JPS63291069A - color image forming device - Google Patents

Abstract

PURPOSE:To control the reproduction of the coloring of a copy original finely by controlling the conditions of an electrostatic charger, a developing device and an exposure light source according to setting conditions selected by a setting condition selecting means. CONSTITUTION:At the time of automatic operation, a detection signal generated by a original reader 24 is sent to an image processing part 58 to decide the original and a microcomputer 53 performs arithmetic control so as to select one condition closest to a program among plural color balance conditions stored previously in a nonvolatile storage element 54. Then a process of copying is performed under the selected condition and the condition setting values are passed through the microcomputer 53 to indicate an electrostatic charging quantity to a high-voltage transformer 55 at the time of electrostatic charging, the quantity of light of a lamp to a lamp regulator 57 at the time of exposure, or a bias potential to a high-voltage transformer 56 at the time of development with respect to respective colors of yellow, magenta, and cyan. Consequently, the color balance of the original is accurately reproduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color balance adjustment device for adjusting the density of separated color component images in a color copying apparatus.

In conventional color copying, originals with different image densities for each color component, such as originals with many blue edges such as maps, originals where skin tones should be emphasized such as people, originals with many lines, etc. ,
In many cases, it is required to perform color copying with optimal image densities for each color component. In such a case,
It is necessary to adjust the density of each color component image every time the original changes.

On the other hand, in the past, the data was stored in advance in the storage control device of the copying machine.
Multiple programs are stored that are set as combinations of lamp light intensity, charge amount, and developing bias amount to best reproduce the image characteristics of the original, and when an operator looks at the original, selects one of the programs. A method has been proposed in which one is selected. However, this method requires the operator's experience and intuition, and has the drawback of generating a large number of trial copies and copy mistakes.

For digital color copying machines, a method has been proposed in which a document is read and the information is subjected to dot processing to obtain a faithful copy. This method requires a huge amount of memory capacity, control capacity, etc., which has the problem of increasing costs.

SUMMARY OF THE INVENTION An object of the present invention is to provide an apparatus which can solve the above-mentioned problems and reproduce the color balance of a document simply and as accurately as possible.

In order to achieve the above object, the present invention provides means for adjusting a plurality of setting conditions for setting the image density of each color component, such as the amount of charge of a charger, the developing bias potential of a developing device, and the amount of light of an exposure light source; a non-volatile memory element for storing the values set by the adjustment means and the selection and setting means; an image density detection means for detecting the image density of each color component of the document; and the image density detection means. an image processing means for performing image processing based on a signal from the image processor; means for selecting an optimal setting condition value from among the setting condition values stored in the nonvolatile memory element based on information from the image processing means; It is characterized by comprising means for controlling the conditions of the charger, the developing device, and the exposure light source based on the setting conditions selected by the condition selection means.

The structure and operation of the present invention will be explained in detail based on the embodiment shown in the drawings.

In FIG. 1, a photosensitive drum 1 and a transfer drum 2 are arranged to face each other at a transfer position, and a document on a document table 4 is irradiated with light R3, and reflected light from the document is reflected by mirrors 5, 6, 7. The light emitted from the lens 8 is further reflected by a mirror 9, separated into colors by a color separation filter 10, and projected onto the exposure position of the photoreceptor drum 1. While the photoreceptor drum rotates, it is primarily charged by the charger 11, and light is projected at the exposure position to form an electrostatic latent image of the color-separated light image of the document, which is then processed by a developer corresponding to the color separation. Visualized. For example, when a "blue" filter is used as the color separation filter IO, yellow is visualized by the developing device 12 with a "yellow" toner, and when a "green" filter is used, a developing device with a "magenta toner" is visualized. 13, a magenta image is visualized, and when a "red" filter is used, a cyan image is visualized by a developing device 14 having a cyan toner.

The image visualized in one of the three colors mentioned above on the photosensitive drum 1 is transferred to the transfer drum 2 at the transfer position.
The image is transferred onto the transfer paper 15 wrapped around the image. The transfer paper 15 is fed from the cassette 16 by the paper feed roller 17, and is sent to the transfer drum 2 at an appropriate timing by adjusting the timing by the registration rollers 18.The leading end is clamped by the clamper 29 of the transfer drum 2. It passes through the transfer position. When the transfer paper passes through the transfer position, the visible image on the photoreceptor drum 1 is transferred onto the transfer paper under the action of the transfer charger 19.

Each rotation of the photoreceptor drum 1, the color separation filter 10 and the developing devices 12, 13, 14 are switched, and color separation light images of different colors are formed one after another on the transfer paper sent by the transfer drum 2. Images of different colors are transferred in a superimposed manner with each rotation, and separated images of three colors are superimposed and transferred onto the transfer paper by three rotations.

When the separated three-color images are superimposed, the transfer paper 15 is separated from the transfer drum 2 under the action of a separation static eliminator 20 and a separation claw 21, fixed by a fixing roller 22, and discharged onto a tray 23.

A document reading device 24 is arranged as image density detection means so as to move integrally with the light source 3 and mirror 5.

The document reading device 24 includes a reading light source 25 that illuminates the document on the document table 4, and a reading mirror 2 that reflects light reflected from the document.
6 and a reading lens 27 into which light from the reading mirror 26 enters.
and a CCD section 28 on which the light emitted from the reading lens 27 is projected. The CCD section 28 is composed of a color separation member, such as a prism and a COD element, which separates the projected light into separated color lights such as blue, green, and red.

When making a color copy using the copying apparatus shown in FIG. 1, the amount of charge in the image forming process of each separated color of yellow Y, magenta M1 and cyan C, and the bias voltage of the developing device are determined on the color balance adjustment operation panel 51 shown in FIG. and set the light intensity. That is, the first charging dial 31 sets the amount of charge of the charger 11 in the yellow image forming process, and similarly the second charge dial 32 and third charge dial 33 set the charge amount of the charger 11 in the magenta and cyan image forming processes, respectively. Set the amount. Further, the first bias dial 34 sets the bias voltage of the developing device 12 in the yellow image forming process, and the second bias dial 35 and third bias dial 36 set the bias voltage of the magenta developing device 13 and the cyan developing device 14, respectively. .

Furthermore, a first light source dial 37, a second light source dial 38,
The third light source dial 39 is used to set the light amount of the light source 3 for the yellow, magenta, and cyan image forming steps, respectively. The setting dial 31 of the color balance adjustment operation panel 51
39 to set the charge amount, developing bias voltage, and light amount for image formation of each color, by pressing the setting switch 40, the values set by each setting dial 31 to 39 are changed.
A microcomputer 53 and a nonvolatile memory element 5 in a controller 52 that controls the copying apparatus shown in FIG.
4, the data is stored in the nonvolatile memory element 54.

When the confirmation switch 41 on the color balance adjustment operation panel 51 is pressed, the type of setting amount such as yellow image forming charge amount, magenta image forming developing bias amount etc. is displayed on the upper display 42, and the lower display 43 is displayed.
The setting amount for the type of condition displayed on the upper display 42 is displayed in the manner described below, and the stored setting condition can be confirmed.

In FIG. 3, a controller 52 including a microcomputer 53 and a nonvolatile memory element 54 is connected to a charger 11.
A high voltage transformer 55 and a developing device 12, 13.1 that control the
4 and a lamp regulator 57 that controls the light source 3.

As shown in FIG. 4, a color balance selection operation panel 58 is provided in a part of the operator operation panel for operating the copying machine.
Selection switch 6 for selecting and setting conditions according to the original color tone
1 to 65 are provided, and respective selection switches 61 to 6 are provided.
5, one destination selection display lamps 66 to 70 are provided. A changeover switch 71 is provided on the color balance selection operation panel 5 to enable switching between automatic color balance adjustment and manual adjustment. If automatic, automatic indicator lamp 7
2 lights up, and in the case of manual operation, the manual indicator lamp 73 lights up. For example, the changeover switch 71 can be configured to switch automatically when pushed down, and manually when pushed back.

The operation of this device will be explained.

First, a plurality of color balance conditions are set and stored in the nonvolatile memory element 54 so as to best reproduce copies of various originals.

For example, select manuscripts with five types of conditions as shown in Table 1,
Five types of color balance conditions suitable for this are set and stored in the nonvolatile memory element 54.

Table 1 There are many types of color originals. For example, there are many types of color originals, those with many characters, and pale ones such as photographs and maps. It is difficult to cover all of them with the same image creation settings, so It was difficult to adjust the color balance in order to obtain the image quality and color tone.

For black and white copiers, only the brightness adjustment was required, but for color copiers, T (gamma) adjustment (soft to high contrast) and color balance adjustment were also required to reproduce the operator's preferred colors. come.

However, after conducting physical analysis and sensory testing of various originals and copy image quality, we found that if the five types of color balance image creation setting conditions mentioned above are used, it is possible to print from the vast majority of color originals. The copy turned out to be very satisfying.

Also, the most important factors in the color balance image formation setting conditions at this time are the γ characteristics and the maximum image density characteristics on the image, assuming that the color characteristics of the toner are constant, and these are controlled by the light amount and charging It was also found that it was the amount of developing bias.

This is illustrated in FIG. 5. Table 1 summarizes the results shown in FIG.

For example, if you want to obtain a copy with a sharp color group, it is better to use a γ characteristic with a steep slope, that is, a type of curve ■×■ in the image characteristic diagram shown in FIG. 5.

In order to obtain images with good halftone portions in printed matter, photographs, etc., it is preferable to have a gamma characteristic with a gentle slope, that is, a type of curve ■×■ in the diagram showing the image characteristics in FIG.

In addition, if the optimum conditions can be programmed according to frequently used documents at the user's site and can be easily called up and used by pressing the corresponding key when necessary, even better quality color copies can be obtained. Become.

When operating a color copying device, first select and set the color tone. The operator first looks at the color balance adjustment automatic/manual indicator lamps 72 and 73 on the color balance operation panel 58 provided in a part of the operator operation panel, and then presses the changeover switch so that the desired automatic or manual indicator lamp lights up. Activate 71.

In the manual mode, the user selects which of the selection switches 61 to 65 to use by looking at the document. The document reading device 24 is configured to operate in automatic mode.

In manual mode, the selection switch 61 is used to set the color tone of a document such as a map with a lot of blue or green, for example.
The selection switches 62 and the like are used to set the color tone of a document whose skin color, such as that of a person, is desired to be emphasized, and the selection switches 61 to 65 correspond in advance to the selection switches 61 to 65 for the color tone of various documents.

If you now want to copy a map original, press the selection switch 61 and check that the selection display lamp 66 indicates that the map original is selected! I approve.

Next, a map original to be copied is placed on the original platen 4.

The first step is to set each condition for a map manuscript.

For this purpose, the setting dials 31 to 39 on the color balance adjustment operation panel 51 are operated as appropriate, conditions considered to be optimal are selected, and the setting switch 40 is pressed. As a result, the currently selected conditions are stored in the nonvolatile storage element 54 via the microcomputer 53 of the controller 52 as the copying conditions for the map document, ie, the selection switch 61.

Next, when the copy start button on the operator operation panel (not shown) is pressed, the copying apparatus performs the steps of charging, exposure, development, paper feeding, transfer, and fixing as shown in FIG. The current color balance setting value is transmitted via the microcomputer 53 to the high-voltage transformer 55 during charging, and to the lamp regulator 57 during exposure.
At the time of development, the amount of lamp light is instructed to the high-voltage transformer 56 and the development bias potential is controlled as a value corresponding to the color at that time. If the copy obtained in this way is satisfactory, the setting value is used as the setting condition in the selection switch 61 for subsequent copies, but if it is not satisfactory, the values of the setting dials 31 to 39 are changed again. Then, the conditions are set again using the setting switch 40, and the above-mentioned copying is performed, and the process is repeated until a satisfactory copy is obtained. Once the optimum reproduction conditions are set for the selected original color tone, from now on, copying will be automatically performed under the optimum color tone reproduction conditions simply by pressing the selection switch 61, etc., without operating the setting dials 31 to 39. Become.

Similarly, in the case of an original with a tone in which the skin color of a person is desired to be emphasized, for example, the selection switch 62 is held down, and the optimum reproduction conditions are set in the same manner as described above.

Each selection switch 63 can also be used for different color tone conditions.
The optimum reproduction conditions are set under the effects of steps 65 to 65, and subsequent copies of various tones can be made under the optimum conditions with simple operations.

That is, an appropriate switch is selected from selection switches 61 to 65 and pressed depending on the color tone of the original to be copied. The selected color tone is lit by the selection display lamps 66 to 70.
This can be confirmed by

When it is confirmed that the selection is correct, by pressing the copy start button, copying is performed under the optimum conditions previously stored in the non-volatile memory element 54, and a copy of the optimum image with the desired color balance is obtained.

When automatic, the signal detected by the document reading device 24 is sent to the image processing section 58, where the document is determined. Originals are determined based on the density distribution of the yellow, magenta, and cyan components of the original, maximum density, minimum density, density distribution, and T.
Calculate characteristics etc.

This data signal is then sent to the microcomputer 53. Within the microcomputer 53, this data signal is used to select the closest color balance condition from among a plurality of (five in this example) color balance condition programs stored in the non-volatile storage element 54. Calculated and controlled. Under the selected color balance conditions, the document undergoes the steps of paper feeding, charging, exposure, development, transfer, and fixing through the operations described above. During the process, the color balance condition setting values are set via the microcomputer 53, and the charging amount is sent to the high voltage transformer 55 during charging, the lamp light amount is sent to the lamp regulator 57 during exposure, and the developing bias potential is sent to the high voltage transformer 56 during development. Instructions are given for each color: yellow, magenta, and cyan.

If it is desired to check the current color balance settings prior to copying, the user selects and presses the color tone to be checked from among the selection switches 61 to 65 in FIG. 4. As a result, the color tone to be confirmed is displayed by the lit lamps among the selection display lamps 66 to 70. Next, the confirmation switch 41 on the color balance adjustment operation panel 51 shown in FIG. 2 is pressed. Set the confirmation switch 41 to 1
If you press it once, “1” will appear on the upper display 42, and if you press it twice, “2” will appear on the upper display 42.
Depending on the number pressed, any number from ``1'' to ``9'' will be displayed. In this case, the numbers rl and ``9'' are displayed sequentially up to the setting dials 31 to 39, respectively. For example, ``1'' indicates the first charging dial 31, which is the yellow charging dial, and ``2'' indicates the magenta charging dial. The second charging dial 32 is a charging dial, and similarly, "8" indicates a second light source dial 38, which is a magenta light source dial, and "9" indicates a third light source dial 39, which is a cyan light source dial. do. In this way, when the confirmation switch 41 is pressed once, the number 1 is displayed on the upper display 42, and at the same time, the data on the amount of yellow charge set and stored on the lower display 43 is converted into a number and displayed. If you press the confirmation switch 41 once again, the upper display 4
The number "2" is displayed at 2, and at the same time, magenta charge amount data is displayed on the lower display 43. When the confirmation switch 41 is pressed nine times in this way, the number "9" is displayed on the upper display 42, and at the same time, the amount of cyan light is converted into a number and displayed on the lower display 43. The setting data numbers displayed on the lower display 43 indicate the values on the equally divided scale displayed on the setting dials 31 to 39, and when the numbers on the scale match the numbers on the lower display 43, the setting data is displayed on the lower display 43. Operation is easy when resetting numerical values for each condition using the dials 31 to 39.

When operating the color copying device, when you press the copy start button on the operator operation panel (not shown), the document reading device 2
4 is driven. The reading light source 25 is turned on and scans the document surface 4. The light that scans the original and enters the reading mirror 26 passes through the reading lens 27 and enters the CC0 section 28. Optical signal is CC
The signal is converted into an electrical signal by the 0 section 28, passes through the image processing section 58 in FIG. 3, and enters the microcomputer 53. Here, the color balance conditions most suitable for reproducing the original are automatically selected. When the document reading device 24 finishes scanning the document surface, the photosensitive drum 1 and the transfer drum 2 start rotating, and the light source 3 and mirrors 5, 6, and 7 are driven. The light source 3 is turned on and scans the document surface 4, and the surface of the photosensitive drum 1 is uniformly charged by the charger 11. The original is scanned again, and the mirror 5
．． The light entering 6.7 passes through a lens system 8 and a color separation filter 10 to form an electrostatic latent image on the photosensitive drum 1 corresponding to the original image. In the first scanning of the document, an electrostatic latent image is formed on the photosensitive drum 1 through a blue color separation filter, and is developed by a yellow developing device 12 to form a visible image on the photosensitive drum. On the other hand, the transfer paper I5 stored in the force set 16 is fed by a paper feed roller 17, aligned with the visualized image on the photosensitive drum by a registration roller 18, and sent to the transfer drum 2. Further, the transfer paper 15 is clamped by a clamper 29 provided on the transfer drum 2, and under the action of the transfer charger 19, the yellow visible image on the photosensitive drum 1 is transferred to the transfer paper 15 on the transfer drum 2. transcribed.

In the second scan of the document, the color separation filter 10 is switched to green, and a visible image is created in the magenta developing device 13 through the same image creation cycle as described above, and the magenta image is superimposed on the yellow image on the transfer paper. match. Do the same for the third time,
The color separation filter 10 is switched to red, a visible image is created in the cyan developing device 14, and the cyan image is superimposed on the yellow-magenta image.

After the three-color images color-separated as described above are superimposed and the same color tone as the original is copied onto the transfer paper 5, it is separated from the transfer drum 2 by the separation static eliminator 20 and the separation claw 21, and then by the fixing roller 22. The image is fixed and discharged onto the tray 23.

In the color balance adjustment system shown in FIG.
The set value signal sent to the microcomputer 53 can be either a digital or an analog signal, and in the case of an analog signal, an AD converter is required before and after the microcomputer 53, but there is an advantage that the number of signal lines is reduced.

The color balance adjustment operation panel is provided with only nine setting dials, and in combination with the selection switch on the color balance selection operation panel shown in Fig. 4, settings for a predetermined color tone are set. It is also possible to provide the number of setting dials on the board in sets corresponding to the number of selection switches, and to fixedly set which condition amount each dial sets for which color tone.

In this case, a large number of dials are required, but all amounts for all tones can be set with a single operation of one setting switch 40, and in this case, the 1m switch 41 and indicators 42 and 43 are unnecessary. All dials allow you to read the current conditions at any time. In this case, the high voltage transformer 5 is directly connected to the color balance adjustment operation panel without going through the microcomputer 53 and the nonvolatile memory element 54.
5.57 and the lamp regulator 56.

According to the present invention, for each color separation, the amount of charge, developing bias voltage, and amount of light can be easily set using a dial according to each color tone to be copied, and once set, the color tone can be selected using the selection switches 61 to 65. By simply doing this, it is now possible to always form each color component image with the optimum image density for that color tone. That is, color balance adjustment, which conventionally required experience, can be automatically performed within the machine.

For example, multiple conditions such as the amount of charge, developing bias voltage, and amount of light can be stored and set for each color, making it possible to more precisely control the reproduction of the color tone of the copied document and to obtain good copies.

According to the present invention, it is easy to set, modify, and change each condition, and furthermore, it is easy to confirm the current setting conditions, so that it is possible to always optimally match the color tone of the original to be used.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram illustrating a copying apparatus according to the present invention, FIG. 2 is a plan view of a color balance adjustment operation panel, FIG. 3 is a configuration diagram of an example of a color balance adjustment system, and FIG. 4 is a color balance selection operation panel. The plan view of FIG. 5 shows the image characteristics, toner color characteristics, and development characteristics 1. FIG. 3 is a diagram showing charging exposure characteristics. 1... Photosensitive drum 2... Transfer drum 3...
Light a 11... Charger 12.13.14...
・Developing device 15...Transfer paper 19...Transfer charger 24・
...Original reading device (image density detection device) 52...Controller 53...Microcomputer 54...Nonvolatile memory element 55...High voltage transformer 56...High voltage transformer 57
...Lamp regulator (and 1 other person)

Claims (1)

[Claims] (1) In a copying device that charges, exposes, and develops each component of a color-separated light image of a color original, and transfers each color component image onto transfer paper, the amount of charge of the charger, the development bias potential of the development device, means for adjusting a plurality of setting conditions for setting the image density of each color component such as the light intensity of the exposure light source; means for selecting and setting the color tone of the original; and a non-volatile memory for storing the values set by the adjusting means and the selection setting means. a storage element, an image density detection means for detecting the image density of each color component of a document, an image processing means for performing image processing based on a signal from the image density detection means, and the nonvolatile storage element based on information from the image processing means. means for selecting an optimal setting condition value from among the setting condition values stored in the setting condition value, and means for controlling conditions of the charger, the developing device, and the exposure light source based on the setting condition selected by the setting condition selection means. A color balance adjustment device for a copying machine, comprising: