JPS59184802A - Original size detecting device - Google Patents

Abstract

PURPOSE:To eliminate the fact that a missing part corresponding to a gap part appears on a copy image by constituting a titled device so that an original is set to a prescribed copy area on a platen, after the size of the original has been detected. CONSTITUTION:Plate electrodes 17A, 17B opposed to a platen 12 side and a registration 13 side are provided so that a gap, namely, air becomes a dielectric, and the size of an original PA is detected by a capacity variation between the opposed plate electrodes, based on the size of an area of the part inserted into the gap of the original PA. Also, the inserted original is pushed by a block member 19, a spring 25 and a rope 22, to a copy area on the platen which is capable of reading completely the original.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a document size detection device used in a copying machine or a facsimile machine, and in particular to a document size detection device used in a copying machine or a facsimile machine. This invention relates to a device for selecting a size corresponding to the size of the object.

In general, (1) a conventional document size detection device includes (1) a plurality of light emitting elements provided at appropriate positions under a platen to correspond to various sizes of originals, and receiving light from the plurality of light emitting elements; A plurality of photosensors are provided on the back side of the platen cover, and the size of the document is detected by the difference in the light reception mode by the plurality of photosensors when the document is placed on the platen and the platen cover is closed. (2) A plurality of light emitting elements and a plurality of photosensors are installed at appropriate positions under the platen in accordance with the sizes of various originals to receive light reflected from the plurality of light emitting elements by the originals on the platen. In some cases, the size of the document is detected based on the difference in the light reception mode by the plurality of photosensors.

However, since all of the conventional devices described above use a plurality of photosensors, this becomes a major obstacle in reducing the cost of the device. Further, since the photosensor or light emitting element is disposed below the platen, it is difficult to arrange it in a position where the operation of the document scanning mechanism or the like is not prevented. Sara K, especially the above (
In method 1), when copying is performed with the platen cover closed, one of the multiple photosensors overlaps the original, so when copying a translucent original such as tracing paper, the photosensor is There was a problem in that the image of the image would appear on the copy, making it impossible to make high-quality copies.

This invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to provide a document size detection device that is inexpensive and has a simple configuration without using a photosensor. - That is, in this invention, a gap of an appropriate width is provided between the platen and the registration guide disposed above the platen, and the platen side and Nine opposing flat plate electrodes are provided on the registration shimming side, and the sizes of various documents placed on the upper button of the platen and inserted into the gap are determined based on the area of the portion of these documents to be inserted into the gap. Detection is performed by the change in capacitance between the platen electrodes, and furthermore, the platen side platen electrode blocks light from the light source from reaching the document, thereby preventing the document placed on the platen from reaching the document. In order to prevent the portion of the document inserted into the gap from becoming a copy image and becoming unreadable, particularly in this invention, the document is inserted into the gap following the closing of the platen cover. The inserted document is pushed out to a copy area on the platen where complete document reading can be performed by providing means for moving the inserted document from the platen.

Therefore, according to the document size detection device according to the present invention, it is possible to realize the following: (1) A device with a cheaper and simpler configuration than conventional devices can be realized.

2) It becomes possible to read all images on the document, and it is possible to prevent missing portions corresponding to the gaps from appearing in the visualized copy image.

3) It will no longer appear on the image b'-copy of the photosensor.

It has excellent effects such as

DESCRIPTION OF THE PREFERRED EMBODIMENTS The document size detection apparatus according to the present invention will be described in detail below with reference to embodiments shown in the accompanying drawings.

FIG. 1 is a perspective view showing an example of a copying machine equipped with a document size detection device according to the present invention.

In FIG. 1, an upper table II of a main body 10 of a copying machine is shown.
K is provided with a platen 12 on which a document is placed.

This platen 12 is provided with four types of copy areas A, B, C, and D to accommodate 114 different sizes of originals. , Case B column No. 5, A column No. 4, B column No. 4, A
It is assumed that the size corresponds to the size of column number 3. Further, a registration guide (hereinafter simply referred to as "guide j") 1 is provided at one end of the platen 12 along the platen 12.
3 is provided and 0 is provided. Fu again.

The Latin cover 14 is rotatably supported in the direction of arrow F using a rotation shaft 15 as a fulcrum. Items 16A and 16B necessary for operating switches and the like are appropriately provided on the top surface of the main body.

Next, FIG. 2 shows an example of the structure of the main embankment part of the present invention. FIG. 2 is a view of the device shown in FIG. 2(B) shows a state in which the platen cover 14 is opened, and FIG. 2(B) shows a state in which the platen cover 14 is closed. Further, a schematic plan view of FIG. 2 is shown in FIG. 3. Also in FIG. 3, (A) shows the state in which the platen cup is opened, and (B) shows the state in which the platen cover is closed.

In FIGS. 2 and 3, the platen 12 and guide 1
3, and an electrode 17A is provided on the lower surface of the guide 13 and an electrode 17B is provided on the upper surface of the platen 12 so as to sandwich this gap. In other words, this configuration is a stone-opposed plate electrode capacitor in which the gap is air as a dielectric. Therefore, if the capacitance of a capacitor with air as a dielectric is used as a reference, the above capacitance will be This is because the dielectric constant of paper is larger than that of air. Also, this capacitance naturally changes depending on the size of the paper inserted between the opposing flat electrodes. For example, as shown in Fig. 3. As shown in the figure, in a state in which a document P4 of size 5 (corresponding to area A) is inserted and a state in which a document PA of size A4 (corresponding to area CB) is inserted (not shown), the capacitance is of course A4. The size of the inserted paper becomes larger when the size of the original FA is inserted. Therefore, if this capacitance change is detected by an appropriate capacitance detection means 18 corresponding to a current change, the size of the document FA can be easily identified.

Incidentally, although the size of the document FA can be accurately detected with the above-described configuration, the following inconveniences occur if only the above-described configuration is used.

That is, if the subsequent copying operation is performed with the original PA inserted into the gap (state (A) in FIGS. 2 and 3), the light source under the platen ( Manuscript FA from (not shown)
This means that the above-mentioned portion of the output copy image will be missing.

Therefore, in this embodiment, a block member 19 that moves back and forth in parallel following the opening and closing of the platen cover 14 is provided in the gap, and the block member 19 is arranged to fill the gap when the platen cover 14 is closed. move it,
As a result, the original FA is pushed out to the copy area where a complete copy can be made.

The configuration for this purpose is that the rotation of the moving shaft 15 that pivotally supports the platen cover 14 is transmitted to the roller 21 by the cross belt 20, and the rotation of this roller 21 is transmitted to the roller 21.
It is adapted to be transmitted to the block member 19 by the rope 22 via t24. Since one end of the rope 22 is fixed to the block member 19 and the other end is fixed to the roller 21, the rotation of the roller 21 causes the rope 22 to
is wound up by the roller 21 to become shorter, or unwound to become longer. Further, one end of the one block member 19 is connected to a spring 25 that is fixed to the wall of the gap.

Therefore, when the platen cover 14 is rotated in the direction to open it as shown in FIG. The information is transmitted to the roller 21. This causes the roller 21 to rotate clockwise, winding up the rope 22 and moving the block member 19 in the direction of arrow A in FIG. 2(A). When the platen cover 14 is rotated to a predetermined position, a gap is formed in which the opposed flat plate electrodes 17A and 17B can detect the document size. Operator is manuscript F
When A is inserted into this gap, the document size detection operation is performed.

Next, the operator turns the platen cover 14 in a direction to close it in order to perform a subsequent copying operation (see FIG. 2(B)). As a result, the rotating shaft 15 rotates clockwise, and the roller 21, which is caught in the conduction of the belt 20, rotates counterclockwise so as to unwind the wound rope 22.

Therefore, the block member moves in the direction of arrow B in FIG. 2(B) due to the elastic force of the spring 25, and the original FA? : Extrude to the copy area. Thereafter, when the operator performs a predetermined copying operation such as turning on a copying switch, a complete copy can be obtained without the occurrence of a copy in which a portion of the image is missing.

Note that the rotational movement of the platen cover 14 is blocked by the blocking member 1.
It goes without saying that the mechanism for converting the reciprocating linear motion into 9 reciprocating linear motions is not limited to the 5 mentioned embodiments, but may also be constructed using other well-known techniques such as link mechanisms, cam mechanisms, etc. .

In addition, in this embodiment, the size of the block member 19 is set to correspond to the entire width of the platen, so that one member can perform all extrusion operations for four different sizes of originals. It is also possible to have a configuration in which separate block members are provided for each of the original documents.

Further, in this embodiment, the block member 19 follows the rotation of the platen cover and performs a reciprocating linear movement, but the movement of the block member 19 may be performed based on other means. . For example, after the original is placed on a printing plate and the size of the original is detected, a predetermined switch may be turned on to cause the block member 19 to push out the original.

FIG. 1 is a perspective view showing an example of a copying machine equipped with a document size detection device according to the present invention, FIG. 2 is a diagram showing an embodiment of the main part of the present invention, and FIG. 3 is a schematic diagram of FIG. FIG.

10... Copying machine body mill... Upper table, 12
... Platen, 13... Registration guide, 14... Platen cover, 15... Rotation axis, 16
...Switch, 17A, 17B... Opposite plate electrode,
18... Capacity detection means, 19... Block member, 2
0... Belt, 21, 23, 24... Roller, 22
...rope, 25...spring, PA-O manuscript

Claims (2)

[Claims] (1) Five flat electrodes are arranged facing each other with a predetermined gap between the platen and a registration storage box guide installed along and above the platen, and a document is inserted into the gap. and a capacitance detecting means for detecting a capacitance change between these flat plate electrodes, and detects the size of the document based on the detected capacitance change, after the size of the document is detected. A document size detecting device characterized in that a document moving means is provided for pushing the document out of the gap and setting the document in a predetermined copy area on the platen. (2) The document size detection device according to claim (1), wherein the document moving means moves the document in accordance with closing of the platen cover.