JPS58157252A - Picture reader serving also as light source for picture formation - Google Patents

Abstract

PURPOSE:To attain the recording and reproduction of a picture at high speed and with miniaturized size, by providing a means for emitting a light emitting diode array with an external electric signal and a means for outputting an electric signal corresponding to the light received by a light emitting diode. CONSTITUTION:In using a light emitting diode LED array as a light source for picture formation, a mode changeover switch SW2 is turned to the GND position to bring a level of a clear terminal 3 to a drive circuit 5 to L. When the level of a chip selection terminal 4 is H, an output Ai(i=1-n) of a scanning circuit 7 goes to H sequentially at each 1CK of a clock CK inputted to a terminal 6. When a picture signal is inputted from a terminal 8, a forward current flows to an LED12-i via an FF9-i and an SW10-i to light the LED sequentially. In reading the image of an original, the SW2 is switched to the power supply side and the terminal 3 goes to H, then no LED is emitted and a charge is given. When the level of the terminal 4 goes to H and the CK is given to the terminal 6, an SW13-i is turned on sequentially with the output Ai of the circuit 7, and when light is irradiated on the LED, the discharge current due to the charge is amplified 15 in response to the amount of light and is outputted as a picture signal.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention has a function of reading a document image and converting it into an electrical signal;
A device for an image forming light source and rigid image reading scissors device used for both functions of forming C1jl in accordance with electrical signals.

In recent years, with the development of facsimiles, etc., it has become possible to convert the original image into an electrical signal and transmit it via communication circuit III, or to store it in a memory device and reproduce it as needed. ing.

In these devices, it is common practice to independently provide means for reading an original image to obtain an electrical signal and means for printing in accordance with the electrical signal. Line image sensors such as COD are widely used as means for reading original images. This is generally 2 to 3 microbes in length, and in order to read a document with a width of several 101, it is necessary to use a lens.

A line image sensor that projects at a reduction ratio of about 10:/
The line image sensor is electrically scanned in the longitudinal direction, and the line image sensor is mechanically moved relative to the direction perpendicular to the Kmm scanning force direction. is required, which has the disadvantage that the device becomes bulky. In order to eliminate the need for such a large screen, attempts have been made to make the size tc of the image sensor the same as the length of one side of the document. If the image sensor is the same size as one side of the document, it may be scanned in close contact with the surface of the document via a F6/(- plate, for example), or it may be imaged by a converging Rondre/Z array, etc. This also eliminates the need for large dark signals.As such an image sensor, a light receiving element array 1 consisting of about 1000 light receiving elements is made of CdS, SeT, etc., and each light receiving element t is It is possible to use a sensor connected to the driving IC.However, these sensors require wire bonding in the same number as the number of light receiving elements, making them expensive, and they also have the disadvantage of being prone to failure, such as the need for bonding. was there.

Devices that print according to electrical signals include thermal recording printers, electrostatic recording printers, laser beam printers, light emitting diode printers, and the like. Among these, laser beam printers and light emitting diode printers, which form grains by exposing the photoreceptor of an electrophotographic device to laser beams or light emitting diode printers, are excellent products that can print on plain paper at high speed and high power. It is. In particular, light emitting diode printers have the advantage of being smaller than laser beam printers, but have the disadvantage that the light emitting diode printers used therein are expensive. This is because it is necessary to connect each diode of the light emitting diode array to the drive IC'i' by wire bonding, which increases the price. On the other hand, as described above, these reading devices and printing devices are generally provided independently, but if the internal devices can be shared, it is possible to make the device large, inexpensive, and compact.

Conventionally, in laser beam printers, a light source for reading manuscripts and an m+
I share the light source t for forming shadows. In other words, an example is known in which a laser scanner* is shared by both parties. When used as a printer, the electrophotographic photoreceptor is scanned by a laser beam, and when used as an image reading device, the optical path is changed using a baller, etc., and the original S surface is scanned with a laser beam. A light receiving device installed near the reflected light vms at the point sequentially receives the light to obtain an electrical signal.

In this method, if a semiconductor laser is used as the laser, the visible original image may not be read correctly because the light emitted by the semiconductor laser is near-infrared light. For example, even if the document has shading in visible light,
Near-infrared light may not have any shading, so it cannot be read correctly.

The same is true for Cape Baguchi, whose manuscript is in red. Therefore.

A large and expensive gas laser must be used.

Not suitable for small devices.

Even if a light emitting diode (hereinafter referred to as LED) array is used, the LED can be used as both the light source for image formation and the light source for image reading in a similar manner.

However, when using an LED as a reading light source,
When using an LED, the emission intensity of the LED is lower than that of a laser, so high-speed reading cannot be performed.

In the laser beam printer, seven laser beams sequentially scan the entire surface of the photoreceptor 11. On the other hand, in LED printers, the light emission intensity of the LEDs is weak, so
- 1ooo or tsoo arranged in columns.

By driving multiple LEDs simultaneously, the amount of light necessary for printing is ensured. However, when using 5K LEDs for reading a document, it is not possible to obtain a signal corresponding to each point on the document unless the LEDs t' are sequentially lit. Furthermore, in this case, since the emission intensity of the LED is weak, the time required to read the document is several thousand times longer than when a laser is used.

The object of the present invention is to eliminate the drawbacks of the above-mentioned prior art, and to be compact and low-cost, the device of the present invention consists of one light emitting diode playback and one driver circuit for driving it. but.

This driver circuit includes means for supplying electric current rILt in the layer direction to one light emitting diode based on an electric signal applied from the outside, causing the light emitting diode to emit light, and using the light emitting diode as a light source for image formation. The array acts as a photodiode.

It has a means for extracting an electric signal corresponding to the light received by the light emitting diode and using it as an element for the castle.

The present invention will be explained below with reference to the drawings.

Figure Jli1 shows an example of a circuit based on the present invention.

iii. When using the LED array as a source for forming skin, set the mode changeover switch to the ground side (GND) and set the clear terminal 3 (hereinafter referred to as CL terminal) to the L (non-operating) state. The chip select terminal 4t (hereinafter referred to as the C8 terminal) is used when multiple driver circuits like the one shown here are used in parallel, and the input or output image signal is connected to the driver circuit! It is set to the H (active) state when it relates to the I and ED arrays belonging to the . c.
When the s terminal is H, when a clock is input from the terminal B (hereinafter referred to as CK terminal), the outputs of the scanning circuit At5Az, . . .
Only books are H. At this time, when the image signal is input from the ifI signal input terminal, the D7 rig 7a knob 9
The image signal at the time when the output A1 becomes H is set to the - quantity, and when the image signal is H, the MOS switch A/a-t is turned on and the light emitting diode l code is turned on via the current limiting resistor //-1v. I is lit. Since the light emitting diode that is turned on continues to be turned on until the first data is set, exposure for a long time, that is, the -scan opening period is possible. As a result of the above, all the light emitting diodes are lit according to the image signal.

Hara S Kent/When reading, switch the mode switch to the electric key side and set the CL terminal to 3ftH. As a result, all the D flips 70 are reset, and the MO8 switch A (10-7 to 10-!1) is turned off. The light emitting diode does not emit light because it is connected to a positive power source.

**When used for formation, set the KC8 terminal 'lkH to both sides,
When a clock is input to CK 1, MO8 switch B
(symbol /J-/~/j-n) is the output AI of the scanning circuit
The light emitting diodes 12-/~/ are turned on sequentially by
A unidirectional voltage of λ-nKII is applied. As you know, when you apply a reverse voltage to a light emitting diode.

No current flows, and the light-emitting diode acts as a microcapacitance capacitor and is charged with electric charge. When a charged light emitting diode is irradiated with light, the charge is discharged according to the amount of light. When the MOS switch B/j-1 is turned on next time, the light emitting diode array I is charged with the amount of t discharged from the previous charging up to that point. The amount of charge charged at this time is the current detection resistor/amplifier
1ii
It is output as an IR signal. This operation is a well-known MO
B image sensor and 1'81.

According to the above structure, according to the present invention, the light emitting diode playback can be used as a light source for image formation and also as a lTi1g1 scraping device I (image sensor) by changing the driving circuit 4r''. I can do things.

Here, a driver circuit that performs the above type of operation.

It is composed of 7 integrated circuits, so one light emitting diode array and the number of wire bondings connected to the driver circuit t' can be the same as in a device using a conventional light emitting diode play which is used only as a light source for forming il+*. . Therefore, the apparatus of the present invention has the functions of both a read-only device or an exposure-only device at approximately the same manufacturing cost. Diode array and drive IC like this
Normally, one piece is made with several 100 pixels to 100 pixels. The reason for this is that a device with many pixels per /@ is difficult to produce and expensive. In order to actually use it, it is necessary to use a large number of diode playbacks and drive ICs of several tens to 1001 elements and arrange them in a line, but it is not possible to use a large number of diode playback devices.
[Since it is difficult to arrange them in a shape, in the present invention they are arranged in a shape.

Figure 2 1 ml [The situation is shown. In this example, the ft image is obtained when one light-emitting diode array 22 is used as a light-emitting element using the spider focusing lens arrays O and I. Lens array column 0 so that column column J is
and 21 are placed. In this embodiment, one light emitting diode plate is composed of /λl elements, and each light emitting part J5 of the light emitting part of each light emitting diode array is pulled out alternately to the left and right as shown in FIG. 2 (-). The 44Iiii element is connected to one driving IC (not shown) through the wiring pattern 4.

FIG. 3 shows -fIJ of a printing device having an original reading function to which the device of the present invention is applied.

When used as a printing device, as shown in FIG. J3 is.

It is a photoreceptor made of a three-layer living body consisting of a conductive substrate, a photoconductive layer, and a transparent insulating layer, and the photoconductive layer is made of Cd5 activated from Cu.
It is considered as a living body. CdS is activated by Cu and has high sensitivity to light of around 430 nm emitted by a light emitting diode.

The photoreceptor 33 is uniformly charged by three water chargers,
- At the same time as the charge is removed by the water charger J5, an image is exposed by the light emitting diode array in the device jl according to the present invention.Then, an electrostatic latent image is formed by uniform exposure by three uniform light rungs.

The electrostatic latent image is developed with Gen@Ku37. The amount of toner on the photoconductor 33 is not large enough), ? The image is transferred onto the transfer paper sent from ff, fixed by the constant voltage device 3t, and discharged.

On the other hand, the toner remaining on the photoreceptor JJ is removed by Cleaner 4IO.
It is removed by soiling. The photoreceptor is a primary pre-exposure lamp.
/ is uniformly exposed to light, and the static electricity is removed by the static eliminator Dako, and the material is reused.

When viewing a manuscript, as shown in FIG.
Move it in the direction of . J [The original on the 11th Sl (not shown) is an exposure lamp! - exposed to light.

As the document table moves left and right, it is driven as an image reading device according to the present invention to deposit a document image.

Light emitting diodes are generally made of materials such as GaAsPJPGaF, and those with a high output power of 4 J Oam
#Can easily form something that emits daylight at his wavelength. On the other hand, when a light emitting diode that emits red light is used as a light receiving element, it has high sensitivity to green wavelengths around j o am. Therefore, it is suitable for use as an image reading device since it is possible to read even red originals correctly.

As explained above, although the image forming light source and image reading device according to the present invention is an extremely small device, it can be used both as a light source for a printing device and as a document reading device, and its manufacturing cost is low. .

This is approximately the same level as a light source device consisting of a light emitting diode and a drive circuit used as a light source for ordinary printing equipment.

Moreover, when the device of the present invention is used as a reading device, the high wavelength of llA#: is within the visible range, so even documents of red color or the like can be read accurately.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the electrical configuration of an image reading device that also serves as a source for forming 11 mm according to the present invention, and FIG. The example in FIG. 2 is a partially enlarged view of the same, and FIG.
-1...Light emitting diode array, Co...Mode changeover switch, 7...Scanning circuit, 10. /3...MOS
Switch tS...Amplifier. Here...Light emitting diode array. J/... Tie reading device that doubles as a light source for mg1 formation JJ
...Photoreceptor, 341...-Water charger. Jj...Secondary charger, 3 units...Uniform exposure lamp. J7...current equipment, jl...XS unit.

Claims (1)

[Claims] l) It has a light emitting diode play and a drive circuit connected to the light emitting diode array. The light emitting diode has a means for supplying a forward current to each light emitting diode to cause the light emitting diode to emit light, and a means for outputting an electric signal corresponding to the light received by the light emitting diode. j1g1 reader that doubles as a forming light source.