JPS6031133A - Image forming device - Google Patents

Abstract

PURPOSE:To decide easily whether an exposure quantity is set to an optimum value or not without executing a trial copying, by comparing picture optical information of the previous operation time with picture information of the subsequent operation time, and raising an alarm with regard to its result. CONSTITUTION:In case of executing newly copying operation by changing an original or a copying rate, etc., after the first copying is executed, when a check switch S is set to on in a state that a print switch 23 remains off, an operating circuit 35 is operated, and at that time point, picture information inputted by a photodetector 28 and the previous picture optical information held in a storing circuit 34 are compared. If each information does not coincide, the operating circuit 35 outputs an alarm signal and the alarm is raised. In such a case, the exposure quantity of a lamp 2 is set newly so that a correct display state is obtained. Watching an indicator 32. By executing such operation, a suitable copying image can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image forming apparatus, and particularly to an image forming apparatus that variably controls the exposure amount to obtain an optimal copy image.

Conventionally, in image forming devices such as electrostatic copying machines, 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. There is a device designed to control the However, a device that performs such automatic control is expensive. In addition, with such devices, when using special originals such as photo originals, it is not possible to automatically obtain the appropriate exposure amount, and in such cases, the only way to do this is to manually control the exposure amount. do not have. However, when doing this manually, the optimum exposure amount cannot be determined unless you make trial copies many times and look at the resulting images, which leads to the problem of making a lot of unnecessary copies. Ta.

The present invention has been made to solve the above problems, and includes an exposing means for exposing a document to be read, and detecting image light containing image density information of the document obtained by the exposure. It has a detection means, and an exposure amount setting means that allows the amount of exposure to be freely set based on the image density information obtained by the detection means, and further includes: a storage means for temporarily holding image density information; a calculation means for comparing and calculating the information held in the storage means with new information newly detected by the detection means; By providing a means for notifying the user of the information, the user can make a copy without making a trial copy.
It is an object of the present invention to provide an image forming apparatus that can easily determine whether the exposure amount is set to an optimal value.

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 G/ and G2, and the glass plates G/ and G2 are moved by a moving handle/ to project images. Position it on the optical axis.

When the projection lamp is turned on, the image of the film F is projected onto the reflective screen g by a projection means consisting of a reflecting mirror S between a condensing lens 3°, a projecting lens 9, and a reflecting mirror 7.

The projected image on the reflective screen g is observed through the observation window formed by the filter /θ provided on the front of the machine box 9, and the position of the film image is aligned with the reference position formed on the screen g using the handle /. , focus is performed by projection lens B.

Next, when the print switch (not shown in the figure) is pressed, the projection lamp turns on for a short period of time to carry out the processing described below, and then is cleared, and the projection screen g changes to the dotted line g.
’ position. At the same time, the photosensitive paper B held in the cassette (cassette) C is sent out by the feed roller 10° and the feed roller //, is charged by the charger /3, and is charged by the feed roller /2. The conveyor belt /I transports the photosensitive paper B to the exposure position /S located on the projection screen first, and when the end of the photosensitive paper B passes the paper feeding completion detection switch /B, the transport belt /1 moves, that is, the photosensitive paper transport is stopped.

Next, the lamp unit lights up again, and the image on the film is transferred to photosensitive paper B.
Projection exposure is performed on the top, and at the same time as the exposure is completed, the conveyor belt rotates, and the exposed paper B is transferred to the guide plate /7 and the feed rotor /g.
The image is guided to the developing section by the developer 20, developed by the developing roller 2/ partially immersed in the developer 20, and then sent by the feed roller/q to be discharged to the outside of the machine via the drying section 22. At that time, the projection screen returns to the exposure position /S, stops all drives, and prepares for the next process.

The present invention relates to an apparatus for controlling exposure in a reader printer or the like as described above, and FIG. 2 shows the configuration of an embodiment of the exposure amount control system, which is a feature of the present invention. It is a block diagram.

As will be described in detail later, 2S is a lamp drive circuit having means for manually variably setting the light intensity of the projection lamp. 2g is a light-receiving element for detecting image density, and a light-receiving element 2g is designed to receive image light that is irradiated onto a document to be read such as a microfilm by a lamp controller and further reflected by a screen g (shown in Fig. 1). As shown in FIG. 1, it is arranged above the screen g. Reference numeral 2q denotes an amplifier for amplifying and waveform shaping the weak image information signal from the light receiving element 2g. 3/ is a display drive circuit for receiving a signal from the amplifier 29 and driving the display 32.

Here, FIG. 3 shows an outline of the display section of the display 32. 3
Reference numeral 2a denotes a pointer, which moves according to the amount of image light detected by the light-receiving element 2g, based on a signal value guided through the amplifier, 2q, and the display drive circuit 3/. 32
b is a reference index, which is set in advance through experiments or the like and is designed to indicate a position corresponding to an appropriate amount of light for the original image density. 32C is a display scale representing the magnitude relationship of the amount of image light.

In addition, in Fig. 2, 3 Hiro is the O of the print switch 23.
This is a storage circuit that holds and stores the image density information from the amplifier 29 using the N signal, and 3s is an arithmetic circuit that uses the ON signal of the exposure amount check switch S to store the image from the amplifier 2 at the time of receiving the ON signal. Taking in concentration information, comparing and calculating the information with the information held in the memory circuit 3,
There is no output signal for alarm only when their information does not match each other. Further, S/ is an initial reset circuit that outputs a clear signal for clearing the memory circuit 3 when the power switch is turned on.

3B is an alarm drive circuit that outputs a signal to drive the alarm 37 only when an alarm signal is issued from the arithmetic circuit 3S, and furthermore, this does not output a signal when the check switch S is OFF ( That is, the alarm operation is prohibited), and when the alarm signal is ON, a signal is output if the alarm signal is issued (that is, the prohibition of the alarm operation is canceled). Here, as the alarm 37, an LED, a buzzer, or the like can be used.

Further, 52 is a delay circuit, which delays the ON signal of the print switch 23 by the processing time necessary for the memory circuit 3q to hold and store the ON signal as described above. SO is a printer drive circuit, which starts the copying operation and drives the printer when the ON signal of the print switch 23 is sent after the delay.

Next, the lamp drive circuit 2S mentioned above will be explained in more detail using FIG. Here, lIO is a power source for making the lamp unit emit light, '72 is a transformer for dividing the voltage of the power source lIO and supplying it to the lamp unit, and RL
is a relay that operates in conjunction with the ON-OFF operation of the aforementioned print switch n, and S is the exposure amount check switch 1 shown in Figure 2. 21I is a variable resistor for setting the light amount of the lamp controller. be. Note that the relay RL has an input terminal It is something that will be done. Check switch S has input terminal Y and output terminal R/.

P', and when it is turned on manually, YpZ
When the terminal is OFF, the terminals Y and R' are connected, and this 0N-OFF signal is also connected to the arithmetic circuit 3S and the alarm drive circuit 3B, as shown in Fig. 2 mentioned above. Let yourself be guided. In addition, the power supply lI0
One end is connected to terminal X, the other end is connected to Rambuco and one end of transformer lI2, and terminals R, P and terminal Y
, P' are connected to each other. The terminal R' and the other end of the transformer '12 are connected, and the other end and the terminal V are connected via a variable resistor 2'l. One end of the lamp is connected to the power supply plug O as described above, and the other end is connected to the predetermined position 7 of the transformer '72, so that a predetermined amount of light can be obtained at one time from the reader.

Next, the operation of this embodiment configured as described above will be explained as follows.
1) When aligning the image projected on the screen (reader temporary), 11) When setting the appropriate exposure amount while checking on the display (when setting the exposure amount), 111) When the printer drives and copies When performing operations (when printing) and 1) When determining the appropriateness of the exposure amount when attempting to perform a new copying operation by changing the original or copying magnification, etc. (when determining the exposure amount), please refer to each drawing. The explanation will be given below in order with reference to the following.

i) Reader Temporary: First, when a power switch (not shown) is turned on, the initial reset circuit S/ outputs a clear signal, and the memory circuit 3'l- is cleared by this signal. By setting print switch 23 and check switch S to OFF, relay RL communicates between Xl and R, and check switch S communicates between y and 81, as shown in FIG. Therefore, regardless of the variable resistor 2q, the Rambuco is turned on with a constant amount of light, and while observing the image projected on the screen in this state, searching and positioning of the original are performed.

11) When setting the exposure amount, leave the print switch 23 OFF and set the check switch S to ON. Then check switch S
The communication between Y and R' is cut off, and the communication between Y and P' is established instead. Therefore, the lamp controller is connected to the power supply lIO via the variable resistor 2'l. Here, the calculation of the calculation circuit 3 is started at the same time as the check switch S is turned on. At this time, since the storage circuit 34' remains cleared and no image density information is stored, the arithmetic circuit 3 outputs an alarm signal. In response to this signal, the alarm 37 is activated via the alarm drive circuit 3B (because the check switch S is ON, the prohibition of alarm operation is canceled).
is activated and an alarm is issued. Therefore, the operator of this device should leave the check switch f's ON and turn on the display.
See 2. If the display is not in an appropriate state (see Figure 3,
When the reference indicator 32b and pointer 32a indicate different display scales 32C), the variable resistor 2'l
By adjusting the resistance value of the pointer 328. and gradually changing the light intensity of the lamps, the pointer 328. to match the scale indicated by the reference index 32F). When the display 32 is in a proper display state (the lamp λ has a proper exposure amount), the check switch S is turned OFF to prohibit the alarm operation of the alarm drive circuit 3A and stop the alarm from the alarm 37.

111) When printing: Keep check switch S OFF and set print switch 23 to ON. Then, relay RL is x
-p is connected, and the lamp is turned on with an appropriate exposure amount according to the variable resistance value set in 11) above.

At the same time, the image light (image density information) detected by the light receiving element 2g is sent to the storage circuit 3'l via the amplifier 2q.
is maintained. After that (after a predetermined time set by the delay circuit S2), the ON signal of the print switch 23 is guided to the printer drive circuit SO.

Then, the copying operation starts, and a copied image with an appropriate density is obtained using the above-mentioned appropriate exposure amount.

When this copying operation is completed, the print switch 23 is turned off.

iv) When determining the exposure amount: After the first copy has been made as described in 1) to 111) above, when attempting to perform a new copying operation by changing the original or copying magnification, etc., the previous appropriate exposure amount is There are many cases where the actual exposure amount differs from the current appropriate exposure amount. For this purpose, the exposure amount can be easily determined as follows.

First, the check switch S is set to ON while the print switch 23 remains OFF. Then, the lamp lights up with the same exposure amount as previously set, but since a new document or copying magnification is being used, the exposure amount is not necessarily appropriate. However, if the amount of image light detected by the light receiving element 2g is equal to the previous amount of light, it can be determined that the exposure amount of the lamp λ is appropriate as in the previous time. Therefore, check switch S is set to O.
At the same time as N, the left side of the arithmetic circuit 3 is activated, and the image light information taken in by the light receiving element 2g at that time is compared with the previous image light information held in the memory circuit 3g.

In the a-ci comparison, if each piece of information matches (that is, when the appropriate exposure amounts match), the arithmetic circuit 3S does not output an alarm signal and no alarm is issued.

Therefore, in this case, since it can be determined that the exposure amount is appropriate, an appropriate copy image can be obtained by performing the same operation as 111) described above.

b) On the other hand, if the respective pieces of information do not match (that is, when the appropriate exposure amounts do not match), the arithmetic port 7 and 3 output an alarm signal and an alarm is issued. In this case, it can be determined that the exposure amount is not appropriate. At this time, while keeping the print switch 23 OFF and the check switch S ON, gradually change the resistance value of the variable resistor 2'l, and
2, set a new exposure amount for Rambuco so that a proper display state is achieved. After completing this setting, a suitable copy image can be obtained by performing the same operation as in step 11i) described above.

Furthermore, when performing a new operation, before starting the copying operation, perform the above-mentioned I■) judgment on the appropriate exposure amount, and if the appropriate exposure amount needs to be reset, repeat the above operation. Good.

As explained above, the present invention makes it possible to compare image light information from a previous operation with image information from a subsequent operation and notify the operator of the result by issuing an alarm. The above-mentioned alarm makes it easy to determine whether the exposure amount is at the optimum value when the original is changed, when the lens is changed to change the magnification, or when the optimum exposure setting value changes due to voltage fluctuations. I can judge. Therefore, it reduces copying errors, eliminates the trouble of making trial copies as in the past, and has a simple configuration that eliminates production difficulties.Furthermore, the exposure amount can be set manually over a wide range, making it possible to use all kinds of special It is highly practical and has an excellent effect in that it can be applied to manuscripts.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an example of a reader printer to which the present invention is applied, FIG. FIG. 7 is a circuit diagram showing the configuration of the lamp drive circuit. λ...Lamp, 23...Print switch. 2g...variable resistor, 23...lamp drive circuit. 2g...Photodetector, 29...Amplifier. 3/... Display drive circuit 3.2... Display, 32a... Pointer. 32b...Reference index, 32C...Display scale. 3ri...memory circuit, 3S...arithmetic circuit. 3. B...Alarm drive circuit. 37... Alarm. SO...Printer drive circuit. Left λ...Delay circuit. S...Check switch. RL...Relay. Patent applicant Canon Co., Ltd./S- Figure 1

Claims (1)

[Claims] An image forming apparatus comprising an exposure means for exposing a document to be read, a detection means for detecting an image density of the document by the exposure, and an exposure amount setting means for variably setting the amount of exposure. storage means for holding image density information obtained by the detection means; calculation means for comparing the information held in the storage means with information newly detected by the detection means; An image forming apparatus comprising: means for notifying results.