JPS622278A - Copying device - Google Patents

Abstract

PURPOSE:To permit easy setting of a density in the stage of changing over copying using an AE mechanism to manual copying and setting the density by displaying the image density set by the AE mechanism during the time when the copying using the AE mechanism is executed. CONSTITUTION:A scanning panel 20 is provided atop a copying device 1. Contacts 24f-1 are closed and the density decreases successively at every time when an operator pushes the upper part 24f of a density setting key 24 of a seesaw type for setting the density of the copied image. Contacts 24g-1 are closed and the density increases successively at every time when the operator pushes the lower part 24g. 24a-24e are the LEDs for density display which are selectively displayed by the AE mechanism in the AE mode when the upper part 24f and lower part 24g of the key 24 are operated; for example, the LED24a for density display is lighted when the image density is lowest and the LED24e for the density display is lighted when the image density is highest.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a copying apparatus equipped with an automatic density control mechanism for one image.

[Prior art]

A copying apparatus 1, such as an electrophotographic copying apparatus, is equipped with various functions in order to faithfully reproduce the image density of an original.

Further, the copy density generally changes depending on factors such as the surface potential of the photoreceptor, the developing bias potential, and the toner concentration in the developer. Conventionally, when setting the copy image density of an original, an optical sensor detects the reflected light from the irradiated original, and the output of the light source for irradiating the original with light or the development bias potential is changed to adjust the original. A so-called auto-exposure (AE) mechanism is used to always obtain a suitable copy image even when the density changes.

Copying machines equipped with this AE mechanism are usually equipped with a manual density setting mechanism so that the density of the copied image can be changed according to the operator's preference.

[Problems with conventional technology]

A copying machine that is equipped with a manual density setting mechanism as well as the AE mechanism as described above switches to the manual density setting mechanism when the AE mechanism is used to copy and the density of the copied image differs from the operator's intended density. be able to. however.

Conventionally, when switching from the AE mechanism to the manual density setting mechanism and continuing copying, it is difficult to set the density because the density level set in the AEll mechanism is not displayed.

Therefore, in such cases, the operator sets the image density based on experience and intuition and makes copies.

In many cases, it is necessary to make several copies until a proper density is obtained, which has the disadvantage of repeating unnecessary copies.

[Purpose of the invention]

In view of the above conventional drawbacks, the present invention displays the image density set by the A2 mechanism while copying using the A2 mechanism, thereby making it easier to set the density when switching to manual mode and setting the density. An object of the present invention is to provide a copying apparatus that can perform the following operations.

[Key points of the invention]

In order to achieve the above object, the present invention has an automatic quality control mode in which the image quality is controlled by detecting the density of the document and controlling the process means based on the detection result; and 1) controlling the process means by manual input. The copying apparatus has a manual image quality control mode for controlling image quality, and is characterized in that control information of the process means during copying is displayed in the automatic image quality control mode.

[Embodiments of the invention]

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 2 shows a schematic diagram of the structure of the copying apparatus. To explain the structure of the copying apparatus, an original (not shown) to be copied is placed on an original table 2 in the figure.

By moving the document table 2 in the direction of the arrow a, the document is irradiated with light from the exposure lamp 3. The light reflected from the original is the first
Mirror 4. Lens 5. The photosensitive surface 7a of the photosensitive drum 7 is irradiated (exposed) via the second mirror 6. A portion of this reflected light is also received by a phototransistor 9 placed behind the lens 5. A charger 8 is installed near the photoreceptor drum 7.
．． Developing device 10, transfer device 11. A cleaner 12 is provided, and a uniform charge is applied to the photosensitive surface 7a by a charger 8 in advance. An electrostatic latent image is formed on the photosensitive surface 7a by the above-mentioned exposure, and the electrostatic latent image formed on the photosensitive surface 7a is visualized by the developing device 10 and becomes a toner image. At the same time as the image, move the paper from the paper feed cassette throat 13 to the paper feed roller 14. timing roller 15
The image is transferred to the transfer paper that is sent through the . After the transferred toner image on the transfer paper is thermally fixed in fixing 316.

The transfer paper is discharged to the outside of the machine by a paper discharge roller 17.

On the other hand, the photosensitive surface 7a that has not been completely transferred by the transfer device 11
The residual toner on the top is removed by a cleaner 12.

A charger 8 applies a uniform charge to the photosensitive surface 7a in preparation for re-exposure.

On the other hand, a scanning panel 2 shown in FIG.
0 is set. To explain the structure of the figure, 21 is a copy key, 22 is a number display for displaying the number of copies, and 23 is a numeric keypad for specifying the number of copies. Furthermore, 24 is a density setting key for setting the density of a seesaw-shaped copy image.

Each time the upper part 24f of the density setting key 24 is pressed, the screen shown in FIG.
The contact point 24f-1 shown in is turned on, and the concentration becomes lighter one after another.
Each time the lower part 24g is pressed, the contact 24g-1 is turned on, and the density becomes darker one after another. Reference numerals 24a to 24e are density display LEDs (hereinafter referred to as density display LEDs) which are selectively displayed by the A2 mechanism when operating the upper part 24r and lower part 24g of the density setting key 24 or at the same time as the AE mode, which will be described later. The display LED 24a lights up when the image density is the lightest, and the density display LED 2413 lights up when the image density is the darkest. 25 is an A/2 switch for switching between a state in which concentration setting is performed by the A2 mechanism (AE mode) and a state in which setting is manually set externally (manual mode).
It is an M switching key.

Reference numeral 26 denotes an AE mode display LED (hereinafter referred to as AE momo display LED) that displays the AE mode when in the AE mode.

A copying apparatus having the above mechanism is shown in FIG. 1(a).

It has a control circuit as shown in (b).

In the same figure, 30 is a microprocessor (hereinafter referred to as CPU).
), and the above-mentioned A/
The M switching key 25 and the pull-down resistor R: are connected, the contact 24f-1 of the concentration setting key 24 and the pull-down resistor R2 are connected to the terminal ■1, and the contact 24. of the concentration setting key 24 is connected to the terminal ■2. g-1 and a pull-down resistor R3 are connected. Also, A/M switching key 25. Contact 24f
A voltage ■cc is applied to the other end of the -1° contact 24g-1.

The other ends of the pull-down resistors R1 to R3 are grounded.

Each time this A/M switch key 25 is pressed, a high signal is input to the CPU 30, and each time a high signal is input, the CPU 30
The E mode and the manual mode are sequentially switched, and in the AE mode, a high signal is output from the terminal Oo of the CPU 30 to the inverter 26a.

The AE display LED 26, to which the voltage cc is applied to the anode via the resistor R4, is turned on.

On the other hand, the above-mentioned foI-) transistor 9 has a copy (exposure)
Reflected light from the document corresponding to the image density of the document inside is incident, and an analog signal corresponding to the amount of light received by the phototransistor 9 is transmitted through the amplifier 2G connected to the connection point between the emitter of the phototransistor 9 and the resistor R13. The voltage value is input to an analog-to-digital (hereinafter referred to as A/D) converter 27.

The A/D converter 27 converts the input analog voltage value into a digital signal composed of 5 pins 1- and outputs it to terminals I3 to I7 of the CPU 30. Here, when the CPU 30 is set to the AE mode by the A/M switching key 25 mentioned above, the CPU 30 encodes the input digital signal and outputs the input signal from the terminals 01 to 01.
Only one terminal in 05 is a high signal and the other terminals are a low signal).

Output to shift register 28. The high signal manually input to the shift register 28 is delayed by a time described later by a clock signal input from the AND gate 29, and is then input to the inverter 3.
It is output to 0a to 30e.

Inverters 30a to 30e invert the input signals.

On the other hand, the cathodes of the aforementioned concentration display LEDs 24a to 24e are connected to the inverters 308 to 30e, respectively.
A resistor R5 is connected to the anode of the concentration display LEDs 24a to 24e.
A power supply V (() is applied through the inverter 30a to 30e. Therefore, the concentration is displayed corresponding to one inverter 30a to 30e that outputs a low signal, and the EDs 24a to 24e are lit.
Relays 31a to 31 are connected to inverters 30a to 30e, respectively.
relays 31a to 30e connected to one inverter 30a to 30e that outputs the above-mentioned low signal.
Turn on 31e.

The contacts of the relays 31a to 31e are connected as shown in FIG.
A single-phase AC transformer 3 is connected to one end of 1a-1 to 31e-1.
2, the voltage is half-wave rectified by a commutator 33, and the voltage is smoothed by a capacitor C.

A voltage set to a predetermined DC voltage value is applied by the resistor R5 and the constant voltage element 34. Contacts 31a-1 to 31e-
The other end of 1 is a resistor R7 to R12 that functions as a ladder resistor.
For example, when the relay 31a is turned on and the contact 31a-1 is closed, a constant voltage is not applied to the bias terminal connected to the developing roll 10a, which will be described later, and is provided at the connection point between the resistor R++ and R12. The voltage value set by the voltage element 34 is output. In addition, when the relay 318 is turned on, the contact 31e-1 is closed, and the voltage value set by the constant voltage element 34 is applied to the bias terminal between the resistors R7 to R++ and R12.
The voltage divided by and is output.

In the copying apparatus configured as described above, the density control operation, which is the main part of the present invention, will be explained below.

When a power switch (not shown) is turned on and a voltage ■cc is applied to the control circuit shown in FIG. Here, the original is placed on the original platen 2 and the copy key 2 is pressed.
When 1 is pressed, the document table 2 moves in the direction of arrow a and starts the copying operation. During this copying operation, when the exposure lamp 3 is turned on by a control (not shown), part of the light that has passed through the lens 5 is irradiated onto the phototransistor 9, and an amount of light corresponding to the image density of the original is incident on the phototransistor 9. For example, when the document is white, the amount of light received by the phototransistor 9 is large, and a high voltage approximately equal to the voltage vcc is generated at the connection point between the emitter of the phototransistor 9 and the resistor R13.

Furthermore, when the reflected light irradiated on the black part of the document enters the phototransistor 9, the amount of light received by the phototransistor 9 becomes small, and the voltage at the connection point between the emitter of the phototransistor 9 and the resistor R13 is higher than the voltage ■cc. Very low voltage is generated. Depending on the magnitude of this voltage value, CPU3
At 0, a high signal is output to one of the terminals 01 to 05, and at 1, for example, if the original is white, the LED 24a is lit and the relay 31a is turned on, and! If the concentration is low, the LED
246 and turns on relay 31G.

Therefore, by lighting the concentration display LEDs 24a to 24e, the operator can know what level of concentration is currently set in the AE mode. At the same time, if relays 31a to 31e are turned on, relay 31
The contacts 31a-1 to 31e-1 of a to 31e are closed, and the voltage value corresponding to the density selected in the AE mode is divided from the bias terminal by the ladder resistors R7 to R12, and the voltage is applied to the inside of the developing device 10 shown in FIG. can be applied to the developing roll 10a.

In the figure, there is a distance indicated by l between the exposure point A of the photoreceptor drum 7 and the development point B where the image is developed via the development roll 10a. Therefore, it is necessary to create a delay time from the time when the phototransistor 9 detects the amount of light until the time when the bias voltage is applied to the developing roll tOa. The clock signals P1 to P1. are sent to the terminal CLK of the shift register 28 through the analogue I.29 in order to be delayed by the length of the distance l of the photosensitive drum 7 as shown in FIG. Enter and create a delay time. These clock signals P1 to P8.

is input to the shift 1 register 28 via the AND gate 29 while the signal k indicating that copying is in progress is at a high level.

For example, if clock signals P1 to Pn corresponding to one pulse are given to the shift register 28 for a scanning distance of 211, the clock signals P1 to P will be 30 to 30 m if the distance p shown in FIG. 4 is 3011. /2=15 clocks should be given. Namely.

The signals output from the terminals O1-0 of the CPU 30 are delayed by the time when the clock signals P1-P1 are inputted with 15 pulses, and are output from the shift register 28 as the signals (for example, d1-0).
d5) d+ to d5 are inverters 30a to 30e
via LEDs 242-24e and relays 31a-31
It is output to e.

Furthermore, in general, when the signal k during copying is output with a delay of time T1 from the lighting of the exposure lamp 3, the signals d1 to d5 can be output from the shift register 28 with a delay of the same time clock signals P1 to Po. . Therefore, a bias voltage is applied to the developing roll 10a so that an image always matching the amount of light detected by the phototransistor 9 can be developed in the developing section J510.

Here, even when the operator switches from the AE mode to the manual mode, one of the concentration display LEDs 24a to 24e is always lit, and the operator can recognize the current concentration level of the AE mode by operating the A/M switch key 25. By switching to manual mode and operating the density setting key 24, the desired density of the copied image can be easily set.

In this embodiment, an example was shown in which the voltage generated at the bias terminal was applied to the developing roll 10a, but it may also be configured to input the voltage to a circuit for setting the light amount of the exposure lamp 3 to vary the light amount of the exposure lamp 3. Of course.

〔Effect of the invention〕

According to the present invention as described in detail above.

When switching to manual mode, the temporary image density of AE Momo is always displayed by LIF, D, etc.

The operator can check the displayed density level and easily determine the desired image density.

Also, because the image i41 density is displayed in the copy middle school.

The density can be set taking into consideration not only the image density in the AE mode at the time of switching to the manual mode, but also the image density of the entire document, and a more appropriate image density can be determined.

[Brief explanation of drawings]

FIG. 1 (al is a circuit diagram of the density control device of the present invention. FIG. 1B) is a circuit diagram of a bias voltage setting circuit for a developing roll of the density control device of the present invention. FIG. 2 is a schematic configuration diagram of a copying machine. FIG. 3 is a configuration diagram of the operation section. FIG. 4 is a configuration diagram showing the relationship between the photosensitive drum and the developing roll. FIG. 5 is a time chart. 1... Copy machine. 7...Photosensitive drum. 9...Phototransistor. 10a...Developing roll. 24...Density setting key. 24a to 24e-i 1 degree display LED. 25...A/M switching key. 30...cpu. 313-31e...Relay. 31a-1 to 31a-1... Contacts. Patent Applicant Casio Computer Co., Ltd. Same as above
Casio Electronic Industries Co., Ltd. Figure 2 Figure 3 Figure 1

Claims (1)

[Claims] It has an automatic image quality control mode in which the image quality is controlled by detecting the density of the document and controlling the process means based on the detection result, and a manual image quality control mode in which the image quality is controlled by controlling the process means by manual input. 1. A copying apparatus characterized in that control information of said process means during copying is displayed in said automatic quality control mode.