the reading device 1. It is installed in the foreground. As a result, the timing at which the control unit of the image reading apparatus starts reading scanning of an image can be reliably taken.

[0008]

However, in the prior art which does not use a document detection sensor, when a document travels in the ADF, slipping or skew occurs due to contact friction with a traveling roller, and a document feed motor is not used. When the rotation speed is not constant, a shift occurs in the timing of starting the scanning for reading the image. In such a situation, for example, in the copy function, the positional relationship between the original and the image in the copy is shifted.

Further, in the case of the prior art in which a dedicated sensor is installed in the ADF to detect a document, the transmitted document can be detected more reliably.
When the ADF is used, the standby position of the reading unit carriage shifts with time due to the extension of the traveling wire for driving the reading unit carriage, the wear of the roller around which the wire is wound, and the like. Therefore, the document detection sensor is ADF
Since it is installed on the apparatus side, the relative position between the document detection sensor and the reading unit carriage is shifted, and as a result, the same problem of image position shift occurs.

Next, when the CCD is used for both reading an image and detecting the leading edge of a document, the CCD must always perform a reading operation for detecting the leading edge of the document. In this case, the document must be conveyed at a low speed necessary for reading the document, and the document processing time is reduced. Also, since it is necessary to always turn on the CCD, C
This may shorten the life of the CD. Furthermore, it is necessary to make the background color that can be distinguished from the original in the direction read by the CCD, for example, a black or gray background color when the original is white,
When reading a transparent thin paper document or the like, it is difficult to distinguish the document from the background when there is no document. Further, even in the case of a plain paper original, it is difficult to distinguish the original from the background in the same manner when the leading end side is blackened. In addition, there is a time lag between the recognition of the leading edge of the document and the start of the document reading process, and there is a possibility that the leading edge cannot be detected correctly because the leading edge is missing.

[0011]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems in the prior art, the present invention reads an image on a document surface of a held document by moving a reading unit carriage and moves the reading unit carriage to a predetermined position. In the image reading apparatus capable of reading the image of the original surface of the original sent by the original feeder while being stopped at the standby position, the reading unit carriage is provided with the leading end of the original sent by the original feeder. Document detecting means for detecting is provided separately from means for reading the image on the document surface, and the leading edge of the document is detected before the image on the document surface of the sent document can be read. Means to start scanning the document surface by detecting,
It is an object of the present invention to provide an image reading apparatus with a document feeding mechanism configured to take a timing to end scanning of a document surface by detecting the trailing edge of the document by the document detecting means.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of an image reading apparatus with a document feed mechanism according to the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a perspective view of an image reading apparatus 1 according to the present invention. The image reading device 1 has both a function of reading a document with a document feeding mechanism and a scanner for reading a fixed document. The frame 2 of the image reading device 1 can be divided into two parts. One is a document reading portion with a document feeding mechanism, which is located at one end of the frame 2 and is capable of feeding a document into the frame 2a and reading an image composed of text and graphics on the document surface.
This is a scanner portion in which a document can be placed on the upper portion b and an image on the document surface can be read by the scanner. A document feed tray 18 on which a plurality of documents can be placed is provided on one side of the frame 2a. The document feed mechanism moves the documents placed on the document feed tray 18 one by one to the frame 2a. To read the image of the original (the reading of the image on the original surface is also referred to as the original reading). On the other hand, on the upper part of the frame 2b, a cover 15 for pressing the original placed on the upper surface of the frame 2b is provided. Cover 15
Is rotatably supported on one side of the frame 2 and can open and close the upper surface of the frame 2b by rotating about the axis. FIG. 1 shows the cover 15 in a closed state. In addition, a pocket cover 1 is provided above the cover 15.
6 are provided. The pocket cover 16 is a cover 1
5, the document jammed in the pocket cover 16 can be taken out. The frame 2a is provided with an openable / closable frame cover 2e so that a document jammed in the frame 2a can be taken out.

FIG. 2 is a transparent side view of the image reading apparatus 1 with the cover 15 closed. The document feed tray 18 is provided with a document intake opening 2c through which a document can be taken, and a document can be inserted into the document feed mechanism 17 inside the frame 2a through the opening. On the opposite side of the document feed tray 18, a document feed opening 2d through which a document taken in the document feed mechanism 17 can be sent out.
Is provided. On the other hand, inside the cover 15, a document storage portion 44 capable of storing a document when the pocket cover 16 is closed is formed, and when the cover 15 is closed, the document sent from the document feed mechanism 17 is stored in the document storage portion 44. It can be temporarily stored in the section 44. For this reason, there is no possibility that the document temporarily sent into the document storage unit 44 is erroneously taken out, and even if the document exists on the platen cover 15, it does not interfere with the document. When the temporarily stored document is jammed, the pocket cover 1
By opening the cover 6 from the cover 15, the document can be removed from the document storage section 44.

A reading glass 13 is provided on the upper surface of the frame 2b, and a document is placed on the reading glass 13 so that the document can be read from below. The cover 15 is provided with a pad 14 facing the reading glass 13. When the cover 14 is closed, the pat 14 presses the original placed on the reading glass 13 against the surface of the reading glass 13 from above and fixes the original.

Inside the frame 2, a rail 3 extending from the cover 15 to the document feed mechanism 17 is provided.
A mirror carriage 8 and a reading unit carriage 7 for reading a document are attached to the rail 3 so as to be movable on the rail 3. The movement of the reading unit carriage 7 and the mirror carriage 8 is performed by a drive system 4 including a motor (not shown), a wire pulley, and a wire that transmits a driving force to the reading unit carriage 7 and the mirror carriage 8 while rotating around the wire pulley. Will be At the bottom of the frame 2, a lens 6 for imaging reflected light from the read original and a CCD 5 for converting the light imaged by the lens 6 into an electric signal, for example, a one-dimensional CCD linear sensor Is provided.
Although the signal conversion processing is further increased, a one-dimensional CCD
A two-dimensional CCD image sensor may be used instead of the linear sensor.

Here, the reading unit carriage 7 reads the original conveyed by the original feed mechanism 17 and reads the original from the frame 2b.
The original placed above can also be read.

FIG. 3 shows the reading unit carriage 7 located below the document feed mechanism 17 for reading a document. Then, the reading unit carriage 7 can read the original surface of the original S which is transported by the reading and transporting roller 36 and reaches a position where the original can be read below the reading and transporting roller 36.

The reading unit carriage 7 includes a lamp 10, a mirror 9, a reflection plate 11, and a timing sensor 12. Here, an ADF platen glass 39 is fixedly attached below the reading and conveying roller 36. A platen guide 38 is provided on the upper part. The platen guide 38 forms a transport path for reading a document. The document S passes between the platen guide 38 and the ADF platen glass 39 and is pushed out by the elasticity of the platen guide 38 downward, and the reading and conveying roller is pressed while only the document S contacts the upper surface of the ADF platen glass 39. 36.

On the other hand, the lamp 10 of the reading unit carriage 7
Is a document S passing above the ADF platen glass 39.
From below. The reflected light from the document is reflected by a mirror 9 as shown by a broken line B, and proceeds to a mirror carriage 8 (see FIG. 2) almost horizontally on the rail 3. As shown in FIG. 2, a mirror 8a provided on the mirror carriage 8,
The reference numeral 8b is provided to face the reading unit carriage 7 at an angle of 90 degrees in order to refract the light reflected by the mirror 9 in the direction of the CCD 5 and send it. The light reflected by the mirrors 8 a and 8 b is imaged on the CCD 5 by the lens 6. Then, the CCD converts the image information of the document S into an electric signal.

The lamp 10 is, for example, a xenon lamp having an elongated shape extending in the plane of FIG. Further, the reflection plate 11 is provided at a position symmetrical to the lamp 10 with the reflected light from the reading portion of the document toward the mirror 9 as an axis. Thereby, the original S is symmetrically illuminated with the direct light from the lamp 10 and the reflected light from the lamp 10 via the reflector 11, so that irradiation with uniform direction is given to the original surface reading position of the original S. I am trying to be.

The timing sensor 12 is a sensor for detecting the presence or absence of the passage of the document S, and is, for example, a reflection type sensor including a light emitting element and a light receiving element. The light emitting element emits light for document detection in the direction of the reading and conveying roller 36 through which the document S passes. The light receiving element is configured to detect reflected light of the light emitted by the light emitting element.
Then, the output is turned ON by detecting a change in the intensity of the reflected light when the document S reaches the irradiation range. Here, as the reflecting member for reflecting the light emitted by the light emitting element, the surface of the platen guide 38 with reduced reflectance or the outer peripheral surface of the reading and conveying roller 36 may be used, or a new reflecting member may be used. May be provided on the reading and conveying roller 36 side.

As described above, especially the timing sensor 1
2 is provided on the reading unit carriage 7 in the same manner as the mirror 9.
The document S can be detected at a position upstream of the reading position of the document S on the F platen glass 39 and at a position very close to the ADF platen glass 39,
The leading portion of the document S sent from the document feed tray 18 to the reading / conveying roller 36 and guided onto the ADF platen glass 39 can be detected immediately before the reading of the document S starts, and when the document S has just reached the reading position. Since the timing when the CCD 5 just starts reading can be easily set, there is almost no time lag.

FIG. 4 is a side view for comparing the reading unit carriage 7 in different positions. FIG. 4 (a)
Indicates that the reading unit carriage 7 is at the home position on the frame 2b side of the frame 2 shown in FIG.
FIG. 4B illustrates a state where the reading unit carriage 7 is moved to the frame 2a side and is at a fixed position for reading a document conveyed by the document feeding mechanism 17 (see FIG. 2).

The reading unit carriage 7 moves the rail 3
When the document is under the reading glass 13, the document is illuminated by the lamp 10 while moving under the document placed on the reading glass 13 and the document is read by the CCD 5, that is, by a so-called scanner. Can read. Here, the mirror carriage 8 moves in the same direction with the movement of the reading unit carriage 7, but the moving length is just half of the moving length of the reading unit carriage 7. Thereby, the original and the reading unit carriage 7
Mirror 9, mirrors 8 a and 8 b of mirror carriage 8,
Since the optical path length to the CCD 5 is kept constant, both the original reading by the original feeding mechanism 17 and the original scanner reading under the reading glass 13 can be used. By providing the CCD 5 in the reading unit carriage 7, the original may be read by moving the CCD 5 with the movement of the reading unit carriage 7 while maintaining a constant optical path length.

On the other hand, in order to read a document by the document feed mechanism 17, the reading unit carriage 7 moves from a reading position of the scanner to a predetermined position where the document feed mechanism 17 can read. However, it does not always stop at exactly the same position, and often stops with a slight shift due to the tolerance of parts, the inertial force of movement, or the like.

However, in the image reading apparatus 1 of the present application, by providing the moving reading carriage 7 with the timing sensor 12 in addition to the lamp 10 and the mirror 9, the lamp 10 irradiates light and passes through the mirror 9. The light irradiation position (so-called document reading position) where the document can be read and the position where the timing sensor 12 senses the document are relatively unchanged. That is, the relationship between the position of the document surface on the ADF platen glass 39 to be read by the CCD 5 and the position at which the timing sensor 12 detects the leading edge of the document is determined by the reading unit carriage 7 with respect to the ADF platen glass 39. Even if you make a difference, it does not change. Therefore, if the document is moved by a relatively fixed position after the document is detected by the timing sensor 12, the leading end of the document always reaches the document reading position. Feed mechanism 17
You are relieved of the effort of strictly fixing it in place for reading below.

As described above, by providing the timing sensor 12 in the reading unit carriage 7, the relative positional relationship between the original reading position and the original detecting position is substantially constant regardless of the movement of the reading unit carriage 7. , The timing of document conveyance to the document reading position can be easily synchronized, and strict management of the fixed position of the moving reading unit carriage 7 is not required.

The timing sensor 12 is a transmission type sensor instead of a reflection type sensor, and one of the light emitting element and the light receiving element constituting the transmission type sensor is installed on the reading unit carriage 7, and the other is a document feeding mechanism. The light-emitting element or the light-receiving element may be installed on the 17 side. In this case, when the document S has not reached between the light emitting element and the light receiving element, the irradiation light from the light emitting element is directly received by the light receiving element, and when the document S has reached the meantime, the irradiation light is blocked. Therefore, the light receiving element turns ON or OFF the output signal indicating the presence or absence of the document according to the change in the amount of received light.
I do. In addition, since the light emitting element or the light receiving element installed on the reading unit carriage 7 moves in accordance with the movement of the reading unit carriage 7, the position at which the document S blocks the irradiation light changes accordingly. The relative positional relationship between the document reading position and the document detection position is determined by the reading unit carriage 7.
It is kept relatively constant regardless of the movement of. In addition, this transmission type sensor can solve the problem that the reflectivity changes due to the change over time of the reflection surface caused when the reflection type sensor is used, thereby erroneously determining the presence or absence of a document.

FIG. 5 is a control block diagram for carrying out conveyance control for reading a document. Control unit 60
Means a CPU for performing arithmetic processing of the image reading device 1
(Central processing unit) and storage means for storing the execution program, such as a RAM and a ROM. The control by the control unit 60 can be divided into the scanner side and the document feed mechanism 17 side.

First, the scanner will be described.
The CD 5 and the lamp 10 are as described with reference to FIG. 3, and the reading of the document and the irradiation of light for that purpose are controlled. The carriage home sensor 52 is a sensor for detecting the home position of the reading unit carriage 7. The reading unit carriage 7 moves to the home position described with reference to FIG. 4 before performing the scanner operation, whereby the relative movement position of the subsequent scanner operation is determined. The scanner pulse motor 50 is used to move the reading unit carriage 7 along the rail 3, and the rotation of the scanner pulse motor 50 is controlled by the drive system 4.
And the reading unit carriage 7 moves accordingly. Then, with the movement of the reading unit carriage 7,
The original can be read by a scanner from below. Here, the size of the document placed on the reading glass 13 can be specified in advance by performing pre-scanning, that is, generally performing rough scanning reading before performing actual scanning reading of the document. Note that the reading unit carriage 7 can be used for both document reading by the document feeding mechanism 17 and scanner reading, and the timing sensor 12 as a component thereof moves the reading unit carriage 7 during scanner reading. Therefore, a block diagram is shown on the scanner side for convenience, similarly to the CCD 5 and the lamp 10.

The document feed mechanism 17 (ADF) will be described. The document detection sensor 20 detects whether a document is set on the document feed tray 18. The size sensor 61 is a sensor for specifying the width of the document. The registration sensor 30 is a sensor for detecting whether or not the originals are correctly aligned, and causing the originals to wait at an alignment position (referred to as a registration position).
The paper discharge sensor 62 is used to determine the position of the document when the document is sent out of the frame 2a, particularly from the document feed opening 2d. The feed solenoid 55 is
A drive source for regulating the end faces of a plurality of originals and pressing the originals when the originals are supplied from the mounted state of the original feed tray 18 into the original feeding mechanism 17. The flapper solenoid 56, the paper feed clutch 57, the paper discharge clutches 58 and 59, and the ADF pulse motor 51 for document conveyance are controlled according to a document advance operation, a one-sided reading operation, and a two-sided reading operation described later. The details will be described later.

FIG. 6 is an enlarged side view of the document feeding mechanism 17. The document feed tray 18 is provided adjacent to the document feed mechanism 17. A document detection arm 19 rotatable around a shaft 19a is provided near the document intake opening 2c of the frame 2. Document detection arm 19
When the original is placed on the original feed tray 18 and inserted through the original intake opening 2c, the original is pushed by the original, and the clock is moved from the steady state of FIG. Rotate in the direction of rotation. Then, the original detection arm 1
The document detection sensor 20 detects that a document has been set, and turns on the output by the accompanying arm 19 b that moves in conjunction with the document 9.

The original detecting sensor 20 includes a light emitting element and a light receiving element. The light receiving element is made different depending on whether the associated arm 19b blocks the light emitted from the light emitting element or not. The output of the element is turned on / off, and the presence or absence of a document is detected. Although not shown here, a sensor for document size identification including a plurality of light emitting elements and light receiving elements is provided at a position in the vertical direction on the paper surface. Also,
The shaft 19a is provided with a weight 22 which can be driven by a paper supply solenoid (not shown) and presses the original against the pickup roller 24 when the original is fed. Also,
A document shutter 21 for stopping the leading edge of the document placed on the document feed tray 18 is provided. Since the leading edge of the document is regulated by the document shutter 21,
The document is positioned. The document shutter 21 is
It is driven by a paper feed solenoid 55 in the same manner as the weight 22. The pickup roller 24 is a semi-circular roller for transporting the document to the separation roller 26 and the separation pad 27. The pickup roller 24 can be interlocked with an ADF pulse motor 51 described later by turning on a paper feed clutch 57 (not shown). Has become.

In order to feed one of the set originals to the inside, the feed clutch 57 (not shown) is turned on to
When the F-pulse motor 51 is driven to rotate forward, the document shutter 21 regulating the document moves downward to release the regulation, and the pickup roller 24 rotates counterclockwise as viewed from FIG. The original placed in the area is extruded downstream.

Downstream, the separation roller 26 and the separation pad 2
7, a document separating means including a pad holder 28 and a pad pressing spring 29 is provided. Separation pad 27
Is in contact with a part of the outer periphery of the separation roller 26 by a pad holder 28 supporting the same and a pad pressure spring 29 for pushing the pad holder 28 in the direction of the separation roller 26, and only one document is The entry of another document is restricted so that it can pass between the separation pad 27 and the separation roller 26.

Further, the separation pad 27 and the document shutter 2
1, a plate-shaped front separation plate 25 having a tip slightly spaced from the separation roller 26 is provided. The front separating plate 25 is an auxiliary unit for separating and separating a plurality of originals so that a plurality of originals do not pass through the separation roller 26. Therefore, the front panel 25
Only the lowermost one of the plurality of originals extruded by the original separating means is separated from the other originals superimposed thereon and sent further downstream. This separation roller 2
6, the ADF is turned on when the paper feed clutch 57 is turned on.
It is connected to the pulse motor 51 so that it rotates counterclockwise about the shaft 26b as viewed from the figure.

A registration loop guide film 31, a registration sensor 30, and registration rollers 32 and 33 are provided between the separation roller 26 and the reading and conveying roller 36. The registration loop guide film 31 is used for the separation roller 2.
6 is a plate for supporting the original sent from 6 from below. In a standby state before the reading operation of the document, the leading end of the document is prevented from proceeding between the registration rollers 32 and 33. In addition, the document waits so that a part of the document is slackened (loop state). Therefore, the resist loop guide film 31 has a role of regulating the direction of the loop. The registration roller 33
Is turned off by turning off the paper feed clutch 57.
The driving roller is driven by the pulse motor 51, and the registration roller 32 is a driven roller that rotates following the movement of the document.

Two flappers 3 rotatable around shafts 34a and 37a around the reading and conveying roller 36 and in the direction of the registration rollers 32 and 33, respectively.
4 and 37 are provided. The registration rollers 32
A transport roller 35 is provided between the flapper 34 and the flapper 37 to be in contact with and follow the reading transport roller 36. In addition, a resist roller 48 is provided above the reading and conveying roller 36 so as to contact and follow the reading and conveying roller 36. Here, the flapper 37 forms a transport path on the outer periphery of the reading and transporting roller 36, and also appropriately guides the document sandwiched between the transporting roller 35 and the reading and transporting roller 36 onto the ADF platen glass 39. Used for In addition, flapper 3
Reference numeral 4 denotes a transfer unit that transfers the document sandwiched between the registration roller 33 and the registration roller 32 between the reading and conveying roller 36 and the flapper 37, and that the ADF platen glass 39 and the registration roller 48 It is used to form a path for transporting a document between them. Further, a platen guide 38 for pressing a document toward the ADF platen glass 39 is provided between the reading and conveying roller 36 and the ADF platen glass 39.

On the other hand, on the side of the document feed opening 2d of the reading and conveying roller 36, a conveying roller 41 which is in contact with and follows the reading and conveying roller 36 is provided. Further, two flappers 42 and 43 for switching the document conveying direction are provided.
Are provided, and are rotatable around shafts 42a and 43a, respectively. Further, a discharge roller 45 and a discharge roller 46 driven by the rotation of the discharge roller 45 are provided adjacent to the document feed opening 2d. Here, the flapper 42
Has a role of switching the document sent from the transport roller 41 to the direction of the transport guide 49 or the discharge roller 46, and the flapper 43 has a role of forming a transport path from the transport roller 41 to the discharge roller 45. Are used to switch the role of forming a transport path from the discharge roller 45 to the transport guide 47.

4 arranged around the reading and conveying roller 36
The flapper 37 of the three flappers 34, 37, 42 and 43 is driven by a flapper solenoid 56. The detailed function of each flapper will be described later.

Next, the document feeding mechanism 17 shown in FIG. 6 will be described with reference to the processing flowcharts of FIGS. 7 to 10 and the schematic diagrams showing the document conveying process of FIGS. 11 to 13.

Here, the document feeding mechanism 17 is provided with three main modes: a document advance operation, a document single-sided reading operation, and a document double-sided reading operation. And
This mode is selected, for example, according to an instruction for document processing (operation instruction) from the operator. In addition, according to this operation instruction, the reading unit carriage 7 moves to a predetermined readable position and waits.

FIG. 7 is a flow chart of a process showing the original advance operation. First, the document width size is detected by the size sensor 61 (S1). Next, by turning on the paper feed clutch 57, the drive connection of the pickup roller 24 and the separation roller 26 is performed (S2). Then, by turning on the paper feed solenoid 55, the document shutter 21 is lowered to open the leading end of the document, and the document is pressed by the weight 22 toward the pickup roller 24 (S3).

Next, the ADF pulse motor 51 is driven to rotate forward to rotate the pickup roller 24 and the separation roller 26 to start feeding one document in the direction of the registration roller 33 (S4). Here, FIG. 11A shows the relationship between the main part of the document feed mechanism 17 and the document S immediately after the document S is fed by the separation roller 26.

Returning to the flowchart of FIG. 7, at this time, the registration sensor 30 monitors whether or not the document S has been sent (S5). When the leading edge of the document S is detected, the registration sensor 30 outputs an output. ON and control unit 60
Send to Next, the ADF pulse motor 51 is controlled, and the document S is conveyed by the separation roller 26 toward the registration roller 33 by a predetermined movement amount (S6). After a certain amount of conveyance, the ADF pulse motor 51 is stopped, and the document S is brought into a so-called reading standby state (also called a registration state) (S7).

Next, the paper feed clutch 57 is turned off (S
8) The ADF pulse motor 51 and the separation roller 26
Is cut off, the operation is switched to driving of the registration roller 33 (S8), and the original advance operation is completed. FIG. 11B shows that the leading end of the original S reaches between the registration rollers 32 and 33, and the middle of the original S is bent by the registration rollers 32 into a loop shape as described above. This shows a state where the apparatus stands by in a so-called resist state.

FIG. 8 is a flowchart of the processing of the one-sided reading operation of the original, following the advance operation of FIG.
When a single-sided reading operation command is issued, the flapper solenoid 56 is turned on and the position of the flapper 37 is switched (S11). FIG. 14B shows the switched state of the flapper 37. In addition, flapper 3
14 is normally urged in the counterclockwise direction by an elastic member such as a spring, and is normally in the state shown in FIG. 14 (a). FIG. 14 shows a clockwise force applied by paper stiffness.
The switching is performed as shown in (b), and it extends so as to guide between the transport roller 35 and the reading transport roller 36. The flapper 37 has a transport surface 37 having a curved surface substantially the same as the outer peripheral curved surface of the read transport roller 36 in order to further transport the document S sandwiched between the transport roller 35 and the read transport roller 36.
b forms a transport path. Here, the leading end 37c of the transport surface 37b in the direction of the ADF platen glass 39 is switched to a position higher than the upper surface of the ADF platen glass 39. Therefore, the leading end of the document S transported in the direction of the ADF platen glass 39 along the transport surface 37b is moved to the transport surface 3
7b, the ADF platen glass 3 is curved clockwise as viewed from the figure, and passes through the tip 37c.
9 so as to reach the surface 9.

Returning to FIG. 8, in addition to turning on the flapper solenoid 56, the discharge clutch 58 and the discharge clutch 59 are turned on. Here, the discharge clutch 58 and the discharge clutch 5
Reference numeral 9 denotes a combination of ON and OFF, in which the rotation direction of the ADF pulse motor 51 and the rotation direction of the discharge roller 45 are interlocked, or the interlock between the ADF pulse motor 51 and the discharge roller 45 is interlocked. This is a switching clutch for disconnecting and making the paper discharge roller 45 free from the ADF pulse motor 51. Discharge clutch 58 is ON
Then, the paper discharge roller 45 and the ADF pulse motor 51 are interlocked, and the paper discharge roller 45 is rotated so that the reverse rotation driving of the ADF pulse motor 51 discharges the document S from the document feed opening 2d ( Rotation in the counterclockwise direction as viewed from FIG. 6) (S11). Then, the ADF pulse motor 51 is driven in reverse rotation at a high speed, so that the registration rollers 3 are rotated.
The document S sandwiched between the sheet 2 and the registration roller 33 is transported at high speed in the direction of the reading transport roller 36. Then, the leading end of the document S is sandwiched between the reading and conveying roller 36 and the conveying roller 35 along a partial side surface 34b of the flapper 34, and is conveyed further downward.

At this time, the timing sensor 12 of the reading unit carriage 7 monitors whether or not the original S has been conveyed. When the timing sensor 12 detects the original S and turns ON (S13), the original is further scanned. S is transported by a predetermined amount (S14). Here, since the reading and conveying roller 36 is driven by the ADF pulse motor 51, its AD
The conveyance amount of the document S is determined by the rotation amount of the F pulse motor 51. The rotation amount of the ADF pulse motor 51 is A
It is determined by the number of pulses for controlling the rotation of the DF pulse motor 51, and the number of pulses and the conveyance amount of the document S have a fixed relationship.

As described above, the detection position of the document S by the timing sensor 12 is provided at a position close to the ADF platen glass 39. Accordingly, when the document S is moved to the reading position by the ADF pulse motor 51 after the detection of the document S, a large error does not occur in the transport amount of the document S. In addition, since the reading position of the document S on the ADF platen glass 39 and the detection position of the document by the timing sensor 12 are relatively constant,
Stabilization of the reading start timing (that is, the timing of rotating the ADF pulse motor 51 to guide the original to the reading position) even with respect to the variation of the stop position or the mounting position of the reading unit carriage 7 or the mounting position of the timing sensor 12. Can be. Therefore, when the document is read, the cue portion of the read image data does not shift.

When it is confirmed that the document S has been conveyed by the predetermined amount by the ADF pulse motor 51 (S14), the ADF pulse motor 51 is temporarily stopped (S15). At this time,
The document S is in a state of stopping just before the reading position on the ADF platen glass 39. In addition, the flapper 42
Using the rotational force of the paper discharge roller 45, the switching is performed according to the rotational direction. Then, the flapper 42 when the paper discharge roller 45 rotates in the direction of discharging the document S
Is in the position state shown in FIG. FIG.
(C) shows a state immediately after step S15,
The document S is securely guided on the ADF platen glass 39 by the flapper 37. Thereafter, the flapper solenoid 56 is turned off, so that the flapper 37 is turned off as shown in FIG.
It is evacuated to the position shown in FIG. 4 (a) (S16). Since the leading end 37c of the flapper 37 switches to a state lower than the upper surface of the ADF platen glass 39, the leading end of the original S is pushed down by the platen guide 38 so that the leading end of the original S is on the surface of the ADF platen glass 39. Touch up and down. The leading end 37c of the flapper 37 does not contact the original S, and a relatively large space is formed between the platen guide 38 and the transport surface 37b of the flapper 37. Therefore, the original S contacts the surface of the ADF platen glass 39. A large area in the carrying direction can be secured. As a result, stable reading can be performed, and the reading accuracy does not significantly change even when the position of the reading unit carriage 7 fluctuates. Further, since the leading end 37c of the flapper 37 does not contact the document S, the rear end of the document S passes through the flapper 37 and
Even when the document S is conveyed onto the platen glass 39, the document S does not fluctuate rapidly, and the rear end of the document S can be read stably.

Referring back to FIG. 8, the lamp 10 is turned on to irradiate the original S with light from below (S17). At this time, since the leading end of the document S has not yet completely reached the reading position and is kept at a predetermined distance from the reading position, the ADF pulse motor 51 is driven in reverse to read the document. The transport roller 36 is rotated clockwise as viewed from FIG. 6 to transport the document S at the reading speed (S1).
8). Then, the original S advances the predetermined distance, and the original S
It is determined from the rotation amount of the ADF pulse motor 51 whether or not the leading end has reached the reading position (S19). If it is determined that the predetermined carry amount has been carried, the document reading is started (S20). Here, the flapper 43 is urged counterclockwise by an elastic member such as a torsion coil spring (not shown), and is normally at the position shown in FIG.
The original S is rotated clockwise by the stiffness of the original S, and FIG.
Position. FIG. 11D shows a state in which the original S is being read, and the original S includes the flapper 42 and the flapper 4.
3 shows a state in which the sheet is conveyed along the conveyance path formed by No. 3 and a part of the sheet is out of the space between the sheet discharging roller 45 and the sheet discharging roller.

Next, when the reading operation is started, it is monitored whether the timing sensor 12 is turned off (S21). The timing sensor 12 turns off the output when the trailing edge of the document S passes the sensing position, so that the trailing edge of the document S can be confirmed. Further, the length of the document can be specified from ON / OFF of the timing sensor 12 and the rotation amount of the ADF pulse motor 51, and the document size can be determined together with the detection of the document width size in step S1. After the timing sensor 12 is turned off, a predetermined amount of conveyance is performed until the rear end of the document S moves to the reading position.
It is determined from the rotation amount of the pulse motor 51 (S22). When the predetermined amount of paper is conveyed, the reading of the document S is terminated (S23), the ADF pulse motor 51 is temporarily stopped (S24), and the lamp 10 is turned off (S25).

Next, the original S is conveyed at a high speed by driving the ADF pulse motor 51 to reversely rotate at a high speed (S2).
6). FIG. 11E shows a process in which the document S is transported by high-speed transport. Next, it is determined whether the output from the paper discharge sensor 62 is OFF (S2).
7) After the sheet ejection sensor 62 is turned off, the document S is completely ejected from the document feed opening 2d by rotating the ADF pulse motor 51 by a predetermined amount (S28). The paper discharge roller 45 is driven by an ADF pulse motor 51. When the ADF pulse motor 51 rotates in the reverse direction, the paper discharge roller 45 is viewed from the drawing so that the carry amount is the same as the carry amount of the reading carry roller 36. Rotate counterclockwise. FIG.
1 (f) shows a state in which the document S has been discharged from the document feed opening 2d in FIG. 5 by carrying a predetermined amount of paper after the output of the paper discharge sensor 62 is turned off.

FIG. 9 and FIG. 10 are flowcharts of the processing of the both-side reading operation of the original following the advance operation of FIG. After the command for the double-sided reading operation is issued, a series of steps from step S31 for turning on the flapper solenoid 56 to step S47 for determining whether or not the paper discharge sensor 62 is off are steps S11 and S2 shown in FIG.
Same as 7. Accordingly, the conveyance process of the document S shown in FIGS. 12A to 12E is the same as that in FIGS. 11A to 11E. In step S47, the output of the paper discharge sensor 62 becomes O.
If it is determined that the document is FF, then a predetermined amount of the document S is conveyed (S48). The predetermined amount at this time corresponds to the conveyance amount before the document S is completely discharged by the discharge rollers 45 and 46, and the rear end of the document S is
This is the transport amount at the position that has passed through the transport path made in Step 3. Next, by stopping the ADF pulse motor 51 (S49), the document is stopped while a part of the rear end of the document is held by the discharge rollers 45 and 46. The flapper 43 is automatically switched by the urging of an elastic member such as a spring when the trailing end of the document S passes through the leading end of the flapper 43. And
The flapper 43 and the transport guide 47 form a transport path in the direction of the resist rollers 48. Next, by rotating the ADF pulse motor 51 forward at high speed, the discharge rollers 4 are rotated.
5 is rotated clockwise in the reverse direction, and the trailing end of the document S is run backward in the direction of the registration rollers 48 (S51). Then, the paper discharge sensor 62 detects the rear end of the document S to determine whether or not the document S has been turned on (S52). After confirming that the document S has been turned on, the document S is placed in a standby state required for resist conveyance. It is determined from the rotation amount of the ADF pulse motor 51 whether or not the fixed amount has been transported (S53). In the conveyance at this time, the trailing end of the document S advances in the direction of the registration rollers 48 along the conveyance path formed by switching between the conveyance guide 47 and the flapper 43.
12 (f) because it is rotated counterclockwise as viewed from above.
As shown by, the destination of the trailing end of the document S is stopped in front of the registration roller 48, and a part thereof is looped by the transport guide 47 (see FIG. 6) bent upward. Since the rotation of the paper discharge roller 45 is reversed clockwise as viewed from FIG. 12, the flapper 42 is switched to a position above in the counterclockwise rotation direction shown in FIG. .

When it is confirmed that a predetermined amount of conveyance has been performed so as to form a predetermined loop, the ADF pulse motor 5
1 is stopped (S54), and the original S is brought into a standby state for reading the back surface (also referred to as a double-sided registration state). next,
By turning off the discharge clutch 58 for linking the discharge roller 45 with the ADF pulse motor 51 (S55), the rotation of the discharge roller 45 and the discharge roller 46 is made free. Further, in order to switch the flapper 37 to the state shown in FIG. 14B, the flapper solenoid 56 is turned on (S56).

Next, the ADF pulse motor 51 is reversely driven at a high speed (S57), and the reading and conveying roller 36 is moved to the position shown in FIG.
Rotate at high speed in clockwise direction. Resist roller 48
The original S, which is sandwiched between the reading and conveying rollers 36, moves on the outer periphery of the reading and conveying rollers 36 along the side surface 34 c of the flapper 34.
After being transported onto the ADF platen glass 39 along the transport surface 37b (see FIG. 14) and the transport surface 37b, it is further transported along the partially curved surface 42b of the flapper 42. FIGS. 13A and 13B show the process of transporting the document S. FIG.

At this time, the timing sensor 12 of the reading unit carriage 7 monitors whether the leading edge of the document S (the end of the document S in the direction opposite to the transport direction) passes or not. The output of No. 12 is turned off. When it is determined that the output of the timing sensor 12 is OFF (S58), the document S is conveyed by a predetermined amount from that time (S5).
9). As described above, the detection position of the document S by the timing sensor 12 is very close to the ADF platen glass 39. Therefore, a small amount of rotation is required to move the leading edge to the reading position by the ADF pulse motor 51 after the leading edge of the document S is detected.
No large error occurs in the transport amount of the document S.

When it is confirmed that the document S has been conveyed by the predetermined amount by the ADF pulse motor 51, the ADF pulse motor 51 is stopped (S60). Further, the flapper solenoid 56 of the flapper 37 is turned off so that the leading end of the document S can be run backward (S61), and the leading end 37c of the flapper 37 is connected to the ADF platen glass 39 as shown in FIG. Switch to evacuate below the surface. FIG. 13C shows the state of the document S and the flapper.
It is stopped just before the upper reading position.

Next, by turning off the discharge clutch 58 and turning on the discharge clutch 59, the ADF pulse motor 5 is turned on.
In step S62, the ADF pulse motor 51 and the paper discharge roller 45 are linked so that the forward rotation drive 1 drives the paper discharge roller 45 and the paper discharge roller 46 in the direction of discharging the paper out of the document intake opening 2c. . Thereafter, the lamp 10 is turned on to irradiate the original S with light from below (S63).

Next, the ADF pulse motor 51 is driven to rotate forward to rotate the reading / conveying roller 36 in a counterclockwise direction as viewed in FIG. 6, and the document S is conveyed backward with the leading end of the original S at the reading speed. (S64). Here, the forward drive of the ADF pulse motor 51 rotates the paper discharge roller 45 in a counterclockwise direction, so that the flapper 42 attempts to switch clockwise. However, since the flapper 42 is connected to the paper discharge roller 45 via a torque limiter (not shown), the drag from the document S abutting on a part of the flapper 42 acts on the torque limiter, and the paper discharge roller 45 Is not transmitted to the flapper 42 any more. Therefore, the flapper 42 is controlled by the torque limiter.
The flapper 42 and the transport roller 41
Then, the original S can be transported later.

Next, whether the leading end of the document S has reached the reading position is determined from the rotation amount of the ADF pulse motor 51 (S65). When the rotation amount of the ADF pulse motor 51 reaches the reading position, reading of the back surface of the document S is started from the leading end of the document (S66).

The leading end of the document S advances on the outer periphery of the reading and conveying roller 36 along a conveying path formed by the conveying surface 37b of the flapper 37 and a partial side surface 34c of the flapper 34 (see FIG. 14A). , The paper discharge rollers 45 and the paper discharge rollers 4 through a conveyance path formed by the flapper 43 and the conveyance guide 47.
Proceed to 6. FIG. 13D shows an intermediate process of reading the document S. Here, the timing sensor 12
Is always sensed to confirm that the trailing edge of the document S passes. Therefore, it is determined whether or not the rear end has passed and the output of the timing sensor 12 has been turned off (S
67). When the output of the timing sensor 12 is turned off,
The reading of the back side of the document is completed (S68), and the ADF pulse motor 51 is temporarily stopped (S69). Then, the lamp 10 is turned off (S70), the ADF pulse motor 51 is driven to rotate forward at a high speed, and the document S is transported at a higher speed than the transport speed for reading (S71). FIG. 13E shows the transport process, in which the document S is transported in the direction of the paper discharge rollers 45 and 46 through the flapper 37, the flapper 34 and the transport guide 47. ing.

At this time, the paper discharge sensor 62 senses whether or not the document S has passed, and outputs the output O
FF. Therefore, when it is determined that the output is OFF (S72), a predetermined amount of conveyance is performed thereafter, and FIG.
As shown in (f), the discharge roller 45 and the discharge roller 46
Then, the document S is completely discharged out of the document feed opening 2d (S73).

As described above, the original feeding mechanism 17 of the image reading apparatus 1 can always read from the same end of the original S when reading both sides of the original S. Regardless, an image read in the same direction from the same end can be re-formed on the sheet.
In addition, in the process of turning over the original, the leading end and the rear end of the original do not overlap, and the original feeding mechanism 17 can be realized with an extremely compact size.

Next, with reference to FIG. 15, a modified example of the double-sided reading conveyance of the document feeding mechanism 17 will be described with reference to a schematic diagram of a document conveyance mode. FIGS. 15A and 15B have different transport modes. The reading position is, as described in the previous example, the reflection position on the document of the light emitted from the reading unit carriage 7 and reflected by the CCD 5 as reflected light. Here, the solid line indicates the transport path of the document,
The broken line indicates the direction in which the document is transported.

First, the original is transported from one position in the direction of the reading position (A1), and the original is read. Next, with the trailing end of the document at the head, for example, the reading and conveying roller 36 used in FIG. 6 is used and the outer periphery thereof is moved backward while drawing an arc in the clockwise direction (A2), and reading is performed without performing reading. Pass the position. Then, after the leading edge of the document has passed the reading position, the document S is transported in the direction (A3) opposite to the direction in which the document was transported for reading, with the leading edge of the document being the leading edge, and the document S is discharged. I do.

Next, referring to FIG. 15B,
FIG. 15A is similar to FIG. 15A in that the document is conveyed from one position to the reading position (A1) and the document is read. Next, the document is rotated backward (B2) at the position of the document to turn the document over, and the leading end of the document is turned toward the reading position. Next, the document S is transported (B3) in the direction opposite to the direction in which the document was transported for reading first, with the leading end of the document being the leading edge, and the document S is read and discharged.

Here, the common point between the original transport described in FIGS. 12 and 13 and the original transport described in FIG.
After reading the original in the direction (referred to as the forward direction), the original is turned upside down while the rear end of the original is running backward, and the original is read again from the leading end of the original facing the reading position. As a result, both sides of the document can be read with the leading edge of the document at the top, and the leading edge and the trailing edge of the document do not overlap at the scanning position, so that compact transport scanning is possible. It becomes possible. The document conveyance described with reference to FIGS. 12 to 13 and FIG. 15 is for describing an embodiment of the present invention, and is not limited thereto. For example, in FIG. 15B, paths B3 and B
It may be conveyed in the reverse direction in the order of 2, B1.

[Brief description of the drawings]

FIG. 1 is a perspective view of an image reading apparatus 1 according to the present invention.

FIG. 2 is a transparent side view of the image reading apparatus 1.

FIG. 3 is a side view of the reading unit carriage 7 at a position where reading is performed by a document feeding mechanism 17;

FIG. 4 is a transparent side view of the image reading apparatus 1 in which the reading unit carriage 7 is moved and the position thereof is changed for comparison.

FIG. 5 is a block diagram for controlling reading and conveyance of a document.

FIG. 6 is an enlarged side view of the document feed mechanism 17;

FIG. 7 is a flowchart of a document process when performing an advance operation of a document S;

FIG. 8 is a flowchart of a document process when a single-sided reading operation of the document S is performed.

FIG. 9 is a flowchart of a document process when a double-sided reading operation of the document S is performed.

FIG. 10 is a flowchart of a document process when a double-sided reading operation of the document S is performed subsequent to FIG. 9;

FIG. 11 is a schematic side view showing a flow of a document from a leading-out operation to a single-sided reading operation of the document S.

FIG. 12 is a schematic side view showing a flow of a document from a leading-out operation to a double-sided reading operation of the document S.

FIG. 13 is a schematic side view showing the flow of the document from the advance operation of the document S to the double-sided reading operation, following FIG. 12;

FIG. 14 is a side view showing switching of the flapper 37 of the document feeding mechanism 17;

FIG. 15 is a side view showing an outline of a document feeding mode according to another modification of the document feeding mechanism 17;

FIG. 16 is a side view of a conventional document reading apparatus.

[Explanation of symbols]

S. . . Manuscript, 1. . . Image reading device 2. . . Frame 2, 2c. . . Document intake opening, 2d. . . Document feed opening, 2e. . . 2. frame cover, . . Rails, 5. . . CCD,
6. . . Lens, 7. . . Reading unit carriage,
8. . . Mirror carriage, 8a, 8b, 9. . . Mirror, 10. . . Lamp, 11. . . Reflector, 1
2. . . Timing sensor, 13. . . Reading glass,
14． . . Pat. . . Cover, 1
6. . . Pocket cover, 17. . . Document feed mechanism,
18. . . Document feed tray, 19. . . Document detection arm, 19b. . . Associated arm, 20. . . Original detection sensor, 21. . . Document shutter, 22. . .
Weight, 23. . . Original set guide film, 24. . . Pickup roller, 25. . . Front panel, 26. . . Separation roller, 27. . . Separation pad, 28. . . Pat holder, 2
9. . . Pad pressure spring, 30. . . Resist sensor,
31. . . Registration loop guide film, 3
2. . . Registration roller, 33. . . Registration rollers, 34, 37, 42, 43. . . Flapper, 34
b, 34c. . . Partial aspect, 35. . . Transport roller, 36. . . Reading and conveying roller, conveying surface 37b,
37c. . . Tip 38. . . Platen guide, 39. . . ADF platen glass, 40. . . Transport guide, 41. . . Transport roller, 44. . . Document storage, 45, 4
6. . . Discharge rollers, 47, 49. . . Transport guide 4
7, 48. . . Resist rollers,

Claims (5)

[Claims] An image on a document surface of a held document is read by moving a reading unit carriage, and the reading unit carriage is stopped at a predetermined standby position to read an image on the document surface of the document sent by a document feeder. In the image reading device capable of reading, the reading unit carriage is provided with document detecting means for detecting a leading end of the document sent by the document feeding device, separately from means for reading an image on a document surface. An image reading apparatus with a document feeding mechanism. 2. A timing for starting scanning of the original surface by detecting the leading end of the original by the original detecting means before the image of the original surface of the sent original can be read, 2. The image reading apparatus with a document feeding mechanism according to claim 1, further comprising control means for setting a timing for terminating scanning of the document surface by detecting the trailing edge of the document by the document detection means. 3. The original detecting means is a reflection type optical sensor comprising a light emitting element and a light receiving element, and a light emitted from the light emitting element is provided at a position corresponding to the original detecting means on the original feeding device side. 3. The image reading apparatus with a document feeding mechanism according to claim 1, further comprising a light reflecting member for reflecting the document, thereby detecting clearly the presence or absence of the document. 4. A transmission type optical sensor is used as an original detecting means, and one of a light emitting element and a light receiving element constituting the transmission type optical sensor is installed on the reading section carriage, and the other is provided on the side of the original feeding device. 3. The image reading device with a document feeding mechanism according to claim 1, wherein the image reading device is installed at a corresponding location. 5. The reading unit carriage according to claim 1, further comprising: a lamp unit for irradiating light to the original surface; and a light reflecting plate for reflecting diffused light from the lamp unit to the original surface. An image reading device with a document feeding mechanism according to the above.