JPH0797799B2 - Electronic blackboard - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electronic blackboard used as a conference record automatic creation apparatus or the like.

Conventional technology Generally, in this type of electronic blackboard, a writing surface that can be written and erased is provided for a plurality of pages on a white sheet, and the writing surface that has been written is moved to illuminate the writing surface with a fluorescent lamp or the like.
The image reflected light from the writing surface is imaged on a photoelectric conversion element, such as a CCD image sensor, via a mirror, a lens, etc.,
The image information on the writing surface is read. The read image information can be given to the printer to obtain a hard copy.

In such a sheet moving type electronic blackboard, the white sheet is exposed from the opening of the housing for the purpose of writing on the sheet surface and visual confirmation of the written content, and the back surface is kept flat by the hard back plate. To be done. Then, it is necessary to detect the position of the sheet for a hard copy of a desired page or the like, but generally, a mark is attached to each page, and this mark is detected by a photo interrupter.

However, considering the usage state on the electronic blackboard, the white sheet moves, and when that happens, there is a problem that fingers and hair etc. are caught in the opening part of the housing and move with the white sheet. There is. Even in such a case, conventionally, once the movement of the white sheet is started, the time for detecting the mark on the next page (about
The motor does not stop for 10 seconds), which is insufficient in terms of safety. On the other hand, such an abnormality in sheet conveyance may be detected by an abnormal rotation of the motor using an encoder and a photo interrupter, but in this case, the structure around the motor becomes large.

The present invention has been made in view of such a point, and immediately stops the sheet conveyance when an abnormality occurs in the sheet conveyance state due to a finger or hair being pinched, etc. The purpose is to get a blackboard.

Structure In order to achieve the above object, the present invention has a plurality of pages of writing surface formed on a sheet that can be freely written / erased, a means including a drive source for moving the sheet, and a writing surface on the moved sheet. In an electronic blackboard provided with a reading means for exposing and scanning the content of the writing surface and a means for printing the content of the writing surface that has been read, a large number formed on the sheet at a predetermined interval finer than the page interval of the writing surface. Marks, mark detection means for detecting these marks, and mark passage time determination means for determining the passage time from the detection of one mark by the mark detection means to the detection of the next mark when the sheet is moved. A sheet conveyance stopping means for stopping the driving source and stopping the feeding of the sheet when the passing time of the mark exceeds a predetermined time. It is a feature.

An embodiment of the present invention will be described below with reference to the drawings. First, FIG. 2 shows a basic structure of an electronic blackboard. A roll-up type white sheet 2 is provided in a casing 1 having a rectangular shape and having an opening 1a on the front surface. The front surface of the white sheet 2 is a writing / erasable writing surface 3.
Five pages are prepared. Both ends of such a white sheet 2 are wound around drive rollers 8 and 9 via rollers 4, 5, 6 and 7, respectively. These drive rollers 8 and 9 are pulse motors 10,
The writing surface 3 of the white sheet 2 is sequentially moved by 11 so that the white sheet 2 is sequentially driven to rotate forward and backward. Here, a back plate 12 is provided on the back surface of the white sheet 2 in the opening portion 1a. The white sheet 2 is usually wound in the left direction, and is provided with a reading means 13 for exposing and scanning the writing surface 3 at the position A where the roller 5 has passed. Specifically, the writing surface 3 is slit-exposed with a phosphor 14, and the reflected light is imaged on a photoelectric conversion element, for example, a CCD 17 via a mirror 15 and a lens 16 to be read. The image information on the writing surface 3 thus read by the CCD 17 is printed by printing means such as a thermal printer (not shown).

Here, FIG. 1 is an expanded view of the white sheet 2, and in this embodiment, the writing surface 3 is ₅ as shown by P _{1 to} P 5.
Although the pages are prepared, the fifth page P ₅ cannot be wound and moved to the exposure position A, so the writing surface 3 of the fifth page P ₅
The contents of can not be hard copied. Therefore, P ₁
Only the contents of writing surface 3 on page ₄ can be copied. A large number of marks 18 for checking the conveyance state of the white sheet 2 are formed on the writing surface 3 of the white sheet 2. That is, these marks 18 are evenly spaced apart from each other on the writing surface 3. A photo interrupter 19 is provided as mark detection means for sequentially detecting the moving state of the mark 18.

Next, the entire control circuit will be described with reference to FIG. First,
Direct memory access controller DMA21 is connected to CPU20 which is the center of control. on the other hand,
ROM22, RAM23, timer 24 are connected to the CPU20 and DMA21 by the address bus AB, data bus DB, and control bus CB, and further CCD17, thermal head 25,
The dynamic RAM DRAM26 also has respective controllers 27, 28,
Connected through 29. Therefore, the DMA21 is a CCD
While sending the image data from 17 directly to DRAM 26,
The data is directly transmitted from the DRAM 26 to the thermal head 25. Further, an I / O port 30 is connected to the CPU 20, and a fluorescent lamp controller 31 for controlling the fluorescent lamp 14, an operation unit 32, and the pulse motor are connected to the I / O port 30.
Pulse motor 33 for conveying 10, 11 and thermal paper for copying
A pulse motor driver 34 for is connected.

Here, specifically, the CCD controller 27 first amplifies the image data read by the CCD 17 from the writing surface 3 by an amplifier, performs A / D conversion by an A / D conversion circuit, and performs image processing by an image processing circuit. Then, after being binarized by the digital comparator, it is converted into an 8-bit parallel signal by the serial / parallel conversion circuit and output to the DRAM. In this way, the image data from the CCD 17 is directly stored in the DRAM 26 under the control of the DMA 21.

In such a configuration, the operation control according to this embodiment will be described with reference to the flow chart of FIG. First, when you press the copy button (or sheet transport key), the pulse motor 10
Alternatively, 11 rotates and the conveyance of the white sheet 2 is started. At this time, the CPU 20 sets the timer 24, which functions as mark passing time determination means, to a fixed time and starts the timer 24. Then, the signal from the photo interrupter 19 is taken in via the I / O port 30. Now the timer
When the first mark 18 passes through the photo interrupter 19 and the mark signal ON is taken into the CPU 20 within the set time of 24, the CPU 20 determines that the sheet conveyance is normal. Then, the timer 24 is reset again, and the signal check of the photo interrupter 19 by the next mark 18 is performed in the same manner. If one page is completed and the operation is normal, the next operation is performed.

Then, when the mark 18 does not pass the photo interrupter 19 within the set time of the timer 24 as described above and the mark detection signal is not input to the CPU 20 from the photo interrupter 19, the CPU 20 determines that the sheet conveyance is abnormal. To do. Then, by the operation of the sheet conveyance stopping means, the pulse motors 10 and 11 are stopped immediately (about 1 second) to stop the sheet conveyance, and an abnormality is displayed. Such a sheet conveyance abnormality occurs even when the operator is caught in a portion such as the opening 1a along with the moving white sheet 2 such as a finger or hair, as described above. In such cases, safety can be ensured by immediately stopping the sheet conveyance.

Here, the set time of the timer 24 set by the CPU 20 is
When the white sheet 2 is conveyed, the first mark 18 is set longer than the time it normally takes to pass the photo interrupter 19, and the next mark 18 is set shorter than the time it normally takes to pass the photo interrupter 19. . With
Such a set time can be freely set depending on the number of marks 18 and the intervals.

In this embodiment, the mark 18 is replaced by the photo interrupter 19
However, the CCD 17 for reading an image may be used as the detection means for detection.

As described above, according to the present embodiment, the photointerrupter 19 detects a large number of marks 18 directly formed on the white sheet 2 with a small interval, and always detects the marks 18 according to the detected state.
The CPU 20 monitors whether or not there is an abnormality in the sheet conveyance, and immediately stops the sheet conveyance when there is an abnormality, so that it is possible to ensure safety in the case where the operator mistakenly catches his / her finger or the like.

Effect Since the present invention is configured as described above, it is possible to finely detect whether or not there is an abnormality in the sheet conveyance state by the state check of the sheet itself, and therefore it is possible that a sheet conveyance abnormality occurs by pinching a finger or the like. It is possible to ensure safety when a trouble occurs.

[Brief description of drawings]

The drawings show an embodiment of the present invention. FIG. 1 is a front view showing a developed white sheet, FIG. 2 is a plan view showing a schematic structure of an electronic blackboard, and FIG. 3 is a whole circuit structure. The block diagram shown in FIG. 4 and FIG. 4 are flow charts showing the operation control. 2 ... white sheet, 3 ... writing surface, 13 ... reading means, 18 ... mark, 19 ... photointerrupter (detection means), 20 ... CPU

Claims (1)

[Claims] 1. A plurality of pages of writing surfaces formed on a freely writable / erasable sheet, a means including a drive source for moving the sheets, and an exposure scan of the writing surface on the moved sheet to obtain the contents thereof. In an electronic blackboard provided with a reading means for reading the reading surface and a means for printing the content of the read writing surface, a large number of marks formed on the sheet at least at predetermined intervals smaller than the page spacing of the writing surface, and these marks. Mark detection means for detecting the mark, mark passage time determination means for determining the passage time from the detection of one mark by the mark detection means to the detection of the next mark when the sheet is moved, and the passage time of the mark An electronic blackboard provided with a sheet conveyance stopping means for stopping the driving source to stop the feeding of the sheet when a predetermined time is exceeded.