JPH04200062A - Electronic blackboard - Google Patents

Abstract

PURPOSE:To allow the check of the change in the luminous flux quantity of a fluorescent lamp in accordance with a detected temp. by disposing a temp. detecting means which detects the ambient temp. of the machine in the electronic blackboard near the fluorescent lamp. CONSTITUTION:A temp. sensor 24 (thermistor) as the temp. detecting means is disposed near the fluorescent lamp 6. This temp. sensor 24 has the function of detecting the ambient temp. of the machine disposed in the electronic blackboard. The ambient temp. of the fluorescent lamp 6 having the luminous flux rising characteristic at which the luminous flux quantity at the time of power source on changes largely according to the ambient temp. is detected by the temp. sensor 24. The change in the luminous flux quantity of the fluorescent lamp 6 is known in this way in accordance with the detected temp.

Description

[Detailed description of the invention] Industrial applications The present invention relates to an electronic whiteboard.

2. Description of the Related Art The structure of an example of a conventional electronic blackboard will be explained based on the top view of FIG. A screen 1 is placed on a contact glass 2 in front of the electronic blackboard, and both ends of the screen 1 are wound up by take-up rollers 3 and 4 provided on the left and right sides, so that the screen 1 is shaped like an arrow. It is in a state where it can move in both directions. Further, a reading optical system 5 is provided between the left and right take-up rollers 3 and 4. The reading optical system 5 includes a fluorescent lamp 6, a mirror 7, a lens 8, and a CCD 9. Further, a reflective sensor 10 for detecting the page on the screen 1 is attached to the front surface of the electronic blackboard.

In such a configuration, the image on the screen 1 passes through point A, so that the light from the fluorescent lamp 6 is irradiated onto the screen 1, and the reflected light is detected by the CCD 9 via the mirror 7 and lens 8. The image information is thereby obtained.

The image information from the CCD 9 is processed as image data and then stored in a DRAM (not shown). Thereafter, the image data in the DRAM is sent to the thermal head 11 (see FIG. 1) and output as an image on thermal paper (not shown).

Problems to be Solved by the Invention FIG. 5 shows the "luminous flux rise characteristics" of the fluorescent lamp 6 used as a light source for the electronic blackboard as described above.

As can be seen from FIG. 5, the amount of light is low and unstable for 1 or 2 minutes when the power is turned on, and thereafter it becomes stable (indicated by P in FIG. 5).

In conventional electronic whiteboards, the optical system is adjusted in a state where the fluorescent lamp 6 is stable without considering the rise characteristics of the fluorescent lamp 6 when the power is turned on. For this reason, when copying immediately after turning on the power first thing in the morning in the winter, the amount of light around the fluorescent lamp is not stable, so the amount of light does not rise, resulting in black streaks etc. on the copy paper. There was something to do. However, since the fluorescent lamp 6 stably goes out after 2 to 3 minutes after the power is turned on, the black streak remains as it is without taking any action in normal cases.

Furthermore, when a fluorescent lamp 6 having such a luminous flux rise characteristic is used in a copying machine, there is a method of installing a heater around the bulb of the fluorescent lamp 6 to keep the ambient temperature constant. On a blackboard, the length of the fluorescent lamp 6 is longer than that on a copy machine (usually a 1000 mm fluorescent lamp 6 is used)
Therefore, if a heater is installed around the tube of fluorescent lamp 6,
This will result in a significant increase in costs.

Means for Solving the Problem Therefore, in order to solve such problems, claim 1
The invention described above includes a screen having a writing surface of a plurality of pages that can be written and erased, a drive control unit that controls the movement of the screen, a reading means that scans the writing surface on the screen with exposure light to read the contents, and the In an electronic blackboard equipped with a printing means for printing the read contents of the writing surface on paper, a temperature detection means for detecting the ambient temperature of the machine inside the electronic blackboard is disposed near a fluorescent lamp.

In the invention set forth in claim 2, in the invention set forth in claim 1, a time measuring means for measuring the elapsed time from the time when the power source is switched on is provided, and the light amount of the fluorescent lamp is calculated and the accumulation time of the reading means is made variable. A storage time variable means is provided.

In the invention according to claim 3, in the invention according to claim 2, the moving speed of the screen in the sub-scanning direction is changed in conjunction with a change in the storage time of the reading means, so that the reading density in the sub-scanning direction is constantly maintained. A reading density holding means is provided to keep the reading density constant.

In the invention according to claim 1, the ambient temperature of a fluorescent lamp having a luminous flux rise characteristic in which the amount of luminous flux at power-on changes greatly depending on the ambient temperature is detected by using a temperature detection means. Changes in the luminous flux of fluorescent lamps can be determined based on the measured temperature.

In the invention as claimed in claim 2, the time measuring means can be used to measure the time from the start of lighting until the stable state is reached, and the accumulation time variable means can be used to change the accumulation time of the reading means. When the light intensity of the lamp is low, the accumulation time is increased, so that the white peak accumulation time can always be kept at a constant value.

In the third aspect of the present invention, the resolution of the image on the screen can be further increased by changing the moving speed of the screen in the sub-scanning direction using the reading density holding means.

Embodiment An embodiment of the present invention will be explained based on FIGS. 1 to 4. The basic configuration and operation of the electronic whiteboard shown in FIG. 2 have been described in the prior art (see FIG. 6);
Explanation of the same parts will be omitted, and the same reference numerals will be used for the same parts.

First, the overall circuit configuration of the electronic whiteboard will be outlined based on FIG. 1. The circuit of this device is roughly divided into a reading means 11 for scanning the writing surface 1a on a screen 1 having a plurality of pages of writing surface 1a that can be written and erased with light to read the contents, and a reading means 11 for controlling the movement of the screen 1. It is composed of a drive control section 12 and a printing means 13 that prints the contents of the writing surface 1a read by the reading means 11 on a sheet (not shown).

The reading means 11 mainly includes a fluorescent lamp 6, a lens 8, and a CC
It is composed of a D9, a CCD drive circuit 14, and the like.

The drive control section 12 mainly includes a CPtJ 15, a DMA controller 16, a ROM 17.5-RAM 18, a motor 19, a sensor group 20, an operation section 21, and the like.

The printing means 13 mainly includes a thermal head 11 having a thermistor 22, a printing timing generation circuit 23, and the like.

Further, this device is provided with means having various functions as shown below. A temperature sensor 24 (thermistor) serving as temperature detection means is arranged near the fluorescent lamp 6. This temperature sensor 24 has the function of detecting the ambient temperature of the machine disposed inside the electronic whiteboard.

Furthermore, a time measuring means, a storage time varying means, and a reading density holding means (not shown) are provided.

In this case, the time measuring means functions to measure the elapsed time from when the power source is switched on. Further, the accumulation time variable means has the function of calculating the light amount of the fluorescent lamp 6 and making the accumulation time of the reading means 11 variable. Furthermore, the reading density holding means changes the moving speed of the screen 1 in the sub-scanning direction S (main scanning direction M) in conjunction with the change in the accumulation time of the reading means 11, and
Its function is to always keep the reading density constant.

FIG. 3 shows a developed view of the screen 1 and the take-up rollers 3 and 4 that take it up. In this case, screen l has five pages in total, of which pages 1 to 4 can be copied, but the fifth page 25 cannot be copied because it cannot be moved to point A in Figure 2. It is possible. The mark 26 on the top surface of the screen l is used to identify the page by the reflective sensor 10. In this case, since the first page is searched when the power is turned on (initialization), the mark is long so that only that one page can be identified from other pages.

In such a configuration, the operation of this circuit will be explained based on FIG. First, when a power switch (not shown) is turned on, a timer (not shown) built into the CPtJ15 starts counting.

Next, the temperature sensor 24 placed near the fluorescent lamp 6 measures the ambient temperature of the machine. The temperature sensor 24
The temperature measured by is input to the A/D converter 27, then digitized and sent to the CPU 15. As a result, the CPU 15 detects the ambient temperature of the fluorescent lamp 6,
The time measurement means measures the elapsed time of the timer from the power switch on, and the accumulation time variable means calculates the specific luminous flux using the fluorescent lamp luminous flux rise characteristic shown in FIG. The signal that determines the accumulation time of one line is determined and numbered accordingly, and the timing of L Y N S C is adjusted based on the ambient environmental temperature and the time obtained from the timer. , Figure 4 shows the standard Glock (CCD9) and L'!
' This is a timing chart showing the relationship with NSC.

Next, CpH5 is LYN
The motor is driven by changing the excitation time of a stepping motor (not shown) (on the winding roller 3 side) corresponding to the change in SC time.

Similarly, in the case of copying the second and subsequent sheets, the environment temperature and the elapsed time since the power was turned on are checked first, and then the same operation as in the case described above is repeated.
A constant amount of light is always input to the CCD 9 even if the environmental temperature changes.

As described above, by using the temperature sensor 24 to detect the ambient temperature of the fluorescent lamp 6, which has a luminous flux rise characteristic in which the amount of luminous flux when the power is turned on changes greatly depending on the ambient temperature,
Based on the detected temperature, changes in the amount of luminous flux of the fluorescent lamp 6 can be known.

In addition, by measuring the time from the start of lighting to entering a stable state using a time measuring means, and changing the accumulation time of the reading means using an accumulation time variable means, the fluorescent lamp 6
When the amount of light is low, the accumulation time is increased, thereby making it possible to always keep the white peak accumulation time at a constant value.

Furthermore, by changing the moving speed of the screen 1 in the sub-scanning direction B using the reading density holding means, it becomes possible to further increase the resolution of the image on the screen 1.

Effects of the Invention The invention as set forth in claim 1 provides a screen for marking the writing surface of a plurality of pages that can be written and erased, a drive control section for controlling the movement of the writing surface, and a screen for exposing and scanning the writing surface on the screen to read the contents thereof. and a reading means for reading the content of the written surface read by the reading means on paper 1. In an electronic blackboard equipped with printing means for printing characters such as By using a temperature detection means to detect the ambient temperature of a fluorescent lamp, which has a luminous flux rise characteristic that causes a large change in luminous flux when the power is turned on, changes in the luminous flux of the fluorescent lamp can be detected based on the detected temperature. It is something that can be known.

The invention according to claim 2 is the invention according to claim 1,
A time measuring means is provided to measure the elapsed time from when the power is switched on, and an accumulation time variable means is provided to calculate the amount of light from the fluorescent lamp and vary the accumulation time of the reading means. It is possible to measure the time from the start until reaching a stable state, and by changing the accumulation time of the reading means using the accumulation time variable means, the accumulation time is shifted to a longer time when the fluorescent lamp has a low light intensity, thereby reducing the white peak. This allows the accumulation time to always be kept at a constant value.

The invention according to claim 3 is the invention according to claim 2,
A reading density holding means is provided which changes the moving speed of the screen in the sub-scanning direction in conjunction with changes in the storage time of the reading means and keeps the reading density in the sub-scanning direction constant at all times. By using this method to change the speed at which the screen moves in the sub-scanning direction, the resolution of the image on the screen can be further increased.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment of the present invention, Fig. 2 is a top view showing the external configuration of the device, Fig. 3 is a front view of the screen, Fig. 4 is a timing chart, and Fig. 5 is a fluorescent FIG. 6 is a characteristic diagram showing the lamp luminous flux rise characteristic, and is a top view showing the external configuration of a conventional electronic blackboard. DESCRIPTION OF SYMBOLS 1... Screen, 1a... Writing surface, 6... Fluorescent lamp, 11... Reading means, 12... Drive control part, 13
...Printing means, 24...Temperature detection means Applicant: Ricoh Co., Ltd., 'Th-lips,' Attachment, %Z replacement J, 3s, %5s, 56

Claims (1)

[Scope of Claims] 1. A screen having a writing surface of multiple pages that can be written and erased, and a drive control unit that controls the movement of this screen;
In an electronic blackboard comprising a reading means for scanning the writing surface on the screen with exposure to read the contents, and a printing means for printing the read contents of the writing surface on paper, a machine inside the electronic blackboard is provided. An electronic whiteboard characterized in that a temperature detection means for detecting the ambient temperature of the computer is disposed near a fluorescent lamp. 2. A claim characterized in that a time measuring means is provided for measuring the elapsed time from when the power source is switched on, and an accumulation time variable means is provided for calculating the amount of light of the fluorescent lamp and varying the accumulation time of the reading means. The electronic blackboard described in 1. 3. A reading density holding means is provided which changes the moving speed of the screen in the sub-scanning direction in conjunction with changes in the storage time of the reading means and keeps the reading density in the sub-scanning direction constant at all times. The electronic blackboard according to claim 2.