JPS61278265A - Facsimile sensor unit - Google Patents

Abstract

PURPOSE:To prevent the heat of a light source from affecting a sensor and to avoid noise interference by arranging a light source in a chamber provided apart from a part irradiated with light and providing a fluorescent flat light condenser leading the light of the light source to the original face in between. CONSTITUTION:The light incident on the contact type image sensor 1 via a rod lens array 6 is projected from the light source 10 such as the light source 10 such as fluorescent light, a halogen lamp or a xenon lamp accommodated in a light source room 9 fitted to the outside of a frame 2 in the face of the original 3 via the fluorescent flat plate light condenser 11. The light source chamber 9 is surrounded by a light wall and the fluorescent flat plate condenser 11 penetrates through the light shield wall. Electromagnetic shield is applied to a barrier 13 extended to the upper part of the part 12 of the light shield wall penetrated with the light condenser and the light source chamber 9 to prevent noise generated from the light source 10 from affecting the sensor 1. Since the light source chamber 9 is spaced away from the sensor 1 and the signal amplifier section 7, the effect of the heat from the light source 10 onto the sensor and the signal amplifier section is less and it is also effective to dissipate heat by providing an air cooling fan or a water cooling pipe to the light source chamber 9.

Description

[Detailed description of the invention] [Technical field to which the invention pertains]

The present invention relates to a facsimile sensor unit that irradiates a portion of the surface of a document with light and causes an image of the portion of the document to be incident on the surface of a contact type image sensor via an optical system.

[Prior art and its problems]

The spread of facsimile has been remarkable, reflecting the recent boom in OA, and along with this, the cost has come down. There is a strong demand for miniaturization, and in response to this demand, a contact type sensor is being developed that uses a sensor of the same size as the original to form an image of the original on the sensor surface at a 1:1 ratio. If a contact type sensor is used, an optical system for reducing and projecting the image of the original document is not required, and the distance between the original surface and the sensor is about 20 m, so that the sensor unit can be made more compact. FIG. 2 is a conceptual diagram of a facsimile sensor unit using a contact type image sensor, in which an image sensor 1 is fixed to a frame 2. As shown in FIG. A document 3 can slide below the frame 2 via a guide 4. A light emitting diode (LED) array 5 for illuminating the surface of the document 3 transmits an image of the document to the sensor 1.
When a document 3 is conveyed by a document conveyance system (not shown) disposed on both sides of a rod lens array 6, which is a long lens system for forming an image on a surface of is due to the rod lens array 6,
For example, an image is formed on an image sensor 1 made up of a large number of optical sensors using A-5T. Each sensor is scanned by an analog switch IC, and sensor signals are sequentially read. This signal is input to a signal amplifier 7 and amplified into a signal of an appropriate magnitude, and the output signal is sent to a facsimile control system via a connector 8. In such a facsimile sensor unit, the more compact the shape, the closer the distance between the light source and the sensor becomes. As the light source emits light, it also emits considerable heat, which increases the temperature of the sensor and changes the temperature of the sensor or signal amplifier during document reading, affecting the magnitude of the signal. Further, in the case of long continuous operation, the sensor is exposed to a high temperature atmosphere, and therefore strict conditions are imposed on the heat resistance and durability of the sensor and the reading circuit. If the current flowing through the LED is reduced, the heat generated by the light source will be reduced, but this will cause problems such as the document surface becoming dark and the sensor signal becoming smaller. Another possible measure is to dissipate heat by placing a fan driven by a motor near the LED, for example. However, a・−5 with pln junction
When the sensor is constructed from the i-layer and a sensor array of 8 pintos/tsuru is made, the photocurrent under a 251x LED (wavelength 565 nm) is approximately 0.2 nA. When reading this signal using a storage type, it is susceptible to noise, so it is not desirable to use something that emits electromagnetic noise, such as a motor.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks, and to provide a facsimile sensor unit with good performance, in which the heat of the light source does not affect the sensor, and there is no noise interference.

[Key points of the invention]

The present invention provides the above-mentioned method by disposing a light source in a chamber provided at a distance from a portion of the document surface to which light is to be irradiated, and providing a fluorescent flat plate condenser in the middle thereof for guiding the light from the light source to the document surface. achieve the purpose of

[Embodiments of the invention]

FIG. 1 shows an embodiment of the present invention, and parts common to those in FIG. 2 are given the same reference numerals. In this case, the light that enters the contact image sensor 1 via the Rondo lens array 6 comes from a fluorescent lamp, halogen lamp, xenon lamp, etc. housed in a light source chamber 9 attached to the outside of the frame 2. Light is projected from a light source 10 onto the surface of the document 3 via a fluorescent flat plate condenser 11 . The light source chamber 9 is surrounded by a light-shielding wall, and the fluorescent flat plate collector 11 passes through this light-shielding wall. A portion 12 of the light-shielding wall on the side where the light condenser passes through and a partition wall 13 extending above the light source chamber 9 are provided with an electric tf
ffi shielding is applied to prevent noise emitted from the light source 10 from affecting the sensor 1. The light source chamber 9 contains the sensor 1. Since it is far from the signal amplification section 7, the heat of the light H10 has little effect on the sensor and the signal amplification section, but it is also possible to further provide an air cooling fan or a water cooling pipe in the light source chamber 9 to dissipate the heat from the light source. It is effective. In order to prevent the influence of heat and noise from the light source 10, it is effective to increase the distance between the light source and the sensor 1 by using a long fluorescent flat plate collector. Using the light device 11, the light source 1
By combining it with a fluorescent lamp as 0, the temperature around the sensor 1 does not rise more than about 5°C compared to the outside air when the document 3 is irradiated, and as shown in FIG. In this case, the temperature increase is significantly smaller than the temperature increase of about 30°C or more. A fluorescent flat plate collector is a sheet of glass or Brexiglass containing fluorescent organic or inorganic dye, and as shown in FIG. Some of it is absorbed by the dye 14 and emits fluorescence in the same direction. Since the refractive index of glass or Plexiglas is higher than that of air, 75% of the light is transmitted toward the sheet of the condenser 11, and the condensed light 31 comes out from the end face 15. The state of condensing light is determined by the area and thickness of the sheet of the condenser 11, and an amount of light that depends on the amount of incident light is emitted from the end surface of the sheet. For example, when a 40W fluorescent lamp is used as the light 1ixo, the illuminance of the document surface irradiated by the light from the end surface 15 is about 50001x. Fluorescent concentrators can match the wavelength of the light they output by selecting the pigment they contain.For example, in the case of the A-5i sensor, the sensitivity is high in the wavelength range of 500 to 620 nm, so it emits orange light. It is advantageous to use a fluorescent concentrator such as the one shown in FIG. Another embodiment is shown in FIG. 4, which is different from the embodiment shown in FIG.
In that the light from the fluorescent plate is guided to the surface of the document 3 by the fluorescent flat plate concentrator, the light can be guided in any direction using the four fluorescent flat plate concentrators 11. Since the light source chamber 9 was placed apart from the image sensor 1, it was sufficient to provide heat dissipation holes 17 at the top for cooling, and the sensor was hardly affected. In addition, placing the light source chamber 9 upward is particularly effective in preventing the effects of heat. Fig. 5 shows a fluorescent flat plate concentrator with good performance. The surfaces other than surface 51 are smoothed, and T i + N i,
A film with good reflectivity, such as lCr+Ag, was attached. Mass productivity can be improved by performing this vapor deposition simultaneously by stacking several fluorescent flat plate concentrators. Three end faces 5
By forming a metal film on 2.53.54 to prevent light from exiting from these end faces, the amount of light emitted from the end face 51 was increased by approximately 30%. Effects of the Invention According to the present invention, the light from the light source of the facsimile sensor unit is condensed through the fluorescent flat plate concentrator and irradiated onto the document surface, so that the heat generated by the light source can be transmitted to the sensor, for example. , it becomes possible to place the light source at a distance so as not to heat up the signal amplification section, etc., and 1! for cooling. There is no need to use a motor that emits magnetic noise, and even if a motor is used, there is sufficient room to insert an electromagnetic shield between the light source and the sensor, so the S/N ratio of the sensor can be improved. In addition, by using a dye in the fluorescent flat plate collector that generates phosphorescence with a long lifetime, the amount of light that illuminates the document surface remains constant even when the light source emits light in a vibrating mode. is possible. Furthermore, by selecting a dye, it is possible to make light at a wavelength for which the sensor has the highest sensitivity enter the document surface, and it is possible to make effective use of light. Furthermore, the light source chamber can be extended to the outside, the restrictions on the size and capacity of the light source are relaxed, and the sensor can be miniaturized.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an embodiment of a facsimile sensor unit according to the present invention, FIG. 2 is a sectional view of a conventional example, and FIG. 3 is a sectional view showing the principle of a fluorescent flat plate concentrator used in the present invention. FIG. 4 is a cross-sectional view of another embodiment of the invention, and FIG. 5 is a perspective view of another embodiment of the fluorescent flat plate concentrator. Close-contact image sensor, 2; frame, 3: original, 6: Rondo lens array, 7: signal amplifier, 9: light source chamber, 10:
Light source, 11: Fluorescent flat plate concentrator. -'1AirJ, LL mountain'l-illusion'-Go, Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1) A chamber in which a light source is provided at a distance from the part of the original surface, in which a part of the original surface is irradiated with light and an image of that part of the original is made to enter the surface of a contact image sensor via an optical system. What is claimed is: 1. A facsimile sensor unit, characterized in that the facsimile sensor unit is provided with a fluorescent flat plate condenser disposed in the middle of the condenser for guiding light from a light source to a document surface.