JPH0347485B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a printing level display device for an automatic printing control device for a diazo copying machine.

Diazo copiers having automatic printing control functions as well as manual printing functions have been known for some time. As is well known, automatic printing control detects the light transmittance of the "base" (the area where nothing is written) of the original, and controls the printing speed (transport speed of the original and photosensitive paper) or the amount of light from the copying machine's light source. control, and automatically performs printing control corresponding to the original.

By the way, conventional diazo copying machines with an automatic printing function are equipped with a display means (lamp, etc.) to indicate that automatic printing control has been switched to, as well as a meter to display the automatic printing level. is normal. The automatic printing level display means (level meter) is provided in consideration of convenience when manually copying the same type of original.

However, in the above-mentioned conventional example, an indicator meter with a pointer is used as the automatic printing level display means, so when the light transmittance of the document is being detected, the meter pointer may swing violently due to the letters or pictures written on the document. In addition to the problem of being an eyesore, there was also the drawback that even after switching to automatic burn-in control, the pointer of the meter that displayed the burn-in level did not swing uniformly. Furthermore, since a separate display means is provided to indicate that the automatic printing control has been switched, there are problems such as design restrictions, complication of the manufacturing process, and an increase in the number of maintenance points.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a diazo copying machine having an automatic printing control function, in which an automatic printing level display means (i.e., a level meter for displaying the automatic printing level) having a plurality of lighting elements is connected to a diazo copying machine having an automatic printing control function. Conventionally, the meter does not turn on while the light transmittance is being detected, but one of the plurality of lighting elements corresponding to the burn-in level is turned on at the printing stage after detecting the light transmittance of the original, so that the indicator meter does not oscillate. An automatic printing control device for a diazo copying machine which eliminates the above-mentioned drawbacks of the conventional example by substituting an automatic printing level display means for the conventional display means that operates when automatic printing control is activated. An object of the present invention is to provide a burn-in level display device.

Hereinafter, one embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a diagram showing parts of a general diazo copying machine related to the present invention, and FIG. 2 is a circuit diagram for explaining an embodiment of the present invention. In Figure 1, 1
0 is a light source for exposure, and 12 is a rotating cylinder glass (baked glass) having the light source 10 inside. As is well known, the conveyor belt rotates in contact with the cylinder glass 12, and the stacked originals and photosensitive paper are transferred to the cylinder glass 1 by the conveyor belt.
During this time, the photosensitive paper is exposed to light. One end of the optical fiber 14 serving as a light guiding means is provided outside or inside the cylinder glass 12 to take in the light from the light source 10, and the other end is provided on the photosensor 16 side. Reference numeral 18 denotes a document feed roller, 20 a document insertion detection sensor such as a micro switch or a photo sensor, 24 a photosensitive paper feed roller, 26 a printing section conveyance roller, 28 a drive motor of the copying machine, and 30 a part of a printing belt.

Next, an embodiment of the present invention will be described with reference to FIGS. 1 and 2. When the power switch of the copying machine is turned on, the light source 10 lights up and the drive motor 28 starts rotating at a predetermined speed. When the light source reaches a steady state, when the original is inserted into the original insertion slot of the copying machine, the original insertion detection sensor 20 detects that the original has been inserted and outputs an insertion detection signal, and the original introduction roller 18 Transport the original into the copier. The leading edge of the document is connected to the optical fiber 14 and the photo sensor 1.
6, the original light transmittance detection circuit 40
(first circuit) detects the light transmittance of the "ground" portion of the document.

The original light transmittance detection circuit 40 includes a photosensor 16
In addition to the transistor 42 for amplification, the comparators C1 to CN of N (any integer), and the resistors R1A and R1 that apply a reference voltage to the inverting input terminal of the comparator C1.
B. Resistors R2A, R2B, which apply a reference voltage to the inverting input terminal of comparator C2, ... Comparator C (N-1)
A resistor R(N-
1) A, R(N-1)B, resistors RNA and RNB that apply a reference voltage to the inverting input terminal of the comparator CN, a resistor 50 provided between the photosensor 16 and the base of the transistor 42, and the collector of the transistor 42 and the resistor 52 provided between the ground and the comparator C1~
It has a resistor (no reference number) etc. connected between each output terminal of CN and the positive voltage source +B. Note that the reference voltages applied to the inverting input terminals of the comparators C1 to CN are made to differ slightly in order to detect the light transmittance of the document based on the outputs of the comparators.

The light transmitted through the document conveyed between one end of the optical fiber 14 and the photosensor 16 is transmitted to the photosensor 16.
When a voltage proportional to the amount of light reached appears at the collector of the transistor 42, this collector voltage is applied to the non-inverting input terminals of each of the comparators C1 to CN. Each of the comparators C1 to CN compares the voltages applied to the inverting and non-inverting input terminals, and if the voltage applied to the non-inverting input terminal is higher than the reference voltage applied to the inverting input terminal, " Outputs a "high" level signal. That is, the comparators (C1 to
CN) is determined.

Comparators C1 to CN of the original light transmittance detection circuit 40
(The value of the analog signal is determined by how many "high" level the outputs of the comparators C1 to CN reach) )5
4 is applied. The second circuit 54 receives the analog signal from the original light transmittance detection circuit 40, converts it into a corresponding digital signal, and holds the digital signal corresponding to the optimum original light transmittance. Here, the digital signal corresponding to the optimum original light transmittance is the highest signal among the outputs of the comparators C1 to CN (that is, the signal output corresponding to the part of the original with the highest light transmittance). This is a digital signal equivalent to . The digital signal corresponding to the optimum original light transmittance held in the second circuit 54 is applied to the encoder 56, and the encoder 56 outputs a signal corresponding to the input signal.

On the other hand, the signal output from the document insertion detection sensor 20 in response to the document insertion is transmitted to the document detection circuit 58.
is applied, and the original detection circuit 58 detects that the original has been inserted. The output signal of the original detection circuit 58 is applied to a timing circuit 60, and the timing circuit 60 applies a control signal to a latch circuit 62 after a predetermined period of time has elapsed. The predetermined period of time refers to the period of time after the insertion of a document into the copying machine is detected until just before the drive motor 28 is controlled. In addition, document insertion detection sensor 2
0, the document detection circuit 58 and the timing circuit 60 constitute a third circuit.

The latch circuit 62 receiving the control signal from the timing circuit 60 latches the output signal of the encoder 56 and outputs the latched signal to the automatic burn level display control circuit 64 and the D/A (digital/analog) conversion circuit 66. . Level display control circuit 64
controls the lighting of the automatic burn-in level display means 68 having a plurality of (15 in the illustrated embodiment) lighting elements based on the signal from the latch circuit 62, and controls the lighting of the burn-in level ( In this embodiment, one element (in the illustrated example, the eighth element) corresponds to the rotational speed of the drive motor to be controlled.
lights up. The number of lighting elements of the automatic printing level display means 68 is made equal to the number of comparators of the original light transmittance detection circuit 40. It should be noted that none of the lighting elements of the level display means 68 are lit while the light transmittance of the original is being detected.

On the other hand, the D/A conversion circuit 66 is connected to the latch circuit 62.
The digital signal from the converter is converted into an analog signal and applied to the drive motor speed control circuit 70. This control circuit 70 controls the rotational speed of the motor 28 based on the applied analog signal and performs automatic burning.

In the above explanation, automatic printing control is performed by controlling the rotational speed of the motor, but the present invention is of course not limited to this, and can also be applied to a method of controlling the amount of light from the light source 10. .

As explained above, in the present invention, an automatic burn-in level display means having a plurality of lighting elements is provided,
This display means is not turned on or operated while the light transmittance of the original is being detected, and at the printing stage after the light transmittance of the original is detected, one of the plurality of lighting elements corresponding to the burning level is turned on. By eliminating the drawback that the indicator meter does not swing uniformly, and by replacing the conventional automatic burn control switching display means with an automatic burn level display means, it is possible to realize a diazo copying machine with a simple configuration and easy operation. There is an effect.

[Brief explanation of drawings]

FIG. 1 is a simple diagram of a diazo copying machine for explaining the present invention, and FIG. 2 is a circuit diagram showing an example of a control circuit used in the present invention. 40...Original light transmittance detection circuit (first circuit),
54...A/D converter and holding circuit (second circuit),
62...Latch circuit, 68...Automatic burn-in level display means.

Claims (1)

[Claims] 1. A diazo copying machine with an automatic printing control function includes a first circuit that outputs an analog signal corresponding to the light transmittance of the original, and a circuit that receives the analog signal from the first circuit, converts it into a digital signal, and outputs an analog signal corresponding to the light transmittance of the original. a second holding a digital signal corresponding to the degree of transparency;
a circuit, an encoder that receives the digital signal held in the second circuit and outputs a corresponding signal, and detects the insertion of a document into the copying machine and outputs a control signal at the printing stage after detecting the light transmittance of the document. a third circuit for outputting, a latch circuit for receiving the control signal from the third circuit and latching the output of the encoder;
An automatic burn-in level display means having a plurality of lighting elements; and an automatic burn-in level display control circuit that receives an output signal from the latch circuit and lights one of the plurality of lighting elements corresponding to the burn-in level. A printing level display device for an automatic printing control device for a diazo copying machine, characterized in that: