JPS604974B2 - size detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a size detection device for detecting the size of a paper sheet such as a document in a copying machine or the like.

In a copying machine, multiple types of copying paper are loaded into the copying machine in advance so that the copying paper can be selected according to the size of the original, and the operator of the copying machine operates a command button according to the original size to make copies. The paper was to be selected.

However, such manual selection complicates the copying operation.

Accordingly, the present invention eliminates the above-mentioned drawbacks of the prior art by providing a size detection device having an extremely simple construction for detecting the size of paper sheets.

That is, in an original exposure device equipped with an original platen on which the original document is pressed, and an optical system that moves the original platen relative to the original platen, the reflected light from the original platen is A light-receiving element that outputs an output according to the intensity of incident light; a comparing means that compares the output of the light-receiving element with a reference value unrelated to the original size; a detection means for detecting a change in the output of the comparison means at the time of relative movement; and a size signal for determining the size of the original placed on the document table based on the detection signal from the detection means and indicating the size. The present invention provides a size detection device having a determination means for outputting a size.

This makes it possible to accurately detect the size of the document placed on the document table with a simple configuration. Hereinafter, one embodiment of the present invention will be described with reference to the drawings.
In Figures 1 and 2, the reference numeral 11 is a manuscript table for placing a manuscript in a copying machine.On the side of this manuscript table 11, a size A manuscript (sheet of paper) is placed in a straight line XO-XO. ',Y
The size B original has a straight line XO-XO, as shown in the part stamped with O-YO', YA-YA', and XA-XA'.
', YO-Y〇, YB-YB,
Indicating arrows 12 are attached to the areas surrounded by O', YO-YO', XC-XC', and YC-YC'.

Reference numeral 18 denotes a document holder that covers the top of the document table 11, and the surface of this document holder 18 facing the document table 11 is coated with a light-absorbing material that absorbs light from a lamp 19, which will be described later. It is made by pasting a light absorbing member.

Further, on the operation panel 13 adjacent to the document table 11, a power switch 14 of the copying machine, a copy start command switch 15, a copy number setting keyboard 16, and a copy number display 17 are provided.

The above-mentioned copying machine has a moving optical system below the document table 11.

This moving optical system consists of a first moving optical system 21 consisting of a halogen lamp 19 and a mirror 20, and a second moving optical system 22 consisting of a mirror 22-1. Said first and second
The home positions of the moving optical systems 21 and 22 are as shown by the dotted lines, but in order to make copies, switch 1 is pressed.
When the optical systems 21 and 22 are moved in the direction of arrow P by pressing 5, the size of the original is measured (the reflected light of the original is not projected onto the photosensitive drum 26), and the optical systems 21 and 22 are moved in the direction of arrow R. When the document is moved, reflected light from the document is projected onto the photosensitive drum 26. In this way, the optical system 21, 2
A filter 58 is provided in a part of the optical path of the reflected light so that the reflected light from the document is projected onto the photosensitive drum 26 only in the specific movement direction of 2, and the optical systems 21 and 22 move in the direction of arrow P. When moving in the direction of arrow R, arrange the shirt cover 58 as shown by the dotted line so that the reflected light 59 is not irradiated onto the photosensitive drum 26. When moving in the direction of arrow R, arrange the shirt cover 58 as shown in the solid line so that the photosensitive drum 26 is not irradiated with the reflected light 59. The structure is such that the reflected light 59 is irradiated to the area. The shirt cover 58 can be easily driven using a known electromagnetic device. The first optical system 21 moves linearly at a constant speed in the direction of arrow P from the position shown by the dotted line, and the second moving optical system 22 also moves in the direction of arrow P from the position shown by the dotted line. It moves at 1/2 the speed of the system 21.

The first and second optical systems 21 and 22, which have moved in the direction of arrow P (forward movement) in this way, stop at the position where they have finished scanning the original on document table 11, and then move in the direction of arrow R (return movement). and reaches the home position.

By reciprocating the first and second optical systems in this way,
The original is illuminated by the lamp 19, and the optical path is designed so that the reflected light from the original enters the lens 23 via the mirror 20 and the mirror 22-1, and reaches the photosensitive drum 26 via the mirrors 24 and 25. has been done. In the present invention, in order to detect the size of the original, a half mirror 52 is inserted into a part of the optical path, and the light 53 reflected by the half mirror 52 forms an image on the light receiving element 55 via the lens 54. It is configured so that

Reference numeral 26 denotes a photosensitive drum that forms an image of the reflected light from the original as described above, and rotates in the direction of arrow F.

The photosensitive drum 26 has a DC corona discharger 2 on its periphery.
7, an AC corona discharger 28, a developing device 29 that attaches toner to the latent image formed on the photosensitive drum 26, a transfer charger 30 that transfers the toner on the photosensitive drum 26 to transfer paper;
Separation loaf 3 for separating the transfer paper from the photosensitive drum 26
1. A cleaner 32 for removing residual toner on the photosensitive drum 26 is provided. Reference numeral 33 indicates a cassette containing transfer paper 34 of size A, and a rotary roller 37 provided on an arm 36 swingably supported on a shaft 35 is moved in the direction of arrow S. By pressing the transfer paper 34 housed in the cassette 33, one sheet of transfer paper is guided to the transfer position of the photosensitive drum 26 via guide rollers 38, 39 and a guide 40.

The transfer paper on which the toner has been transferred is separated, passes between fixing rollers 41 and 42, is heated and fixed, and is then discharged onto a discharge tray 43.

Reference numeral 44 indicates a cassette containing transfer paper 45 of size C, and a rotary roller 48 provided on an arm 47 that is swingably supported on a shaft 46 is connected to the arm 47 by an arrow T.
The transfer paper 4 moved in the direction and stored in the cassette 44
5, one sheet of transfer paper is moved to the guide roller 4.
9, 50, 38, 39 and guides 51, 40 to the transfer position of the photosensitive drum 26, and is discharged to the discharge tray 43 through the same steps as described above.

In addition, in the guide rollers 38 and 39, 38-3,
Reference numeral 39-3 indicates a timing roller, and the transfer charger 30 is connected to the timing roller 38-3, 39-3.
The distance from the exposure position of the photosensitive drum 26 to the transfer charger 30 is assumed to be equal.

In the copying machine constructed as described above, when a size A original 56 is placed on the original platen 11 and the original presser 18 is placed on top of it, the switch 15 is pressed, and the optical systems 21 and 22 are moved to the direction indicated by the arrow. Start moving at a constant speed in the direction.

When the optical systems 21 and 22 move in the P direction, the cover plate 58 is controlled to be at the position indicated by the dotted line, so that the photosensitive drum 26
The reflected light of the document is not irradiated upward, and the light receiving element 55 only detects the intensity of the reflected light.

Since a light absorbing material 57 is coated or fixed on the document facing surface of the document presser 18, the amount of light reflected from the document 56 is large, the amount of reflected light from the document presser 18 is small, and the output of the light receiving element 65 is The result is as shown in FIG. 3A. That is,
The optical systems 21 and 22 start moving from their home positions, reach the end of the document after time to, and have finished scanning the document at time t^.

As is clear from FIG. 3A, the reflected light from such a document does not reduce the output level E, so it is possible to detect the size using a circuit as shown in FIG. 4. It is. That is, the light receiving output of the light receiving element 55 is applied to a terminal 62 and applied to the comparator 61, and a reference voltage (for example, E, mentioned above) is applied to the other terminal 63 of the comparator 61. When the received light output is higher than that, a high level output is derived, and when it is lower, a low level output is derived.

Therefore, an output signal as shown in FIG. 3B is obtained from the comparator 61. The output of the comparator 61 is further applied to a waveform shaping circuit 69 including a differentiating circuit to obtain a pulse signal as shown in FIG. 3C. Reference numerals 64 to 67 indicate one-shot multis, and a trigger pulse derived from pressing the switch 15 is applied to the terminal 68, and the one-shot multi 64 is driven by this pulse, resulting in the output shown in FIG. 3D. As shown, a high level signal is derived for a period of time t^-1.

Since the output of the one-shot multi 64 is further applied to the one-shot multi 65, the one-shot multi 65 is applied at times t^-1 to t^-1 as shown in FIG. 3B.
A high level signal is derived for a period of tB-1. Similarly, the one-shot multi 66 derives a high level signal from time tB-1 to tc-1 as shown in FIG. -2 to derive a high level signal.

Note that tB and tc indicate the time required to complete scanning of the original when the original of sizes B and C is remounted on the original table. The output of the waveform shaping circuit 69 is applied to AND gates 70 to 72, the output of the one shot multi 65 is applied to the AND gate 70', the output of the one shot multi 66 is applied to the AND gate 71, and the output of the one shot multi 66 is applied to the AND gate 71. gate 7
2, the output of the one-shot multi 67 is left open. Since the outputs of the AND gates 70 to 72 are respectively led to terminals 73 to 75, a signal indicating that the original is size A is output from the terminal 73.
A signal indicating that the original is size B can be obtained from the terminal 74, and a signal indicating that the original is size C can be obtained from the terminal 75. As mentioned above, if a size A original is placed on the document table, the pulse signal shown in FIG. However, no output signal can be obtained from the terminals 74 and 75.

Furthermore, the outputs of the AND gates 70 to 72 are applied to an OR gate 76, and the output of this OR gate 76 is led out to a terminal 77.
This is used as a stop signal to stop the motors 1 and 22. Therefore, as mentioned above, when the scanning of the A size original is completed, a size signal is obtained at the terminal 73 and a stop signal is also obtained at the terminal 77, so the arm 36 is driven in the direction of arrow S by the size signal and the size A transfer paper 3
4 to the guide 40, and the optical systems 21, 2
Stop the movement of 2.

Therefore, the optical systems 21 and 22 stop at a position slightly moved in the direction of arrow P from the edge of the A-size original, and after this stop, they start moving in the direction of arrow R.

At the start of this movement in the direction of arrow R, the shirt sleeve 58 is flipped up to the position shown by the solid line.

When the optical systems 21 and 22 start moving in this manner and reach the left edge of the document, the timing roller 38
-3, 39-3 start rotating and convey the transfer paper 34 to the transfer position, and the reflected light from the document is also transferred to the photosensitive drum 26.
It starts projecting upward. Note that, as described above, the transfer paper 34, which is ejected from the cassette 33 upon derivation of the size signal, is moved by the timing rollers 38-3 and 39 until the optical system 21 stops, starts moving again, and reaches the left edge of the document. It is assumed that the timing rollers 38-3 and 39-3 start moving immediately after the timing rollers 38-3 and 39-3 start rotating.

As described above, the reflected light from the document projected onto the photosensitive drum 26 is transferred onto a transfer sheet in a process similar to that of a normal copying machine, and is then ejected onto the ejection tray 43. In the above embodiment, the half mirror 52 is inserted in a part of the optical path of the reflected light 59, but a mirror (which does not transmit light) is inserted in place of the half mirror 52, and the shirt cover 58 is omitted, and the optical When the systems 21 and 22 move in the direction of arrow P, the mirror is inserted into the optical path in the same way as the half mirror 52 in FIG. 2, and when the systems 21 and 22 move in the direction of arrow R, the mirror is removed from the optical path. It may be configured. Further, in the above embodiment, the document size is detected by the light reflected from the document, but in other embodiments, a document holder as shown in FIG. 5 or 6 may be used. That is, FIG. 5 is a side view of a document holder of a copying machine according to another embodiment, when viewed from the direction of arrow L in FIG.
0, a transparent and highly elastic light-transmitting layer 81 for guiding light provided under the protective member 80, and a translucent thin layer such as Tetoron resin provided below the light-transparent layer 81. 82 are fixed together.

The document holder is fixed to the main body of the copying apparatus by fixing one end thereof with a fixing member 83.

A lamp chamber 84 is provided in the fabric of the document holder fixed by the fixing member 83 in this way, and the light from the honeycomb lamp 85 housed in the lamp chamber 84 is transmitted through the transparent layer 81 and the thin layer. The light is uniformly irradiated onto the document table 11 via the light source 82 .

Therefore, if you want to detect the size using such a document holder, by pressing the switch 15,
The lamp 19 is turned off, the crab light lamp 85 is turned on, and at the same time the optical systems 21 and 22 are moved in the direction of the arrow P.

Assuming that an A-sized original is placed on the original platen 11, when the optical system 21 is positioned below the original, most of the light from the light-transmitting layer 81 is blocked by the original and reaches the light-receiving element 55. does not reach. On the other hand, after passing through the document part, the light from the transparent layer 81 directly enters the two mirrors, and the strong light reaches the light receiving element 55, so that the light from the comparator 61 in FIG. An output signal as shown in FIG. 3 can be obtained. Therefore, by only slightly changing the configuration of the waveform shaping circuit 69, the size can be detected using the circuit shown in FIG. 4 as is.

Note that when using such a document holder, the optical systems 21, 2
Of course, when the robot 2 moves in the direction of arrow R, the crab light 85 is turned off and the lamp 19 is turned on.

The reason why a thin layer is provided under the transparent layer is so that when the crab light lamp 85 is not lit, the surface of the document holder that comes into contact with the document has a density close to that of a white background. . FIG. 6 shows a document holder according to another embodiment based on the same idea as FIG. The lamp 90 is embedded according to the size, and the other configuration is the same as that explained in FIG.
This is done based on the principle described in the figure.

In all of the embodiments described above, a solid-state image sensor in which a large number of light-receiving elements are arranged in a straight line as the light-receiving element 55 (the straight line of the light-receiving elements is arranged at right angles to the paper surface in FIG. 2) is used to capture the solid-state image. By electronically scanning the sensor at high speed, it is possible to read all the image information on the document, so the developing bias and DC corona charger can be adjusted according to the image information obtained in this way. It is also possible to control, etc. As detailed above,
According to the present invention, it is possible to detect the size of a document extremely easily, so that it is possible to automatically perform various controls using such detection output.

[Brief explanation of the drawing]

FIG. 1 is a top view of a copying machine to which the present invention is applied, FIG. 2 is a side sectional view of the copying machine to which the present invention is applied, and FIG. 4 is a circuit diagram configuring the size detection device according to the present invention, and FIG. 5 and FIG. 6 are side views showing main parts of other embodiments of the size detection device according to the present invention. Here, 15 is a switch; 18 is a document holder, 19 is a lamp, 20, 22-1 is a mirror, 26 is a photosensitive drum, 52
55 is a half mirror, 55 is a light receiving element, 56 is an original, 58 is a cover plate, 61 is a comparator, 64 to 67 are one-shot multis, and 70 to 72 are AND gates. Act 4 Figure 2 Figure 4 Figure 5 Younger brother Figure 6

Claims (1)

[Scope of Claims] 1. A document exposure device comprising a document table on which a document is placed, and an optical system that moves relative to the document table to expose the document on the document table,
a light-receiving element that receives reflected light from the document table and outputs an output according to the light intensity; and a comparison means that compares the output of the light-receiving element with a reference value unrelated to the document size.
detecting means for relatively moving the document table and the optical system before exposing the document and detecting a change in the output of the comparing means at that time; What is claimed is: 1. A size detection device comprising: determination means for determining the size of an original document and outputting a size signal indicating the size.