JPH04249268A - Color image copying device - Google Patents

Abstract

PURPOSE:To stably output a stable image regardless of the number of copies or environment. CONSTITUTION:A recording part consisting of a photosensitive drum 122, a developing device 123, and a transfer drum 124 performs specified recording by using recording materials respectively corresponding to plural different colors, and a sensor 122 measures the amount of the recording materials in the case that recording is performed by a recording means, then the density signal correction information is set based on the measured results of the respective colors.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, a color image copying apparatus equipped with an auto-calibration function.

0002

2. Description of the Related Art Conventionally, in this type of apparatus, calibration has been performed by a service person when replacing consumables such as a photosensitive drum. Calibration is to correct the deviation of an output image from an ideal image with respect to an input signal.

0003

[Problem to be Solved by the Invention] However, in the conventional example, the operation is complicated for the user, and calibration is only performed by a service person, so it is difficult to output a stable image immediately after maintenance by a service person. Although this is possible, there is a drawback that the output image becomes unstable due to deterioration of each element and environmental fluctuations as the number of copies increases.

The present invention has been made in view of the above-mentioned drawbacks of the conventional example, and its purpose is to perform calibration without bothering service personnel or users, and to adjust the number of copies and the environment. The object of the present invention is to provide a color image device that can always output stable images without any influence.

[0005]

[Means for solving the problem] Solving the above problems,
In order to achieve the object, a color image copying apparatus according to the present invention includes a recording means for performing predetermined recording using recording materials respectively corresponding to a plurality of different colors; The apparatus is characterized by comprising: a measuring means for measuring the amount of each recording material at a time; and a setting means for setting correction information for the density signal based on the measurement results for each color by the measuring means.

[0006]

[Operation] According to this configuration, the recording means performs predetermined recording using recording materials corresponding to a plurality of different colors, the measuring means measures the amount of each recording material when recording by the recording means, The setting means sets correction information for the density signal based on the measurement results for each color by the measuring means.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. <First Embodiment> FIG. 1 is a block diagram showing a first embodiment of a color image copying apparatus according to the present invention. In the figure, 101 is an original table glass, 102 is an original, 103 is a halogen lamp for illuminating the original, 104 is a rod lens array, 105 is a CCD line sensor, 106 is a sample hold (hereinafter referred to as "S/H") circuit, 107 108 is an AD conversion circuit, 108 is a shading correction circuit, 109 is a logarithmic conversion circuit, 110 is a black extraction circuit, 111 is a masking circuit, 112 is a UCR circuit, 113 is a γ correction circuit, 11
4 is a selector, 116 is a D/A conversion circuit, 117 is a triangular wave generation circuit, 118 is a comparator, 119 is a laser driver, 120 is a semiconductor laser, 121 is a polygon mirror, 122 is a photosensitive drum, 123 is a developer, 124 is a transfer drum, 125 is a sensor, 129 is a CPU that instructs auto-calibration for γ correction, 129a is a CP
A ROM stores a program according to the flowchart of FIG. 3 for operating the U129, and a RAM 129b is used as a work area for various programs. Reference numeral 130 denotes a table used when the CPU 129 executes a program instructing auto-calibration, and will be described in detail in the explanation of FIG.

To explain the operation of the above configuration, an original 102 placed on an original platen glass 101 is illuminated by a halogen lamp 103 for illuminating the original, and a CCD line sensor 105
imaged on top. 105 has R, G, and B CCD line sensors dot-sequentially applied to separate the originals into 400 colors.
Output with pixel density of dpi resolution. The halogen lamp 103 for illuminating the document, the rod lens array 104, and the CCD line sensor 105 are scanned in the direction of the arrow, and sequentially read and output the document image line by line. 106 S/H circuit is C
CD output is sampled and held for each pixel, and 107 A/
A D conversion circuit converts it into a digital signal, and a shading correction circuit 108 corrects output unevenness due to variation between CCD pixels.

The R, G, and B signals output from the shading correction circuit 108 are sent to the logarithmic conversion circuit 109, and are converted into complementary colors C (cyan), M (magenta), and Y (yellow) by logarithmic conversion, thereby rendering black. C in the circuit 110,
The minimum value K (black) of Y and H is depicted. The masking circuit 111 and the UCR circuit 112 perform well-known color correction processing and are sent to the γ correction circuit 113. γ correction circuit 11
The details of 3 will be explained later.

The γ correction circuit 113 outputs C, M, Y, and K frame sequential signals and sends them to the selector 114. The output of the selector 114 is converted into an analog signal again by the D/A converter 116 and is then converted to a triangular wave generation circuit 11 synchronized with the image clock.
7 and pulse width modulates the semiconductor laser 120 through the laser driver 119. The recoil laser output is collimated by a suitable optical system and scans a polygon mirror 121 rotating at high speed over a photosensitive drum 122 to form a latent image on the drum. The latent image on the photosensitive drum 122 is developed by a developing device 123, and is transferred onto a transferred paper onto a transfer drum 124. Here C, M, Y, K
The images are superimposed, fixed, and output as a hard copy.

At this time, a sensor 125 is provided to measure the amount of toner in the toner image formed on the photosensitive drum 122. The sensor 125 includes a light source and a light receiving element, and measures the density of the toner image formed on the drum.
Or, when copying a certain test pattern chart, C, M, Y, K is formed by forming a solid toner image on the drum and measuring its height to determine the amount of toner.
Measure the amount of each toner. Information on the amount of toner of each color from the sensor 125 is sent to the CPU 129. C.P.
At U129, the signal sent from the sensor 125 is compared with the table 130.

FIG. 2 shows a table 13 according to the first embodiment.
It is a figure explaining 0. The table 130 stores in advance the amount of toner for outputting the gradation pattern of each of the four monochromatic colors of YMCK, and sends the comparison result to the γ correction circuit 113 so that the input signal and output image are linear with respect to the input signal. γ correction is performed on the signals of each color using an LUT so as to output an ideal hard copy with the same relationship.

The operation of the first embodiment will now be explained. FIG. 3 is a flowchart illustrating the autocalibration procedure according to the first embodiment. first,
When a user instructs to copy the test pattern chart using an operation panel (not shown), the copying operation is started (step S1). Thereafter, toner images C, M, Y,
The amount of K toner is measured (step S2), and this measured value is compared with the gradation pattern of each color in the table 130 to detect deviation from the ideal state (input signal and output image are linear). (Step S3). In this way, the correction amount is determined from the detected deviation amount (step S4), and γ
A signal indicating the amount of correction is sent to the correction circuit 113 (step S5). The γ correction circuit 113 that receives this signal adjusts the γ correction amount using a lookup table.

As explained above, according to the first embodiment, by measuring the amount of toner through a test and performing auto-calibration, it is possible to maintain stability without being affected by changes in the environment of the copying machine or an increase in the number of copies. It is possible to obtain an output image.

[0015]

[Other Embodiments] <Second Embodiment> FIG. 4 is a block diagram showing a second embodiment of a color copying apparatus according to the present invention. FIG. 4 shows only the main parts of the second embodiment, and
Circuits with functions corresponding to those in the diagram are represented by similar numbers with a dash added.

The second embodiment is an example in which auto-calibration of the masking circuit 111' is performed using a table 130' as shown in FIG. 6, which associates the measured amount with the color mixture. According to the signal from the sensor 125 provided on the photosensitive drum 122 of the first embodiment, it is possible to automatically perform auto-calibration of the masking coefficient of the masking circuit 111 by the method of least squares or the like. Incidentally, since the auto-calibration procedure follows the flowchart shown in FIG. 3, a description thereof will be omitted.

As a modification of the second embodiment, in the configuration shown in FIG.
It may be configured such that i can also be output to the masking circuit 111. <Third Embodiment> In the first embodiment, a sensor 125 for measuring the amount of toner may be provided on the transfer drum 124 to perform calibration including transfer efficiency. This embodiment can also be applied to the second embodiment. <Fourth Embodiment> FIG. 5 is a block diagram showing a fourth embodiment of a color image copying apparatus according to the present invention. In the figure, 44 indicates the output section of the main body of the copying machine, 41, 42,
43 indicates different readers connected to the output section 44. In the output section 44, 45 indicates a γ correction circuit, and 46 indicates a toner amount detection sensor. According to the above configuration, since the toner amount detection sensor 46 is disposed following the γ correction circuit 45, the configuration is such that changes due to correction are fed back.

In operation, when a specific document is read by each of the readers 41, 42, 43 and a hard copy is output, the toner amount detection sensor 46 detects toner on the photosensitive drum or transfer drum (not shown). The amount of toner forming an image is detected and auto-calibration is performed within the output section 44. As a result, no matter what kind of reader is connected, stable image output can be provided without being affected by the characteristics of the reader itself.

The first embodiment is a copying machine, and the image reading device (reader) side is equipped with γ correction and the like. The fourth embodiment is a standalone printer, and is not affected by reading characteristics when used in connection with various devices (models, manufacturers, etc.). The printer has a correction device (circuit). This may be done automatically every time a certain number of pictures are taken, or it may be done when the user feels that the color is strange.

Alternatively, a patch pattern may be written at the leading edge of the image for each copy. However, a margin is provided at the leading edge of the image, and that portion is not transferred.

[0021]

[Effects of the Invention] As explained above, according to the present invention,
Stable output images can be obtained without being affected by environmental changes or increases in the number of copies.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a first embodiment of a color image copying apparatus according to the present invention.

FIG. 2 is a diagram illustrating a table according to the first embodiment.

FIG. 3 is a flowchart illustrating the autocalibration procedure according to the first embodiment.

FIG. 4 is a block diagram showing a second embodiment of a color copying apparatus according to the present invention.

FIG. 5 is a block diagram showing a fourth embodiment of a color image copying apparatus according to the present invention.

FIG. 6 is a diagram illustrating a table according to a second embodiment.

[Explanation of symbols]

41-43 Leader 44 Output section 45 γ correction circuit 46 Toner amount detection sensor 101　Original table glass 102 Manuscript 103 Halogen lamp for document illumination 104 Rod lens array 105 CCD line sensor 106 S/H circuit 107 AD conversion circuit 108 Shading correction circuit 109 Logarithmic conversion circuit 110 Black extraction circuit 111, 111' Masking circuit 112 UCR circuit 113 γ correction circuit 114 Selector 116 D/A conversion circuit 117 Triangular wave generation circuit 118 Comparator 119 Laser driver 120 Semiconductor laser 121 Polygon mirror 122 Photosensitive drum 123 Developing device 124 Transfer drum 125 sensor 129,129' CPU 129a, 129a' ROM 129b, 129b' RAM 130,130' table

Claims (6)

[Claims] 1. A color image copying apparatus, comprising a recording means for performing predetermined recording using recording materials respectively corresponding to a plurality of different colors, and a measurement method for measuring the amount of each recording material when recording by the recording means. 1. A color image copying apparatus, comprising: a setting means for setting correction information for a density signal based on a measurement result for each color by the measuring means. 2. A color image copying apparatus according to claim 1, wherein said recording means includes a photosensitive drum, and said measuring means is disposed on said photosensitive drum. 3. A color image copying apparatus according to claim 2, wherein said measuring means includes a sensor. 4. A color image copying apparatus according to claim 1, wherein said setting means includes a table that associates said measurement results with said correction information. 5. The color image copying apparatus according to claim 1, wherein the correction information includes γ correction information. 6. The color image copying apparatus according to claim 1, wherein the correction information includes masking information.