JPH0116070B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image display device that forms and displays an erasable image on an image carrier.

[Prior art] CRTs (cathode ray tubes) have traditionally been used as image devices that visually display image information converted into electrical signals.
Display devices and liquid crystal display devices have been put into practical use.

Among these, CRT display devices are the most commonly used and highly reliable devices, but they are used to display fine-sized characters such as those used in newspapers and magazines, especially fine characters with a large number of strokes such as kanji. Displaying the image in its original size has nothing to do with resolution. Although the text is enlarged and displayed to make it easier to read, the problem is that the number of characters that can be displayed on the screen decreases in inverse proportion to the enlargement rate, and the amount of information per screen decreases. Furthermore, if the same image is displayed continuously for a long time, the screen will be burned in and the display performance will deteriorate. Furthermore, if the screen flickers, your eyes will get tired. Next, liquid crystal display devices are display devices that have recently been put into practical use, but like CRT display devices, not only do they have insufficient resolution, but they also have the problem of being difficult to manufacture with large screens and being expensive. There is.

Therefore, the present applicant previously proposed an image display device using electrophotography as a third image display device that does not have the above-mentioned drawbacks (Japanese Patent Application No.
197410-197413). This display device reproduces and displays image information as a toner image, has excellent resolution, makes the image easy to see, can be manufactured with a large screen at a relatively low cost, and is a highly reliable device.

[Problems to be Solved by the Invention] However, image display devices using electrophotography form images by attaching toner to a belt-shaped photoreceptor and display the images.
Because it is not an electrical image display method like
Even if the displayed image is no longer needed, the image will remain displayed if you simply turn off the power. For this reason, there is a possibility that the residual image may be seen by a person other than the operator, which is a real inconvenience in terms of confidentiality. In addition, since the device is configured to visually observe the toner image by shining external light onto the photoreceptor on which the toner image has been formed, the portions of the photoreceptor that are in the shadow of the toner are directly exposed to the external light. There is a physical difference between the two parts. Therefore, if this state continues for a long time, there is a risk that adverse effects such as occurrence of image unevenness may occur during the next image formation.

[Means for Solving the Problems] In order to solve the above problems, the present invention provides an image carrier for forming an image in an image display device that maintains image display even when power supply to the device is cut off. 9, moving means 71 and 72 for moving the image carrier, and forming an erasable image on the image carrier moved by the moving means and erasing the image formed on the image carrier. image forming means 10, 16; display means 4 for displaying the image formed on the image carrier;
Switch 3 for turning off the power to the above device:
power-off) and a control means 70 for controlling the moving means and the image forming means, and when the switch is operated, the control means moves the movable image carrier to form the image. The image displayed on the display means is erased by the forming means (521 in FIG. 5).

[Function] According to the present invention, with the above configuration, when the power to the device is turned off, it is possible to protect the confidentiality of the image being displayed and to eliminate any negative influence on the next displayed image. be.

[Example] Hereinafter, the present invention will be described in detail with reference to the drawings.

1 and 2 show an example of the configuration of the image display device of the present invention, in which 1 is a vertical device exterior casing, and 2 is a display image viewing window formed with a large opening on the front plate surface of the exterior casing 1. 3 is an operation panel arranged on the upper surface of the front panel with the lower part of the front panel protruding forward; 4 is a display window glass installed in the window hole 2; 5, 6, 7, and 8 are the upper parts of the exterior housing 1; and four endless belt-shaped photoreceptor suspension instruction rollers, two each of which are disposed at the bottom, parallel to each other with their axes oriented in the left and right directions of the exterior casing, and individually supported with freely rotatable bearings; 9 indicates the four of them. It is an endless belt-shaped photoreceptor that is suspended and supported by rollers 5 to 8.

The endless belt-shaped photoreceptor 9 (hereinafter simply referred to as a belt) has a base layer made of a transparent sheet such as a polyester sheet, and a very thin layer of metal is deposited on the outer surface of the sheet to substantially maintain transparency. By imparting conductivity while leaving the metal evaporated, a photosensitive material layer (photoconductive layer) such as CdS is formed on the metal-deposited side, and the entire structure is flexible. It is suspended and supported by the four rollers mentioned above.

Among the four rollers 5 to 8, roller 5 is used as a driving roller to transmit the rotational force of motor M ₁ (not shown). At least one of the other three rollers 6 to 8, for example roller 6, acts as a belt tension roller and applies tension to the suspended belt 9. Therefore, when the drive roller 5 is rotated counterclockwise in FIG. 2 by the motor M, the suspension belt 9 rotates counterclockwise without waving, sagging, or slipping. Along with this rotation, the tension side outer surface of the belt 9 moves and passes through the display screen viewing hole 2 from the bottom to the top between the rollers 5 and 8.

Reference numeral 10 denotes a laser beam scanning type image exposure device that is fixedly arranged in a space inside the hanging belt 9, and includes a semiconductor laser oscillator 11 and a polygon mirror scanner 1.
2, an fθ lens (imaging lens) 13, a reflecting mirror 14, and a transparent plate 15. The transparent plate 15 is a horizontally long transparent flat plate made of glass or plastic, which is placed in pressure contact with the inner surface of the tensioned belt portion between the belt suspension support rollers 7 and 8 with an appropriate force.

In this image exposure apparatus 10, an intermittent laser beam L corresponding to time-series electric pixel signals supplied from a computer, an image reading device, etc. is transmitted from a semiconductor laser oscillator 11 at the front of the drawing to a rotating polygon mirror scanner 12 at the back of the drawing. It is oscillated towards. The laser beam L incident on the scanner 12 is swung in the belt width direction and is incident on the inside of the belt 9 between the rollers 7 and 8 through the path of the fθ lens 13, the reflector 14, and the transparent plate 15, and is converted into a laser beam in the belt width direction. scanned. As a result, an image is exposed by a laser beam from inside the belt, with this laser beam scanning as a main scanning and the rotational movement of the belt 9 as a sub-scanning.

Reference numeral 16 denotes a toner developing device disposed on the outer surface side of the belt portion between rollers 7 and 8. In addition, transparent plate 1
5 is disposed with its lower surface slightly protruding downward from the common tangent below the rollers 7 and 8, and is in pressure contact with the inner surface of the belt 9. The plate 15 has a belt entry side and an exit side. The end faces 15 ₁ and 15 ₂ of the belt 9 are chamfered and rounded so that the belt 9 can smoothly contact and move. Further, the transparent plate 15 prevents the belt 9 from waving, vertical movement, and vertical movement of the belt 9 caused by contact with the magnetic developing brush 35 of the developing device 16.
Improves resolution by keeping the exposure position constant.

First, after setting the required conditions such as calling up the image information and specifying the image display position by operating the buttons on the operation panel 3, when a display start command is input by key, the belt 9, which is a photoreceptor, rotates at a predetermined speed. movement begins. Laser beam scanning exposure of designated image information is then started on the inner surface of belt 9 between rollers 7 and 8. At the same time as this exposure, the developer 16
Since the toner acts on the outer surface of the belt, the belt 9
Toner images corresponding to the exposed images are sequentially formed on the outer surface of the toner image. When the toner image formed on the outer surface of the belt rotates from the bottom to the top of the two surface image viewing holes as the belt rotates and moves to the designated window hole range position, the belt 9 is rotated. will be stopped.
As a result, an image is displayed in the window hole 2, and the image is visually recognized through the display window glass 4. Next, when the belt 9 is rotated again by a belt re-rotation operation command, the next display image moves to the window hole range position, and the next screen is displayed. After the image is displayed, the toner image on the outer surface of the belt reaches the toner developing unit 16 as the belt rotates, where it is cleaned and removed by the developing brush 35, and immediately after this cleaning, it is newly exposed and simultaneously developed. A new toner image is formed by receiving the toner image. In this way, image information is reproduced and displayed as a toner image, and the image exposure is performed using a very narrow laser hole L.
This method allows for high-resolution image display that allows fine characters and other images to be displayed clearly and easily, and because it uses a simultaneous exposure toner application method, there is no need for corona charging means or special cleaning. With an extremely simple configuration that does not require any means, it is possible to configure a highly reliable display device that can be manufactured at a relatively low cost even with a large screen, and has less failure and photoreceptor deterioration.

FIG. 3 shows an example of the configuration of the control section of the device shown in FIG. 1, where 70 is a sequence controller that receives various input signals from the operation panel 3 such as specifying the start of display operation and specifying the number of pages to be displayed. Recognizes the action specified by the operator based on the
Control and manage predetermined operations. Also, the operation panel 3
In addition to the switches for setting conditions such as calling image information and specifying the display device, there are also switches SW1 to SW1.
There are SW3 and switches for power on and power off. The control switch SW1 is a switch that supports erasing of the image displayed on the photoreceptor 9.
SW2 is a switch that notifies the sequence controller 70 that the operator is using the image displayed on the photoreceptor 9;
3 is a switch that supports rotating the belt-shaped photoreceptor 9 by half a rotation in the opposite direction, and the power cut-off switch Power-OFF is connected to the sequence controller 70.
This is a switch that cuts off the power through the 71 is a driver (drive circuit) for a roller drive motor (M ₁ ) 72 that drives an endless belt-like photoreceptor (belt) 9; 73 is a driver for a developer motor 74 that drives a developing sleeve (developing brush) 35; +
Apply a developing bias voltage of 200V to +300V to the developing unit 16.
The drivers 71 and 73 and the developing bias circuit 75 are turned on/off (on/off) by control signals from the sequence controller 70.

The output signal HP of a home position sensor 63, such as a photo encoder, which is directly attached to the drive shaft 53 of the drive roller 5 (see FIG. 2) is supplied to the sequence controller 70 as a position detection signal of the belt-shaped photoreceptor 9, respectively. Based on the reception of these signals BCLK and HP, the sequence controller 70 determines the drive timing of each drive section 71, 73, and 75, and performs appropriate sequence control. The output signal HP at this time indicates the reference position of the display page portion of the photoreceptor 9, for example, the tip position. Therefore, for example, if the light shielding plate of the sensor 63 rotates once for each rotation of the belt-shaped photoreceptor 9, and it is possible to write two pages on the photoreceptor 9, the rear part of the light shielding plate is Two locations are provided at intervals, so that the signal HP is 2 for each rotation of the light shielding plate.
Make sure that the output is emitted.

76 is a scanner driver that drives the scanner 12 that scans the laser beam from the laser oscillator 11 in the main scanning direction;
A signal indicating whether or not 2 is rotating at a constant rate.
SCNRDY is supplied to the sequence controller 70. 77 is a laser driver that drives the laser oscillator 11, and a signal indicating whether or not the laser oscillator 11 has an abnormality such as a temperature control abnormality.
The LaserRDY signal is supplied to the sequence controller 70.

78 is an unblanking signal ANB used to emit laser light in a non-image area in the main scanning direction.
unblanking signal generation circuit that generates 79
detects the laser beam and outputs the laser beam detection signal BD
The unblanking signal generating circuit 78 outputs external equipment (not shown) such as an image reading device or an external storage device according to the detection signal BD from the beam detector 79. Generates a synchronization signal Hsync used to synchronize the video signals transmitted from the main scanning direction. Therefore, the above-mentioned unblanking signal ANB is supplied to the laser driver 77 via the OR gate 80 together with the video signal. Furthermore, the unblanking signal generation circuit 78 also performs detection operations such as detection of synchronization deviation of scanning in the main scanning direction based on the detection signal BD of the beam detector 79, and supplies the detection signal BDRDY to the sequence controller 70.

Furthermore, the sequence controller 70 is also supplied with an interface signal for communication connection with an external device, and can exchange commands or data with the external device.

Reference numeral 81 is a breaker that turns off the power in response to a power cut instruction signal, and its support signal is generated by the sequence controller 7 based on a power on release signal generated when the power cutoff switch Power-OFF on the operation panel 3 is pressed.
Supplied from 0.

FIG. 4 shows a subroutine of the operating procedure of the apparatus shown in FIG. 3 when image display is supported. first,
If there is an instruction to call up the image information from the operation panel 3, after turning on each motor 72 and 74 and the developing bias voltage (step 401), it is used to distinguish between a half rotation and a single rotation of the belt-shaped photoreceptor 9. Flag F in the sequence controller 70 is set to "0" (step 402). If the home position signal HP generated in response to the rotation of the belt-shaped photoreceptor 9 is received (step 403),
Counting of the number of pulses of the belt clock signal BCLK is started (step 404). Then,
If neither the image erasing switch SW1 nor the power cutoff switch Power-OFF on the operation panel 3 is pressed (step 405), the count of the belt clock signal BCLK reaches a predetermined value n1 indicating the image writing reference position. Wait (step 406).

When the belt clock signal BCLK is counted up to a predetermined value n1, a video signal output command is sent to an external device (step 407), and the received video signal is written on the page portion of the belt-shaped photoreceptor 9 (step 408). Next, the belt clock signal
Counting of the belt clock signal BCLK and image writing are continued until the count number of BCLK reaches a predetermined position n2 indicating the end position of image writing, and when the count number reaches the predetermined position n2 (step 409), the above-mentioned belt The writing process to the photoreceptor 9 is completed.

Next, if switch SW1 or Power-OFF is not pressed (step 410), the rotation of each motor 72 and 74 is stopped, the application of the developing bias voltage is stopped (step 413), and a write end signal is transmitted to the external device. (Step 41)
4) Return to the main routine shown in FIG. 6, which will be described later, and proceed to the next operation. As a result, the instruction image processing is completed, and an image is displayed on the belt-shaped photoreceptor 9.

On the other hand, if the image erasing switch SW1 or the power cutoff switch Power-OFF is pressed, the above-mentioned step 405 becomes an affirmative decision, so the process jumps to step 409 and continues to step 408 until the count number of the belt clock signal BCLK reaches n2. Process. However, in this case, since the external device is not requested to output a video signal, step 408
By the writing process, one page of the displayed image on the belt-shaped photoreceptor 9 is erased. Here, in this example, since the number of possible display image pages is assumed to be 2, further steps 410 to 411 are performed.
It is determined whether the flag F is "1" or not, and if the determination is negative, it is determined that the display image erasure of the entire circumference of the belt-shaped photoreceptor 9 has not been completed.
After the flag F is reset to "1" in step 412, the process returns to step 403 and the above-described process is repeated. After that, in step 411, it is determined that the flag F is "1", so it is determined that the belt-shaped photoreceptor 9 has rotated once, and the process proceeds to step 413, and the process proceeds to the next step 41.
After performing the process in step 4, the process returns to the main routine shown in FIG. 6, which will be described later, and proceeds to the next operation. As a result, the belt-one-rotation screen erasing process is completed, and all display images written on the belt-like photoreceptor 9 are erased.

Further, as will be described later, when the timer has elapsed for a set time, the process jumps from step 405 to step 409, and the count number of the belt clock signal BCLK is
The process in step 408 is performed to form one page of non-image surfaces until n2 is reached, and when the count reaches n2, the process advances to step 410. Since it is not necessary to rotate the belt-shaped photoreceptor 9 once, a negative determination is made in step 410, and after performing the processing in steps 413 and 414, the process returns to the main routine shown in FIG. 6, which will be described later, and moves on to the next operation. do. This completes the belt half rotation non-screen display process, and the non-screen portion of the belt-shaped photoreceptor 9 is displayed.

FIG. 5 shows a subroutine of the operating procedure of the apparatus shown in FIG. 3 when a reverse half-rotation instruction for rotating the belt-shaped photoreceptor in the opposite direction is given. First, if there is an instruction from the operation panel 3 to rotate the belt-shaped photoreceptor 9 by half a rotation in the opposite direction, the roller drive motor 72 and developer motor 74 are turned on and rotated in the opposite direction, and the developing bias power is turned on to the developer 16. (step 421). Next, the system waits until the home position signal HP is generated (step 422).
Belt clock signal depending on the reception of that signal HP
Start counting the number of BCLK pulses (step 423).

When the count number of the belt clock signal BCLK reaches a predetermined value n3 indicating the position of the belt-shaped photoreceptor 9 half a rotation in the reverse direction (step 424), it is determined that the belt-shaped photoreceptor 9 has rotated half a rotation in the opposite direction. Then, the rotation of the motors 72 and 74 and the application of the developing bias voltage are stopped (step 425), and the process returns to the main routine shown in FIG. 6, which will be described later, to proceed to the next operation. This completes the belt reverse half-rotation image display process, which will be described later, and the original screen is displayed on the display window 2 as it is. In addition, the count number n3 mentioned above
The following relationship exists between and n2.

n3=n-n2 However, n is the first home position signal HP
indicates the number of pulses of the belt clock signal BCLK that occur between the generation of the home position signal HP and the next generation of the home position signal HP.

FIG. 6 shows the main routine of the operating procedure of the apparatus shown in FIG. First, after turning on the power, set the device to its initial state (step 501), and then turn on the operation panel 3.
Steps 502 to 507 for monitoring input from
Move to the main loop. That is, it is determined whether there is an instruction to call up the image information (step 502), it is determined whether the image deletion switch SW1 is on or not (step 503), and the image use switch is
Determining whether SW2 is on (step 504),
Determine whether reverse half-rotation switch SW3 is on or not (step 505), power cutoff switch Power-OFF
is on (step 506), and whether or not the timer T in the sequence controller 70 has exceeded the time set in the memory M are sequentially performed.
Returning to step 02, the above-described main loop determination process is repeated until one of the steps becomes an affirmative determination. Thereafter, when an instruction to display an image is received from the operation panel 3 (step 502), the subroutine shown in FIG. 4 is executed to display the instruction image (step 511).
Next, after setting a predetermined time T1 in the memory M in the sequence controller 70 (step 512), the above-mentioned timer T is cleared to zero and time measurement is started (hereinafter referred to as clear start) (step 513). ), the process returns to step 502 of the main loop. In this state, the image remains displayed.

When the image erasing switch SW1 is pressed (step 503), the entire photoconductor shape is erased during one rotation of the belt-shaped photoconductor 9 by repeating the processing procedure of steps 403 to 409 of the subroutine shown in FIG. 4 twice. Erase the display screen (step 521),
Then, after stopping the timer T (step 522), the process returns to step 502 of the main loop. At this time, no image is formed on the belt-shaped photoreceptor 9.

When the image use switch SW2 is pressed (step 504), if the timer T is in operation, it is cleared to zero, and time measurement starts again. If the timer T is stopped, it is cleared to zero, and remains stopped ( At step 531), the process returns to step 502 of the main loop to monitor key input.

When the reverse half-rotation switch SW3 is pressed (step 505), the belt-like photoreceptor 9 is rotated in the reverse half by executing the subroutine shown in FIG. 5, and the previous page formed on the photoreceptor 9 is The image of M is displayed again (step 541), and then the image of
After setting the predetermined time T1 to (step 54)
2) Clear and start timer T (step 543), and return to step 502 of the main loop.

When the power cutoff switch Power-OFF is pressed (step 506), the belt-shaped photoreceptor 9 is rotated once to erase the image by executing the subroutine shown in FIG. 4 (step 551), and then the breaker 8 is turned off.
1, the power is turned off (step 552).

If the timer T exceeds the time set in the memory M (step 507), the belt-shaped photoreceptor 9 is removed by executing the subroutine shown in FIG.
to display the non-image plane (step 56).
1) If the contents of memory M at this time are T1 (step 562), after changing the contents of memory M to T2 (step 563), clearing and starting timer T (step 564), and starting the main loop. Return to step 502. On the other hand, the contents of memory M are T
If not 1, after stopping timer T (step 565), the process returns to step 502 of the main loop. At this time, just before the timer T reaches the time set in the memory M, the operator is notified by light or sound that the time-up is near (not shown).At this time, if switch SW2 is pressed, the timer T will start again. Start timing from the beginning.

In this embodiment, two pages of images can be displayed per belt rotation, but it is of course possible to display images of a larger number of pages. In this case, the "half rotation of the belt" in the description of this embodiment may be changed to "one rotation of the belt per number of pages" (see steps 541 and 561).

[Effects of the Invention] As explained above, according to the present invention, by erasing the image formed when the power switch is turned off, it is possible to protect the confidentiality of the displayed image, and to eliminate the negative influence on the next image display. It becomes possible to do it.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an example of the external appearance of the image display device of the present invention, FIG. 2 is a sectional view showing an example of the internal configuration of the device shown in FIG. 1, and FIG. 3 is a configuration of the control section of the device shown in FIG. 1. FIGS. 4 to 6 are flowcharts showing examples of the operation of the control section shown in FIG. 3, respectively. 1... Device exterior casing, 2... Display image viewing hole (display window), 3... Operation panel, 4... Display window glass,
5... Drive roller, 6... Belt tension roller, 7, 8... Endless belt-like photoreceptor hanging support roller, 9... Endless belt-like photoreceptor (belt), 10
...Laser beam scanning image exposure device, 11...
... Semiconductor laser oscillator, 12 ... Polygon mirror scanner, 13 ... fθ lens (imaging lens), 1
4...Reflector, 15...Transparent plate, 16...Toner developer, 35...Magnetic developing brush, 56
... Belt clock sensor, 63 ... Home position sensor, 70 ... Sequence controller, 71 ... Roller drive motor driver, 72 ...
...Roller drive motor ( _M1 ), 73...Developer motor driver, 74...Developer motor ( _M2 ), 75
...Development bias circuit, 76...Scanner driver, 77...Laser driver, 78...Unblanking signal generation circuit, 79...Beam detector (horizontal synchronization signal generation circuit), 80...OR gate, 81... Breaker, HP...home position signal, BD...beam detector signal,
SCNRDY……Scanner rotation detection signal, Laser
RDY...Laser status signal, Hsync...Synchronization signal,
ANB...Unblanking signal, SW1...Image erase switch, SW2...Image use switch,
SW3……Reverse half-rotation switch, Power-OFF……
Power erase switch.

Claims (1)

[Scope of Claims] 1. An image display device that maintains image display even when power supply to the device is cut off, comprising: an image carrier for forming an image; a moving means for moving the image carrier; image forming means for forming an erasable image on an image carrier moved by the moving means and erasing the image formed on the image carrier; displaying the image formed on the image carrier; a switch for turning off the power to the apparatus; and a control means for controlling the moving means and the image forming means, and the control means, when the switch is operated,
An image display device characterized in that the image carrier is moved by the moving means and the image displayed on the display means is erased by the image forming means.