JPH01277833A - Original size detecting device for copying machine - Google Patents

Abstract

PURPOSE:To surely detect an original size with one sensor by conducting reflected light from an original to an optical sensor through a small hole provided in a light shielding member which regulates a detection range and comparing the output signal of the optical sensor with a reference signal. CONSTITUTION:The optical sensor 16 is provided out of the optical path of the reflected light which passes through the image forming lens 6 of an exposing device equipped with a light source 2 which optically scans the original while moving on a specified path and on a position where the reflected light from the original by the light source 2 is made incident through the mirrors 3-5 of said device. The light shielding member 18 is provided, which is arranged in a member moving in the same direction as the light source 2 at 1/2 speed thereof and where the small hole 19 through which the reflected light from the specified width of original is conducted to the optical sensor 16 is formed, so that the existence of the original is detected by comparing the output signal from the optical sensor 16 which is in the middle of exposing and scanning with the reference signal every plural check timings previously set. Thus, many original sizes can be detected with one sensor without making the constitution complicated.

Description

[Detailed description of the invention] Yotoyo branch The present invention relates to a document size detection device for a copying machine.

In order to automatically control the selection of transfer paper and the selection of magnification in a conventional copying machine, it is necessary to detect the size (including orientation) of the document set on the contact glass.
``Therefore, in conventional document size detection devices, for example, a plurality of sensors are provided, the detection end of each sensor is configured with an optical fiber, etc., and is attached to a scanner for driving a mirror. Another sensor was used to detect the setting direction of the document (for example, portrait/horizontal orientation of A4 size, etc.).

Therefore, multiple sensors are required, which increases the number of parts, and since the detection end is attached to a reciprocating scanner, special processing is required to connect it to the main body control section, making the configuration complicated. There was a problem that the cost would be high.

Additionally, a device has been developed that detects the document size by moving the sensor or its detection end diagonally along the bottom surface of the contact glass.In this case, only one sensor is required, but the sensor or its detection A mechanism for moving the end in a diagonal direction is required, and the problem of high cost has not been solved.

This invention has been made in view of the above points, and an object thereof is to enable one sensor to detect multiple document sizes without complicating the configuration.

1-2 In order to achieve the above-mentioned object, the present invention provides an exposure device that is equipped with a light source that optically scans an original while moving along a predetermined path. A light sensor is installed at a position where the light reflected from the original by the light source enters through the mirror, and a light sensor is installed in the same direction as the light source of the exposure device.
a light shielding member that is disposed on a member that moves at a speed of 2 and has a small hole that guides reflected light from a predetermined document width to an optical sensor;
Document size determination means for detecting the presence or absence of a document by comparing the output signal of the optical sensor during exposure scanning with a reference signal at preset multiple check timings, and determining the document size based on the results. It is.゛Hereinafter, a detailed description will be given based on one embodiment of the present invention.

FIG. 1 is a schematic sectional view of a copying machine embodying the present invention.

In this copying machine, an original (not shown) placed on a contact glass 1 on which a pressure plate 17 is opened and closed is irradiated by an exposure lamp 2, which is a light source of an exposure device, and the reflected light is reflected by a first mirror 3. 2nd mirror 4. Third mirror5. The light is guided through an imaging lens 6 and a fourth mirror 7 onto a photosensitive drum 8 for exposure.

The exposure lamp 2 and the first mirror 3 are attached to the same moving member and move back and forth as shown by arrows A and A', and the first mirror moves to the position shown by 3'. The exposure lamp 2 is turned on when moving in the direction of arrow A, and optically scans the document on the contact glass 1.

At this time, the second mirror 4 and the third mirror 5 are
As shown in the figure, the optical path length is kept constant by reciprocating in the same direction as the exposure lamp 2 and the first mirror 3 at half the speed. The second mirror 4 and the third mirror 5 are 4' and 5, respectively.
It moves to the position indicated by ', and its moving length is half the moving length of the first mirror 3.

The photosensitive drum 8 is actively rotated in the direction shown by the arrow C, and around it is a charger 9, a developing section 10 that visualizes a latent image formed by exposure after charging, and a toner transfer section that applies toner to the transfer paper. Transfer charger 1 that separates transfer and transfer paper
1. Cleaning section 12 for removing residual toner. A static elimination lamp 13 is arranged to remove residual charges. Also,
The transfer paper is sent from the paper feeding device 14 to the fixing device 15 via the diverting charger 11.

1st mirror 3. 2nd mirror 4. Third mirror 5 and lens 6
There is a third lens located outside the optical path of the reflected light passing through the lens 6.
An optical sensor for detecting the document size is provided at a position where the light reflected by the mirror 5 is incident, and detects the light irradiated onto the document from the exposure lamp 2 and reflected.

In addition, a reciprocating member (not shown) to which the second mirror 4 and the third mirror 5 are attached has a light shielding member 1 formed with a small hole 19 for regulating the range of reflected light detected by the optical sensor 16. A day is set.

FIG. 2 is a plan view of the optical system showing the positional relationship between the optical sensor 16 and the light shielding member 18.

The reflected light emitted by the exposure lamp 2 and reflected by the document surface on the contact glass 1 is reflected by the first mirror 3 . 2nd mirror 4. It passes through the third mirror 5, proceeds in the direction of the arrow, and reaches the fourth mirror 7 through the lens 6.

The light shielding member 18 provided with the small hole 19 is placed at the position (■) at the start of scanning. At the start of scanning, the reciprocating member to which the second mirror 4 and third mirror 5 are attached moves along the arrow P1.
When the light shielding member 18 reaches the position (■), the optical sensor 1 passes through the small hole 19 of the light shielding member 18 at this time.
6 receives the reflected light from the third mirror 5 and starts detecting the document size.

When the reciprocating member further moves in the direction of arrow P2 and the light shielding member 18 reaches the position indicated by the broken line, the optical sensor 1
Step 6 ends the detection of the document size.

FIG. 3 is an explanatory diagram illustrating the document size detection area.

In this figure, 3', 4', and 5' are the first mirror, the second mirror, and the second mirror at the start of document size detection, respectively.
5 1 and 41° 5' indicate the position of the third mirror, and 5 1 and 41° 5' indicate the positions of the first mirror and 41°, respectively, at the end of document size detection.
The positions of the second mirror and the third mirror are shown. In addition, the position of ■ and the position of ■ of the light shielding member 18 having the small hole 19 are as follows.
The same position as described in FIG. 2 is shown.

The original size is A3. B4. A4T (portrait).

B5T, A5T and A4Y (horizontal), B 5 Y, A
The optical sensor 16 detects the reflected light of the reflection area indicated by diagonal lines entering the small hole L2 throughout the day during the document size detection period. In addition.

p5 indicates the starting point of detection, and PE indicates the ending point.

FIG. 4 is a circuit diagram showing a schematic configuration of the control system of this embodiment.

One terminal of the exposure lamp 2 is connected to an alternating current power supply AC,
The other terminal is connected to a lamp regulator 21 controlled by a microcomputer (hereinafter abbreviated as rCPUJ) 24.

Further, an optical system drive motor 23 that reciprocates the exposure lamp 2 and the mirror support member is connected to a motor driver 22 that is controlled by an output signal from the CPU 24, and is driven by a predetermined signal.

The operation section 25 is provided with a copy start switch 2nd, and this copy start switch 2nd on/off switch is provided.
The off signal is input to the CPU 24.

The optical sensor 16 that detects the document size is composed of a photodiode with a filter, and the output of the sensor for the next day is amplified in two stages by operational amplifiers 27 and 28, and is input to the CPU 24 as a voltage signal Vo. A feedback resistor Rf and a capacitor C are connected in parallel to the operational amplifier 27, and a variable resistor Rv and a fixed resistor R1 are connected to the operational amplifier 28. Further, a fixed resistor R2 is connected between the output terminal of the operational amplifier 28 and ground.

When the optical sensor 16 detects reflected light from the original,
A voltage signal V is the output of this detection circuit.

is at a high level °H', and when there is no document and the reflected light from the pressure plate 17 is detected or the pressure plate is open, this voltage signal vO becomes a low level 'L'. A specific example of determining the document size based on this voltage signal Vo will be described later.

FIG. 5 is a characteristic diagram for explaining the characteristics of the optical sensor and the photoreceptor, and shows the relationship between wavelength and sensitivity.

As shown in the figure, the color of the lower surface of the pressure plate 17 is determined by the sensitivity of the photosensitive drum 8 and the sensitivity of the filtered photodiode used as the light sensor 16 so that the optical sensor 16 can distinguish between the document and the pressure plate. It is chosen to reflect light at very low wavelengths, for example 500 nm.

FIG. 6 is a time chart illustrating the principle of detecting each size of the document using the voltage signal vO, which is the detection signal from the optical sensor 16.

In this figure, Vo is the optical sensor 16 explained in FIG.
The voltage signal vth, which is a detection signal, is a threshold voltage that is a reference for determining the presence or absence of a document. The cpU 24 in FIG. 4 determines that there is a document if Vo≧vth, and determines that there is no document if Vo<Vth.

The cpU 24 has the function of a document size determination means, and has a check timing for checking the document size in advance.
(2) is set, and the document size is determined by comparing the voltage signal Vo, which is the detection signal of the optical sensor 16, with the threshold voltage vth at each timing.

As shown in Figure 3, the detection area of the optical sensor is between B4 size and A3 size at the start of detection, and is set to an area where B4 size does not apply, and at the end of detection it is set to an area that has passed the rear end of BST size. It is set.

In this embodiment, the detection of each document size is made possible by combining the detection area settings of the optical sensor 16 as described above and the settings of each check timing ■ to ■ described in detail below. .

The check timings ■ to ■ are set as follows.

The check timing ■ is set at the time when the detection area is outside B4@.

The check timing (2) is set at a point in time when the detection area is outside A4Tl1i and straddles the width of B4 and A3.

Check timing ■ is A4T-A3 outside B5T#i
Set to the point in time of the area that spans the width.

Check timing ■ is immediately after passing B5Y length and A4Y
Set to the point in the area within the length.

Check timing ■ is immediately after passing A4Y length and B5T.
Set to the point in the area within the length.

The check timing (2) is set at the time of the area after passing B5T.

Next, for each document size in Figure 6 (1) to (8),
The principle of detecting the document size will be explained with reference to the drawings.

(1) For A3 size, each check timing ■~
At any of the timings in (2), the magnitude relationship between the voltage signal Vo and the threshold voltage vth is Vo≧vth.

(2) In the case of B4 size, VO<Vth at the check timing (■), but Vo≧vth at the check timing (■) to (■).

(3) In case of A4Y size, check timing■～
In ■, Vo≧vth, and in ■ and ■, Vo(Vth).

(4) In case of BSY size, check timing■,
For ■～■, Vo<Vth, and for ■ and ■, Vo≧vt
h.

(5) For A4T size, the check timing is
In (2), Vo(Vth), and in (2) to (2), Vo≧vth.

(6) If the size is B5T, check timing■
~ For ■, ■, Vo<Vth, and for ■, ■, Vo≧v
It becomes th.

(7) If the size is A5Y or smaller, VO<Vth at all check timings ① to ②.

(8) In the case of AST size, Vo≧vth only at check timing ■, and ■ to ■ and ■.

In case (2), Vo<Vth.

FIG. 7 is an explanatory diagram comparing the magnitude relationship between the voltage signal Vo and the threshold voltage vth for each document size and each check timing.

In this figure, the 0 mark indicates the relationship vo≧vth, and
The mark indicates the relationship V o < V th.

FIG. 8 is a flowchart showing the procedure for determining the document size by the CPU 24 in FIG. 4.

When this program starts, it first displays the data buffer (DB) document size and flag (F) document size 1 to M.
(M is an arbitrary integer; in this embodiment, M=4) is cleared to perform initialization.

Next, at the aforementioned check timing (2), the voltage signal vO and the threshold voltage vth are compared.

If Vo≧vth, the flag document size 1 is set to 1°.

Subsequently, at check timing (2), the voltage signal vO and the threshold voltage vth are compared again, and if vO≧vth, the flag document size 2 is set to 1°.

Similarly, when the check timing ■ comes, Vo≧v
If it is th, set the flag document size 3 to °1°, and when the check timing ■ comes, vO≧vth
If so, set the flag document size 4 to 1°. At this time, if Vo≧vth is not found, it is determined whether flag original size 2 is °1°, and if flag original size 2 is °1°, data buffer original size is set to "B".
5YJ is set, and if the flag document size 2 is not 1, rA5YJ is set in the data buffer document size.

In this judgment, as shown in Fig. 7, if the document size is B5Y or A5Y if it is marked with an X at check timing
This corresponds to the process of classifying B5Y and A5Y depending on whether the O mark or the x mark appears at the check timing (3).

Furthermore, when the check timing ■ comes, Vo≧v
If it is not th, then it is determined whether the flag original size 1 is °1°, and if it is °1, rA4YJ is set as the data buffer original size, and if it is not °1°, then flag original size 4 is set. Determine whether or not is 1°, and if it is 1°, add rA to the data buffer document size.
5T".

As shown in FIG. 7, this process also shows the document sizes A4Y, B5Y, A5Y, A, which are marked with an x at the check timing ■.
From the four types of 5T, we classify A4Y, which will be marked O at check timing ■, and A5T, which will be marked O at check timing ■, from among the three types of B5Y, A5Y, and A5T, which will be marked X at check timing ■. This corresponds to the process of classifying.

Next, when the check timing ■ comes, Vo≧vt
If h, then it is determined whether the flag document size 1 is 1 degree, and if it is 1 degree, "A3" is set in the data buffer document size.

At this time, if flag original size 1 is not 1°, then it is determined whether flag original size 2 is 1°,
If it is 1°, set the data buffer original size to "B4". If flag document size 2 is not 1°,
Set the data buffer original size to rA4TJ.

On the other hand, if vO≧vth is not found at check timing ①, it is determined whether the data buffer original size is 0°. If it is 0°, the data buffer original size is r.
Set B5TJ.

As shown in FIG. 7, the process of this check timing (■) is performed when A3. B4.
Among the three types of A4T, A3 is classified as having an O mark at the check timing, and B4 is classified as having an X mark at the check timing ■ and an O mark at the check timing ■.

In addition, check timings ■ and ■ are classified into A4Ts marked with an x mark. Furthermore, from among the three types of A4Y, B5Y, B5T, A5Y, and A5T that are marked with an , B5T is classified excluding A5T.

The operation of the copier when detecting the document size in this way is as follows:
When the copy start switch 26 in FIG. 4 is turned on, the exposure lamp 2 is turned on to detect the document size without starting the paper feeding operation, and the optical system consisting of the exposure lamp 2 and mirrors 3 to 5 scans once. Let's do it.

During this scanning, the presence or absence of a document is detected at check timings ① to ②, and the size of the document is sequentially determined according to the procedure explained in the flowchart of FIG.

Then, after scanning for document size detection is completed, the CPU 2 selects transfer paper or variable magnification according to the document size determined in this way, and moves on to the copying operation.
The sequence operation is set to 4.

In this way, the document size detection device of this copying machine detects light reflected from the document by the optical system (mirror) of the exposure device moving along a predetermined path through a small hole provided in the light shielding member that regulates the detection range. The document size is detected by comparing the output signal of the optical sensor with a reference signal at multiple preset timings, so a simple configuration using - number of fixed sensors can reliably detect the document size. The document size can be detected.

As described above, according to the present invention, a document size detection device for a copying machine can be constructed at low cost.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a copying machine showing an embodiment of the present invention, and FIG. 2 is a plan view of its optical system. FIG. 3 is an explanatory diagram explaining the document size detection area by the optical sensor, FIG. 4 is a circuit diagram showing the schematic configuration of the control system of this embodiment, and FIG. 5 is the light beam used in this embodiment. Characteristic diagrams of the sensor and photoreceptor; Figure 6 is a time chart explaining the principle of document size detection according to this embodiment; Figure 7 is an explanatory diagram thereof; Figure 8 is a diagram of document size discrimination by the CPU 24 in Figure 4. It is a flow diagram of processing. 1... Contact glass 2... Exposure lamp 3.
...First mirror 4...Second mirror 5...
Third mirror 6... Imaging lens 7... Fourth mirror 8... Photosensitive drum 16... Optical sensor 17... Pressure plate 18... Light shielding member
1 day... Small hole Figure 1 Figure 2 Figure 3 t, :5' I! ,,s''3'b Figure 4 Figure 5 Photoreceptor

Claims (1)

[Claims] 1. Outside the optical path of the reflected light passing through the imaging lens of an exposure device equipped with a light source that optically scans the document while moving along a predetermined path, the light reflected from the document by the light source is incident through a mirror of the exposure device. A small hole is formed in a member that moves in the same direction as the light source of the exposure device at 1/2 the speed of the light source and guides reflected light from a predetermined document width to the light sensor. a light shielding member, and a document size determining means for detecting the presence or absence of a document by comparing the output signal of the optical sensor during exposure scanning with a reference signal at preset check timings a plurality of times, and determining the document size based on the result. A document size detection device for a copying machine, comprising: