JPS59148047A - Image forming device - Google Patents

Abstract

PURPOSE:To make an adjustment to the proper exposure corresponding to image density, and to perform the same display in adjustment and copying operations and eliminate the need for readjustment by inhibiting the level display on a display device after the proper exposure is set. CONSTITUTION:The block of an exposure control mechanism consists of an amplifier 29, copy button 23, detecting element 28 for reflected light from paper placed at an exposure position, arithmetic circuit 30 which receives and processes a signal from the amplifier 29, driving circuit 31 for the display device, display device 32 for displaying the exposure, lamp control circuit 25 which sets the luminance in exposure, etc. A display inhibiting circuit 33 transmits the output of the circuit 30 to the circuit 31 according to the output signal of the lamp control circuit 25 to display it on the display device 32, or inhibits the transmission of the output of the circuit 30 to the circuit 31 to inhibit the level display on the display device 32.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image forming apparatus, and particularly to a device for controlling exposure amount.

Generally, in an image forming device such as an electrostatic copying machine, in order to obtain an appropriate exposure amount according to the image density of the original, the image density of the original is detected and the exposure amount is automatically adjusted according to the detected density. However, the equipment is expensive, and when using photographic originals, it is not possible to automatically obtain the appropriate exposure amount. The problem is that the optimum exposure value cannot be known unless copies are made many times, resulting in a large number of unnecessary copies. Therefore, before the lightless process, the photoreceptor is not actually exposed to light, but under the copying conditions: L'? ', compare the display level of the path light amount display with the appropriate exposure amount reference level 1rt that is fixedly displayed in advance, and adjust the light level so that the display level matches the water width position. itll i'U1 adjusting means. By the way, Chuo Copy Works (during normal times, lamp jiJX
Due to instability of the viewing pressure in the operating control circuit, the level display of the sight on the display may become blurred, causing trouble to the operator. Because the display gave a different impression than the display at the time of the revenge photo, there was also the waste of having to make unnecessary adjustments again.

The present invention has been proposed in view of the above drawbacks, and an object of the present invention is to provide an image forming apparatus that makes it possible to prohibit level display on a display after setting an appropriate exposure amount.

The present invention will be explained below with reference to the drawings. FIG. 1 shows an example of a reader printer to which the present invention is applied, in which a microfilm F is sandwiched between transparent glass plates G1 and G2, and the glass plates G] and G2 are moved using a moving handle 1 to project light. Position it on the axis.

When the projection lamp 2 is turned on, the condenser lenses 3 and 4 degrees and the reflecting mirror 5. A projection means comprising a projection lens 6 and a reflecting mirror 7 projects the image of the film F onto a reflecting screen 8.

Observe the projected image on the reflective screen 8 through the observation window formed by the filter 1o provided in the front of the machine box 9, align the position of the film image with the reference position formed on the screen 8 using the handle 1, and start the projection. Focusing is performed using the lens 6.

Next, press the print button (not shown in the figure) and the projection lamp"
2 is dissolved in oil, and the projection screen 8 moves to the position indicated by the chain line 8'. At the same time, the photosensitive paper B held in the cassette C is sent out by the paper feed roller 10 and feed roller 11, charged by the charger 13, and transferred to the exposure position 15 where the projection screen 8 was previously located by the feed roller 12 and the conveyor belt 14. When the end of the photosensitive paper B passes the paper feeding completion detection switch 16, the movement of the belt 14, that is, the conveyance of the photosensitive paper is stopped.

Next, the rung 2 lights up again to project and expose the image of the film onto the photosensitive paper B. At the same time as the exposure is completed, the conveyor belt 4 rotates, and the exposed paper B is transferred to the developing section by the guide plate 17 and the feed roller 18. It is developed by a developing roller 21 partially immersed in the developer 20, and then sent by a feed roller 19 through a drying section 22 and discharged outside the machine. At that time, the projection screen 8 also returns to the exposure position 15, stops all drives, and prepares for the next process.

The present invention relates to an apparatus for controlling exposure of a reader printer such as the above example, and FIG. 2 is a block diagram showing an exposure amount control mechanism for explaining an embodiment of the present invention. 23 is a print button; 28 is a light-receiving element that detects the image density by receiving the reflected light of the image light projected onto the paper B placed on the exposure position 15; 29 is an amplifier; An arithmetic circuit that performs arithmetic processing, 31 a display drive circuit, and 32 a display that displays the exposure amount.

24 is a lamp control circuit that controls the brightness of the lamp 2 based on a set value of a brightness setting circuit 24 that manually sets the brightness during exposure. 33 is a display prohibition circuit, which transmits the output of the arithmetic circuit 30 to the display device drive circuit 31 and displays it on the display device 32 according to the output signal of the lamp control circuit 25, or transmits the output of the arithmetic circuit 30 to the display device drive circuit. 3j is prohibited, and the display of the level by the display 32 is prohibited.

FIG. 3 is a circuit diagram of a lamp control circuit 250, which includes a brightness setting circuit 24 made up of a variable resistor. RL is a relay that switches the connection of the end terminal from the R terminal to the P terminal, and operates in conjunction with the button operation of the print button 23. Further, S is a manual changeover switch, which is composed of two switches that are switched in conjunction with each other. That is,
When switching the connection of the Y terminal from the R terminal to the P terminal, it becomes possible to adjust the brightness of the lamp 2 during printing, and at the same time, the connection of the 2 terminals is also switched from the M terminal to the N terminal. ``L'' level signal is output.When the brightness setting circuit 24 finishes adjusting the brightness of the lamp 2, the Y terminal is switched to the R terminal, but at the same time the Z terminal is also switched to the M terminal. Since it is switched, a ``H'' level signal is output to the display circuit 33. In addition, /IO is a power supply, and 42 is a transformer. FIG.
Reference numeral 52 indicates a reference index indicating an appropriate exposure position set in advance through experiments or the like, and 53 indicates a display scale indicating the magnitude relationship of the exposure amount.

Next, the operation of the embodiment according to the present invention will be explained with reference to the drawings.

First, when you turn on the power switch (not shown), lamp 2
lights up, but at this time, the X terminal of the relay RL is connected to the R terminal, the Y terminal of the switch S is connected to the R terminal, and the Z terminal is connected to the M terminal, and the image forming apparatus is in the reader state. Therefore, the screen 8 is at the light position 15, and the image of the microfilm F is projected onto the screen 8. At this time, the Z terminal of the switch S is connected to the M terminal, so the output signal of the lamp control circuit 25 to the display prohibition circuit 33 becomes an 'H' level signal.This signal causes the display prohibition circuit 33 to Since the operation of the drive circuit 31 is stopped, display on the display 32 is prohibited.

Next, when switch S is manually changed, the Y terminal becomes P.
' terminal and the Z terminal is connected to the N' terminal.The brightness of the lamp 2 changes to the brightness during printing. In addition, the display prohibition circuit 33
The output signal of the lamp control circuit 25 for II L I
Since it becomes an I level signal, the output of the arithmetic circuit 30 is directly transmitted to the 1-display drive circuit 31.

□ That is, the light receiving element 28 receives the image light reflected by the screen 8 and outputs a voltage according to the amount of received light. This output voltage is applied to the amplifier 29. Display circuit: Displays the current non-light setting value on the display 32 via the 30° display prohibition circuit 33 and the display drive line 31. When this display does not match the index 52 indicating the proper exposure position, the brightness setting circuit 24 adjusts the 1' value of the lamp 2 to HI+4 to match the index 52. This completes the adjustment of the appropriate exposure amount for printing.

Next, the switch S is manually changed to connect the Y terminal to the R' terminal, and therefore the Z terminal to the M terminal, in preparation for the next actual division printing operation. At this time, the input signal of the lamp control circuit 25 to the display prohibition circuit 33 becomes a ``H'' level signal, so the operation of the display drive circuit 31 is stopped and display by the display 32 is prohibited.At this time, the display 32
The pointer 51 is moved to a position away from the display scale 53, and the operation 1'
``It is not visible to the naked eye (see Figure 4 (a)). This indicates that the exposure amount setting is complete.

Next, when the print button 23 is pressed, the image forming apparatus i! /1
The printing operation is started, the screen 8 is moved to the position 8', and the charged photosensitive paper B is sent to the exposure position ]5. When the paper feeding completion detection switch 16 detects the completion of paper feeding, a lamp drive current is supplied to the lamp 2 and the lamp 2 is illuminated for a predetermined period of time.

As described above, according to the image forming apparatus according to the embodiment of the present invention, it is possible to adjust the appropriate exposure amount according to the image density, and display of the exposure amount level is prohibited during the sudden copying process. Does not cause trouble to the operator. In addition, since the display during adjustment and the display during actual copying do not give different impressions, there is no need to adjust the exposure amount again, which is excellent in economy.

FIG. 5 shows a display switching circuit 34 instead of the display prohibition circuit 33.
FIG. 7 is a block diagram showing an exposure amount control mechanism according to another embodiment of the present invention when a device is provided.

The display switching circuit 34 is controlled by the output signal of the lamp control circuit 25 in the same manner as described above, and the display switching circuit 34 is controlled by the output signal of the lamp control circuit 25.
An output signal of 0 is input to the display drive circuit 31, and after setting the illumination amount, a constant voltage output from the constant voltage generation circuit 35 is input. Thereby, the display level of the display 32 can always be kept at a constant value during actual copying, and the same effect as the above-mentioned display prohibition circuit 33 can be obtained. FIG. 4(b) is an example diagram in which the display level is constant. Incidentally, the same effect can be obtained by lighting the LED 54 (see FIG. 4(c)) or using a device that emits sound instead of the display prohibition circuit 33 or the display switching circuit 34.

[Brief explanation of the drawing]

FIG. 11 is a schematic cross-sectional view of a reader printer to which an embodiment of the present invention is applied, FIG. 2 is a block diagram showing an exposure control mechanism for explaining the embodiment of the present invention, and FIG. 3 is a diagram of the invention. A circuit diagram of a lamp control circuit according to an embodiment of
FIG. 4 is a schematic front view of a display device according to an embodiment of the present invention, and FIG. 5 is a block diagram showing an exposure digit control mechanism according to another embodiment of the present invention. 2...Lamp, 3.4...Condenser lens, 5.7...Reflector, 6...Projection lens, 8...Reflective screen, 23...Print button, 24.Brightness Setting circuit, 25... Lamp control circuit, 28... Light receiving element, 29... Amplifier, 30... Arithmetic circuit, 31... Display drive circuit, 32... Display, 33... Display prohibited. Circuit: U4...Display switching circuit, 35...Foot rest pressure generation circuit, RL...Relay, S...Manual switch. Figure 3 (0) Figure 4

Claims (1)

[Scope of Claims] A detection means for detecting the image density of a document; a control means for inputting an output signal of the detection means, processing it and outputting a control signal; and a control means for inputting the control signal and outputting a control signal; In the image forming apparatus, the image forming apparatus includes a display means for displaying a level corresponding to the degree of exposure, and a means for adjusting the exposure amount for the document according to the display level of the display means, the output signal of the control means being adjusted when adjusting the exposure level. 11iJ is transmitted to the display means to display the level, and during the copying process, the M
An image forming apparatus characterized by comprising means for prohibiting the transmission of the exposure amount and for displaying that the adjustment of the exposure amount is completed.