JPH01172147A - Original detecting device - Google Patents

Abstract

PURPOSE:To enable plural sizes of originals to detect their existence and discriminate the original sizes by shading the light receiving part of a photosensor at different rates with plural number of actuators. CONSTITUTION:For example, when the document 1 of A4 size is set to a predetermined sheet charging position, only a first actuator 15 rotates making a rotating shaft 16b as its center corresponding to an original 1 to release a light receiving part 14a from shading. However, because a second actuator 16 does not come into contact with the document 1 and maintains its original state, so the light receiving part 14a is kept to be shaded by half with the shading part 16c of the second actuator 16. At this time, the output voltage of a photosensor 14 becomes VA. Here, by beforehand setting a voltage a little lower than this output voltage VA to a first thresh level V1, the fact that the original has already set to the device can be detected as well as the fact that the original 1 is of A4 size can be discriminated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a document detection device used in a document feeding mechanism in a copying machine or an image communication device.

2. Description of the Related Art Conventionally, as shown in FIG. A document detection device including two photosensors 7 and a second actuator 8 was provided. The photosensors 5, 7 have light receiving parts 5a, 7m and light emitting parts 5b, ?, which are arranged facing each other, respectively. b
The actuator 6.8 normally occupies a position that shields the light receiving section 5m of the photosensor 5 and the light receiving section 7a of the photosensor 7 (when no original is set), but when the original is not placed in the original When set at the paper position, the document is rotated by the document around rotation shafts 9 and 10 as shown by arrows A and B, and the light shielding is released. Further, the first actuator 8 is located at a position where a narrow original (for example, an A4 size original) is set, and the second actuator 8 is located outside the position where the narrow original is set. It is placed at a position where a wide original (for example, a B4 size original) is set. Note that a document guide (not shown) that is movable symmetrically in the width direction is provided so that the document can always be guided to the center XX of the paper feeding mechanism.

Now, when an A4 size document is moved along the document guide and set at the document feed position where the leading edge hits between the paper feed roller 2 and presser roller a, only the first actuator rotates and the first photosensor 5 output changes. As a result, it is detected that an A4 size document has been set. Next, when a 4-size document is set at the document feeding position, the first actuator unit 8 and the second actuator 8
both rotate, and the outputs of both the first photosensor 5 and the second photosensor 7 change. As a result, it is detected that a B4 size original is set.

Problems to be Solved by the Invention However, with this configuration, in order to detect the presence or absence of documents of multiple sizes and recognize the document sizes, multiple photosensors and multiple actuators must be provided.
There was a problem in that the number of parts increased and the cost increased.

The present invention has been made in view of the above-mentioned problems, and provides a document detection device capable of detecting the presence or absence of documents of multiple sizes and recognizing the document size using a single photosensor. The purpose is to

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a plurality of actuators for each document so that the actuators can be selectively actuated depending on the documents of different sizes set at the document feeding position. The actuators are arranged apart from each other in the width direction, and are configured so that the light receiving portion of a single photosensor is shielded from light to different degrees by the plurality of actuators.

According to the present invention, with the above-described configuration, when a document is set at the document feeding position, the document actuates the number of actuators corresponding to the width of the document, and the activated actuators change the degree of light shielding of the photosensor. In the end, the photosensor outputs a signal with a level corresponding to the width of the document, and from this output signal, it is possible to detect the presence or absence of the document and to identify the width of the document.

Embodiment FIG. 1 is a schematic perspective view showing a paper feeding mechanism equipped with a document detection device according to an embodiment of the present invention, FIG. The same cross-section as in the figure is shown in different operating states. In FIGS. 1 to 3, 1 is a document, 2 is a paper feed roller, and 3 is a presser roller. In front of the paper feed roller 2, a document guide (not shown) is provided which is movable symmetrically in the width direction so that the document 1 can always be guided to the center XX of the paper feed mechanism. Reference numeral 13 denotes a document detection device, a single photosensor 14 having a light receiving section 14a and a + light emitting section 14, and a first actuator 15.
and a second actuator 16. The second actuator 16 is used for narrow width documents (for example, A4 size documents).
a contact portion 16a that does not contact the contact portion 16a but is placed at a position where it is pressed by a wide document (for example, a B4 size document) when the document is set; and a rotating shaft 16b fixed to the contact portion 16a.
The light receiving part 14 of the photosensor 14 is fixed to the rotating shaft 16 &
It has a light shielding part 16c disposed at a position that shields light from light. Note that the rotating shaft 16b is rotatably held by a bearing (not shown). On the other hand, the first actuator 15 has a contact portion 15a placed in a position where it is pressed by a narrow document (for example, an A4 size document) when the document is set, and a light receiving portion 14af of the photosensor 14 located in a light shielding position. The light shielding portion 15b is rotatably held on a rotating shaft 16b. Furthermore, as shown in FIGS. 2 and 3, the light shielding part 15b of the first actuator 15 has a length that can completely shield the light receiving part 14a of the photosensor 14, and the light shielding part 15b of the second actuator 16 has a length that can completely shield the light receiving part 14a of the photosensor 14. The length 16c has a length that can shield half of the light receiving portion 14a of the photosensor 14 from light.

The operation of the document detection device having the above configuration will be described below.

When the paper feeding mechanism is on standby, that is, when the document 1 is not set, both the first actuator 15 and the second actuator 16 are in the states shown in FIGS. The portion 14a is completely shielded from light. Therefore, as shown in FIG. 4, the photosensor output voltage is the lowest voltage V. It becomes.

Next, when the document 1 is set at a predetermined paper feeding position during document feeding, the first actuator 1 is activated according to the width of the document.
5 or the first actuator 15 and the second actuator 16 are selectively rotated. For example, A
When a document 1 of 4 sizes is set at a predetermined paper feeding position, only the first actuator 15 is moved to the rotation axis 1 by the document.
The light receiving section 14a is rotated about 6b as shown by the arrow A, and the light receiving section 14a is unblocked as shown in FIG. However, since the second actuator 16 does not come into contact with the original 1, it maintains its original state, and therefore half of the light receiving section 14a remains blocked by the light blocking section 16c of the second actuator 16. The output voltage of the photosensor 14 at this time is 1ctTV in FIG. Therefore, by setting the first threshold level V in advance to a voltage that is slightly lower than the output voltage vA, it is possible to detect that a document is set in the device, and to detect whether the document is A4 size or not. You can recognize that something is there.

Further, when a B4 size original is set at a predetermined paper feeding position, both the first actuator 15 and the second actuator 16 rotate as shown by arrows A and B, respectively.
This opens the entire surface of the light receiving section 14m. The output voltage of the photosensor 14 at this time becomes v8 shown in FIG. Therefore, although the output voltage vA is higher than the output voltage vA,
By setting a voltage slightly lower than 84 as the second threshold level v2, it is possible to detect that a document is set in the device and to recognize that the document is 84 size. can.

In the above embodiment, the actuator blocks light from the light receiving section 14a when no document is set, but conversely, when no document is set, the actuator opens the light receiving section and shields the light receiving section 14a. The light receiving section may be configured to be shielded from light when rotated by a document.

Further, although the number of actuators is two in the above embodiment, this number is not limited to two, and three or more actuators may be used depending on the type of document width. However, even in that case, it is necessary to change the length or width of the light shielding portion of each actuator so that the degree of light shielding by each actuator is different.

Effects of the Invention As is clear from the above description, the present invention has a plurality of actuators spaced apart in the width direction of the document so that they can be selectively actuated depending on documents of different sizes set at the document feeding position. By configuring the light-receiving area of a single photosensor to be shielded from light to different degrees by the plurality of actuators, when the original is set at the original feeding position, the original will correspond to the width of the original. The activated actuators change the degree of light shielding of the light-receiving part of the photosensor, so the photosensor outputs a signal with a level corresponding to the document width, and from this output signal the presence or absence of the document is detected. In addition, the document width can be identified, and compared to the conventional case where a large number of photosensors are used, the number of photosensors can be reduced and costs can be reduced.

[Brief explanation of the drawing]

Fig. 1 is a schematic perspective view showing a paper feeding mechanism equipped with a document detection device according to an embodiment of the present invention, Fig. 2 is a sectional view taken along the ■-■ arrow in Fig. 1, and Fig. 3 is Fig. 2. 4 is a graph showing the relationship between the rotation angle of the first actuator and the second actuator and the output voltage of the sensor in the above embodiment, and FIG. FIG. 1...Document, 2...Paper feed roller, 3.
...Press roller, 13...Document detection device, 14.Old...Photo sensor, 14a...Light receiving section, 14b.Old..Light emitting section, 15.. ...First actuator, 15a...Contact part, 15b...
... light shielding part, 16 ... second actuator,
16a...contact part, 16b...rotation shaft, tea...light shielding part. Dictionary of
droplets

Claims (1)

[Claims] A single photosensor including a light-emitting part and a light-receiving part, and a plurality of actuators that are actuated by a document set at a document feeding position and shield the light-receiving part of the photosensor, the plurality of actuators comprising: Document detection, characterized in that the device is arranged at a distance in the width direction of the document so as to be selectively activated depending on documents of different widths, and is configured to shield light receiving portions of the photosensor to different degrees. Device.