JPH01306829A - Original reader - Google Patents

Abstract

PURPOSE:To surely detect original size by moving a sensor supporting arm below an original platen glass when an original platen cover is opened and detecting the original size in a prescribed manner. CONSTITUTION:The title reader is provided with sensors 46-49 detecting original features such as size and image density, the sensor supporting arm 40 equipped with at least one of the sensors 46-49 and movable between the position below the original platen glass 16 and the position retreating from underneath the glass 16, and a sensor supporting arm driving and controlling means which normally retreats the arm 40 from underneath the original platen glass 16, but moves the arm downwardly toward the original platen glass 16 when the original platen cover is opened. With the cover opened, the original features such as original size and image density are detected. As a result, an optical system need not to be scanned preliminarily, and even if the color of the rear surface of the original platen cover is the same as the base color of an original, it can be detected.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image reading device that optically scans a document placed on a document platen glass to read a document image, and particularly relates to The present invention relates to an improvement of a device that detects document properties such as size and density of a document prior to reading.

When reading a conventional original image, it is necessary to detect the original size and image density in order to set the scanning range of the optical system and the amount of light.

For example, conventional methods for detecting the size of a document include a method in which a CCD itself for reading an image performs a preliminary scan, and a method in which a sensor for detecting the size of the document is separately provided below the surface of the document placement glass.

However, the method of pre-scanning the CCD has the problem that the copying time becomes longer due to the time required for the pre-scanning, and the copying speed becomes slower. There is a problem in that the size of the document cannot be determined unless the bottom surface of the cover is made different from the background color of the document.

In view of these problems, the present invention provides an extremely convenient image reading device that does not require preliminary scanning and is capable of detecting the document size, etc. even if the color of the lower surface of the document holding cover is the same as the background color of the document. With the goal.

In order to achieve the above object, the present invention provides an image reading device that optically scans a document placed on a document platen glass to read the document image. , a sensor that detects document properties such as image density, and at least one sensor that detects document properties such as image density.
The sensor support arm is movable between a position below the document glass and a position retracted from below the document glass, and the support arm is normally retracted from below the document glass. The present invention is characterized in that it includes a sensor support arm drive control means that moves the holding cover below the document table glass when the presser cover is opened.

Sakuji --- Eni -- ADF etc. (Yauto Document Feeder
), the document holding cover opens when placing the document on the platen glass. In the present invention, when the document holding cover is open, the sensor support arm is moved below the surface of the document table glass to detect document properties such as document size or image density. Therefore, according to the present invention, there is no need to pre-scan the optical system, and the document properties can be detected even if the color of the lower surface of the document holding cover is the same as the background color of the document.

EMBODIMENT OF THE INVENTION Hereinafter, one embodiment of an image reading device according to the present invention will be described with reference to accompanying drawings.

(Overall Configuration and Operation of Copying Machine) FIG. 1 shows a copying machine to which the present invention is applied, in which a photosensitive drum 1 is supported substantially at the center of a main body 100 of the copying machine so as to be rotatable in the direction of arrow a in the figure. Around it are an eraser lamp 2, a charger 3, and an inter-image eraser 4 at the other end.
Developing device6. A transfer charger 7, a separation charger 8, and a cleaning device 9 are arranged in this order. The photoreceptor drum 1 has a photoreceptor layer provided on its surface, and this photoreceptor layer is uniformly charged by passing through the eraser lamp 2 and the charger 3, and then passed through the scanning optical system 10 through the slit section 5. Upon image exposure, an electrostatic latent image is formed on its surface. The other end and inter-image eraser 4 has a plurality of light emitting diodes arranged in the image width direction, and removes unnecessary charges from the surface of the photoreceptor drum 1 during image formation.

The optical system 10 is installed below the document table glass 16 so as to be able to scan the document image, and includes an exposure lamp 17, movable mirrors 11, 12, 13, a lens 14, and a mirror 15. The exposure lamp 17 and the movable mirror 11
moves integrally in the direction indicated by the arrow at a speed of (v/m) (however, 1 m: copying magnification) with respect to the circumferential speed of the photoconductor drum 1 (constant regardless of whether the magnification is the same or variable magnification). , movable mirror 1
2.13 are driven by a scan motor M3 so as to move integrally in the direction indicated by the arrow at a speed of (V/2 m). In addition, when changing the copy magnification, use the stepping motor M.
4, the lens 14 moves on the optical axis and the mirror 15 moves and swings to correct the optical path.
Such a magnification changing mechanism is already known in principle.

Also, regarding control of the scanning speed of the optical system 10,
A control l is performed to change the rotational speed of the scan motor M3 according to the copy magnification data, but a detailed explanation of the control method and the like will be omitted.

Copy paper is fed into the machine by an automatic paper feed mechanism 20 provided on the left side of the copy machine main body 100 in the drawing, which has two upper and lower feeder mounting sections, or by a manual paper feed mechanism 30 provided above the automatic paper feed mechanism 20. After being temporarily stopped by a pair of rollers 21, the same image as the image formed on the surface of the photosensitive drum 1 is sent to a transfer section, the toner image is transferred by a transfer charger 7, and the toner image is transferred by a separation charger 8. It is separated from the surface of the photoreceptor drum 1, sent to a fixing device 23 by a conveyor belt 22, where the image is fixed and delivered to a paper output tray 24.
Second, it is discharged. After the transfer, the photosensitive drum 1 is cleaned by a cleaning device 9. The toner and charge remaining on the surface are removed by the eraser 2 in preparation for the next copying process.

Either the automatic paper feed mechanism 20 or the manual paper feed mechanism 30 is selectively used. In case of automatic paper feeding, copy machine 10
The image forming system including the photoreceptor drum 1 is started by operating the print key that starts the copying operation of 0. When the pre-Oi drive process for the photoreceptor drum 1 is completed, the paper feed roller 25 or 26 is driven and the copying operation is started. Drive of the optical system 10 is started by a scan start signal output as the paper is fed, and the copy paper is fed in synchronization with the image forming operation. The copy paper is not necessarily one sheet, but multiple sheets are fed to the paper feed roller 2.
Although it may be pushed out by 5 or 26 rotations,
Only the top layer is sent out by the next-stage sorting mechanism 27, 27'.

In the handling mechanism 27, 27', the upper roller 27a,
27. a' is the lower roller 27b in the feeding direction.

27b' is rotationally driven in the push-back direction in the direction of the arrow in the drawing. The second and subsequent sheets of copy paper that are pushed out together with the top layer copy paper by the paper feed roller 25 or 26 are pushed back by the lower rollers 27b and 27b', and only the top layer copy paper is sent to the next intermediate roller pair 28. or 28'
sent towards. The intermediate roller pair 28.28' is
As will be described later, it is associated with the next-stage timing roller pair 21 and its drive is controlled.

On the other hand, in the case of manual paper feeding, when copy paper is inserted from the manual paper insertion slot 32 and the sensor 34 detects this,
The manual feed roller 33 rotates to feed the copy paper into the machine, and at the same time or a little later, the print key 7 is pressed.
Driving of the photoreceptor drum 1 and the like starts in the same manner as in operation 1. Then, the manually fed copy paper is temporarily stopped and on standby at the detection part of the copy paper leading edge detection switch 35, and when the preliminary (i/4 drive process including rotation of the photosensitive drum 1) is completed, the paper feed roller 33 is stopped. It rotates again and is sent into the aircraft.

In addition, size detection switches 5WII to 5W14 and SW21 to SW are provided in each cassette mounting section of the automatic paper feeding mechanism 20.
The operation state of the switch is changed by the arrangement of protrusions or magnets (not shown) provided on the cassette 91 and 92, and the size of the loaded copy paper can be changed into a 4-bit binary number. It can be determined by code.

Next, the top of the copying machine main body 100 is equipped with an automatic original document (fastest device 200 (hereinafter referred to as ADF). ADF
200 generally includes a document sending unit 201 that stocks originals and sends them out one by one, and a Seido belt 105 that transports the sent originals over the top surface of the document table glass 16 and stops them at a predetermined position on the surface of the glass 16. The document transport unit 202 also includes a document transport unit 202 that sends the document onto a paper discharge tray 204 after scanning the document. The document conveyance section 202 can be used alone as a manual document conveyance device, and can be opened and closed with respect to the copier body 100 so as to expose the document table glass 16 when mounted on the copier body 100. It can be used as a normal document holding cover when copying thick books.

A magnet (not shown) is installed in the main body 100 of the copying machine, and when the document conveying section 202 is closed, the magnet is notified and the switch O8W, which is a reed switch, is turned on, and when it is opened, it is turned off.

This allows detection of opening and closing of the document holding cover.

Also, when this switch O8W is turned on, the ADF200
and the control of the copying machine main body lOO are associated with each other, and the operation mode of the copying machine main body lOO is switched to the ADF mode.

[Original size detection sensor]

In the optical system 10, a long lamp as shown in FIG. A sensor support arm 40 having a shape is arranged. As shown in FIGS. 3 and 4, the base end 40a side of the sensor support arm 40 is swingably supported by the copying machine frame 101 via a coil spring 41, and is moved to a position below the document glass 16 by a solenoid 42. It is configured to be driven in and out. The details of the connection structure between the solenoid 42 and the sensor support arm 40 are as follows.
The pin portion 43b at the other end is inserted and locked into a long hole 44b of a swing lever 44 connected to the base end 40a of the sensor support arm 40. When the solenoid 42 is not energized, the crank lever 43 stands up as shown by the solid line in FIG.
The sensor support arm 40 swings back to the state shown by the solid line due to the restoring force of the coil spring 41. This return position is a position where the original platen glass 16 is retracted from below to the side, as shown in FIG. 2 (A) in plan view. When the solenoid 42 is energized, the sensor support arm 40 swings against the restoring force of the coil spring 41 to the position shown in FIG. . At the position (b), the base end of the sensor support arm 40 comes into contact with the stopper 45, so the sensor support arm 40 is held at that position. Note that the swing angle θ at this time is 30° in this embodiment.

For example, four sensors 4 are mounted on the sensor support arm 40.
6, 47, 48, and 49 are arranged at predetermined intervals at every corner in the longitudinal direction. As shown in FIG. 5, each of the sensors 46 to 49 includes a light emitting element 46a that emits light in an oblique direction and a light receiving element 46b that receives light from above. Therefore, as shown in FIG. 5(A), when there is no original on the document glass 16, the light emitted from the light emitting element 46a passes through the document glass 16, so that the light is incident on the light receiving element 46b. do not. On the other hand, as shown in FIG.
00, the light emitted from the light emitting element 46a illuminates the original f height surface directly above the light receiving element 46b. Therefore, diffusely reflected light from the irradiated portion of the document enters the light receiving element 46b. The light-receiving element 46b changes to the "■" level due to the incidence of this diffusely reflected light. Note that each sensor 46 to 49
Both the light emitting element and the light receiving element are synchronized by a synchronization circuit 50 shown in FIG. 6, so that only the light from the light emitting element is received by the light receiving element.

When the sensor support arm 40 is swung to the position shown in FIG. 2 (b), the document size can be detected from the detection states of the sensors 46 to 49.

The reason for this is explained with reference to FIG. 2. First, when an A5 original is placed vertically on the original platen glass 16 as shown by A5T, all the sensors 46 to 49 are off from the original A5T. level output (see ■ in Table 1).

Next, if you print the B5 original vertically as shown at 85T,
Since only the sensor 48 enters below the original B5 'T', only the sensor 48 changes to the "L" level (■ in Table 1).
reference).

Next, when an A4 document is placed vertically as shown by Δ4T, sensors 48 and 49 enter below the document A4T, so these two sensors 48 and 49 change to the "L" level (see ■ in Table 1). ).

If you place a B4 document vertically as shown at 84 '1',
Except for the sensor 46, the remaining three sensors enter under the document B4T, so only the sensor 46 is at the "H" level, and the other sensors are at the "L" level (see ■ in Table 1). Below, A
3 The sensor output when the original is placed vertically is shown in ■ in Table 1, and B
5 The sensor output when the original is placed horizontally is shown in ■ in Table 1.
The sensor output when four originals are placed horizontally is as shown in 0 in Table 1.

In addition, the sensor output shown in ■■, ■～@ and [phase] in the table
.

The pattern is a pattern not found in document size detection.

[Margin below]

Table 1 From the above results, it can be seen that the sensor output patterns differ depending on the document size and whether the document is placed horizontally or vertically. Therefore, it is possible to determine the document size from the output pattern of all the sensors.

[Configuration and operation of control circuit]

FIG. 7 shows the control circuit of the copying machine. Main control section 70
Input signals include detection signals from various switches, etc., and key input signals from pressing keys on the operation panel. Specifically, the detection signal is sent to the switches 5W11 to 14.
, 5W21 to 24, an open/close detection signal of the ADF document conveying section 20, and a detection signal of the sensors 46 to 49.

The key human input signals include an on signal of the printer key, an on signal of the print number selection key, and the like. In addition, the main control unit 7
From 0, the main motor M1 and other motors M2. M3・
..., a energization control signal for the solenoid 42, and a display signal to the display section of the operation panel 72 are output.

FIG. 8 is a main flow showing the copy operation controlled by the control circuit. When the device is started, an internal timer is set in step S1. The internal timer controls one copy operation routine, and control in each process is measured based on this timer. When this timer is set, steps 82 to S5 are advanced and predetermined processing is performed.

In other words, if there is a key on the operation panel, it can be read.
(S2), detects the size of the original set on the original platen glass, (S3), then performs a copying operation (S4),
At this time, additional processing such as displaying an error message if there is a paper jam is performed (35).

When all the above processes are completed, the process waits for the time set in the internal timer to elapse (36), and repeats the process from 82 to S5 again.

The document size detection process in step S3 is performed automatically by the ADF in the ADF mode, and in a non-ADF mode by swinging the sensor support arm 40 to detect the size of the document placed on the document table glass. This shows both processes. This process is shown in detail in the subroutine shown in FIG. In this subroutine, first, in step S7, it is determined whether the sensor support arm 40 swings downward from the document table glass (this swing is referred to as arm opening in the flowchart) and whether the conditions are good. This judge is shown in Figure 10.

This is performed in steps 371 to S76 shown in the routine. That is, when the device is in the process of copying (S71), even if the device is not in the process of copying, the original is set in the ADF (S72).
), if the device is set to ADF mode (373
), and even if the mode is not the ADF mode, the arm open flag is set to O if the document transport section 202 is closed (S74). This prohibits arm opening.

On the other hand, when the copying operation is not in progress, the ADF mode is not in progress, and the document transport section 202 is open, the arm open flag is set to 1, and it is judged that the arm open condition is satisfied.

After completing this J-7, the program will move to step S.
Proceed to step 8 and check the count value of the state counter. The state counter can have seven types of state values from "0" to "6", and the values can be set by the program from "0" to "6".
” is rewritten when stepping through each routine. “0”
The routines "6" to "6" refer to a group of steps on each multi-branch line branched from step S8. This "0" to "6"
Each routine includes steps SL0, 312. S24゜S
33. S36. S45. S53. S63. It has a processing step of changing the state value of the state counter as follows. When the device is first started, the state value of the state counter is "0", so the program advances through the 0" routine and returns to the main flow. Then, when the program advances to step S8 again, Checks the state value of the state counter and jumps to the routine specified by the state value.After stepping through that routine, returns to the main flow again and steps through the main flow.Then, step S
When it reaches 8, it jumps to the routine indicated by the state value of the state counter and advances through that routine. Repeat this operation thereafter.

Next, each routine from “0” to “6” will be explained.
In the "O" routine, first, in step S9, the data at the time of initial setting (at start-up after troubleshooting, at power-on, etc.) and the data at the previous detection are cleared, and then at step S9
The state counter is set to 1'' by IO, and the process returns to the main routine.

In the routine "1", it is determined in step Sll whether or not the test scan has been completed. If it has been completed, the process advances to step S12 and the state counter is set to "2"; if it has not been completed yet, Return to the main routine without changing the contents of the state counter. Then, each time the routine advances to "1" and waits for the test scan to be performed. When the test scan is completed, the process advances to step S12 and the state counter is set to "2". Note that the test scan is a preliminary scan that is performed at regular intervals (for the first time) υ11, for example, when the power is turned on, when returning after clearing a blockage, etc., to check for abnormalities in the optical system.

In the routine 2'', if the arm release flag is set to "1" in step 321, the process proceeds to step S22, where the arm solenoid is turned on and the sensor support arm 40 is swung below the document table glass 16.Subsequently, In step S23, a timer T-A is set to set the time required for the arm 40 to stop after it starts swinging.Then, in step S24, a state counter is set to 3''. On the other hand, if it is determined in step S21 that the flag is not "1", the process does not proceed through steps 322 to 24 (returns to the main routine. Therefore,
In this case, the program will run through routine 2'' until the flag is set to ``1''.

In the routine 3'', it is determined in step S31 whether the arm release flag is set to "1", and the answer is Yes.
In this case, the process proceeds to step 332, where it is determined whether or not timer TA has timed up. If the time is up, the process advances to step S33 and the counter is set to 4. If the time has not expired yet, return as is.

On the other hand, if it is determined in step S31 that the flag is not 1'', in such a case, as explained in the subroutine of FIG. In any of the three cases when the document transport section 202 is closed, the program proceeds to step S34 and turns off the arm solenoid 42.

As a result, the sensor support arm 40 begins to swing toward the retracted position due to the elastic restoring force of the coil spring.

Then, in step S35, the time required for the arm 40 to be retracted to the retracted position is set in the timer TA, and the state counter is set to "5".

In the routine "4", it is determined again in step S41 whether the arm release flag is "1", and if the flag is "1", the process proceeds to the steering knob S21, and the sensor 46 to
9 is taken in, the document size is determined, and the document size data in the memory is updated. Then, when the operator finishes setting the original on the original platen glass 16 and closes the original transport unit 202, the flag is set to "0" in the arm open judgment routine shown in FIG. The process advances to 843, the arm solenoid is turned off, and in step S44, the timer TA is set to the time until the arm is retracted to the retracted position. Thereafter, in step S45, the state counter is set to "5" and the process returns to the main flow.

When the arm solenoid 42 is turned off, the sensor support arm 40 begins to swing in the retracting direction due to the elastic restoring force of the coil spring 41.

In the routine "5", the timer T-
A judgment is made as to whether or not the time has expired. When the time has expired, the timer T-B is set in step S52, and the state counter is set to "6" in step S53.
The timer T-B is a timer for setting a time for trouble detection, and is set to a predetermined time that allows enough time for the arm to be retracted.

6'' routine, it is determined in step S61 whether or not the arm has been retracted.This determination is made by providing a rimming switch or an optical detection switch to confirm the presence of the arm in the retracted position of the arm. If the arm does not retreat, step S64
The program then proceeds to step 1 to determine whether or not timer 1-B has timed up.

If the timer T-B times up while the arm is not retracted, the process advances to step S65, where an error is displayed on the operation panel and a process is performed to prohibit the copying operation. On the other hand, if the arm is completely retracted before the timer T-B times up, the process proceeds to step S62, where the timer T-B is cleared and the state counter is set to "2" at step 363. Therefore, every time a new document is set from now on, the process will start from routine "2".

Incidentally, in the above embodiment, the sensors 46 to 49 are used for determining the document size, but the present invention is not limited to this, and sensors for measuring the image density of the document, for example, may also be used. When measuring image density, the number of sensors may be at least one.

Further, although the sensor support arm is configured to rotate around one point, the sensor support arm is not limited to this, and may be configured to move in parallel between the lower part of the document platen glass and the retracted position.

Further, in the above embodiments, the present invention is applied to a copying machine equipped with an ADF, but it goes without saying that the present invention can be applied to a copying machine not equipped with an ADF.

As explained above, the image reading device according to the present invention moves the sensor support arm below the document table glass to detect a predetermined document size, etc. when the document holding cover is opened. Therefore, it is not necessary to pre-scan the reading optical system as in the past, reducing copying time.
This has the effect of making it possible to reliably detect the original size even when the original size is detected.

[Brief explanation of the drawing]

FIG. 1 is an overall view of a copying machine to which the present invention is applied, FIG. 2 is a plan view showing a sensor support arm, FIG. 3 is a perspective view of the arm, FIG. 4 is a side view of the arm, and FIG. The figure is a diagram explaining the detection principle of the sensor, FIG. 6 is a diagram showing the electric circuit of each sensor, and FIG. FIG. 8 is a main flow chart showing a copying operation, FIG. 9 is a flow chart showing a subroutine for document size detection, and FIG. 10 is a flow chart showing a subroutine for arm open judge. 16...Original table glass, 46-49...Sensor, 4
0...Sensor support arm, 202...Document transport unit (
document holder cover). Patent applicant: Minolta Camera Co., Ltd. Figure 5 Figure 6 Figure 7 Figure 8

Claims (1)

[Claims] (1) In an image reading device that optically scans a document placed on a document platen glass to read the document image, the sensor includes at least a sensor that detects document properties such as document size and image density; One or more sensor support arms are provided and are movable between a position below the document glass and a position retracted from below the document glass, and the support arm is normally retracted from below the document glass. An image reading device comprising: a sensor support arm drive control means for moving the document platen glass downward when the document holding cover is opened.