JPH04291275A - Document carrier device - Google Patents

Abstract

PURPOSE:To exactly read the images of a document by stabilizing speed for carrying the document at the reading position of the document images. CONSTITUTION:The document passing through a document entrance part 21 is fed by a supply roller 24 and a platen roller 25 and guided along the outer periphery by a document guide 26 so as to be wound and adhered around the platen roller 25. Therefore, the document is prevented from being warped from the supply roller 24 to a document reading position 40 of document supporting glass 27. Since a space between the platen roller 25 and the document supporting glass 27 is set larger than the thickness of the document, the head of the document does not collide the document supporting glass 27 in the case of entering the space. Next, the document fed out to a document carrying-out mechanism composed of a document discharge roller 29 and a movable guide 30 is fed and discharged without colliding the movable guide 30 since the movable guide 30 is turned at timing for the head of the document to pass through a space between the document discharge roller 29 and the movable guide 30.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a document conveying device for transporting a document through a document reading position of a copying machine, scanner, facsimile machine, or the like.

0002

2. Description of the Related Art FIG. 4 is a schematic diagram of a conventional document conveying device.

As shown in the figure, this conventional document conveying device includes a pair of supply rollers 11, a document support drum (platen roller) 12, a transparent document support glass 13, and a pair of discharge rollers 15.

A pair of supply rollers 11 and a pair of discharge rollers 15 are each configured to sandwich the original 10 and drive in the direction of the rotation arrow shown in the figure.

The platen roller 12 is configured to be rotatable in the direction of the rotation arrow shown in the figure, and the document support glass 13 is disposed below the platen roller 12 in contact with the platen roller 12.

For example, a copying machine equipped with this document conveying device has an optical system (not shown) disposed below the document reading position 14 of the document supporting glass 13, and detects the document image passing through the document reading position 14. Configured to read.

[0007] Therefore, the original 10 is transferred to the pair of supply rollers 11.
The document is conveyed while being sandwiched between them, and is supplied between the platen roller 12 and the document support glass 13. The supplied original 10 is pressed against the original supporting glass 13 by the platen roller 12 at the original reading position 14, and is supplied to the pair of ejection rollers 15 through the original reading position 14 while sliding, and is sandwiched between the pair of ejection rollers 15. Ejection roller 1
5 is discharged by rotation in the direction of the rotation arrow shown in the figure.

[0008]

[Problems to be Solved by the Invention] In such a conventional document conveying device, when conveying a document, the conveyance force by the supply roller 11 and the conveyance force μF3 due to the friction of the platen roller 12 are reduced.
, and the conveyance force by the discharge roller 15 acts on the document 10. Among these conveying forces, the conveying force μF3 due to the friction of the platen roller 12 is caused by the contact area between the platen roller 12 and the document 10 being small, and the contact area between the document 10 and the document supporting glass 13.
Sliding friction occurs between the two, resulting in unstable conveying force.

Due to these conveying forces, the document 10 is transferred from the supply roller 11 to the platen roller 12 and document support glass 13.
Before the document 10 reaches the document reading position 14 after being sandwiched between the document 10 and the document 10, a deflection 16 occurs. Further, the leading edge of the original 10 that has passed through the original reading position 14 is placed on the ejection roller 15.
Upon contact, a deflection 17 occurs in the original 10.

These deflections 16 and 17 are mainly caused by:
This occurs when the leading edge of the document 10 collides with the platen roller 12, the document support glass 13, and the discharge roller 15, respectively.

Due to the deflections 16 and 17 generated on both sides of the document reading position 14, reaction forces F1 and F are applied to the document 10.
2 act respectively. When these reaction forces F1 and F2 exceed the frictional force μF3 of the platen roller 12, variations occur in the document conveyance speed at the document reading position 14.
There is a problem that blur occurs in the original image read at the original reading position 14.

In particular, since the platen roller 12 has a curved surface, the contact area is small, and the contact area between the original 10 and the original support glass 1 is small.
Since there is sliding friction between platen roller 12 and F3, the frictional force μF3 of the platen roller 12 becomes unstable, and the reaction forces F1 and F2
The balance between the frictional force μF3 and the frictional force μF3 is likely to be lost.

The present invention provides a document conveying device that can contribute to accurate reading of a document image by stabilizing the conveyance speed of the document 10 at the document image reading position.

[0014]

[Means for Solving the Problems] A document conveying device that allows a document to pass through a document reading position of a document support plate, comprising:
a document supply means capable of supplying a document; a roller facing the document support plate; a guide means for guiding the document from the document supply means to a document reading position along the surface of the roller;
The document discharging means is configured to be able to guide and discharge the document that has passed through the document reading position, and is configured such that the distance between the surface of the roller and the document support plate at the document reading position is greater than the thickness of the document. .

[0015]

[Operation] The original supplied by the original supply means is conveyed by the guide means along the surface of the roller to the original reading position on the original support plate, so the leading edge of the original does not collide with the original support plate. No bending occurs in the original on the paper side. The document conveyed in this manner passes through the document reading position. Since the distance between the roller and the original support plate is set to be larger than the thickness of the original, the original passes between the roller and the original support plate without being subjected to sliding frictional force by the original support plate. After passing, the original is ejected while being guided by the original ejection means, so the leading edge of the original does not collide with the original ejection means, and the original does not bend on the ejection side.

[0016] Therefore, since the original does not bend on both sides of the original reading position along the original transport direction, the original transport speed at the original reading position is stabilized, which contributes to accurate reading of the original image. can.

[0017]

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

FIG. 1 is a vertical sectional view schematically showing the simplest embodiment of the document conveying device according to the present invention.

As shown in the figure, the document conveying device 20 of this embodiment includes a document entrance section 21, a document detection sensor 22,
Controller 23, supply roller 24, document support drum (
platen roller) 25, document guide 26, transparent document support glass 27, spring 28, document discharge roller 29,
A movable guide 30, a pivot 31, a spring 32, and a solenoid 33 are provided.

A document detection sensor 22 is provided at the document entrance section 21, and the document detection sensor 22 is configured to detect the arrival of the leading edge of the document to be conveyed and send a signal to the controller 23. .

A supply roller 24 is provided next to the document detection sensor 22 along the direction of conveyance of the document. In this embodiment, the supply roller 24 cooperates with a platen roller 25 to rotate in the direction of the arrow shown in the figure. The device is configured to transport the original using the same method.

The document guide 26 extends along a part of the outer periphery of the platen roller 25 from below the supply roller 24 to the document support glass 2 disposed below the platen roller 25.
7 and is biased by a spring 28.

Therefore, the original that has passed through the original entrance section 21 is conveyed by the supply roller 24 and the platen roller 25, and is guided by the original guide 26 along the outer periphery of the platen roller 25 so as to wrap around the platen roller 25 and come into close contact with it. .

Therefore, the original is prevented from being bent between the supply roller 24 and the original support glass 27. Further, the original is moved to the platen roller 25 by the original guide 26.
Therefore, when the leading edge of the original in the transport direction enters the nip between the platen roller 25 and the original supporting glass 27, the leading edge of the original does not substantially collide with the original supporting glass 27. do not have.

Original reading position 4 of original supporting glass 27
A document reading device for reading a document image is arranged below the document reading position 40, and the document reading device is configured to read the image of the document passing through the document reading position 40.

[0026] Platen roller 25 and document support glass 27
The nip interval t0 between the two is set to be larger than the thickness t1 of the document (t0>t1).

Therefore, the original transported by the supply roller 24 and guided by the original guide 26 slides against the original support glass 27 without substantially sliding friction.
Pass through this nip smoothly.

The original is then conveyed to an original ejection mechanism consisting of an original ejection roller 29 and a movable guide 30.

The movable guide 30 is configured to be rotatable around a pivot 31, and is configured to move toward and away from the document discharge roller 29. This movable guide 3
0 is biased by a spring 32 in a direction away from the document discharge roller 29, and is configured to be biased toward the document discharge roller 29 when a solenoid 33 is energized.

The solenoid 33 is connected to the controller 23, and the controller 23 determines the timing when the leading edge of the document in the conveying direction passes between the document discharge roller 29 and the movable guide 30, based on the signal from the document detection sensor 22. At the same time, the solenoid 33 is configured to be excited.

Therefore, the original is transported without the leading edge of the original in the transport direction colliding with the movable guide 30.

[0032] In this way, the original is transported without causing any deflection of the original on both sides of the original reading position 40 along the original transport direction.

The supply roller 24 is an embodiment of the document supply means of the present invention. The platen roller 25 is one embodiment of the roller of the present invention. The document guide 26 is an embodiment of the guide means of the present invention. The document discharge roller 29 and the movable guide 30 are an embodiment of the document discharge means of the present invention. The document support glass 27 is an embodiment of the document support plate of the present invention.

FIG. 2 is a vertical sectional view of a digital copying machine equipped with a document conveying device 55 according to another embodiment of the present invention.

As shown in the figure, this digital copying machine includes a scanner section 50, a laser printer section 51, a multistage paper feeding unit 52, and a sorter 53.

[0036] At the top of this digital copying machine, an operation panel (not shown) equipped with various input keys is installed according to a well-known aspect.

The scanner section 50 is composed of an original table 54 made of transparent glass, an original transport device 55 capable of automatically transporting double-sided originals, and a scanner unit 56.

The document conveying device 55 is configured so that when a plurality of documents are set at once, the documents can be automatically conveyed one by one to the document reading position where the document image is read. The details will be described later.

The scanner unit 56 includes a lamp reflector assembly 57 for exposing the original, a plurality of reflecting mirrors 59 for guiding the reflected light image from the original to a photoelectric conversion element (CCD) 58, and a plurality of reflecting mirrors 59 for guiding the reflected light image from the original to the CCD 58. It includes a lens 60 for forming an image.

The scanner unit 50 is configured such that when scanning an original placed on the original placing table 54, the scanner unit 56 reads the original image while moving along the lower surface of the original placing table 54. When the document conveyance device 55 is used, the document image is read while conveying the document with the scanner unit 56 stopped at a predetermined position below the document conveyance device 55.

[0041] The image data obtained by reading the original image with the scanner unit 56 is subjected to various processing according to known methods and then temporarily recorded in a memory (not shown).
In response to an output instruction, the image data in the memory is given to the laser printer section 51 to form an output image.

Since the laser printer section 51, multistage paper feeding unit 52, and sorter 53 are all known,
I'll stop at a simple explanation.

The laser printer section 51 includes a laser writing unit 61 and an electrophotographic processing section 62 for forming an output image.

[0044] The electrophotographic process section 62 is configured by arranging a charger, a developer, a transfer device, a stripper, a cleaning device, and a static eliminator around a photosensitive drum 68 in accordance with a well-known manner, and includes the above-mentioned memory. An image is written on the surface of the photoreceptor drum 68 by scanning a laser beam by the laser writing unit 61 based on the image data read from the image data, and the electrostatic latent image formed on the surface of the photoreceptor drum 68 is The toner image is visualized with toner and is configured to be electrostatically transferred onto the surface of the paper conveyed from the multistage paper feeding unit 52.

The multi-stage paper feeding unit 52 has the first cassette 6
3, a second cassette 64, a third cassette 65, a fourth cassette 66, and a fifth cassette 67 that can be added according to the user's selection.

In the multistage paper feeding unit 52, sheets are fed out one by one from the top of the sheets stored in the cassettes of each stage, and are conveyed toward the laser printer section 51.

FIG. 3 is an enlarged sectional view of the document conveying device 55 of the digital copying machine shown in FIG.

Next, the document conveying device 55 will be explained with reference to FIG.

Basically, this document conveying device 55 is a document conveying device that can automatically convey double-sided documents, and it automatically transfers documents one by one from a plurality of documents placed on the document tray 70. The scanner unit 56 is configured to transport the document and have the scanner unit 56 read one side or both sides of the document depending on the user's selection.

The document conveyance device 55 is equipped with a main motor (its output shaft is indicated by reference numeral 71) equipped with an electromagnetic clutch, and its rotational driving force is transmitted to various rollers to be described later using a known suitable transmission means (see FIG. (not shown).

This document conveying device 55 has an electromagnetic clutch (
(not shown), a pair of transport rollers 73, a solenoid-driven change lever 74 that switches the path of the document, and a document support drum (platen roller) that is rotatable in two directions (in the direction of the arrow in the figure). 7
5. Left and right supply rollers 76L and 76R that feed the original in cooperation with the platen roller 75, left and right original guides 77L and 77R, transparent original support glass 78, left and right original ejection rollers 79L and 79R, and original ejection roller 79L and 79R, solenoid-driven left and right movable guides 80L and 80R, solenoid-driven document discharge movable guide 81, document discharge conveyance path 82, paper discharge roller pair 83, paper discharge tray 84, solenoid-driven rotation It includes a reversing conveyance path 86 formed on one side by a possible document reversing guide 85, a pair of reversing conveyance rollers 87 driven via an electromagnetic clutch, and a rotation shaft 88.

[0052] Platen roller 75 and document support glass 78
The gap (nip) between the two is set to be larger than the thickness of the document.

[0053] In the document conveyance path, document detection sensors S1 to
Signals from the document detection sensors S1 to S5 sent out when a document is detected are sent to a controller (not shown). The controller operates various electromagnetic clutches and solenoids at predetermined timings to be described later, thereby transporting the original through the original reading position (exposure position) 90 as described later.

Next, the operation of this document conveying device 55 will be explained.

[Movement of the original being transported in the single-sided original copy mode] When copying only one side of the original, set a plurality of originals on the original tray 70, and press the input key on the operation panel to switch to the copy mode ( Single-sided original scanning, number of copies,
(copy density, etc.).

When the print switch on the operation panel is pressed, the main motor of the document transport device 55 starts rotating. Next, the clutch of the document pickup roller 72 is turned on, and the rotating document pickup roller 72 feeds only the topmost document of the plurality of documents set on the document tray 70. At this time, the clutch of the transport roller pair 73 is also turned on at the same time, and the transport roller pair 73 is also rotationally driven.

When the leading edge of the fed document reaches the first document detection sensor S1, the solenoid of the change lever 74 is energized, and the change lever 74 moves from the position shown by the dashed line in FIG. 3 to the position shown by the solid line. can be switched to the position. As the document continues to be conveyed, the leading edge of the document is guided by the side surface of the change lever 74 and directed toward the fourth document detection sensor S4.

After the leading edge of the document is detected by the fourth document detection sensor S4, the conveyance of the document is temporarily stopped at the timing when the document is supported by the platen roller 75 and the right supply roller 76R.

Next, in synchronization with the scanner unit 56, feeding of the original to the exposure position 90 of the original supporting glass 78 is started again.

The original is pressed against the surface of the platen roller 75 by the right original guide 77R, and passes through the exposure position 90 in a clockwise direction without being bent. At the exposure position 90, the image data of the document is read by the scanner unit 56.

The original that has passed through the exposure position 90 passes under the left original guide 77L and is conveyed toward the left original discharge roller 79L. The solenoid of the left movable guide 80L is energized at the timing when the leading edge of the document reaches the document discharge roller 79L, and the movable guide 80L is pressed against the document discharge roller 79L with the document sandwiched therebetween. As a result, the document is given a conveying force due to the frictional force of the document ejection roller 79L.

[0062] Movable guide 80L and document ejection roller 79
The document transported by being sandwiched between
The document is guided by the upper surface of the document discharge movable guide 81 , passes through the document discharge conveyance path 82 , and is discharged onto the paper discharge tray 84 along a pair of paper discharge rollers 83 . The fifth document detection sensor S5 in the document discharge conveyance path 82 is for detecting the trailing edge of the document and determining that the document has been discharged onto the paper discharge tray 84.

When a plurality of originals are set on the original tray 70, the next original is fed in synchronization with the timing at which the trailing edge of the previous original passes through the exposure position 90.

The document tray 70 is provided with a document detection sensor (not shown) for detecting whether or not a document is set, and the above-described operation is repeated until the last document is exhausted.

[Movement of the original transported in the original double-sided copy mode] When copying both sides of the original, the original tray 7
A plurality of originals are set on the 0, and the copy mode (scanning both sides of the original, number of copies, copy density, etc.) is input using the input keys on the operation panel.

When the print switch on the operation panel is pressed, the main motor of the document conveying device 55 starts rotating. Next, the clutch of the document pickup roller 72 is turned on, and the rotating document pickup roller 72 feeds only the topmost document of the plurality of documents set on the document tray 70.

When the leading edge of the fed original reaches the first original detection sensor S1, the clutch of the transport roller pair 73 is turned on, and the transport roller pair 73 is also driven to rotate. At this time, the solenoid of the change lever 74 is in a de-energized state, the change lever 74 is in the position shown by the dashed line in FIG. 3, and the leading edge of the document is guided toward the second document detection sensor S2. be done.

The leading edge of the document that has passed through the second document detection sensor S2 is connected to the platen roller 75 and the left supply roller 76L.
When the original is sandwiched between the two, the conveyance of the original is temporarily stopped.

Next, in synchronization with the scanner unit 56, feeding of the original to the exposure position 90 of the original supporting glass 78 is started again.

The original is pressed against the surface of the platen roller 75 by the left original guide 77L, and passes through the exposure position 90 in a counterclockwise direction without being bent.

The original that has passed through the exposure position 90 passes under the right original guide 77R and is sent toward the right original discharge roller 79R. At the timing when the leading edge of the document reaches the document discharge roller 79R, the solenoid of the right movable guide 80R is energized, and the movable guide 80R is pressed against the document discharge roller 79R while holding the document.

[0072] Movable guide 80R and document ejection roller 79
The document that is conveyed by being sandwiched between R and
The document is guided to a reversing conveyance path 86 and conveyed by a pair of reverse conveying rollers 87 toward the third document detection sensor S3.

When the leading edge of the document reaches the third document detection sensor S3, the solenoid of the document reversing guide 85 is energized, and the document reversing guide 85 moves from the position shown by the solid line around the rotation axis 88 to the position shown by the dashed line. It rotates along the arrow shown in the figure to the indicated position to open the reversing conveyance path 86. At the same time, the solenoid of the change lever 74 is energized, and the change lever 74 is switched from the position shown by the dashed line to the position shown by the solid line.

The leading edge of the document is further moved by a pair of reversing conveyance rollers 87.
along the side of the change lever 74, which is guided to the pair of conveyor rollers 73 and switched to the position shown by the solid line.
The document is guided toward the document detection sensor S4. Then, when the leading edge of the document is sandwiched between the platen roller 75 and the supply roller 76R, the conveyance of the document is temporarily stopped.

In this state, the reverse conveyance path length L (from the contact point between the platen roller 75 and the supply roller 76R, the fourth document detection sensor S4, the change lever 74, the conveyance roller pair 73, the third document detection sensor S3, Passing through the reversing conveyance roller pair 87 and the reversing conveyance path 86, the movable guide 80R
If the length of the document is longer than the length of the document (to the point of contact between the document ejection roller 79R and
Since the reversing conveyance path 86 is opened by the rotation of
Even if the leading edge of the document is in a stopped state, the portion of the document after the reverse conveyance roller pair 87 is moved by the reverse conveyance roller pair 87.
A natural flexure is formed between the position sandwiched between the movable guide 80R and the document discharge roller 79R.

Next, after the trailing edge of the document passes the exposure position 90, the timing with the scanner unit 56 is determined, and
Feeding of the original to the exposure position 90 on the original supporting glass 78 is started again.

The original is pressed against the surface of the platen roller 75 by the original guide 77R, and the original passes through the exposure position 90 in a clockwise direction without being bent. At the exposure position 90, the image data of the document is read by the scanner unit 56.

The original that has passed through the exposure position 90 passes under the left original guide 77L and is conveyed toward the left original discharge roller 79L. When the leading edge of the document reaches the document ejection roller 79L, the solenoid of the left movable guide 80L is energized, the movable guide 80L is pressed against the document ejection roller 79L with the document sandwiched between them, and the document is transported. do.

When the reading of the second side of the original image is completed, the solenoid of the original reversing guide 85 becomes de-energized, the original reversing guide 85 returns to the position shown by the solid line, and the leading edge of the next original is reversed. It waits to be guided to the conveying roller pair 73.

[0080] Movable guide 80L and document ejection roller 79
The document transported by being sandwiched between
The document is guided along the upper surface of the document discharge movable guide 81 , passes through the document discharge conveyance path 82 , and is discharged onto the paper discharge tray 84 by a pair of paper discharge rollers 83 .

When a plurality of originals are set on the original tray 70, when the second side of the previous original is scanned and exposed, the next original is scanned at the timing when the trailing edge of the original passes the exposure position 90. The original is ready to be fed. The above operation is repeated until the last document is exhausted.

Therefore, according to the embodiment described above, by stabilizing the conveyance speed of the document at the document image reading position, it is possible to contribute to accurate reading of the document image.

[0083]

As described above, the present invention provides a document conveying device that allows a document to pass through the document reading position of a document support plate, and includes a document supply means capable of supplying the document, and a device that is arranged opposite to the document support plate. A guide device that guides the document from the document supply device to the document reading position along the surface of the roller, and a document ejecting device that can eject the document while guiding the document that has passed the document reading position. The distance between the surface of the roller and the document support plate at the document reading position is configured to be larger than the thickness of the document.

[0084] Therefore, since the original does not bend on both sides of the original reading position along the original transport direction, the original transport speed at the original reading position is stabilized, which contributes to accurate reading of the original image. Can be done.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view schematically showing the simplest embodiment of a document conveying device according to the present invention.

FIG. 2 is a vertical sectional view of a digital copying machine equipped with a document conveying device according to another embodiment of the present invention.

FIG. 3 is an enlarged sectional view of the document conveyance device of the digital copying machine shown in FIG. 2;

FIG. 4 is a schematic diagram of a conventional document conveying device.

[Explanation of symbols]

20, 55 Document conveyance device 24, 76R, 76L Supply roller 25, 75
Platen rollers 26, 77R, 77L Original guides 27, 78
Original support glass

Claims (1)

[Claims] Claims: 1. A document conveying device for passing a document through a document reading position on a document support plate, the device comprising: document supply means capable of supplying the document; a roller facing the document support plate; A guide means for guiding the original from the supply means to the original reading position along the surface of the roller, and an original ejecting means capable of ejecting the original while guiding the original that has passed the original reading position, and the original is read. A document conveying device characterized in that the distance between the surface of the roller and the document support plate at the position is larger than the thickness of the document.