JPH05204209A - Document feeder - Google Patents

Abstract

PURPOSE:To provide a document feeder by which the image of an original is accurately read. CONSTITUTION:Bearings 17 are provided on both sides of a platen roller 16 by setting the same shaft as the rotary shaft of the roller 16 as a rotary shaft, and the surface of the outside diameter of the bearing 17 is provided at a position where it abuts on the upper surface of a document supporting glass 20 at the time of assembling. A bottom plate 41 has nearly the same thickness as that of the glass 20, and a hole 41a is provided along a longitudinal direction in the center of the plate 41. A leaf spring 31 is fixed on a leaf spring fixing plate 42, and the plate 42 where the spring 31 is fixed is fixed on the plate 41 so that the tip of the spring 31 may press the lower surface of the glass 20 by screwing a screw 43 in a through hole 41b provided on the plate 41 through a through hole 42a respectively provided at both ends of the plate 42.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a document feeder for feeding a document and passing it through a document reading position such as a copying machine, a scanner and a facsimile.

[0002]

2. Description of the Related Art FIG. 5 is a schematic view of a conventional document feeder.

As shown in FIG. 1, the conventional document feeder comprises a pair of supply rollers 91, a document support drum (platen roller) 92, a transparent document support glass 93, and a pair of discharge rollers 95.

A pair of supply rollers 91 and a pair of discharge rollers
Reference numerals 95 are each configured to be driven in the direction of the arrow shown in the figure with the original 90 interposed therebetween.

The platen roller 92 is configured to be rotatable in the direction of the arrow shown in the figure, and the document supporting glass 93 is arranged below the platen roller 92 so as to be substantially in contact with the platen roller 92.

For example, a copying machine equipped with this document feeder has an optical system (not shown) below the document reading position 94 on the document supporting glass 93, and a document passing through the document reading position 94 by this optical system. Is configured to read the image of.

Therefore, the original 90 is conveyed while being sandwiched between the pair of supply rollers 91, and the platen roller 92 and the original supporting glass 93 are provided.
Supplied between and. At the original reading position 94, the supplied original 90 is pressed against the original supporting glass 93 by the platen roller 92, and while sliding, is conveyed to the pair of discharge rollers 95 via the original reading position 94 and is sandwiched by the pair of discharge rollers 95. The discharge roller 95 is discharged by rotation in the direction of the arrow shown in the figure.

[0008]

In such a conventional document feeder, since the document supporting glass 93 is not fixed to the platen roller 92, the leading edge of the document 90 is not conveyed when the document 90 is transported. Due to factors such as collision with the document support glass 93 and rotation of the platen roller 12 when the document 90 passes between the platen roller 92 and the document support glass 93, the vertical height of the document support glass 93 ( The distance between the surface of the platen roller 92 and the document support glass 93) cannot be kept stable and constant.

For this reason, there is a problem that the original image read at the original reading position 94 is blurred. Further, there is a problem that it takes time to focus the document when the document feeder is attached to the copying machine.

Therefore, according to the present invention, by keeping the height of the document supporting glass at the reading position of the document image stable and constant, it is possible to eliminate the need for focusing and to accurately read the document image. The present invention provides a document feeder that can contribute.

[0011]

A document feeding device for feeding a document and passing it through a document reading position of a document support plate,
A document feeding unit for feeding a document to a document reading position, a roller facing the document supporting plate, an abutting unit formed on the same axis as the rotation axis of the roller and abutting on the document supporting plate, and a document. An elastic body that presses the support plate from the side opposite to the abutting means, and an original discharging means that discharges the original that has passed the original reading position are provided.

[0012]

The document is supplied to the document reading position of the document supporting plate along the surface of the roller by the document feeding means, passes through the document reading position of the document supporting plate, and is then discharged by the document discharging means. In this way, when the document passes between the roller and the document support plate, the document support plate is in contact with the contact means formed on the same axis as the rotation axis of the roller, and the contact means is supported by the elastic body. Since it is pressed from the opposite side, the height of the document support plate at the document reading position,
That is, the distance between the surface of the roller and the document support plate is kept stable and constant. Therefore, it is possible to eliminate the need for focusing and contribute to accurate reading of the document image.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is a side view showing the construction of an embodiment of the document feeder according to the present invention.

In the figure, a bottom plate 41 shown in FIG.
The leaf spring fixing plate 42 is omitted.

As shown in FIG. 1, the original document feeder 10 of this embodiment is an original document feeder capable of automatically feeding double-sided originals, and one original from a plurality of originals placed on an original tray 11. It is configured to be automatically conveyed sheet by sheet, and one side or both sides of a document can be read by a scanner unit described later according to a user's selection.

The document feeder 10 is provided with a main motor (the output shaft of which is indicated by reference numeral 12) having an electromagnetic clutch, and its rotary driving force is not shown in the figure as it is well known for various rollers described later. It is configured to be transmitted by transmission means.

The document feeder 10 includes a document pickup roller 13 driven by an electromagnetic clutch (not shown),
Conveyor roller pair 14, solenoid-driven change lever 15 for switching the path of originals, two directions (direction of arrow shown in the figure)
Rotatable document supporting drum (platen roller) 16, bearing 17, left and right supply rollers 18L and 18R for feeding a document in cooperation with the platen roller 16, left and right document guides 19
L and 19R, transparent document support glass 20, left and right document ejection rollers 21L and 21R, and solenoid driven left and right movable guides 22L that cooperate with document ejection rollers 21L and 21R, respectively.
And 22R, a solenoid driven movable document discharge guide 23, a document discharge transport path 24, a discharge roller pair 25, a discharge tray 26, and a solenoid driven rotatable document reverse guide 27, one side of which is inverted transport. Path 28, reversing conveyance roller pair 29 driven via an electromagnetic clutch, rotating shaft 30, leaf spring 3
1 and left and right guides 32R and 32L for guiding the document supporting glass 20.

The bearing 17, the document supporting glass 20 and the plate spring 31 have a sandwich structure in which the document supporting glass 20 is sandwiched between the bearing 17 and the plate spring 31 which is an elastic body.

Document detection sensors S1 to S5 are provided in the document conveyance path.
Are arranged, and the signals from the document detection sensors S1 to S5 sent when the document is detected are sent to a controller (not shown). The controller conveys a document through a document reading position (exposure position) 35 as described later by operating various electromagnetic clutches and solenoids at predetermined timings described below.

The exposure position 35 corresponds to the document reading position of the present application.

FIG. 1 is a perspective view before assembly showing a main structure at an exposure position 35 of an embodiment of a document feeder according to the present invention. Figure 3 shows the diameter of the platen roller 16 and the bearing 17
FIG. 4 is a side view of a main part at an exposure position for explaining the relationship with the diameter of the.

In these figures, the same components as those of FIG. 2 are designated by the same reference numerals as those of FIG.

As shown in FIG. 1, the bearings 17 are provided on both sides of the platen roller 16 with the same axis as the axis of rotation of the platen roller 16 as the axis of rotation.
The bearing 17 is provided at a position where the outer diameter surface of the bearing 17 contacts the upper surface of the document supporting glass 20.

The bottom plate 41 has substantially the same thickness as the original supporting glass 20, and a hole 41a is provided in the center of the bottom plate 41 along the longitudinal direction.

When the original supporting glass 20 is assembled,
It is formed so as to fit inside the hole 41a.

The leaf spring 31 is fixed to a leaf spring fixing plate 42, and the leaf spring fixing plate 42 to which the leaf spring 31 is fixed has screws 43 through holes provided at both ends of the leaf spring fixing plate 42, respectively.
The tip of the leaf spring 31 is fixed to the bottom plate 41 so as to press the lower surface of the document supporting glass 20 by being screwed into the through hole 41b provided in the bottom plate 41 via 42a.

The position where the tip of the leaf spring 31 presses the lower surface of the document supporting glass 20 is preferably a position where the bearing 17 contacts the upper surface of the document supporting glass 20 and a position where the bearing 17 faces the document supporting glass 20. ..

In this embodiment, the two sets of plate spring fixing plates 42 to which the plate springs 31 are fixed are fixed to the bottom plate 41, but this does not hinder reading of the original image at the original reading position. As long as such leaf spring fixing plate
The method of fixing 42 to the bottom plate 41 is not limited to this embodiment.

As shown in FIG. 3, the platen roller 16 and the bearing 17 are constructed so that the diameter (BD) of the bearing 17 is larger than the diameter (PRD) of the platen roller 16.

When the platen roller 16 and the bearing 17 are assembled, the bearings are arranged so that the axial direction of the platen roller 16 and the longitudinal direction of the original supporting glass 20 are parallel to each other.
The original support glass with 17 in contact with the original support glass 20
It is arranged above 20.

At this time, the distance t (= (BD-PRD)) between the surface of the platen roller 16 and the surface of the document supporting glass 20.
/ 2) is 0.16 mm when the maximum document thickness is 0.15 mm.
It is recommended to set to mm.

By making the diameters of the platen roller 16 and the bearing 17 highly accurate, the clearance at the distance t can be maintained with high accuracy and is constant regardless of the inclination of the original supporting glass 20 with respect to the horizontal direction.

Document tray 11, document pickup roller 1
3, the conveying roller pair 14 and the change lever 15 are an embodiment of the document feeding means of the present invention. The platen roller 16 is an example of the roller of the present invention. The bearing 17 is an embodiment of the contact means of the present invention. The document support glass 20 is an example of the document support plate of the present invention. Movable document ejection guide
23, document discharge / transport path 24, discharge roller pair 25, and discharge tray
Reference numeral 26 is an embodiment of the document discharging means of the present invention.

Next, the operation of the document feeder 10 of this embodiment will be described with reference to FIG.

[Movement of Document Conveyed in Original Single Sided Copy Mode] When copying only one side of an original, a plurality of originals are set on the original tray 11 and an input key on an operation panel (not shown) is used. Input a copy mode (one-side scanning of original, number of copies, copy density, etc.).

When the print switch on the operation panel is pressed, the main motor of the document feeder 10 starts rotating. Next, the clutch of the document pickup roller 13 is turned on, and the rotating document pickup roller 13 is placed in the document tray.
11 Only the top original of the multiple originals set above is fed. At this time, the clutch of the transport roller pair 14 is simultaneously turned on, and the transport roller pair 14 is also driven to rotate.

When the leading edge of the fed document reaches the first document detection sensor S1, the solenoid of the change lever 15 is excited, and the change lever 15 is shown by the solid line from the position shown by the chain line in FIG. Switched to position. As the document is further conveyed, the leading edge of the document is guided to the side surface of the change lever 15 and guided toward the fourth document detection sensor S4.

After the leading edge of the original document is detected by the fourth original document detection sensor S4, the transportation of the original document is temporarily stopped at the timing when the original document is supported by the platen roller 16 and the right supply roller 18R.

Next, the document is fed again to the exposure position 35 of the document supporting glass 20 in synchronization with the scanner unit described later.

The document is pressed against the surface of the platen roller 16 by the document guide 19R on the right side, and passes through the exposure position 35 in the clockwise direction without any bending. Exposure position 35
At, the image data of the document is read by the scanner unit.

The original that has passed the exposure position 35 is conveyed to the left original discharge roller 21L through the lower side of the left original guide 19L. The solenoid of the movable guide 22L on the left side is excited at the timing when the leading edge of the document reaches the document discharge roller 21L, and the movable guide 22L is inserted with the document sandwiched.
Is pressed against the document discharge roller 21L. As a result, the document is provided with a conveyance force by the frictional force of the document discharge roller 21L.

The document conveyed by being sandwiched by the movable guide 22L and the document discharge roller 21L is guided by the upper surface of the document discharge movable guide 23, and the document discharge conveyance path is provided.
After passing through 24, the sheet is discharged onto the sheet discharge tray 26 along the sheet discharge roller pair 25. The fifth document detection sensor S5 in the document discharge / conveyance path 24 detects the trailing edge of the document, and the document is discharged to the discharge tray 26.
This is for determining that the ink has been discharged upward.

When a plurality of originals are set on the original tray 11, the next original is fed at the timing when the trailing edge of the previous original passes the exposure position 35.

The document tray 11 is provided with a document detection sensor (not shown) for detecting whether or not a document is set, and the above operation is repeated until the last document is exhausted.

[Movement of Document Conveyed in Original Duplex Copy Mode] When copying both sides of an original, the original tray 11
A plurality of originals are set on the top, and the copy mode (double-sided scanning of originals, number of copies, copy density, etc.) is entered by using the input keys on the operation panel.

When the print switch on the operation panel is pressed, the main motor of the document feeder 10 starts rotating. Next, the clutch of the document pickup roller 13 is turned on, and the rotating document pickup roller 13 is placed in the document tray.
11 Only the top original of the multiple originals set above is fed.

When the leading edge of the fed document reaches the first document detection sensor S1, the clutch of the transport roller pair 14 is turned on, and the transport roller pair 14 is also driven to rotate. At this time, the solenoid of the change lever 15 is in the non-excited state, the change lever 15 is at the position shown by the alternate long and short dash line in FIG. 2, and the leading edge of the document is guided to the second document detection sensor S2. To be done.

In the state where the leading edge of the original that has passed the second original detection sensor S2 is sandwiched between the platen roller 16 and the left supply roller 18L, the transportation of the original is temporarily stopped.

Next, the document is fed again to the exposure position 35 of the document supporting glass 20 in synchronization with the scanner unit.

The document is pressed against the surface of the platen roller 16 by the document guide 19L on the left side and passes through the exposure position 35 in the counterclockwise direction without causing any bending.

The original that has passed the exposure position 35 is sent to the right-side original discharge roller 21R through the lower side of the right-side original guide 19R. The solenoid of the right movable guide 22R is excited at the timing when the leading edge of the original reaches the original discharge roller 21R, and the movable guide 22R is pressed against the original discharge roller 21R with the original sandwiched.

The original conveyed by being sandwiched by the movable guide 22R and the original discharge roller 21R is guided to the reverse conveying path 28 and conveyed by the reverse conveying roller pair 29 toward the third original detecting sensor S3. ..

When the leading edge of the document reaches the third document detecting sensor S3, the solenoid of the document reversing guide 27 is excited, and the document reversing guide 27 is indicated by a chain line from the position shown by the solid line about the rotation shaft 30 thereof. The reversal conveyance path 28 is opened by rotating to the indicated position along the arrow shown in the figure. At the same time, the solenoid of the change lever 15 is excited, and the change lever 15 is switched from the position shown by the alternate long and short dash line to the position shown by the solid line.

The leading edge of the original is further guided by the reverse conveying roller pair 29 to the conveying roller pair 14 and guided toward the fourth original detecting sensor S4 along the side surface of the change lever 15 which is switched to the position shown by the solid line. To be done. Then, when the leading edge of the document is sandwiched between the platen roller 16 and the supply roller 18R, the transport of the document is temporarily stopped.

In this state, the reverse conveyance path length L (from the contact point between the platen roller 16 and the supply roller 18R to the fourth document detection sensor S4, the change lever 15, the conveyance roller pair 14,
The third original detection sensor S3, the reverse conveyance roller pair 29, and the reverse conveyance path 28 are passed through the movable guide 22R and the original discharge roller 21R.
If the length of the original is longer than the length (up to the contact point with), the reverse conveyance path 28 is opened by the rotation of the original reverse guide 27, so that the leading edge of the original is stopped. Even if there is, the part of the document after the reversing conveyance roller pair 29 is naturally bent from the position between the reversing conveyance roller pair 29 and the position between the movable guide 22R and the document discharge roller 21R. Form.

Next, after the trailing edge of the document passes through the exposure position 35, the document is fed again to the exposure position 35 of the document supporting glass 20 in synchronization with the scanner unit.

The original document is pressed against the surface of the platen roller 16 by the original document guide 19R, and the original document passes through the exposure position 35 in the clockwise direction without bending. Exposure position
At 35, the image data of the document is read by the scanner unit.

The original that has passed through the exposure position 35 is conveyed to the left original discharge roller 21L through the lower side of the left original guide 19L. The solenoid of the movable guide 22L on the left side is excited at the timing when the leading edge of the document reaches the document discharge roller 21L, and the movable guide 22L is inserted with the document sandwiched.
Is pressed against the document discharge roller 21L to convey the document.

When the reading of the original image on the second side is completed, the solenoid of the original reversing guide 27 is de-energized, and the original reversing guide 27 returns to the position shown by the solid line.
The system waits for the leading edge of the next document to be guided to the pair of reverse conveyance rollers 14.

The document conveyed by being sandwiched by the movable guide 22L and the document discharge roller 21L is guided along the upper surface of the document discharge movable guide 23, and the document discharge conveyance path is provided.
It is discharged onto a paper discharge tray 26 by a paper discharge roller pair 25 through 24.

When a plurality of originals are set on the original tray 11, during scanning exposure of the second surface of the previous original,
The next document is fed at the timing when the trailing edge of the document passes the exposure position 35. The above-described operation is repeated until the last original is exhausted.

FIG. 4 is a side sectional view showing the construction of an embodiment of a digital copying machine equipped with the document feeder according to the present invention.

As shown in the figure, this digital copying machine includes a scanner section 50, a laser printer section 51, a multi-stage sheet feeding unit.
It is equipped with 52 and a sorter 53.

An operation panel (not shown) equipped with various input keys is installed on the upper part of the digital copying machine according to a known mode.

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

The document feeder 55 is the document feeder shown in FIG.
Equivalent to 10.

The document feeder 55 is constructed so that when a plurality of documents are set at one time, the documents can be automatically conveyed one by one to a document reading position where the document images are read.

The scanner unit 56 includes a lamp reflector assembly 57 for exposing the original document, and a plurality of reflecting mirrors 5 for guiding a reflected light image from the original document to a photoelectric conversion element (CCD) 58.
9 and a lens 60 for forming a reflected light image from the original on the CCD 58.

When the document placed on the document placing table 54 is scanned, the scanner section 50 is configured to read the document image while the scanner unit 56 moves along the lower surface of the document placing table 54. When the document feeder 55 is used, the document image is read while the document is fed while the scanner unit 56 is stopped at a predetermined position below the document feeder 55.

The image data obtained by reading the original image with the scanner unit 56 is temporarily recorded in a memory (not shown) after being subjected to various kinds of processing in accordance with a known mode, and the image in the memory is output according to an output instruction. The data is given to the laser printer section 51 to form an output image.

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

The electrophotographic process section 62 has a charging device, a developing device, a transfer device, and
A peeling device, a cleaning device and a static eliminator are arranged, and based on the image data read from the above-mentioned memory, the laser writing unit 61 scans a laser beam on the surface of the photoconductor drum 68. An image is written, the electrostatic latent image formed on the surface of the photoconductor drum 68 is visualized with toner, and the toner image is electrostatically transferred onto the surface of the sheet conveyed from the multi-stage sheet feeding unit 52. Has been done.

The multi-stage paper feeding unit 52 includes a first cassette 63,
It has a second cassette 64, a third cassette 65, a fourth cassette 66 and a fifth cassette 67 which can be added by the user's selection.

In the multi-stage paper feeding unit 52, the papers are fed out one by one from the papers stored in the cassettes of the respective tiers, and are conveyed toward the laser printer section 51.

Therefore, according to the above-described embodiment of the document feeder according to the present invention, the bearings 17 are provided on both sides of the platen roller 16, and the document supporting glass 20 with which the outer diameter surface of the bearing 17 is in contact. Since the reading position of the document image is positioned by pressing from below with the spring plate 31, the height of the document supporting glass at the reading position (the distance between the surface of the platen roller and the document supporting glass) is stable and constant. Therefore, the original image can be read accurately.

As described above, the simple structure using generally inexpensive bearings enables high-accuracy positioning, and since this high-accuracy positioning is possible, when the document feeder is attached to the main body of the copying machine. Focusing is unnecessary, and the document feeder can be attached to the main body of the copying machine with one touch.

Further, since the mounting can be done with one touch, maintenance such as cleaning of the platen roller can be facilitated.

Further, according to this embodiment, since the height of the document supporting glass at the reading position is kept stable and constant, the rotatability of the platen roller is improved and the document passes smoothly through the document reading position. can do.

In the above embodiment, the example using the bearing has been described. However, the height of the document supporting glass at the reading position can be stably fixed by contacting with the document supporting glass without being limited to the bearing. Other members may be used as long as they can be kept.

[0081]

As described above, the present invention is a document feeder for feeding a document and passing it through the document reading position of the document support plate, and a document feeding means for feeding the document to the document reading position and a document feeding device. A roller facing the support plate, an abutting means formed on the same axis as the rotation axis of the roller and abutting the original support plate, and an elastic body for pressing the original support plate from the side opposite to the abutting means. And a document ejection unit for ejecting the document that has passed the document reading position. Therefore, since the height of the document supporting glass at the reading position of the document image is stably kept constant, it is possible to eliminate the need for focusing and contribute to the accurate reading of the document image.

[Brief description of drawings]

FIG. 1 is a perspective view before assembly showing a main part configuration at an exposure position of an embodiment of a document feeder according to the present invention.

FIG. 2 is a side view showing the configuration of an embodiment of a document feeder according to the present invention.

FIG. 3 is a side view of essential parts at an exposure position for explaining the relationship between the diameter of the platen roller and the diameter of the bearing.

FIG. 4 is a side sectional view showing the configuration of an embodiment of a digital copying machine equipped with a document feeder according to the present invention.

FIG. 5 is a schematic view of a conventional document feeder.

[Explanation of symbols]

 10, 55 Document feeder 11 Document tray 13 Document pickup roller 14 Conveyor roller pair 15 Change lever 16 Platen roller 17 Bearing 20 Document support glass 23 Document ejection movable guide 24 Document ejection transport path 25 Paper ejection roller pair 26 Paper ejection tray

Claims (1)

[Claims] 1. A document feeding device for feeding a document and passing it through a document reading position of a document supporting plate, and a document feeding means for feeding the document to the document reading position, and a roller facing the document supporting plate. An abutting means formed on the same axis as the rotation axis of the roller and abutting against the original supporting plate; an elastic body for pressing the original supporting plate from the side opposite to the abutting means; An original document feeding device comprising: an original document ejecting unit for ejecting an original document that has passed a reading position.