JPS59201043A - Automatic exposure quantity adjusting device of copying machine - Google Patents

Abstract

PURPOSE:To attain an automatic exposure quantity adjusting device of a copying machine which is capable of securing an optimum exposure quantity and to improvde an exposure printing performance by comparing and operating a detecting signal of a light transmittance detecting circuit for detecting a light transmittance of an original drawing paper which is carried in, and a detecting signal of a luminous intensity variation detecting circuit for detecting a luminous intensity variation of an exposing lamp. CONSTITUTION:A light source 12 is installed adjacently to an original drawing paper carrying- in driven roller 9. A light transmission quantity detecting sensor 13 is provided opposingly to the light source by placing an original drawing paper carrying path 16 between, detects the light transmission quantity of an original drawing paper A passing through between the sensor and the light source 12, and transmits it to the light transmittance detecting circuit 18. A luminous intensity detecting sensor 14 is provided adjacently to the outside circumferential surface of an exposure printing drum 3, detects a luminous intensity of an exposing lamp 1 transmitting through the exposure printing drum 3, and transmits it to a luminous intensity variation detecting circuit 19. A comparing and operating circuit 21 compares and operates a light transmittance detecting signal of the light transmittance detecting signal, and a luminous intensity variation detecting signal of the luminous intensity variation detecting circuit 19, by which a proper correction is added to the light transmittance detecting signal, also a necessary amplification is given by an amplifying circuit 22, and said signal is transmitted to a peak voltage detecting circuit 23.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention adjusts the exposure amount according to changes in the amount of light transmitted through the original paper, and also adjusts the exposure amount according to changes in the light intensity (luminous intensity) of an exposure light source (exposure lamp). The present invention relates to an automatic exposure adjustment device for a copying machine.

Conventionally, automatic exposure adjustment devices irradiate the original paper with light from an arbitrary light source, detect and measure the amount of light that passes through the original paper, and
Using a control signal that calculates the amount of transmitted light at a predetermined ratio,
Regulate the light intensity of the exposure lamp or exposure baking time (speed)
iii! Arrange. Since the so-called exposure amount has a correlation between the luminous intensity of the exposure lamp and the exposure printing time, the exposure amount can be adjusted by adjusting either one of them. However.

Exposure Lang line Usually a discharge tube such as a mercury lamp or a fluorescent lamp is used. These discharge tubes have problems such as fluctuations in the amount of exposure due to environmental conditions such as temperature or reduction in the amount of exposure due to long-term use. Therefore, it is difficult to automatically adjust the appropriate exposure amount based only on the light transmittance of the original paper.

In view of the above-mentioned points, an object of the present invention is to provide an automatic exposure amount adjustment device for a copying machine that effectively solves the problems of the prior art, ensures an optimal exposure amount, and improves exposure and printing performance. shall be.

According to the present invention, this purpose is to detect the light transmittance of the original paper passing between the light source and the light source, which is installed in the vicinity of a carry-in roller for carrying the original paper. A light transmission wheel detection circuit detects the light transmittance of the original paper based on the detection signal of the light transmission amount detection sensor, and a light intensity detection sensor is provided close to the outer peripheral surface of the exposure and printing drum and detects the luminous intensity of the exposure lamp. A light intensity change detection circuit detects a change in the light intensity of the exposure lamp based on a detection signal, and a detection signal from an original paper detection sensor provided close to the light transmission amount detection sensor detects that the original paper has been carried in. an original paper detection circuit that operates a light transmission car detection circuit and a light intensity change detection circuit; a comparison calculation circuit that compares and calculates a light transmission amount signal of the light transmission car detection circuit and a light intensity change signal of the light intensity change detection circuit; This is achieved by having the following.

Next, one embodiment of the present invention will be described in detail with reference to the drawings.

The figure shows a schematic configuration diagram of an embodiment of the present invention. In the figure, the original paper case is guided to a table 7 and carried in by a driving roller 8 and a driven roller 9 for carrying in the original paper. Also,
This original 11wah is transported δ in the direction of the exposure and printing drum 3 via an original paper transport path 16 in which a main transport roller 10 and a driven roller 11 are arranged. At this time, the original paper A is overlapped and brought into close contact with the photosensitive paper B conveyed through the photosensitive paper conveyance path 17. The superimposed and adhered original image fiA and photosensitive paper MB are conveyed to an exposure and printing drum 3 by a conveyor belt 4, and are printed onto a photosensitive paper B by an exposure lamp 1 built in the exposure and printing drum 3. This conveyor belt 4 is
It is suspended between a drive roller 5 driven by a drive motor 26 and a plurality of driven rows 26, and is conveyed in the direction of the arrow. The exposure and printing drum 3 is given rotation by contact friction with the conveyor belt 4. After printing, the original paper A and the photosensitive paper B are discharged from the exposure and printing drum 3 by the conveyor belt 3. Incidentally, the reflector plate 2 is housed inside the exposure and printing drum 3 and supports the rear side of the exposure lamp l.

Furthermore, the light source 12 is installed close to the driven row 29 for carrying in raw paper. A light transmission amount detection sensor, a photo sensor 13 in this embodiment, is provided facing the light source 12 across the original paper transport path 16, and detects the light transmittance of the original paper A passing between it and the light source 12. , sends this detection signal to the light transmittance detection circuit 18. The light transmission vehicle detection circuit 18 sets, for example, a voltage corresponding to the output voltage of the photosensor 13 that detects the entire amount of light from the light source 12 that does not pass through the original paper A as a reference voltage, and compares this reference voltage with the light transmission amount detection signal. Calculate the light transmittance to the original paper.

The light intensity detection sensor, in this embodiment the photo sensor 14, is provided close to the outer circumferential surface of the exposure and printing drum 3, detects the light intensity of the exposure lamp 1 passing through the exposure and printing drum 3, and uses this detection signal to detect changes in light intensity. A signal is sent to the detection circuit 19. The light intensity change detection circuit 19 calculates the unavoidable change in light intensity that occurs due to environmental conditions of the exposure lamp 1 or due to long-term use by comparing the light intensity with a reference voltage.

In addition, the original paper detection sensor, in this embodiment, the photo sensor 15
is the original paper transport path 1 near the light transmission amount detection sensor 13
6. The original drawing paper A is carried in, and the photo sensor 15
When the original paper detection circuit 20 reaches the installation position of the original paper A
The light transmission vehicle detection circuit 18 and the light intensity change detection circuit 19 are activated.

Next, the comparison calculation circuit 21 performs a comparison operation between the light transmission amount detection signal of the light transmission vehicle detection circuit 18 and the light intensity change detection signal of the light intensity change detection circuit 19, thereby making appropriate corrections to the light transmission amount detection signal. is added, the necessary amplification is given by the amplifier circuit 22, and the signal is transmitted to the peak voltage detection circuit 23. However, since the necessary characters and cane shapes are written on the original drawing paper AJCa, if the light transmittance of only a part of the original drawing paper A is detected, the light transmittance of the unwritten part (the ground part) is not appropriate. It cannot be determined with certainty that it will be detected. For this purpose, as the original drawing mA is carried in, the peak voltage detection circuit 23 detects a voltage corresponding to the best light transmittance by continuously detecting the voltage and holds the voltage. This voltage is
The output signal is converted into an appropriate output signal and input to the control circuit 250.

Furthermore, the control circuit 25 controls the input voltage of the drive motor 26 to adjust the rotational speed of the drive motor 26, thereby adjusting the optimum exposure amount. That is, even if the light transmittance of the original paper A remains unchanged, if the luminous intensity of the exposure lamp 1 attenuates, the rotation speed of the drive motor 26 will be slowed down (by slowing down the rotation speed of the drive motor 26).
Exposure printing time has been extended to ensure the required amount of exposure,
Optimal exposure and printing adjustment is possible. The activation signal of the original paper detection circuit 20 is held until the exposure printing of the original paper A and the photosensitive paper B is completed, and is released by a trap, for example, a timer, at the end of the exposure printing. Furthermore, although the original paper detection circuit 15 is described as a photo sensor in this embodiment, it is not limited to this (for example, it can also be a micro switch).

As described above, according to the present invention, there is provided a light transmittance detection circuit that detects the light transmittance of the original drawing paper being carried in, a light intensity change detection circuit that detects a change in the light intensity of an exposure lamp, and this light intensity change detection circuit. By comparing and calculating the detection signal of the light intensity change detection circuit with the detection signal of the light intensity change detection circuit, changes in the light intensity of the exposure lamp are taken into account in the light transmittance of the original drawing paper, and the optimal exposure amount is automatically ensured at all times. This has effects such as improving exposure printing performance.

[Brief explanation of the drawing]

The figure is a schematic configuration diagram of an embodiment of the present invention. l: Exposure lamp, 3: Exposure and printing drum, 12: Light source, 1
3, 14, 15: Photo sensor, 18: Original paper transmittance detection circuit, 19: Light intensity change detection circuit, 20: Original paper detection circuit, 21: Comparison calculation circuit.

Claims (1)

[Scope of Claims] l) Exposure printing that includes an exposure lamp and a second exposure lamp, and prints the photosensitive paper, which is irradiated by the exposure lamp and is conveyed in superimposed contact with the original paper, with the required amount of exposure. In a copying machine having a drum, a light transmission device is provided facing a light source installed close to a carry-in roller for carrying in the original paper, and detects the amount of light transmitted through the original paper passing between the light source and the light source. A light transmission detection circuit detects the amount of light transmitted through the original paper based on the detection signal of the amount detection sensor, and a light intensity detection sensor that is located close to the outer circumferential surface of the exposure and printing drum and detects the light intensity of the exposure lamp with CV & vignetting. a light intensity change detection circuit that detects a change in light intensity of the exposure lamp based on a signal;
an original paper detection circuit that operates the light transmission detection circuit and the light intensity change detection circuit in response to a detection signal from an original paper detection sensor that is provided close to the light transmission amount detection sensor and detects that the opening paper has been carried in; and a comparison operation □ circuit for comparing and calculating the light transmission wheel signal of the original paper of the light intensity change detection circuit and the light intensity change signal of the light intensity change detection circuit. Adjustment device.