JPH11133523A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To appropriately detect original size even in the case that an original covering plate is stopped halfway when it is closed by providing a device with a means measuring the opening amount of an original covering member. SOLUTION: The resistance value of a slide volume 3 is changed in accordance with that the original covering plate 2 is opened and closed. When the plate 2 is closed and it arrives at a position 101, it is detected based on a value outputted from the volume 3 and the detecting actions of respective sensors 4 and 5 are started by a control part 6. Since an original 7 does not exist on the sensor 4 but it exists on the sensor 5, the sensor 4 is turned off and the sensor 5 is turned on. Besides, when the plate 2 is closed and it arrives at a position 102, the sensor 4 is turned on by detecting the reflection of the plate 2. Then, it is detected by the control part 6 that the original 7 does not exist at the position of the sensor 4 but is exists at the position of the sensor 5. When the plate 2 is elevated again after it is lowered to be equal to or under the position 2 once, the state thereof is initialized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus for scanning and reading an original image and copying and recording the image on a recording medium.
In particular, the present invention relates to an image forming apparatus that controls the operation by detecting the size of a document.

[0002]

2. Description of the Related Art Conventionally, as this type of image forming apparatus,
A leaf-shaped document is placed stationary on a flat platen, and the document is sequentially scanned by a scanning optical system to irradiate a recording medium (electrostatic (photosensitive) drum, photoelectric converter, etc.) to form an image. There is a copying machine for copying and recording an image on a recording sheet.

In this type of copying machine, A3, A
Documents of various sizes, such as legal and letter, and recording paper are used outside Japan, such as 4, B4, and B5. Therefore, as illustrated in FIGS. 6 and 7, for example, the respective original size detection sensors 4 and 5 are arranged below the original platen 1 and various originals 7 are detected.
By judging the size of the copying machine, the operation of the copying machine main body, such as determining an appropriate scanning length and selecting a recording sheet, is appropriately controlled.

As the above sensors, reflection sensors 4, 5, 4a, 5a of an infrared light source are generally used, but there is a possibility that erroneous detection is performed on a low reflectance original such as a black original. Therefore, as shown in FIG. 7, the presence or absence of the document D is detected before and after opening and closing by using a switch 501 for detecting the opening and closing of the document pressing plate 2, thereby improving the detection accuracy.

[0005]

However, in the above conventional example, since the detection distance (position) 1 of each size detection sensor 4 and 5 in FIG. 7 is longer than the distance to one document table, The open / close detection switch 501 is also turned on at the time (position) m at which the document pressing plate 2 exists above the detection distance l. After the power is turned on, a change in the output of each of the size detection sensors 4 and 5 within a certain period of time is monitored to determine the document size.

Accordingly, for example, when the operator
When the original pressing plate 2 is closed and the original pressing plate 2 is stopped at a point r (position) where l <r <m for a long time, the size detection sensors 4 and 5 cannot detect the original. However, there is a problem that the document size is erroneously determined.

Further, when replacing the placed original 7 with an original of a different size, there is also a problem that if the original pressing plate 2 is lifted only to the point r2 where r2 <l, a new original size cannot be detected. I do.

SUMMARY OF THE INVENTION The present invention has been made in view of the above situation. By providing means for measuring the opening / closing amount of a document holding plate, even if the document holding plate is stopped in the middle of closing, An object of the present invention is to provide a means capable of appropriately issuing an instruction to an operator since the size can be appropriately detected and the case of opening and closing with a small movement amount that cannot be detected can be predicted.

[0009]

SUMMARY OF THE INVENTION Therefore, in the present invention, the above object is achieved by providing an image forming apparatus according to any one of the following items (1) to (3).

(1) A flat and transparent document supporting member for arranging a sheet-shaped document, a document pressing member for bringing the document into close contact with the supporting member, and a document on the side of the document supporting member facing the document arranging surface. An image forming apparatus having size detecting means, comprising means for measuring an opening amount of the document pressing member.

(2) The image forming apparatus according to (1), wherein the image forming control means controls an image forming operation based on a measurement result of the opening amount measuring means.

(3) The image forming apparatus according to (1), wherein the image forming control means controls the operation of the document size detecting means based on the measurement result of the opening amount measuring means.

[0013]

According to the configuration of the present invention as described above, it is possible to optimize the monitoring of the document detection sensor and to issue a warning outside the detectable range.

[0014]

Embodiments of the present invention will be described below in detail based on a plurality of examples.

[0015]

【Example】

(First Embodiment) FIG. 1 (a) shows a schematic configuration diagram of a first embodiment of an image forming apparatus according to the present invention. 1 is a document table made of highly transparent glass, 2 is a document pressing plate, 3 is a slide volume as a means for measuring the opening amount of the document pressing plate 2, and 4 and 5 are each infrared reflection type as document size detecting means. Sensor, 6 is an operation control unit (module),
7 is a manuscript. Reference numerals 101 to 103 denote respective positions in the course of closing the document pressing plate 2, and (b)
In the figure, ON / OFF of each sensor 4 and 5 at each position is shown.
FIG. 4 shows an OFF state transition diagram.

FIG. 2 is an enlarged view for explaining the operation of the slide volume 3. 201 is the document holding plate 2
Slide levers 202 and 203 formed of conductors that move up and down in conjunction with opening and closing of the rails 202 and 203 are slide rails formed of high-resistance conductors, respectively.
03 (between a and b), the slide lever 201
The right side changes as shown in the figure in accordance with the vertical movement of the document (ie, the opening / closing of the document pressing plate 2). Therefore, the opening amount of the document pressing plate 2 can be measured by the resistance value.

Next, an operation outline of the embodiment of the present invention will be described with reference to FIG. 3 showing an operation sequence flowchart.

First, the document 7 is placed on the document table 1 as shown in FIG. 1 by the operator (step S1). Thereafter, the operator closes the document holding plate 2 at the position of the lower portion 103 and tries to bring the document 7 and the document table 1 into close contact (step S).
2). At that time, the control unit 6 detects that the document pressing plate 2 has reached the position 1 from the output value of the slide volume 3 and determines that the document pressing plate 2 has begun to close, and starts detection by the sensors 4 and 5 (step S1). S3).

As is apparent from FIG. 1, there is no original 7 on the sensor 4 and the original 7 exists on the sensor 5. Therefore, the state of each of the sensors 4 and 5 at this time is as indicated by 101 in FIG. 1B (step S4). Further, when the document pressing plate 2 is closed and comes to the position 102 (step S5), the sensor 4 detects the reflection of the document pressing plate 2, so that the state changes as indicated by 102 in FIG.

Next, when the original pressing plate 2 is lowered to the vicinity of the position 103 (step S6), the control unit 6 stops the detection of the original sensors 4 and 5 (step S7), and FIG.
From the result of (b), there is no original 7 at the position of the sensor 4,
The presence of the document 7 at the position of the sensor 5 is detected (step S8), the corresponding paper size is selected, the scanning width of a scanning optical system (not shown) is determined, and an appropriate recording paper cassette is selected (step S8). Step S9).

At this time, the control unit 6 determines from the output of the slide volume 3 that the original pressing plate 2
The detection by each of the sensors 4 and 5 is continued until it is detected that the sensor has descended to the position 2. In addition, in step S5, after once descending to the position 102 or less, before reaching the position 103, the position is higher than the position 102 (near 101).
When it is lifted up again, the state is initialized (step S2).

(Second Embodiment) FIG. 4 (a) shows a schematic diagram corresponding to FIG. 1 for explaining another embodiment of the above description, and FIG. 4 (b) shows a transition diagram of each operation. . Corresponding elements similar to those in FIG. 1 are given the same numbers. FIG. 5 shows an operation sequence flowchart of the second embodiment.

In the copying machine, as shown in FIG. 4A, the document pressing plate 2 is once closed to the position 103, the size of the document 7 is determined by the control unit 6, and then the image is scanned by an optical system. Is copied (step S11).

Thereafter, the original 7 is transferred to the original 30 having a different size.
When the document holding plate 2 is lifted only up to the position 302 (step S13), the output of the sensor 4 is lower than the maximum detection distance 102 of each of the sensors 4 and 5 (step S12). The detection of the holding plate 2 is continued. Therefore, even if the document 7 is replaced, no change point of the output occurs, and the document size cannot be detected (step S14).

At this time, the control section 6 knows from the output of the slide volume 3 that the original pressing plate 2 has been opened to the position 302 and the original size cannot be detected, and that the original 7 may have been replaced. 4 is displayed on the display unit 303.
A warning such as 304 shown in (b) is displayed, and the continuation of the operation of the copying machine is prohibited (step S15).

When the operator lifts the document pressing plate 2 above the position 102 in accordance with this warning (step 1)
6), the controller 6 displays that the document detection has been initialized, as indicated by 305 in FIG. 4B (step S1).
7), permit operation continuation. Then, the document pressing plate 2 is closed again to the position 103 (step S1).
8) The size of the document 301 can be correctly detected (step S19).

(Third Embodiment) In the second embodiment described above, the copying operation is prohibited when the original size cannot be detected correctly. It is. Also, instead of prohibiting the operation, a sheet of a usable maximum size may be selected.

(Fourth Embodiment) In the first to third embodiments described above, the case where the slide volume 3 is used to measure the opening amount of the document pressing plate 2 has been described.
The present invention is not limited to this, but means for measuring the opening amount of the document pressing plate 2 with sufficient resolution, for example, a potentiometer mounted so as to measure the rotation amount of the mounting hinge of the document pressing plate 2 Of course, there is no harm in doing so.

[0029]

As described above, according to the present invention,
By configuring so as to measure the opening / closing amount of the document pressing plate, it is possible to optimize monitoring of the document detection sensor and perform a warning outside the detectable range.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a configuration of a first embodiment (a) and a state transition diagram of each sensor (b).

FIG. 2 is an enlarged view of a slide volume 3 of FIG.

FIG. 3 is an operation sequence flowchart of the embodiment of FIG. 1;

FIG. 4 is a schematic diagram of a configuration of a second embodiment (a) and a transition diagram of each operation / display (b).

FIG. 5 is a sequence flowchart of a second embodiment.

FIG. 6 is an explanatory view of a conventional sensor arrangement.

FIG. 7 is an explanatory diagram of a document size discriminating operation in a conventional example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 document table 2 document pressing plate 3 slide volume 4, 5, 4a, 5a each infrared reflective sensor 6 operation control unit 7 document 101, 102, 103, 302 each position 201 slide lever 202, 203 slide rail 301 document of different size 303 display unit 304, 305 display 501 open / close detection switch

Claims (3)

[Claims] 1. A flat and transparent document supporting member for arranging a sheet-shaped document, a document pressing member for bringing the document into close contact with the supporting member, and a document size on a side of the document supporting member opposed to the document arranging surface. An image forming apparatus having detecting means, comprising: means for measuring an opening amount of the document pressing member. 2. The image forming apparatus according to claim 1, wherein the image forming control unit controls an image forming operation based on a measurement result of the opening amount measuring unit. 3. The image forming apparatus according to claim 1, wherein the image forming control unit controls an operation of the document size detecting unit based on a measurement result of the opening amount measuring unit.