JPH05257365A - Document feeder - Google Patents

Abstract

PURPOSE:To provide an image forming device capable of accurately carrying a documents having different size and thickness to a document reading position. CONSTITUTION:When a name card or a postcard is detected by a document detecting sensor S8, the main motor of a RDF starts rotating. The solenoid of a document ejecting movable guide is excited, and a timer T1 is set. When the time of the timer T1 is up, and after the document is detected by the document detecting sensor S7 respectively exciting the solenoids of the movable guides 60L and 60R, the time of the timer T2 is set. When the document detecting sensor S7 is turned on before the time of the timer T2 is up, the document is scanned on the document reading position while making paper feeding reference as a corner reference. When the document detecting sensor S8 is decided as that it is not turned on, and when the document detecting sensor S6 is turned on, the document is normally read while making the paper feeding reference as a center reference.

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 A document transport operation in a conventional document transport device will be described.

First, an operation of conveying an original when reading one side of the original at an original reading position of, for example, a copying machine, a scanner or a facsimile will be described.

FIGS. 6 and 7 are schematic views of a conventional document feeding device for explaining the document feeding operation when one side of the document is read.

As shown in these figures, the conventional document conveying device includes a document setting table 91, a supply roller group 92, a conveying belt.
It includes 93, clutches 94 and 97, a paper output / reversing roller 95, and a paper output tray 96.

First, when the original 99 is placed on the original setting table 91 (FIG. 6 (A)), the rollers of the supply roller group 92 rotate to start the operation of conveying the original 99 to the original reading position R ( 6B), the original 99 is conveyed by the conveyor belt 93 (FIG. 6C).

Next, when the original 99 reaches the original reading position R, the conveyance is stopped, the image of the original 99 is read by an optical system (not shown), and an operation such as copying is executed (FIG. 7A). ).

Next, when the reading of the original image is completed,
The tip of the clutch 94 moves downward in the figure and
When the reversing roller 95 starts to rotate, the discharge operation of the original 99 is started (FIG. 7 (B)), the clutch 97 moves to guide the original 99 toward the discharge tray 96, and the original 99 is discharged. The paper is discharged to the table 96 (Fig. 7 (C)).

Next, the operation of conveying the original when reading both sides of the original at the original reading position will be described.

FIG. 8, FIG. 9, FIG. 10 and FIG. 11 are schematic views of a conventional document feeding device for explaining the document feeding operation when reading both sides of the document.

The structure of the conventional document conveying apparatus shown in these figures is the same as the structure of the apparatus shown in FIGS. 6 and 7. Therefore, in these drawings, the same reference numerals as those in FIGS. 6 and 7 are given to the respective components as the same components.

First, when the original 99 is placed on the original setting table 91 (FIG. 8 (A)), the rollers of the supply roller group 92 rotate to start the operation of conveying the original 99 to the original reading position R ( 8B, the original 99 is conveyed by the conveyor belt 93 (FIG. 8C).

Next, the front end of the clutch 94 moves downward in the figure, and the clutch 97 conveys the original 99 to the conveying belt 93.
The document 99 which has moved to guide the document and has passed the document reading position R is guided by the rotation of the sheet discharge / reversing roller 95 toward the conveying belt 93 along the sheet discharge / reversing roller 95 (FIG. 9).
(A)).

Next, the conveyor belt 93 rotates in the opposite direction (counterclockwise direction shown in the figure) to start the operation of conveying the original 99 (FIG. 9 (B)).

Next, the original 99 is conveyed by the conveying belt 93, and once it has passed the original reading position R, the conveying belt 93 starts to rotate in the opposite direction (clockwise direction shown in the figure) (see the figure). 9 (C)).

Next, when the original 99 reaches the original reading position R, the conveyance is stopped, an image on the back surface of the original 99 is read by an optical system (not shown), and an operation such as copying is executed (see FIG. 10 ( A)).

Then, when the reading of the original image is completed,
As the tip of the clutch 94 moves downward in the figure, the clutch 97 moves so as to guide the original 99 toward the conveyance belt 93, and the original 99 that has passed the original reading position R is rotated by the discharge / reverse roller 95. It is guided to the conveyor belt 93 along the paper discharge / reversal roller 95 (FIG. 10 (B)).

Next, the conveyor belt 93 rotates in the opposite direction (counterclockwise direction shown in the figure) to start the operation of conveying the original 99 (FIG. 10 (C)).

Next, the original 99 is conveyed by the conveying belt 93, and once it has passed the original reading position R, the conveying belt 93 starts to rotate in the opposite direction (clockwise direction shown in the figure) (see the figure). 11 (A)).

Next, when the original 99 reaches the original reading position R, conveyance is stopped, an image on the surface of the original 99 is read by an optical system (not shown), and an operation such as copying is executed (see FIG. B)).

Then, when the reading of the original image is completed,
The front end of the clutch 94 moves downward in the figure, and the discharge / reversal roller 95 starts rotating, so that the discharge operation of the original 99 is started (FIG. 11C), and the original 99 is transferred to the discharge tray 96. The paper is ejected (Fig. 11 (D)).

[0022]

In such a conventional document conveying apparatus, since the document is similarly conveyed regardless of the size and thickness of the document, for example, when conveying a document having a small width, There is a problem that the document is fed obliquely with respect to the document reading position, and the skew feeding occurs.

Further, for a thick original such as a business card, it is not possible to bend the conveying section, for example, the portion of the sheet discharging / reversing roller 95 in FIGS. 6 to 11, so that the original conveying device is used. There is a problem that you cannot do it.

Therefore, the present invention provides an image forming apparatus capable of accurately conveying originals having different sizes and thicknesses to the original reading position in order to contribute to accurate reading of the original image.

[0025]

A document feeding device for feeding a document and passing it through a document reading position of a document support plate,
A first conveying unit that conveys an original by aligning the center of the original with the center of the original supporting plate in the original conveying direction, and bends the original by aligning the end of the original with the end of the original supporting plate in the original conveying direction. It is provided with a second transporting means for transporting the document without any action, and a selecting means for selecting either the first transporting means or the second transporting means according to the size of the document when transporting the document.

[0026]

When the original is conveyed, either the first conveying means or the second conveying means is selected by the selecting means according to the size of the original. The first conveying means conveys the original by aligning the center of the original with the center of the original supporting plate with respect to the conveying direction of the original, and the second conveying means has an end of the original at the end of the original supporting plate with respect to the conveying direction of the original. And feed the document without bending it. For example, for a small-sized original or an original having a large paper thickness, the second conveying unit can convey the original to the original reading position without bending the original by aligning the edge of the original with the edge of the original supporting plate. Therefore, documents of different sizes and thicknesses can be accurately conveyed to the document reading position, which contributes to accurate reading of document images.

[0027]

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

First, a digital copying machine will be described as an example of an image forming apparatus equipped with a document feeder according to the present invention.

FIG. 2 is a side sectional view showing the overall construction of a digital copying machine which is an embodiment of an image forming apparatus equipped with a document feeder according to the present invention.

As shown in the figure, the digital copying machine 10 of this embodiment is provided with a scanner section 11, a laser printer section 12, a multi-stage paper feeding unit 13 and a sorter 14.

A double-sided automatic document feeder (RDF) 15, which is an example of a document feeder according to the present invention, is installed above the scanner unit 11, and the scanner unit 11 is made of transparent glass. It is composed of a mounting table 16, a movable scanner unit 17, and a position control device for controlling the position of the scanner unit 17.

This position control device is a scanner unit
The position control device includes a scanner motor 18 for driving the motor 17, a pulley 19, and a wire 20 stretched between the scanner motor 18 and the pulley 19, and the position control device moves the scanner unit 17 along the longitudinal direction of the document table 16. It is configured so that it can be moved and stopped at a predetermined document reading position.

The scanner unit 17 includes a lamp reflector assembly 21 for exposing a document, a CCD (photoelectric conversion element) linear image sensor 22, and a plurality of reflecting mirrors 2 for guiding a reflected light image from the document to the CCD linear image sensor 22.
3 and a lens 24 for forming a reflected light image from the original on the CCD linear image sensor 22.

When scanning an original placed on the original placing table 16, the scanner section 11 reads the original image while the scanner unit 17 moves along the lower surface of the original placing table 16 and uses the RDF 15. In this case, the original image is read while the original is being conveyed while the scanner unit 17 is stopped at a predetermined original reading position below the RDF 15.

The image data obtained by reading the original image with the scanner unit 17 is subjected to various kinds of processing by an image processing control unit, which will be described later, included in the digital copying machine 10. The image is temporarily stored in a memory provided therein, and image data in the memory is given to the laser printer section 12 in accordance with an output instruction to form an image on a sheet.

The multi-stage paper feeding unit 13 includes a first cassette 28,
It has a second cassette 29, a third cassette 30, and a fourth cassette 31 that can be added by selection. In the multi-stage paper feeding unit 13, the papers are sent out one by one from the papers stored in these cassettes, and are conveyed toward the laser printer unit 12.

The laser printer unit 12 is a manual document tray 2
5. A laser writing unit 26 and an electrophotographic process unit 27 for forming an image are provided.

The laser writing unit 26 is a semiconductor laser which emits a laser beam according to the image data from the above-mentioned memory, a polygon mirror which deflects the laser beam at an equal angular velocity,
It has an f-θ lens or the like for correcting so that the laser beam deflected at a constant angular velocity is deflected at a constant velocity on the photoconductor drum 27a of the electrostatic photography process section 27.

The electrophotographic process section 27 comprises a charging device, a developing device, a transfer device, a peeling device, a cleaning device, a static eliminator and a fixing device 32 arranged around the photosensitive drum 27a according to a known manner. ..

A transport path 33 is provided downstream of the fixing device 32 in the transport direction of the sheet on which the image is to be formed.
33 is a transport path 34 leading to the sorter 14 and a multi-stage paper feeding unit
It branches off to a conveyance path 35 leading to 13.

The conveyance path 35 is branched in the multi-stage sheet feeding unit 13, and a reversal conveyance path 36 and a double-sided / composite conveyance path 37 are provided as the conveyance paths after branching.

The reverse conveyance path 36 is a conveyance path for reversing the front and back sides of the sheet with respect to the image forming position of the photosensitive drum 27a in the double-sided copy mode for copying both sides of the original. The duplex / composite transport path 37 transports paper from the reverse transport path 36 to the image forming position on the photoconductor drum 27a in the duplex copying mode, or forms an image of different originals or images of different colors on one side of the paper. Photosensitive drum 27a without reversing the paper in single-sided composite copy mode for composite copy
Is a transport path for transporting to the image forming position.

The multi-stage paper feeding unit 13 includes a common conveyance path 38, and the common conveyance path 38 transfers the papers from the first cassette 28, the second cassette 29 and the third cassette 30 to the electrophotographic process section 27. It is configured to be carried out toward.

The common transport path 38 joins the transport path 39 from the fourth cassette 31 on the way to the electrophotographic process section 27 and communicates with the transport path 40.

The conveying path 40 merges with the double-sided / composite conveying path 37 and the conveying path 41 from the manual document tray 25 at a confluence point 42 to form an image between the photoconductor drum 27a of the electrostatographic process section 27 and the transfer device. It is configured to reach the formation position.
The confluence point 42 of the two conveyance paths is provided at a position close to the image forming position.

Therefore, in the laser writing unit 26 and the electrophotographic process section 27, the image data read from the above-mentioned memory is scanned by the laser writing unit 26 with a laser beam, so that the photosensitive drum 27a is scanned.
The toner image formed as an electrostatic latent image on the surface of the sheet is visualized by the toner, and is electrostatically transferred and fixed on the surface of the sheet conveyed from the multi-stage sheet feeding unit 13. The sheet on which the image is formed in this way is fed from the fixing device 32 to the conveying paths 33 and 34.
It is sent to the sorter 14 via the, or is transported to the reversing transport path 36 via the transport paths 33 and 35.

Next, the structure and operation of the RDF, which is an embodiment of the document feeder according to the present invention, will be described.

FIG. 3 is a side sectional view of the RDF 15 attached to the scanner section 11 of the digital copying machine 10 of FIG. 2, which is an embodiment of the document feeder according to the present invention.

The RDF 15 sets a plurality of set originals to one.
It is configured so that it is automatically fed sheet by sheet to the scanner unit 11 and one or both sides of the document can be read by the scanner unit 17 of FIG. 2 according to the operator's selection.

As shown in FIG. 3, the RDF 15 is an ordinary document.
Document tray 50 for setting 51, document pickup roller driven via an electromagnetic clutch (not shown)
52, a pair of conveyance rollers 53, a solenoid driven change lever 54 capable of switching the conveyance path of the original 51, an original support drum (platen roller) 55 rotatable in two directions (arrow directions shown in the figure), and a platen roller 55. And the left and right feed rollers 56L and 56R that work to feed the document 51, the transparent document support glass 57, the left and right document guides 58L and 58R, the left and right document ejection rollers 59L and 59R, and the document ejection rollers 59L and 59R, respectively. Working solenoid driven left and right movable guide 60L
And 60R, a solenoid driven movable document discharge guide 61, a document discharge conveyance path 62, a discharge roller pair 63, a discharge tray 64, a solenoid driven rotatable document reverse guide 65, and a document reverse guide 65 to form one side. The reverse conveyance path 66,
A pair of reversing conveyance rollers 67 driven via an electromagnetic clutch,
A rotary shaft 68 and a business card / postcard document insertion slot 69 for inserting a document such as a business card or a postcard are provided.

Document detection sensors S1 to S5 are provided on the conveyance path of the document 51.
Are arranged, and the signals from the document detection sensors S1 to S5, which are respectively output when the document 51 is detected, are sent to the CPU (central processing unit) of the image processing control unit described later. A document detection sensor S6 is arranged on the document tray 50, and a document detection sensor output when a document 51 is detected.
The signal from S6 is sent to the CPU of the image processing control unit.
Business card / postcard manuscript insertion slot 69 and business card / postcard manuscript insertion slot
In the conveyance path leading from 69, the document detection sensors S7 and S8
Are arranged respectively, and a document detection sensor S7 and a document detection sensor S7 which are respectively output when a document such as a business card or a postcard is detected.
The signal from S8 is sent to the CPU of the image processing control unit.

Next, the operation of the RDF 15 will be described.

When copying only one side of the original 51, a plurality of originals 51 are set on the original tray 50 and input through an operation panel (not shown) provided in the digital copying machine 10 in FIG. Enter the copy mode (original single-sided copy mode, number of copies, copy density, etc.) using the keys.

When the print switch on the operation panel of the digital copying machine is pressed, the main motor (not shown) of the RDF 15 starts rotating.

Next, the clutch of the original pickup roller 52 is turned on, and the original pickup roller which rotates is rotated.
The reference numeral 52 feeds only the uppermost original of the plurality of originals 51 set on the original tray 50. At this time, the clutch of the transport roller pair 53 is also turned on at the same time,
53 is also driven to rotate.

The leading edge of the fed document 51 is a document detection sensor.
When S1 is reached, the solenoid of the change lever 54 is excited, and the change lever 54 is switched from the position shown by the alternate long and short dash line in FIG. 3 to the position shown by the solid line. As the document 51 continues to be fed, the tip of the document 51 changes at the change lever.
It is guided along the side surface of 54 and guided toward the document detection sensor S4.

A predetermined time after the leading edge of the original 51 is detected by the original detection sensor S1, the original 51 is placed on the platen roller.
While being supported by 55 and the right supply roller 56R, the conveyance of the document 51 is temporarily stopped.

Next, at a predetermined timing, the clutch of the right transport roller 56R is turned on, and the document supporting glass 57
Then, the feeding of the original 51 to the original reading position P is started again.

The platen roller 55 rotates the document reading position P in the clockwise direction in a state where the document 51 is pressed against the surface of the platen roller 55 by the document guide 58R on the right side, and the document 51 is not bent. , The document reading position P, which is a contact point between the platen roller 55 and the document supporting glass 57, is passed from right to left in FIG. At the document reading position P, the image of the document 51 is read by the scanner unit 17 of FIG.

The original 51 that has passed the original reading position P is
It is conveyed toward the left side document ejection roller 59L through the lower side of the left side document guide 58L. The solenoid of the left movable guide 60L is excited at the timing when the leading edge of the document 51 reaches the document discharge roller 59L, and the movable guide 60L is pressed against the document discharge roller 59L while the document 51 is sandwiched.

As a result, the document discharge roller 59 is attached to the document 51.
The conveyance force is given by the frictional force of L, and the document 51 is guided along the upper surface of the document discharge movable guide 61,
After passing through 62, the sheet is discharged onto a sheet discharge tray 64 by a pair of sheet discharge rollers 63.

The document detection sensor S5 provided in the document discharge / conveyance path 62 is for detecting the rear end of the document 51 and determining that the document 51 has been discharged onto the discharge tray 64. ..

When a plurality of originals 51 are set on the original tray 50, the next original is fed at the timing when the trailing edge of the previous original passes the original reading position P.

The document tray 50 is provided with a document detection sensor S6 for detecting whether or not the document 51 is set, and the above operation is repeated until the last document 51 is exhausted.

Next, when copying both sides of the document 51,
Multiple originals 51 are set on the original tray 50, and a copy mode (double-sided copy mode, number of copies, copy density, etc.) is entered by using the input keys on the operation panel provided in the digital copying machine 10 in FIG. To do.

When the print switch on the operation panel of the digital copying machine is pressed, the main motor (not shown) of the RDF 15 starts rotating.

Next, the clutch of the document pickup roller 52 is turned on, and the rotating document pickup roller 52 is rotated.
The reference numeral 52 feeds only the uppermost original of the plurality of originals 51 set on the original tray 50. At this time, the clutch of the transport roller pair 53 is also turned on at the same time,
53 is also driven to rotate.

The leading edge of the fed document 51 is a document detection sensor.
When S1 is reached, the clutch of the transport roller pair 53 is turned on, and the transport roller pair 53 is also driven to rotate. At this time, the solenoid of the change lever 54 is in the non-excited state, the change lever 54 is at the position shown by the alternate long and short dash line in FIG. 3, and the leading edge of the document 51 is guided toward the document detection sensor S2.

A predetermined time after the leading edge of the original 51 is detected by the original detection sensor S1, the original 51 is placed on the platen roller.
While being supported by 55 and the left supply roller 56L, the conveyance of the original 51 is once stopped.

Next, at a predetermined timing, the transport roller 56L
The clutch is turned on, and the feeding of the original 51 is restarted to the original reading position P on the original supporting glass 57.

The platen roller 55 rotates the document reading position P in the counterclockwise direction while the document 51 is pressed against the surface of the platen roller 55 by the document guide 58L on the left side, and the document 51 is bent. Instead, the document passes through the document reading position P from left to right in FIG. In this way, the exposure scanning of one side of the document 51 is started.

The original 51 that has passed the original reading position P is
The paper passes under the right document guide 58R and is sent to the right document ejection roller 59R. The solenoid of the movable guide 60R on the right side is excited at the timing when the leading edge of the document 51 reaches the document discharge roller 59R, and the movable guide 60R is pressed against the document discharge roller 59R while the document 51 is sandwiched.

The document 51 conveyed by being sandwiched by the movable guide 60R and the document discharge roller 59R is guided to the reversal conveyance path 66, and is conveyed to the document detection sensor S3 by the reversal conveyance roller pair 67.

When the leading edge of the document 51 reaches the document detection sensor S3, the solenoid of the document reversing guide 65 is excited, and the document reversing guide 65 is moved from the position shown by the solid line to the position shown by the alternate long and short dash line around the pivot shaft 68 thereof. To rotate along the arrow shown in the figure, the reversal conveyance path 66 is opened. This open state continues until a predetermined time elapses after the document detection sensor S1 is turned off.

Simultaneously with this opening, the solenoid of the change lever 54 is excited, and the change lever 54 is switched from the position shown by the chain line to the position shown by the solid line.

The leading edge of the original 51 is further provided with a pair of reverse conveyance rollers 67.
It is guided by the conveying roller pair 53 by the guide roller 53 and guided toward the document detection sensor S4 along the side surface of the change lever 54 which is switched to the position shown by the solid line. Then, when the leading edge of the document 51 is sandwiched between the platen roller 55 and the right supply roller 56R, the conveyance of the document 51 is temporarily stopped.

Next, the rear end of the document 51 is at the document reading position P.
After passing through, the document is fed again to the document reading position P on the document supporting glass 57 at the timing with the scanner unit 17.

On the platen roller 55, the document 51 is a document guide 58.
While being pressed against the surface of the platen roller 55 by R, rotate the document reading position P in the clockwise direction,
The document 51 passes through the document reading position P from the right to the left in FIG. 3 without any bending. At the document reading position P, the image of the document 51 is read by the scanner unit 17.

The original 51 that has passed the original reading position P is
It is conveyed toward the left side document ejection roller 59L through the lower side of the left side document guide 58L. The solenoid of the left movable guide 60L is excited at the timing when the leading edge of the original 51 reaches the original discharge roller 59L, and the movable guide 60L is pressed against the original discharge roller 59L while the original 51 is sandwiched, and the original is discharged. Convey 51.

After the document detecting sensor S3 detects the trailing edge of the document 51, the solenoid of the document reversing guide 65 is de-energized, the document reversing guide 65 returns to the position shown by the solid line, and the leading edge of the next document 51 is reached. Is waited for to be guided to the reverse conveyance roller pair 67.

The document 51 conveyed by being sandwiched by the movable guide 60L and the document discharge roller 59L is guided along the upper surface of the document discharge movable guide 61, passes through the document discharge / conveyance path 62, and passes through a pair of discharge rollers. The sheet is discharged onto the sheet discharge tray 64 by 63.

The document detection sensor S5 provided in the document discharge / conveyance path 62 detects the rear end of the document 51, and thereby determines that the document 51 has been discharged onto the discharge tray 64.

When a plurality of originals 51 are set on the original tray 50, when the scanning exposure of the second surface of the previous original is performed, the trailing edge of the original passes the original reading position P at the same timing. The next manuscript will be sent.

The above-described operation is performed by detecting the original detecting sensor S6 provided on the original tray 50 to detect the original tray.
The process is repeated until the last document 51 on the 50 is exhausted.

In this embodiment, in copying in the above-described one-sided and two-sided copy mode, the normal document 51 is fed to the document reading position P and fed to the center, which will be described later.

The center reference, which is the paper feed reference, will be described below.

FIG. 4 is a plan view of the main part of the RDF 15 showing the position of the original document on the original document support glass 57 and the business card / postcard original document insertion port 69 of FIG. 3 for explaining the paper feed standard.

In the figure, the document detecting sensors S8a and S8b correspond to the document detecting sensor S8 shown in FIG.

As shown on the left side of the figure, in copying in the single-sided and double-sided original copy mode, for example, when an A4 size original 71 is at the original reading position P of the original supporting glass 57, the original 71 and the original supporting glass 57 are shown. Means that the center line C of the document 71 coincides with the center line of the document supporting glass 57, that is, the document 71
The center line C of the is orthogonal to the line P'corresponding to the document reading position P on the document supporting glass 57.

Therefore, the RDF 15 of this embodiment is configured to convey the original to the original reading position P of FIG. 3 so that the paper feeding reference becomes the center reference in copying in the original single-sided and original double-sided copy mode. ..

Next, the operation of copying an original such as a business card or a postcard using the RDF 15 will be described.

FIG. 1 is a flow chart for explaining the operation of the RDF which is an embodiment of the document feeder according to the present invention when copying a document such as a business card or a postcard.

As shown in FIGS. 1 and 3, a plurality of originals are set in the business card / postcard original insertion slot 69, and the operation panel (not shown) provided in the digital copying machine 10 of FIG. The copy mode (business card / postcard copy mode, number of copies, copy density, etc.) is entered using the input keys.

First, when a document such as a business card or a postcard is detected by turning on a document detection sensor S8 provided in the business card / postcard document insertion opening 69 (step ST1
), The main motor (not shown) of the RDF 15 starts rotating (step ST2).

Then, the solenoid of the document discharge movable guide 61 is excited (step ST3), and thereafter, the solenoid of the document discharge movable guide 61 is always excited in this copy mode.

Then, the timer T ₁ is set (step
ST4), determines whether or not the timer T ₁ is time-up has occurred (step ST5). If the time is up, the solenoids of the movable guides 60R and 60L are excited (step ST6).

Next, after the document detection sensor S7 provided on the conveyance path from the business card / postcard document insertion port 69 to the document reading position P detects a document such as a business card or a postcard, the timing for starting the document reading is set. A timer T ₂ for setting is set (step ST7).

Next, it is determined whether or not the document detection sensor S7 is on (step ST8), and if the document detection sensor S7 is not on, it is determined whether or not the timer T ₂ is up (step S8). ST9), if the time has not expired, the process returns to step ST8, and if the time has expired, the operation is terminated and the document is jammed.

If it is determined in step ST8 that the document detection sensor S7 is on, the document is scanned at the document reading position P with the sheet feeding standard as the corner standard described later (step ST10).

Thereafter, the scanned original is moved by the movable guide 60.
By being pressed against the document discharge roller 59L by L, a conveyance force due to the frictional force of the document discharge roller 59L is given, guided along the upper surface of the document discharge movable guide 61, and passed through the document discharge conveyance path 62. The paper is discharged onto the paper discharge tray 64 by the paper discharge roller pair 63.

When it is determined in step ST1 that the document detection sensor S8 is not turned on, it is determined whether the document detection sensor S6 is turned on (step ST11), and the document detection sensor S6 is turned on. If not, return to step ST1,
If it is on, normal document reading is performed with the paper feed standard as the center standard, that is, copying in the single-sided or double-sided copy mode is performed (step ST12).

In this embodiment, in copying in the business card / postcard copy mode, the paper feeding standard for feeding and feeding a document such as a business card or a postcard to the document reading position P is the corner standard to be described later.

The corner standard, which is the standard for feeding, will be described below.

As shown on the right side of FIG. 4, in copying in the business card / postcard copy mode, for example, when the business card 72 is placed as a document in line L of the business card / postcard document insertion port 69, the document detection sensor S7 When the business card 72 is detected by S8a and S8a, the feeding roller 74 starts to rotate at a predetermined timing and conveys the business card 72 along the line L to the document reading position P. Here, the line L is the edge 57 of the document supporting glass 57.
It is a line that extends along a.

Also, when the postcard 73 is placed as a manuscript in line with the line L of the business card / postcard manuscript insertion port 69, it is the same as when the business card 72 is placed, but in this case, the manuscript detection sensor S6. , S8a and S8b detect the postcard 73, the feeding roller 74 starts to rotate at a predetermined timing, and the postcard 73
Is conveyed to the document reading position P along the line L.

In this way, documents such as business cards and postcards that are transported from the business card / postcard document insertion port 69 to the document reading position P along the line L are transported without being bent during transport.

Therefore, in copying in the business card / postcard copy mode, the feeding standard is the corner standard, and if the document detecting sensors S7 and S8a do not detect the document, the document is not conveyed to the document reading position P. , No copying is done.

Next, the structure and function of the image processing control unit included in the digital copying machine 10 shown in FIG. 2 will be described.

FIG. 5 is a block diagram of an image processing control unit included in the digital copying machine 10 shown in FIG. 2 for performing processing from input to output of image data.

As shown in the figure, the image processing control unit includes an image data input unit 81, an image data processing unit 82, an image data output unit 83, a memory 84 including a RAM (random access memory), and a CPU 85. There is.

The image data input section 81 includes a CCD section 81a, a histogram processing section 81b and an error diffusion processing section 81c.

The image data input unit 81 binarizes and converts the image data of the original read from the CCD linear image sensor 22 of FIG. 2 to obtain a histogram as a binary digital amount, and the image data by the error diffusion method. Are processed and stored in the memory 84 once.

That is, in the CCD section 81a, after the analog electric signal corresponding to each pixel density of the image data is A / D (analog / digital) converted, MTF correction, black and white correction or gamma correction is performed, and the 256th floor It is output to the histogram processing unit 81b as a key (8-bit) digital signal.

In the histogram processing section 81b, the CCD section 81
The digital signal output from a is added for each pixel density of 256 gradations to obtain density information (histogram data), and the obtained histogram data is sent to the CPU 85 or as pixel data, if necessary. It is sent to the error diffusion processing unit 81c.

The error diffusion processing section 81c performs an error diffusion processing which is a kind of pseudo halftone processing. That is, in the error diffusion processing unit 81c, the 8-bit / pixel digital signal output from the CCD unit 81a is converted into 1-bit (binary) by the method of reflecting the binarization error in the binarization judgment of the adjacent pixel. The redistributed calculation is performed in order to faithfully reproduce the density of the local area in the original that has been converted.

The image data processing unit 82 includes multi-valued processing units 82a and 82b, a synthesis processing unit 82c, a density conversion processing unit 82d, a scaling processing unit 82e, an image processing unit 82f, an error diffusion processing unit 82g and a compression processing unit 82h. Is included.

The image data processing unit 82 is a processing unit for finally converting the input image data into image data desired by the operator, and is stored in the memory 84 as output image data obtained by finally converting the image data. Until this is done, processing is performed in this processing unit.

The processing units included in the image data processing unit 82 function as necessary, and the processing may not be executed in some cases.

In the multi-value processing units 82a and 82b, the data binarized by the error diffusion processing unit 81c is converted again into 256 gradations.

In the synthesizing section 82c, a logical operation for each pixel,
That is, an operation such as a logical sum, a logical product or an exclusive logical sum is selectively performed. The data that is the target of this operation is the memory 84
Pixel data stored in, and bit data from the pattern generator (PG).

The density conversion processing unit 82d arbitrarily sets the relationship between the input density and the output density for a digital signal of 256 gradations based on a predetermined gradation conversion table.

In the scaling processing section 82e, the pixel data (density value) for the scaled target pixel is obtained by performing interpolation processing with the known data that is input according to the designated scaling ratio. After the scanning is scaled, the main scanning is scaled.

In the image processing unit 82f, various image processings may be performed on the input pixel data, and information collection such as feature extraction may be performed on the data string.

The error diffusion processing unit 82g performs the same processing as the error diffusion processing unit 81c of the image data input unit 81.

In the compression processing section 82h, binary data is compressed by the encoding called run length. Regarding the compression of the image data, the compression functions in the final processing loop when the final output image data is completed.

The image data output unit 83 includes a restoration unit 83a, a multi-value quantization processing unit 83b, an error diffusion processing unit 83c, and a laser output unit 83d.
Is included.

The image data output unit 83 is a memory in a compressed state.
The image data stored in 84 is restored, the original 256 gradations are converted again, and the error diffusion of the four-valued data, which is a smoother halftone expression than the binary data, is performed, and the image is sent to the laser output unit 83d It is configured to transfer data.

That is, in the decompression unit 83a, the image data compressed by the compression processing unit 82h is decompressed.

In the multi-value processing section 83b, the image data processing section
Processing similar to that of the multi-value quantization processing units 82a and 82b of 82 is performed.

The error diffusion processing unit 83c performs the same processing as the error diffusion processing unit 81c of the image data input unit 81.

In the laser output section 83d, the digital pixel data is converted into an on / off signal for driving the laser based on a control signal from a sequence controller (not shown), and the laser is turned on / off.

The data handled by the image data input section 81 and the image data output section 83 are basically stored in the memory 84 in the form of binary data in order to reduce the capacity of the memory 84. It is also possible to process in the form of four-valued data in consideration of deterioration of image data.

The operation of the flow chart shown in FIG.
It is programmed in advance and stored in a ROM (read only memory) (not shown) of the image processing control unit. The CPU 85 can read and execute the program stored in this ROM.

The document supporting glass 57 shown in FIGS. 3 and 4 is an embodiment of the document supporting plate of the present invention. The document tray 50 of FIG.
Document pickup roller 52, conveyance roller pair 53, change lever 54, platen roller 55, supply rollers 56L and 56R
, Document guides 58L and 58R, document ejection rollers 59L and 5R
9R, movable guides 60L and 60R, document reversing guide 65, reversing conveying path 66, reversing conveying roller pair 67, and rotating shaft 68,
It is one Example of the 1st conveyance means of this invention. The business card / postcard original insertion slot 69 of FIG. 3 and the feeding roller 74 of FIG. 4 are an embodiment of the second conveying means of the present invention. Original detection sensors S6, S7 and S8 of FIG. 3 and original detection sensor S7 of FIG.
S8a and S8b, and the CPU 85 of FIG. 5 are examples of the selecting means of the present invention. The document reading position P in FIG. 3 is an example of the document reading position of the present invention.

According to this embodiment, a normal original and an original such as thick paper are fed differently to the original reading position, that is, when the original is copied in the single-sided or double-sided copy mode, the feeding is performed. Use the paper standard as the center standard,
When copying in the business card / postcard copy mode for documents with small width or thick paper, such as business cards or postcards, the corners are used as the paper feeding standard to stabilize even documents with small width or thick paper. The document can be conveyed. Therefore, documents having different sizes and thicknesses can be accurately conveyed to the document reading position, which contributes to accurate reading of document images.

[0136]

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, wherein the center of the document is located at the center of the document support plate with respect to the document transport direction. And a second transporting means for transporting the original without bending the original by aligning the edge of the original with the edge of the original supporting plate in the transport direction of the original.
And a selecting means for selecting either the first conveying means or the second conveying means according to the size of the original when the original is conveyed. Therefore, documents having different sizes and thicknesses can be accurately conveyed to the document reading position, which contributes to accurate reading of document images.

[Brief description of drawings]

FIG. 1 is a flowchart for explaining an operation of an RDF which is an embodiment of a document feeder according to the present invention when a document such as a business card or a postcard is copied.

FIG. 2 is a side sectional view showing the overall configuration of a digital copying machine which is an embodiment of an image forming apparatus equipped with a document feeder according to the present invention.

3 is a side sectional view of an RDF attached to the scanner unit of the digital copying machine of FIG. 2, which is an embodiment of a document feeder according to the present invention.

FIG. 4 is a plan view of an essential part of the RDF showing the position of the document in the document supporting glass and the business card / postcard document insertion port of FIG. 3 for explaining the paper feed standard.

5 is a block configuration diagram of an image processing control unit included in the digital copying machine of FIG. 2 for performing processing from input to output of image data.

FIG. 6 is a schematic view of a conventional document feeding device for explaining a document feeding operation when reading one side of a document.

FIG. 7 is a schematic diagram of a conventional document feeding device for explaining a document feeding operation when reading one side of a document.

FIG. 8 is a schematic diagram of a conventional document feeding device for explaining a document feeding operation when reading both sides of a document.

FIG. 9 is a schematic diagram of a conventional document feeding device for explaining a document feeding operation when reading both sides of a document.

FIG. 10 is a schematic diagram of a conventional document feeding device for explaining a document feeding operation when reading both sides of a document.

FIG. 11 is a schematic view of a conventional document feeding device for explaining a document feeding operation when reading both sides of a document.

[Explanation of symbols]

 50 Document tray 52 Document pick-up roller 53 Conveyor roller pair 54 Change lever 55 Platen roller 56L, 56R Supply roller 57 Document support glass 58L, 58R Document guide 59L, 59R Document ejection roller 60L, 60R Movable guide 65 Document reversing guide 66 Reverse conveying path 67 Reversing conveyance roller pair 68 Rotation axis 69 Document card / postcard document insertion slot 74 Feeding roller S6, S7, S8, S8a, S8b Document detection sensor

Claims (1)

[Claims] 1. A document feeder for feeding a document and passing the document reading position of a document support plate, wherein the document is transported by aligning the center of the document with the center of the document support plate with respect to the document transport direction. No. 1 conveying means, second conveying means for conveying the original without bending the original by aligning the end of the original with the end of the original supporting plate in the conveying direction of the original, and the first conveying means for conveying the original. An original conveying apparatus, comprising: a conveying means for selecting the second conveying means and a selecting means for selecting one of the second conveying means according to the size of the original.