JPH0326592B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application This invention relates to an image scanning and recording apparatus, and more particularly to an input scanning section of an image scanning and recording apparatus that irradiates a document with light and performs photoelectric scanning with the light.

(b) Prior art An image recording device, for example, a conventional plate-making device, in which a manuscript is wound around a manuscript drum, the manuscript is irradiated with light, and a reproduced image is exposed and scanned based on an image signal obtained by photoelectrically scanning the light. In devices such as color scanners, the amount of light and wavelength range that irradiates the original is only the amount of light and wavelength range necessary for image resolution, and the infrared rays, including heat rays that are harmful to the original, are filtered out by an infrared absorption filter and the light source Use light bulbs with sufficient wattage. However, as the functions of color scanners become more diverse, it has become necessary to not only decompose pictures but also to decompose characters at the same time. When photoelectrically scanning a picture and text at the same time, the text information is smaller than the pixel area from which picture information is obtained.
It is necessary to obtain it from a pixel area of several to several tenths.
In other words, the image information was obtained by halftone dotting at the expense of resolution, thereby obtaining the shading, gradation, and hue of the image. However, text information is binary, black and white, and must not be duplicated, expressed as small dots of the same size as picture information.
For example, if the pixel area for obtaining pattern information is 5 x 5,
Text information had to be obtained by dividing it into 25 small sections.

Since it is a small section, the amount of light received by the optical sensor is, for example, 1/25, and sufficient photoelectric conversion cannot be performed with this amount of light. Therefore, it is necessary to increase the amount of light irradiated onto the original.

In general, many optical sensors have their sensitivity peak in the infrared region, and text information is binary (black and white), and since text information can be obtained from the optical sensor even in the infrared region, if the infrared cut filter is removed, A sufficient amount of light can be obtained for character information, and a sufficient amount of light can also be obtained for picture information (without using a particularly large light source). Naturally, by removing the infrared cut filter, there will be more heat rays, and conventionally the light used to irradiate documents was infrared light without heat rays, but if the same part of the document is irradiated for a long time for about 1 minute or more, the same part of the document will be It will be burnt out.

This "irradiating the same part of the document for a long time"
This occurs during normal machine preparation and when stopping after photoelectric scanning, and there is no risk of burnout during photoelectric scanning.

This concern is due to the fact that the operator has a large amount of work to do and may not necessarily be present when the rotation of the original image drum stops at the end of photoelectric scanning, or that the operator may not be present when the rotation of the original image drum stops after photoelectric scanning is completed, or that the operator may not be present when the original image drum is irradiated and basic calibration is performed. There are times when an urgent matter arises and you have to leave your post while you are at work, and basic calibration takes about a minute or more.

Therefore, the operator must be careful not to cause a burnout accident, which will have a serious negative impact on the sales of the scanner device.

(C) Purpose This invention provides an image scanning system that prevents the occurrence of document burnout accidents caused by irradiating the same part of the document for a long time due to the need to increase the light intensity of the light source in the conventional image scanning recording device. It was developed for the purpose of providing an input scanning section for a recording device.

(D) Configuration The input scanning section of the image scanning and recording device according to the present invention photoelectrically scans the original by irradiating the original loaded on the original drum with light containing infrared rays from a light source while rotating the original drum. In the input scanning unit of the image scanning and recording device that obtains an image signal by using The present invention is characterized in that a detection and timer circuit is provided for activating the light blocking means when the rotary encoder stops and no output pulses from the rotary encoder are detected for a predetermined period of time.

(e) Embodiment An input scanning section of an image scanning recording apparatus which is an embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic structural explanatory diagram showing the main parts of an input scanning section of an image scanning and recording apparatus according to an embodiment of the present invention. A document 2 is wound around the document drum 1,
In this state, it rotates at a constant speed. For the reflective original 2, a halogen light bulb 3 is installed in a part of the color separation light-receiving device 4 disposed facing the original drum 1, and the light from the halogen bulb 3 is diagonally transmitted through a condensing lens (not shown). The light is irradiated onto the original 2. The light reflected on the original is collected and color-separated by the pick-up lens of the color-separating light-receiving device 4, and the color-separated signals are sent to the electronic circuit section 10 (not shown), undergo color correction, and then are supplied to the recording section, as is conventional. That's right.

A rotary encoder 5 is installed on the rotation shaft of the document drum 1, and generates a pulse signal as the document drum 1 rotates. The pulse signal is input to the light source control circuit 6. The control circuit 6 includes a pulse signal detection circuit 7 and a timer that operates when no pulse detection signal is input from this detection circuit and outputs a relay drive signal when no pulse signal is continuously detected within a preset time. It is composed of a circuit 8. That is, while the document drum 1 is rotating at a constant speed during photoelectric scanning, a pulse signal is generated, and while the pulse signal is being detected, the timer circuit 8 is activated.
does not operate and the rotation of the drum stops when replacing the original 2 loaded on the original drum 1, when setting the electronic circuit for the reference density of the original (calibration), or when the drum drive unit has completed its work. When the drum stops for a certain period of time or more, the timer circuit 8 is activated and outputs a relay drive signal after the set period of time has elapsed. The relay circuit 9 is activated by this relay drive signal, the power supply from the power source 11 to the light bulb 3 is cut off, and the light bulb 3 is turned off. When the document drum 1 starts rotating again, the detection circuit 7 of the light source control circuit 6 detects the pulse signal of the rotary encoder 5, and the detection signal causes the timer circuit 8 to stop operating, turn off the relay circuit 9, and send the light bulb 3 to the light bulb 3. power supply will be resumed. Here, the detection and timer circuit is used as a retriggerable monostable multivibrator that outputs an output for a certain period of time when an output pulse of the rotary encoder occurs, and outputs an output for a certain period of time if the pulse occurs again during that period.
(For example, Texas Instruments SN74LS123
(equivalent).

FIG. 2 is a schematic structural explanatory diagram showing the structure of another embodiment of the present invention. In FIG. 2, the output of the timer circuit 8 of the light source control circuit 6 is configured to operate as a drive signal for the drive relay circuit 12 of the shielding plate 13. When the document drum 1 does not rotate, the shielding plate 13 blocks the optical path from the light bulb 3 to the document 2, thereby preventing the document from being irradiated more than necessary.

Needless to say, when there is a pulse from the rotary encoder, it is also possible to turn on the lamp for a certain period of time after the pulse is received, or to remove the optical path shielding plate.

(F) Effect The input scanning section of the image scanning and recording device according to the present invention is equipped with the document burnout prevention device configured as described above, so it can be used even when photoelectric scanning is not performed or when the drum drive device has completed its work. This can prevent the same part of the document mounted on the document drum from being irradiated for a long time when the document drum is stopped. Therefore, it is possible to cope with the need to increase the amount of irradiated light when trying to obtain not only images but also characters, etc. as decomposed signals, and the active use of sensors with sensitivity peaks in the infrared region, and increase the amount of light. , it is possible to prevent the accident of burning out the original due to unnecessary irradiation that is expected to occur due to the use of light in the infrared region. There is also the economical effect of not having to use a light source with a large amount of light, and it is now possible to use inexpensive lamps and sensors as light sources.

[Brief explanation of drawings]

FIG. 1 is a schematic structural explanatory diagram showing the main structure of a scanning section of an image scanning and recording apparatus which is an embodiment of the present invention, and FIG. 2 is a schematic structural explanatory diagram showing a modified embodiment. 1... Original drum, 2... Original, 3... Light bulb (light source), 5... Rotary encoder, 6... Light source control circuit, 7... Pulse detection circuit, 8... Timer circuit, 9... Relay Circuit, 12... Shielding plate drive relay circuit, 13... Shielding plate.

Claims (1)

[Claims] 1. While rotating the document drum, light containing infrared rays is irradiated from a light source onto the document mounted on the document drum, and the document is photoelectrically scanned to obtain an image signal.
In the input scanning section of the image scanning and recording device, a light blocking means is provided for blocking light irradiation from the light source to the document, and a rotary encoder is installed on the rotation shaft of the document drum, so that the document drum is stopped. An input scanning section of an image scanning and recording apparatus, characterized in that a detection and timer circuit is provided for activating the light blocking means when no output pulses from the rotary encoder are detected for a predetermined period of time. 2. A patent for a circuit in which the detection and timer circuit starts to operate when the output pulse of the rotary encoder disappears and activates the light blocking means when no pulse is detected for a predetermined period of time after the detection and timer circuit has been activated. An input scanning section of an image scanning and recording apparatus according to claim 1. 3. The detection and timer circuit begins to operate when the output pulse of the rotary encoder is generated, and when the next pulse is detected within a preset predetermined time, it starts to operate again in an update manner, and starts operating again at the preset predetermined time. 2. The input scanning section of an image scanning and recording apparatus according to claim 1, wherein the input scanning section is a circuit that activates the light blocking means when no pulse is detected across the line. 4. The input of the image scanning recording device according to any one of claims 1 to 3, wherein the light blocking means for blocking light irradiation from the light source to the document is a circuit that cuts off power supply to the light source. Scanning section. 5. Claims in which the light blocking means for blocking light irradiation from the light source to the document comprises a shield plate that is removably inserted into the irradiation optical path from the light source to the document, and a circuit that drives the shield plate. An input scanning unit of an image scanning and recording device according to any one of items 1 to 3.