JPH01580A - color image forming device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to a simple electrophotographic color copying machine that records a desired color image through a plurality of exposure processes. The present invention relates to a suitable color image forming apparatus.

[Background of the Invention] In order to record a color original in a color image forming apparatus using an electronic copying machine, the color original is first separated into a plurality of color separated images, and then an image is formed for each separated color signal. A color image corresponding to a color original is recorded (copied) by writing on the original, repeating development and transfer, or by performing transfer and fixing processing after the development process for all colors is completed. ing.

Therefore, in a color image forming apparatus that performs such color recording processing, in order to perform color recording, it is necessary to rotate the image forming member multiple times at least for each of a plurality of color signals. In this case, mutual alignment (alignment at the leading edge of the image) is required between the previously developed latent image and the next developed latent image.

In other words, if the writing start position of the previously developed latent image differs from the writing start position of the next developed latent image, color misregistration will occur and the image quality of the recorded color image will deteriorate significantly. be. Therefore, registration adjustment regarding recorded colors is very important.

In order to adjust the registration, it is sufficient to synchronize the optical scanning system with the rotational position of the image forming drum or the transfer drum. It may also be used as an element.

That is, the optical scanning system can be started based on the drum index signal obtained from the drum index element, or other image processing can be executed by starting the optical scanning system.

Such technology is disclosed in, for example, ``Japanese Patent Application Laid-Open No. 189066/1986.
No. 61-51178, etc.

For example, ``Japanese Unexamined Patent Publication No. 189066/1989'' describes a device that forms a plurality of color toner images in a superimposed manner on an image forming body and transfers them onto a transfer material at once to form a color image. Are listed.

A drum index element is provided on the image forming body to synchronize the optical scanning system with the rotational position of the image forming body.

Furthermore, ``Japanese Unexamined Patent Publication No. 61-51178'' discloses that each time a color toner image is formed on an image forming body, it is transferred onto a transfer drum, and a plurality of color toner images are superimposed on the transfer drum. An apparatus for forming images is described.

In this publication, an index element is provided on the transfer drum to synchronize the rotational position of the transfer drum with an optical scanning system.

In these known color image forming apparatuses, there is only one tram index element, and the index signal is obtained only once per rotation of the drum.

When detecting drum index signals to control image writing, etc., especially when recording color images,
The relationship between the recording start, that is, the copy start, and the drum index signal is as shown in FIG. That is, based on one index signal, forward rotation, image exposure for the first to third colors, and back rotation are executed.

That is, when copying starts, pre-rotation processing is executed.

The pre-rotation processing refers to processing necessary for the copy sequence, such as preparing the optical scanning system to start writing, pressing the cleaning blade, starting charging, and turning on the developing motor. The pre-rotation process is completed within a period of one revolution of the drum.

When the pre-rotation process is completed, the mode shifts to color recording mode, and electrostatic latent image and development processes are performed sequentially from the first color. Accordingly, the optical scanning system performs optical writing only during a predetermined period during one rotation of the drum, as shown in Figure B, and the optical system returns to its original position (home position) at the same time as the writing is completed. This completes one revolution of the drum.

If the recording of the color original is to be completed with the third color, then the post-rotation process will be executed and the printer will be in a state of standby for recording the color original again.

The post-rotation process refers to a series of processes such as transporting the recording paper (transfer paper) to the fixing system, releasing the cleaning blade from pressure, and turning off the developing motor.

Therefore, this post-rotation process requires at least one revolution of the drum.

[Problems to be Solved by the Invention] Incidentally, as is clear from FIG. 36, the time point at which the post-rotation process ends is immediately before the drum index signal is obtained, and this time T is always constant. Then, when the copy button is operated, the same copy operation as before is repeated.

Therefore, a color image writing operation always starts from the same position on the drum.

In this way, if image writing always starts from the same position, the photoreceptor at that position deteriorates, causing a significant deterioration in the service life of the photoreceptor.

Furthermore, as mentioned above, when the number of drum indexes is one, even if the pre-rotation process does not require time for one rotation of the drum, the pre-rotation process may be performed in, for example, 2/3 to 1/2 rotation. Even if the copying process is completely completed, the first color is copied only after the next drum-in-deluxe is detected.

Similarly, in the post-rotation process, although the time required for two rotations of the drum is not required, as long as one drum index per rotation is used as a reference, it takes at least a little less than two rotations. This is because the post-rotation process also takes about one and a half rotations.

The fact that the pre-rotation and post-rotation processes take time is a bottleneck in reducing the copying time.

Furthermore, when making multiple copies, the number of copies per unit time is constant even if the paper size used is different.

That is, as shown in FIGS. 37A to 37D, when the paper sizes are different, the time required to copy one sheet is the same even if the size is B4, for example, just because the optical scanning time is different.
The BS size is also always constant.

This is because, as shown in FIG. 37, the drum index is obtained only once per rotation of the drum, so the position of the electrostatic latent image on the drum cannot be changed depending on the paper size.

Ideally, the copying time would be shorter when copying in 85 format than when copying in 84 format, and the number of copies per unit time could be increased.

Therefore, this invention solves these conventional problems, and prevents fatigue of the photoreceptor, thereby extending the life of the photoreceptor drum and shortening the copying time. It is.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention forms a color image by rotating the image forming body multiple times and repeating at least latent image formation and development processing. In the color image forming apparatus, the image forming apparatus includes means for generating reference signals corresponding to a plurality of predetermined positions on the image forming body, and a start timing of an image forming cycle using the reference signal corresponding to any one of the predetermined positions. In addition to controlling
The image forming apparatus is characterized in that it includes means for controlling the start timing of another image forming cycle using a reference signal corresponding to any one of the other predetermined positions.

[Operation] Color image information is read by an image reading means such as a CCD and converted into a color image signal. The color image signal is separated into a plurality of color signals (in the embodiment, three colors of red, blue, and black) by the color signal forming means.

An electrostatic latent image is formed by the separated color signals. The writing timing of the electrostatic latent image, that is, the color signal, is regulated based on the index signal obtained from the drum.

Since there are a plurality of drum indexes, the pre-rotation process can be performed based on 3 to 4 drum indexes, and the post-rotation process can be performed based on about 10 drum indexes.

In this way, by making the pre-rotation process and the post-rotation process different in time, the position on the drum at the start of the next copy is shifted in order, so the relationship between the start of copying and the position of the drum can be made indefinite.

As a result, the copy start position moves evenly over the drum, and the copy start positions are averaged. Therefore, deterioration in specific parts of the image forming body is prevented, and the life of the image forming body is extended.

Furthermore, since there are a plurality of drum indexes, the pre-rotation processing time and the post-rotation processing time can be selected to the optimum minimum value. Furthermore, since the copying time varies depending on the paper size, this contributes to shortening the copying time.

Although the number of notches in the index element is 6 in this example, it is not limited to this and may be 2 to 10.
It can be set to 0 pieces.

However, if the number is 100 or more, it may be difficult to obtain the accuracy of the notch interval (pitch accuracy) during machining.

In this way, when a large number of cuts are formed, it becomes easy to change the exposure position on the image forming body, and fatigue of the image forming body can be reduced.

Another advantage is that copying can be stopped at any position. That is, no matter at which rotational position the copy mode is stopped, the next copy can be started because the index notch is located near the stopping position.

[Example] Hereinafter, an example of a color image forming apparatus according to the present invention will be described in detail with reference to FIG. 1 and subsequent figures.

FIG. 1 shows a schematic configuration of a system in a color image forming apparatus according to the present invention.

Color image information such as a manuscript is read by an image reading device 10,
In addition to being converted into a color image No. 8, the image data is converted into image data with a predetermined number of bits, for example, image data with 16 gradations (0-F), by performing A/D conversion processing and other image processing. Ru.

The image data is separated into a plurality of color signals by the color signal forming means 20. In this example, as multiple color signals,
Although the case is shown in which three colors of red light, blue No. 8, and black light are used, it is easy to understand that it is also possible to separate the signals into other color signals.

The separated color signals are sequentially binarized in a binarization circuit 30. In the embodiment, it is converted into a binary dither using a dither matrix having a predetermined threshold value or the like.

The dithered image is supplied to the output device 100 via the interface circuit 40. The interface circuit 40 is used to control the output state of the dither image, exit of the test pattern, and the like.

As the output device 100, a laser recording device or the like can be used. When a laser recording device is used, a dither image is converted into a predetermined optical signal, and this is converted into a predetermined optical signal based on the binary data of the dither image. Modulated. Therefore,
Although the signal modulation in this example is internal modulation, external modulation may equally well be used.

An electrostatic latent image is formed for each color by the optical signal obtained from the output 'A position 100. After the electrostatic latent image, development processing is performed for each color, and then a fixing processing is performed, so that no image is formed on the recording paper. A desired color image will be recorded.

Processing from the image reading device 10 to the output device 100 described above is performed according to a predetermined algorithm based on command signals sent from the two control units 200 and 250. Therefore, microcomputers are used for both the control units 200 and 250.

The first control unit 200 controls the main body of the image processing apparatus,
The second control unit 50 mainly controls peripheral devices provided for image reading.

Note that 99 indicates a system bus through which these various command signals are exchanged.

Therefore, in addition to sending out the various command signals described above, the first and second control sections 200 and 250 also control various hardware for image reading and control the color copying machine attached to the output device 100. is executed according to the specified sequence.

Next, a specific example of such a color image forming apparatus will be explained.

First, a simplified color copying machine suitable for application to the present invention will be explained with reference to FIG. 2 and subsequent figures.

B-type color copying machines attempt to record color images by separating color information into approximately three types of color information. In this example, black BK is used as the color information of the 3gl class to be separated.
, red R and helmet B are exemplified.

In FIG. 2, 60 is an example of the main parts of a color copying machine, in which IA is a platen glass on which the original 1 is placed, and IB is a reciprocating carriage. The linear halogen lamp IC can be used as a light source for exposure, and is installed in the carriage IB so that its tube axis is perpendicular to the plane of FIG. 2.

It moves together with carriage IB.

The document 1 is irradiated with light by the halogen lamp IC.

IF is a movable mirror unit with mirrors arranged at an opening angle of 90°, and IE is a stepping motor for driving.

(2) D is a lens that receives reflected light from the document surface via a mirror; 2 is a dichroic prism; 3.4 is a line-shaped image sensor; in this example, a CCD is used;

The red separated image separated by the dichroic prism 2 is focused on the CCD 3, and the cyan separated image is focused on the CCD 4.
is imaged.

The detection elements of the CCDs 3 and 4 are arranged in a direction perpendicular to the paper surface of FIG. 2 (main scanning direction).

61 is a drum-shaped image forming body with OPC on its surface.
A photoconductive photoreceptor surface layer such as (organic photoconductor) is formed,
This is done by forming an electrostatic image (electrostatic latent image) corresponding to the optical image.

The following members are sequentially arranged on the circumferential surface of the image forming body 61 in the direction of rotation thereof.

The surface of the image forming body 61 is charged in the - direction by the charger 62, and the surface of the image forming body 61, which is completely charged in the - direction, is subjected to image exposure (its optical image) based on each color separation image (color i image). 64) is performed. After the image is exposed, it can be developed using a predetermined developing device. The developing units can be arranged in the number corresponding to the color separation images.

In this example, the developing device 6 filled with red toner developer
5, a developing device 66 filled with blue toner developer,
A developing device 67 filled with a black toner developer is sequentially arranged facing the surface of the image forming body 61 in this order toward the rotation direction of the image forming body 610.

The developing units 65 to 67 are sequentially selected in synchronization with the rotation of the image forming body 610. For example, by selecting the developing unit 67, toner adheres to the electrostatic image based on the black color separation image, and thus the black color separation is performed. The image is developed.

A pre-transfer charger 69 and a pre-transfer exposure lamp 90 are provided on the developing device 67 side, and these make it easier to transfer the color image to the recording medium P and to make it easier to separate the recording medium P from the image forming body 61. ing.

However, these pre-transfer charger 69 and pre-transfer exposure lamp 90 are provided as necessary.

The color image developed on the image forming body 61 is transferred onto the recording medium P by a transfer device 91. Transferred recording body P
The fixing process is completed by the subsequent fixing process "a92," and the recording medium P is then discharged.

Note that the static eliminator 93 can be one of a static elimination lamp and a corona discharger for static elimination, or a combination of both, as required.

The cleaning device 94 is composed of a cleaning blade, a magnetic brush, a fur brush, etc., and is used to remove residual toner adhering to the drum surface after the color image of the image forming member 61 has been transferred.

It is well known that this removal operation is performed so that the developed surface is separated from the surface of the image forming member 61 by the time the developed surface is reached.

As the charger 62, a scorotron corona discharger or the like can be used. This is due to the previous charging. g
This is because stable charging can be applied to the image forming body 61 with little J effect, and a constant surface potential can be obtained.

As the image exposure 64, fi exposure obtained by a laser beam scanner is used. In the case of a laser beam scanner, clear color images can be recorded, as will be described later. The image exposure means not shown in FIG. 3 shows an example of this laser beam scanner (optical scanning device) 80.

The laser beam scanner 80 has a laser 81 such as a semiconductor laser, and the laser 81 is controlled on and off based on a color separation image (for example, binary data). A laser beam emitted from the laser 81 enters a mirror scanner (polygon) 85 made of an octahedral rotating polygon mirror via mirrors 82 and 83. A laser beam is deflected by the mirror scanner 85 and is irradiated onto the surface of the image forming body 61 through an f-θ lens 87 for imaging.

88 and 89 are cylindrical lenses for negative tilt correction.

The laser beam is directed to the image forming body 6 by the mirror scanner 85.
1 is scanned at a constant speed in a predetermined direction a, and such scanning results in image exposure corresponding to a color-separated image.

Note that the collimator lens 86 is used to adjust the beam diameter on the image forming body 61 to a predetermined diameter.

As the mirror scanner 8S, a galvanometer mirror 1 optical crystal deflector or the like can be used instead of the rotating polygon mirror.

Since the developing units 65 to 67 have almost the same configuration, the developing unit W
The configuration of 65 will be explained.

FIG. 4 shows an example of the developing device 65.

In the figure, 70 is a housing, 71 is a toner replenisher, 72 is a sponge roller, 73a and 73b are toner stirring members, 74 is a scraper, 75 is a developing sleeve, 76 is a magnet (roller-shaped developing magnet), and 78 is a H-cut board,
79c is a resistor, 79b is an AC power supply, and 79a is a DC power supply.

The toner supplied from the toner supply 'a71 is sent to a developing section consisting of a developing sleeve 75 and a magnet 76 by the action of a sponge roller 72 and stirring members 73a and 73b. A layer of developer 77 made of toner and carrier whose thickness is regulated to be constant by a cut plate 78 is formed on the developing sleeve 75, whereby the latent material formed on the surface of the image forming body 61 is completely developed. .

After development, the developer on the surface of the sleeve 75 is removed by the scraper 7.
scraped off by 4.

Note that the clockwise arrow indicates the moving direction of the developer, and the counterclockwise arrow indicates the rotating direction of the magnet body 76.

An alternating current signal of a predetermined level superimposed on the direct current signal is applied to the developing sleeve 75 via a resistor 79c, thereby applying a predetermined developing bias between the developing sleeve 75 and the image forming body 61.

In addition, for the second and subsequent development steps that are repeated to superimpose color toner images, care must be taken to ensure that the toner that has adhered to the image forming body 61 due to the previous development is not shifted during the subsequent development. In this sense, it is preferable that such development be performed under non-contact jumping development conditions.

FIG. 4 shows a type of developing device that performs development based on such non-contact jumping developing conditions.

As the developer, it is preferable to use a so-called two-component developer in which a non-magnetic toner and a magnetic carrier are mixed.
Yes. This is because this two-component developer has clear colors and can easily control the charge of the toner.

As the image reading device 10, one having a configuration as shown in FIG. 5 can be used.

In the figure, color image information (optical image) of a document 1 placed on a mounting table IA is separated into two color-separated images by a dichroic mirror 2.

In this example, the image is separated into a color-separated image of red R and a color-separated image of cyan Cy. Therefore, the cutoff of the dichroic mirror 2 used is about 600 nm. As a result, the red component becomes transmitted light, and the cyan component becomes reflected light.

The red R and cyan cy color separation images are each supplied to an image reading means 3.4 such as a CCD, and the red component R is
And image No. 43 containing only the cyan component Cy is output.

Figure 6 shows the relationship between the image (No. 8 R, cy) and various timing signals necessary for image output, and the horizontal effective area signal (H-VALID) (C in the figure) is the maximum Corresponding to the original reading width W, the image signals R and CY shown in F and G in the figure can be read out in synchronization with the synchronization clock CLK (E in the figure).

These images No. 43 R and CY are supplied to the Δ/D conversion PJ5 via a normalizing amplifier (not shown), and are converted into digital signals of a predetermined number of bits J! ! ! ! be done.

Shading correction is performed during Δ/D conversion. For this reason, a memory 6 for shading correction is prepared, and one line of white image data is extracted from outside the image reading area, and then used as data for shading correction. The memory 6 is read out in synchronization with the clock of the CCD drive pulse generation circuit 7.The generation circuit 7 is provided with a clock generator 8.The timing of the memory is determined by an index signal for starting scanning supplied to the generation circuit 7. and second control unit 250
regulated by control signals from.

The digital color image signal is supplied to the next stage color separation circuit 150, where it is separated into a plurality of color signals necessary for color image recording.

In the above example, it is a simple recording device that records a color image in three colors: red, R, blue, and black.
In the color separation circuit if@150, these three color signals R, B,
It will be separated into BK.

A specific example of color separation will be described later.

The color signals R, B, and BK are supplied to a ghost canceller 9, where ghost removal processing is performed to cancel ghost signals generated in the main scanning direction and the sub-scanning direction.

Here, as shown in FIG. 7, the main scanning direction with respect to the original 1 is the line direction (horizontal scanning direction) of the CCDs 3 and 4, and the sub-scanning direction is the moving direction of C0D3°4 (vertical scanning direction). direction).

Color 4z R, B, BK after ghost removal is color selection circuit 1
60, one color No. 43 can be selected per rotation of the image forming body 61.

This is because, as mentioned above, an image forming process is adopted in which one color image is developed in one rotation of the image forming body 61, and the image forming process is synchronized with the rotation of the image forming body 61. The developing devices 65 to 67 are sequentially selected, and the color signals corresponding to the selected developing devices are sequentially sent to the color selection circuit 16.
0 will be selected.

Selection signals 01 to G3 for color signals are sent to the second control unit 25.
0 (second microcomputer). The output states of the selection signals 01 to G3 differ depending on the case of three-color recording, that is, the normal recording mode, and the case of monochrome recording, that is, the color-specified recording mode.

Note that color separation processing for separating color signals from a color original into three color signals is executed every rotation of the image forming body 61.

The above-mentioned color separation (color separation into three color signals from two colors) is performed based on the following idea.

Figure 8 schematically shows the spectral reflection characteristics of a color chart of color components, in which Figure A shows the spectral reflection characteristics of achromatic colors, Figure B shows the spectral reflection characteristics of blue, and Figure 8 shows the spectral reflection characteristics of blue. C
indicate red spectral reflection characteristics, respectively. The horizontal axis is the wavelength (n
m), and the vertical axis is relative sensitivity (%).

Now, if the level of the red signal R normalized by white is ■R, and the level of the cyan signal Cy is VC, then these signals VR
, V, and C, the colors red, blue, and black can be separated based on the created color separation map.

When determining the coordinate axes, the following points need to be considered.

■In order to express halftones, the reflectance (reflection density) of original 1, which corresponds to the brightness signal of the television signal, is
Introduce the concept of

II. Contains the concept of color difference (including hue and saturation) such as red and cyan.

Therefore, it is preferable to use the following as the luminance 4:J second information (for example, a 5-bit digital signal) and the color difference number 43 information (similarly, a 5-bit digital number 43).

Luminance signal information = VR + vC (1) Tako, 0≦VR:ii, 1, O (2) O≦VC≦1.0 (3) 0≦VR
+VC≦2.0 (4) Sum of VR and VC (
VR + VC) ranges from black level (=O) to white level (=2.
0), and all colors exist in the range from 0 to 2.0.

Color difference signal information = VR/ (VR+VC) or VC/
(VR+VC) (5) In the case of an achromatic color, the proportions of the reddish level VR and cyan level VC included in the overall level (VR+VC) are constant. Therefore, VR/ (VR+VC)=Vc, / (VR+vC)=
0.5 (6).

On the other hand, in the case of chromatic colors, 0.5<
VR/ (VR+VC)≦1.0 (7)0≦VC
/ (VR+VC)<0.5 (8) For cyan colors, 0≦VR/ (VR+VC)<0.5 (9) 0.
It can be expressed as 5<VC/(VR+VC)≦1.0 (10).

Following, the coordinate axes and 1,4 (VR+VC) and VR/(
VR+VC) or (VR+VC) and VC/(V
By using a coordinate system having two axes of R+VC, chromatic colors (red and cyan) and achromatic colors can be clearly separated just by level comparison processing.

FIG. 9 shows a coordinate system in which the vertical axis represents the luminance signal component (VR+VC) and the horizontal axis represents the color difference signal component VC/(VR+VC).

If VC/(VR+VC) is used as the color difference ε3 component, areas smaller than 0.5 will be red-ish R, and areas larger than 0.5 will be cyan-ish Cy. Achromatic colors exist in the vicinity of color difference signal information=0.5 and in areas with little luminance signal information.

FIG. 10 shows a specific example of a color separation map in which colors are classified according to such a color separation method.

A ROM table is used for the color separation map, and the illustrated example shows an example in which the map is divided into 32×32 blocks. Therefore, the number of address bits for this ROM table is 5 bits for the row address and 5 bits for the column address. This ROM table stores quantized density corresponding values obtained from the original reflection density.

FIG. 11 is a system diagram showing an example of a color separation circuit 150 (A in the figure) and a color selection circuit 160 (B in the figure) for realizing such color separation.

To explain from A in the figure, terminals 150a and 150b have 3 terminals.
A red signal R and a cyan signal cy before color separation are supplied, and processing such as gradation conversion and γ correction is executed in an arithmetic processing circuit 151.

The data after the arithmetic processing is used as an address signal for the memory 152 in which the arithmetic results of (VR+VC) for obtaining luminance signal data have been stored, and the arithmetic results of the color difference signal data VC/(VR+VC) are also stored. It is used as an address signal for the memory 153.

- Each output of these memories 152 and 153 is a separate memory (
ROM configuration) is used as an address signal for 154 to 156. The memories 154 to 156 use a data table in which data of the color separation map shown in FIG. 10 is stored for each color.

The memory 154 is for the black signal BK, the memory 155 is for the red signal R, and the memory 156 is for the blue signal B.

As is clear from the color separation map shown in FIG. 10, by detecting the levels of the red signal R and cyan signal Cy, three color signals R, red, blue, and black are extracted from the color information signal of the color original. B.

It is possible to separate the output into BK.

Each of the memories 154 to 156 outputs density data (4-bit configuration) regarding each color signal and color code data of 2-bit configuration at the same time.

Density data and color code data are synthesized in the subsequent stage A2
Synthesized at 157.158. The combined density data and color code data are supplied to the ghost canceller 9, where ghost toy No. 3 removal processing is performed.

Each data after ghost removal is supplied to a color selection circuit 160 shown in FIG. 11B.

The color code data supplied to the terminal 161 is supplied to the decoder 164, where the color code is decoded, and the output of the code is supplied to OR circuits 166-169. Similarly, the data contents of the color selection signals G1 to G3 supplied to the terminal 163 are decoded by the decoder 165, and the decoded outputs are supplied to the plurality of OR circuits 166 to 169 described above to select colors from red to black. and signals including all of these colors (all colors), any color signal can be selected.

A selection signal for the color signal output from each OR circuit 166 to 169 is supplied to a density signal separation circuit 170 as a density selection signal. The concentration signal separation circuit 170 is supplied with the above-mentioned concentration data through the terminal 162.
This density data is selected in response to the above-mentioned selection signal.

The selected density data is supplied to the binarization circuit 30.

The color selection signals 61 to G3 correspond to the separated color signals, and in the normal color recording mode, three-phase gate signals G1 to G3 synchronized with the rotation of the image forming body 61 are formed (see FIG. 12). G-I). At the same time, the developing bias shown in FIG. 12 CE is supplied to the developing devices 65 to 67 in synchronization with the rotation of the image forming body 61.

As a result, the exposure and development processing steps are sequentially performed using exposure processes I-Ill (FIG. 5F) for each color.

On the other hand, in the color designated recording mode, a single designated image forming process is performed. The example shown in FIG. 13 is a case where red is specified, and in this case, three selection signals 01 to G3 are obtained in the same phase regardless of the specified color signal (G to ■ in the figure).

At the same time, the 'gl image bias is supplied only to the corresponding developing device 65 (D in the same figure), and this becomes in operation.

Therefore, since only the developing device 65 containing red toner (developer) is driven, an image is recorded in red regardless of the color information of the color original 1.

Even when specifying another color (black or blue), the image forming process is the same, so a detailed explanation thereof will be omitted.

FIG. 14 is a system diagram showing an example of the binarization circuit 30.

In the figure, a threshold table 32 includes a main scanning counter 33 that counts write clocks, a sub-scanning counter 34 that counts horizontal synchronization signals, and predetermined threshold data based on the count values of these counters 33 and 34. It has a matrix (ROM configuration) 35 that outputs.

If the document to be read is a line drawing, the threshold data is
Data of a constant threshold value corresponding to the concentration is used. On the other hand, when the original is a photographic image, binarization using the dither method is preferable, and in that case, the dither matrix is used as threshold data. Approximately three types of dither matrices are prepared depending on the density of the original, and these are selected based on the density information of the original obtained via the I10 boat 36.

The image data output from the color selection circuit 160 is compared with predetermined threshold data obtained from the threshold value table 32 in the comparison circuit 37 for binarization processing, and is binarized for each pixel.

Note that it is also possible to perform enlargement/reduction processing on the original image data before performing the binarization processing.

Enlargement/reduction processing in the main scanning direction is performed by electrical signal processing, and enlargement/reduction processing in the sub-scanning direction is performed by changing the moving speed of CCD 3°4 or image information while keeping the C0D3.4 exposure time constant. Let's do it.

An image processing circuit is provided for enlarging/reducing processing in the main scanning direction. Although a detailed explanation thereof will be omitted, an interpolation method is adopted when enlarging or reducing.

Interpolation method ξ is an image processing method that attempts to obtain enlarged or reduced images by increasing or thinning data related to a pair of original image data based on the level of the data of a pair of adjacent original images. be.

For example, when enlarging the original image twice, as shown in FIG. 15, the original image level D1. ．． An intermediate level S1 is obtained for D2, and this level S1 and the levels DI and D2 of the original image are used as image data after enlargement processing, that is, interpolated data S.

Enlargement/reduction is processed in real time. Therefore, the above-mentioned interpolation data is stored in advance in a ROM or the like, and the interpolation data S is addressed using a pair of original image data or the like.

Furthermore, in color separation, color ghost processing, and the like, these data are processed without being stored in a RAM or the like, so real-time processing is possible, which allows speeding up and downsizing.

FIG. 16 shows the interface circuit 40.

The interface circuit 40 is composed of a first interface 41 that receives binary data, and a second interface 42 that receives binary data sent therefrom.

The first interface 41 includes a timing circuit 43
from horizontal and vertical valid area signal (H-VALID), (
V-VALID) is supplied, and a predetermined frequency (in this example, 6M11.) is supplied from the counter clock circuit 44.
clock is supplied. Generally, a CCD drive clock is supplied.

As a result, binary data is sent to the second interface 42 in synchronization with the CCD drive clock only during the period when the horizontal and vertical effective area signals are generated.

The counter clock circuit 44 generates a main scanning side timing clock synchronized with the optical index signal.

The second interface 42 is an interface for selecting the binary data sent from the first interface 41 and other image data and sending the selected data to the output device 100 side.

Other image data refers to the following image data.

The first is test pattern image data obtained from the test pattern generation circuit 46, and the second is test pattern image data obtained from the test pattern generation circuit 46.
Thirdly, it is control data obtained from the printer control circuit 45.

The test pattern image data is used when inspecting image processing, and the batch image data for toner density detection is used during batch processing.

Both the test pattern generation circuit 46 and the batch circuit 47 are driven based on the clock of the counter clock circuit 44, thereby adjusting the timing with the binary data sent from the first interface 41.

The binary data output from the second interface 42 will be used by the output device 100 as a modulation signal for the laser beam.

FIG. 17 shows the peripheral circuit of the output device 1000. The semiconductor laser 81 is provided with its drive circuit 101, and the above-mentioned binary data is supplied to this drive circuit 101 as a modulation signal, and the modulation signal causes the laser to emit light. The beam is internally modulated. The timing circuit 10 is configured so that the laser drive circuit 101 is in a driving state only in the horizontal and vertical effective area sections.
It is controlled by the control1llII signal from 2. Further, a signal indicating the amount of light of the laser beam is fed back to the laser drive circuit 101, and the driving of the laser is controlled so that the amount of light of the beam is constant.

The mirror scanner 85 is driven by a polygon motor 104, and the scanning start point of the laser beam deflected by the mirror scanner 85 is detected by an index sensor 105, and the index signal is converted into a voltage signal by an I/V amplifier 106. Afterwards, this index signal is supplied to a counter clock circuit 44 or the like to adjust the timing of optical main scanning.

Note that 103 is a polygon motor drive circuit, and its ON/OFF signal 8- is supplied from the timing circuit 102.

Now, the various devices or circuits described above are
All are controlled by control units 200 and 250 of. The explanation will start from the second control unit 250.

As shown in FIG. 18, the second control unit 250 mainly controls the image reading system and its peripheral equipment, and 251 is a microcomputer (second microcomputer) for controlling the optical drive. ), and various information signals are exchanged with the main body control microcomputer (first microcomputer) 201 through serial communication. Further, the optical scanning start signal sent from the first microcomputer 201 is directly supplied to the interrupt terminal of the second microcomputer 251.

The second microcomputer 251 generates various command signals in synchronization with a clock of a predetermined frequency (12Mt(z)) obtained from a reference clock optical generator 258.

The second microcomputer 251 detects data for shading correction and sends a command signal for storing this to the memory 6 for shading correction. The length signal and the color selection signal for color recording are sent to the color selection circuit 1.
60.

The second microcomputer 251 outputs the following control signals.

First, a control signal for turning on and off the drive circuits of the CCDs 3 and 4 is supplied to their power supply control circuits (not shown). Second, for the lighting-side iM1 circuit 254 for the light source (such as a fluorescent lamp) 255 for irradiating the document 1 with the necessary light,
A predetermined control signal is supplied. Third, a drive circuit 2 that drives a stepping motor 253 for moving a movable mirror unit provided on the image reading device 10 side.
52 is also supplied with a control signal. Fourth, heater 25
7 (a control signal is also supplied to the wholesale circuit 256).

Note that the second microcomputer 251 receives data indicating the light amount information of a light source 255 such as a fluorescent lamp and the home position.

The first microcomputer 201 is mainly used to control the color copying machine. FIG. 19 shows an example of an input system and an output system from a color copying machine.

The operation/display unit 202 can input various input data such as magnification designation, recording position designation, and recording color designation, and display the contents thereof.

As the display means, an element such as an LED is used.

The paper size detection circuit 203 is used to detect and display the size of the cassette paper loaded in the tray, or to automatically select the paper size according to the size of the document.

The rotational position of the drum 61, which is an image forming member, is detected by a drum index sensor (detection means) 22°, and the timing of the electrostatic processing process is controlled by the index signal. Details of the drum index detection system will be described later.

The cassette zero sheet detection sensor 221 detects whether there are no sheets in the cassette. Similarly, the manual feed zero sheet detection sensor 222 detects the presence or absence of paper for manual feed in the manual feed mode.

The toner density detection sensor 223 detects the density of toner on the drum 61 or after fixing.

In addition, a 3m toner remaining amount detection sensor 224 to 226
The amount of toner remaining in each of the developing units 65 to 67 is individually detected, and when toner replenishment is necessary, a display element for toner replenishment provided on the operation section is controlled to light up.

- The time stop L sensor 227 is used to detect whether or not paper is correctly fed from the cassette to the second paper feed roller (not shown) side during use of the color copying machine.

Contrary to the above, the paper ejection sensor 228 is used to determine whether or not the fixed paper is correctly ejected to the outside.

The manual feed sensor 229 is used to detect whether a manual feed tray is set. If it is set, it will automatically switch to manual feed mode.

The sensor output obtained from each sensor as described above is taken into the first microcomputer 201, and necessary data is displayed on the operation/display unit 202, and the driving state of the color copying machine is controlled as desired. Ru.

In the case of color copying, a motor 230 for red and blue copying.
In addition, a motor 231 exclusively for black is provided, and these are all controlled by command signals from the first microcomputer 201. Similarly, the driving state of the main motor (drum motor) 204 is controlled by a drive circuit 205 having a PLL configuration, and the driving state of this drive circuit 205 is also controlled by a control signal from the first microcomputer 201. That will happen.

During color development, it is necessary to apply a predetermined high voltage to a developing device during development. Therefore, a high-voltage power supply 232 for charging, a high-voltage power supply 233 for EA action, a high-voltage power supply 8234 for transfer and separation, and a high-voltage power supply 235 for toner receiver are provided, and when necessary, a predetermined power supply is applied to them. A high voltage will be applied.

Note that 237 is a cleaning roller drive unit, 238 is a first paper feed roller drive unit, 239 is a second paper feed roller drive unit, and 236 is a cleaning piezoelectric release motor. Roughly speaking, 240 is a drive unit for the separation claw.

The second paper feed roller is used to transport the paper that has been completely transported by the first paper feed roller to the electrostatic latent image formed on the drum 61.

The fixing heater 208 is controlled by a fixing heater on/off circuit 207 according to a control signal from the first microcomputer 201.

The fixing temperature is read by the thermistor 209, and the first microcomputer 2
Controlled by 01.

206 is a clock circuit (12Mt (about z)).

A nonvolatile memory 210 provided along with the first microcomputer 201 is used to store data that should be preserved even when the power is turned off. for example,
This includes talk counter data and initial setting values.

In this way, the first and second microcomputers 20
1.251, various controls necessary for color image processing are executed according to a predetermined sequence.

FIG. 20 is a diagram showing an example of a drum index signal detection system, in which an index element 95 shaped like a disc is attached to one end of the rotating shaft 61A of the drum 61 so as to be rotationally integrated with the drum 61. It will be done. Further, as shown in FIG. 21, a plurality of notches, which are U-shaped in this example, are formed on a part of the circumferential surface of the index element 95, maintaining a predetermined angular interval and having a predetermined depth and width. .

In this example, 86 drum indexes are obtained per drum rotation, so E30'
Six cuts 97a to 97f are formed with the angular spacing of .

On the other hand, an index sensor (detection means) 96 is provided opposite to the circumferential surface of the index element 95, in this example, so as to straddle a part of the circumferential surface.

As a result, a pulse-like index signal (FIG. 30A) is obtained from the index sensor 96 every time the notches 97a to 97f of the index element 95 pass, so that the rotational position of the drum 61 can be detected using this index signal. It's loud.

It should be noted that such a drum index element 95 can be placed on the drum 6 as long as it does not interfere with the conveyance of the recording paper.
It may be provided on a part of the circumferential surface of 1.

Next, a series of processes in color recording will be explained in detail with reference to FIGS. 22 to 24. In this embodiment, in addition to multicolor recording (three colors of blue, red, and black), it is also possible to record in a specified color (single color) in a predetermined image readout area from the outside. Color recording will be explained with reference to FIGS. 22 and 23.

However, the explanation partially overlaps with the explanation of FIGS. 12 and 13.

In FIGS. 22 and 23, section F1 indicates the section from when the main power of the apparatus is turned on until when the copy button is operated. Section F2 is a section for pre-rotation processing of the image forming body (hereinafter referred to as drum).

Section ■ is a helmet development section, section II is a red development section, and section 1]1 is a black development section. And section IV
is the post-rotation processing section.

Further, the numbers shown in the figure indicate the count value of a drum counter or the count value of another counter such as a pre-rotation counter which will be described later.

When the main power is turned on, the main motor such as the drum motor 204 rotates for a predetermined period of time, and when the copy button is operated, the main motor rotates (FIG. 22C), and the index element 95 attached to the drum 61 is rotated. When the index sensor detects, the drum counter is cleared (
To the same figure, B). Subsequent processing operations are executed based on the count value of this drum counter.

The lengths (times) of sections 1 to IV are equal, and in this example, the count value is 778 and the drum 61 makes one revolution.

When the pre-rotation section F2 is reached, charging of the drum 61 is started (D in the figure). The drum charging continues until the first exposure is completed (see section ■).

In the pre-rotation section F2, the pre-transfer lamp is turned on for a certain period of time (until the middle of the blue development section 2) from approximately the middle of the pre-rotation section F2, and pre-processing for color development is executed (E in the figure).

When entering the developing zone from dark to black, the magnets 76 and developing sleeves 75 provided in the developing devices 65 to 67 are rotated in the corresponding zones, and the developing bias is rotated in synchronization with the timing of these rotations. It is launched (Figure F-
K).

The cleaning blade 94 is pressed in synchronization with the rise of the drum index signal in the previous rotation section F2, and
The toner adhering to the drum 61 is removed (L in the same figure), and the release can be completed when the drum 61h rotates once after pressure bonding (M in the same figure), but even after this toner removal, some toner remains on the drum. If the blade is released, the toner may scatter when the blade is released, so the cleaning roller starts operating a little later after the blade is released to remove the remaining toner (see figure N). ).

Immediately before the blue development period I, the first paper feed roller rotates and the recording paper is conveyed to the second paper feed roller side (O in the figure). 1st
The paper feed roller is provided to convey the paper in the cassette, and the paper conveyed by the first paper feed roller is conveyed to the drum 61 side by driving the second paper feed roller. .

The transport timing is the final exposure process period (in the figure,
The exposure process I11) is (P in the same figure).

The paper feeding operation by the first paper feeding roller stops when the recording paper reaches a temporary stop sensor provided just before the second paper feeding roller, and when the second paper feeding roller is driven and the recording paper passes,
The sensor output becomes zero (S in the figure).

The transfer process is executed a little later than the drive of the second paper feed roller, and in synchronization with this, the drum 61 is
In order to prevent the paper from wrapping around the paper, a predetermined AC voltage is applied to the paper separation electrode (Q in the same figure).

After the temporary stop sensor 227 falls to zero, the development and fixing processing are completed, and the paper ejection sensor 228 detects the paper ejection state after fixing (see T in the same figure).
).

In the case of color recording, toner density detection can be accomplished for each development process. The density detection timing is determined by the count value of each detection counter for blue to black (U2 to U4 in the same figure)
. All of these counters are reset based on the timing when writing the density detection batch starts, and the blue counter is reset when the count value of the drum counter is 706, and the toner density is detected when the count value after reset is 602. Ru.

Similarly, the red counter is reset at 707, and the black counter is also reset at 707.

Here, the toner density is detected with reference to a certain specific image area. Therefore, a patch signal for density detection (for example, an image signal corresponding to an 8X16+*m size image area) shown in Z in the same figure is used, and after a predetermined period of time has elapsed since this patch signal is obtained, the signal for toner density detection ( R) in the same figure is output, and the image density of that specific area is detected.

The front rotational force/clear is cleared at the timing when the first drum index No. 743 is entered after copying on,
When the count f reaches 1266 and t2, the pre-rotation process ends (Ul in the figure).

When the main power is turned on, the polygon motor 104 that drives the mirror scanner 85 is also driven at the same time, so that the mirror scanner 85 is always driven to rotate at a constant speed ((2) in the figure).

Image data necessary for image recording is sent out at the following timing. In other words, the video gate is set so that it reaches °゛1゛° in synchronization with the blue counter, and becomes °゛O°° at the same time as the black laser writing ends (W in the same figure), and only during the period when the video gate is 1゛'. Image data is output device 100
sent to the side.

The vertical valid area signal (V-VALID) is sent out so that it remains valid for a certain period of time (in the case of A4 size recording paper, the period until the count value reaches 528) in each development process step. Y).

Note that a copy signal is sent from the first microcomputer 201 on the main body side to the second microcomputer 251 for controlling the optical system (AA in the same figure).
A start signal for optical scanning is output. This optical scanning signal enters the start state at the falling edge from °1° to °00° (FIG. BB).

Furthermore, in the case where the image reading device 10 is configured to move a movable mirror unit to which a light source, which is part of the image reading means, is attached, a home position signal indicating the home position of this optical system is used for each development process. For each step, the data is sent from the second microcomputer 251 to the first microcomputer 201 (
Same figure CC).

The first microcomputer 201 receives the home position signal, and when it wants to perform the next exposure process, the copy R signal (AA in the figure) is sent to the second microcomputer 201.
Can you send it to the 51st side? , (Figure DD).

The above is a timing chart showing an outline of multi-color recording.

When recording the original image with externally specified colors, use the second
The timing chart is as shown in FIG. 4, and image processing regarding the designated color is executed, and no other image processing steps are executed.

Therefore, a detailed explanation of each operation of this monochromatic image processing step will be omitted.

The image processing steps shown in FIG. 24 are for a case where an image is recorded in black (ordinary black and white copy).

Now, the series of color image processing as described above is performed by the first and second microcomputers 201 and 25 described above.
1.

Next, a control program for executing such processing will be explained in detail with reference to FIG. 25 and subsequent figures.

For convenience of explanation, a flowchart for realizing the general processing operation of color recording in the entire apparatus will be described with reference to FIG. 25.

In FIG. 25, 300 is a flowchart showing an example of the gJ control program #8 stored in the first microcomputer 201. In FIG.

First, when the main power is turned on, this control program operates to transition to a mode in which the initial state of device processing operation is achieved. Therefore, after the device is initialized (step 301), the beginning of the drum 61 is performed (step 302). This cueing process refers to a rotation control process in which the drum 61 reaches a predetermined rotational position using an index signal obtained from an indexing element provided on the drum.

Next, warm-up processing such as fixing processing and lighting of the light source (step 303), input data processing such as color specification input from the scanning/display unit and number of copies specification (step 304), and temperature control in the heater for fixing. Processing (step 305), copy waiting 15, idling jam processing such as paper jam (step 306) are executed in this order.

Whether or not these warm-up processes are completed is determined in the next step 307. If the warm-up processes are not completed, the process returns to step 303 and the same process is executed again, and the warm-up processes are completed. Occasionally, a check is made to see if a copy button provided on the operation/display section has been operated, and if no copy operation has been performed, the process returns to step 304 and enters a standby state for input data (step 308).

When the copy button is operated, various input information such as color specification, C degree specification, paper size specification, etc. input on the operation/display side is transferred from the first microcomputer 201 side to the second microcomputer 251 side. At the same time as serial transmission (step 309), the copy mode is specified as single color (hereinafter referred to as 1 color copy), all three colors, that is, multicolor (hereinafter referred to as 3 color copy), or 2 colors.
It is determined whether a color is specified (hereinafter referred to as two-color copy) (step 310).

For one-color copying, the one-color copy processing routine (subroutine configuration) in step 320 is called, and for two- or three-color copying, a two- or three-color copy processing routine configured as a subroutine is called (step 360). ).

When the processing of these subroutines is executed and the process returns to the main routine, paper size, density processing, fixing heater processing, and operating jam processing are performed (steps 311 to 313), and then it is determined whether or not copying has been completed (step 314). If the copying is not completed, the process returns to step 310, and if the copying is completed, the process returns to the input data processing step 304, and similar processing steps are executed.

FIG. 26 is a flowchart showing an example of one-color copy processing.

When the one-color copy routine is called, a flag indicating the number of copies is checked (step 321). This flag is set each time the recording paper is conveyed to the second paper feed roller. If the number of copies flag is not set, the process moves to step 325. When flagged,
The data on the number of copies has been processed (step 322).

When the number of copies does not reach the preset number of copies (number of copies), the process moves to step 325, a paper feeding and conveyance processing step, but when the number of copies matches the set number, the end flag for the number of copies is set. (Step 324).

When the paper feeding and conveyance processing is completed, the writing processing of the laser 81 and the high voltage power supplies 232 to 2 applied to the processing devices 65 to 67- are completed.
35 processing is executed (steps 326 and 327).

After determining the presence or absence of such processing, development processing is performed (steps 328 to 336). In the development processing step, the timing of each development start is detected.

In the case of one-color copying, development processing can be executed only for the designated color, but for the sake of explanation, we will explain the case where red is designated. In that case,
The start timing of each color processing is determined regardless of the color specification.

For this reason, first, the red development process start timing can be determined, and when it matches the red development start timing, the presence or absence of the red copy flag (actually, the input specification on the operation/display section is checked) is checked. When the red copy flag is set, red development starts (steps 328 to 330).

When this development process is completed, next is the blue and black development process star! However, since the designated color is only red, in this example, the blue and black development processing steps are skipped, and the development off timing in step 337 is determined.

If it is time to turn off development, the development processing is turned off (steps 337, 338), and the presence or absence of a reverse copy is determined, and if a reverse copy is specified, the reverse bit is set in the register, otherwise (step 339).
~341).

Next, if the number of copies does not match the number of set copies,
Since the end flag is not set to 1, in this case, it is determined whether the optical scanning system is at the home position (step 345), and if it is at the home position, the start flag for the next copy sequence is set at step 346. is set.

Then, the scan start output timing of the optical system is detected (step 347), and when it is the output timing, the scan start signal is sent to the second microcomputer 251 side, and the writing timing of the laser beam is determined. The timer to adjust (in this example,
10m5ec timer) can be restarted (Step 3)
48,349).

When the optical system scans from the home position to the end of the document (writing start position), a writing start state is entered.

On the other hand, if the timer restarts, the vertical effective area signal (
V-VALID) is set, and the corresponding counter is cleared (steps 350, 351). As a result, the image based on the red signal becomes a write mode, and based on this, the red color separation image is converted into an electrostatic latent image, and development processing is executed.

Once the counter is cleared, it can then be determined whether the end flag is 1 (step 352).

Then, when the end flag is 1 (step 35
2) After a post-rotation process is executed and a cue process for the drum 61 is performed (step 354), the process returns to the main routine.

Similar processing is performed when a color other than red is specified. If blue is specified, steps 331 to 333
When the process of steps 334 to 336 is executed, and when black, that is, the normal monochrome recording mode is specified, the processes of steps 334 to 336 are executed.

Each step of the above-described one-color copy processing routine 320, paper size and copy density processing routine 311, fixing heater control processing routine 312, and operating jam processing routine 313 is repeatedly executed until the copying operation is completed.

FIG. 27 shows an example of a control program when a two- or three-color copy sequence is called.

When the two- or three-color copy routine is called, the processing steps from determining the state of the flag for the number of copies to setting the end flag are the same as the one-color copy sequence (steps 361 to 364). Next, it is determined whether the copy mode is present (step 365), and when the optical scanning system is in the home position in the copy mode, the color signal to be scanned next is transmitted to the second microcomputer 251 side. At the same time (steps 366 and 367), the state of the color development processing routine start timing is checked, and if it is the color development processing routine start timing, the processing routine flag is set (steps 368 and 369').

If the copy mode is not in effect or the optical scanning system is not in the home position, the process proceeds to step 368.

When the processing routine flag is set, the state of the pre-rotation flag is checked, and if the flag is 1, the pre-rotation processing is executed (steps 370 and 371), and then the process moves to the processing routine corresponding to each color. Therefore, the blue routine flag is checked first, and the flag is set to 1.
If so, blue sequence processing is performed (steps 372 and 373). Similarly, each color processing routine for red and black is sequentially determined while checking each flag.
(steps 374-377).

Therefore, in the case of multi-color copying, each of these color processing routines is used, but in the case of two-color copying, only the designated color processing routines are processed.

When the color processing sequence is completed, the transfer flag is checked, and if the transfer flag is set, after the transfer and developing units 65 to 67 are cleaned, the state of the end flag is determined, and the copy end flag is set. When the post-rotation flag is 1, drum post-rotation processing and drum cue processing, which are copy post-processing, are executed (steps 378 to 382).

By the way, when the color processing routine flag is set,
A color processing identification routine 400 shown in FIG. 28 is called.

Therefore, first, the color being scanned is determined (step 401). Initially, a scan related to blue is executed, so in that case, the red flag status is set, and if the red flag is set and the black flag is also set, the flag for the red processing routine is set. (Steps 402, 403, 405). The black flag is sera! - If not, a blue transfer flag is set (step 404).

If the red flag is not set, the transfer flag is set after the black processing routine flag is set (steps 408, 409).

When the color being scanned changes to red, the presence or absence of the black flag is checked (step 4o7). If the flag is set, the process moves to step 408, but if the flag is not set, the end flag is checked. The presence or absence is determined, and if the flag is not set, a flag for the next color processing routine, the blue processing routine, is set (steps 410 and 411).

If black is being scanned and the end flag is set, the process returns to the 2nd or 3rd scan processing routine, but if not, the flag for blue processing, which is the next processing scan, is checked and that flag is present. Sometimes, a flag for the blue processing routine is set in step 411.

When the flag is not set, return to step 405 and
A flag for the red color processing routine will be set (steps 412, 413).

The reason why the color identification processing routine was designed this way is because there may be two or three colors specified, so that it can be processed no matter what color is specified. This is because it is necessary to execute color processing while checking the specified color each time.

By the way, in 2 or 3 color copy mode, two drums
By rotating or rotating it three times, electrostatic images corresponding to each color are overwritten to form a predetermined color image into an electrostatic latent image, after which a fixing process is executed. Therefore, in such a copy mode, the registration relationship between the previously developed image and the electrostatic image to be overwritten this time is very important. This is because if the registration is poor, the quality of the recorded color image will be significantly degraded.

Further, the pre-rotation process, the post-rotation process, and the image writing process are performed based on the rotation of the drum.

Therefore, a drum index signal is used.

FIG. 29 shows an example of such a luck control routine.

The rotational position of the drum 61 is determined by the 'f!' of the index drum 95 which functions as an index element provided in relation to the drum 61. This is done by detecting l number of cuts 97a to 97f.

Notches 97a to 97f of this index drum 95
If the optical or electromagnetic detecting means 96 is used to detect the passage of the index signal, and this detected position is associated with the optical write start position in advance, the writing start position and the write start position can be determined simply by detecting the index signal. The rotational positional relationship of the drums can be regulated as desired. Roughly speaking, processing times such as pre-rotation processing can be regulated based on the drum index signal.

In addition, FIG. 21 is a timing diagram when using the index element 95 having six notches 97a to 97f, and by using this index element 95, the time required for forward rotation and backward rotation is shortened. is,
An example is shown in which copy efficiency is improved as a result.

In other words, when an index element with one notch is used, it would take one rotation of the drum for forward rotation and about two rotations for rear rotation, but by using the index element 95 as described above, the front rotation can be completed. drum 2/3~1/2
The rotation can be reduced to about 1.5 degrees, and the back rotation can be reduced to about 1 and a half rotations.

In this example, the pre-rotation processing time is for 4 index signals (one rotation of the drum corresponds to 6), and the post-rotation processing time is for 10 index signals.

Furthermore, by appropriately selecting and using six index signals, it is possible to change the starting position of the optical scanning system, that is, the writing position on the image forming body, and as a result, fatigue of the image forming body can be reduced. can.

In this example, the start position of the second time is shifted by one index signal in terms of the start position of the optical scanning system during the first image formation.

Now, when the index signal (Δ in FIG. 30) is detected, the above-mentioned control routine which is an index interrupt routine is called and its control program is started.

When the index interrupt starts, interrupts other than the index signal are prohibited (step 501). The reason for providing such a step is to prevent this control processing routine from malfunctioning due to pulse-like external noise other than the falling edge of the index signal.

The index interrupt inhibition period is a period slightly longer than the run-up period from when the index signal is obtained until laser writing starts, or a period until just before the next index signal.

This period was selected because it is necessary to match the rotational position of the drum 61 with the laser writing timing using the index signal, so at least during the run-up period until the laser writing starts, the index signal and other This is because interrupts must be prohibited.

Detection of the interrupt disabled period is determined by step 555 inserted in a different processing routine 550, which will be described later (FIG. 31).

When the index interrupt disabling process is executed, it is determined whether the flag ■ is present or not (step 502).

Flag I is °°O°° only during multicolor copying, and at other times, that is, when monochrome copying, copy standby, power on, and just before the end of post-rotation during multicolor copying. Both are set to 1°.

In the monochrome copy mode, there is no need to match the rotational position of the drum with the optical scanning system etc. using the above-mentioned index signal, so in this mode, after the drum counter DN is reset to ○, no interrupt other than the drum index signal is generated. Processing permission (enable/interface) is performed, and the process returns to the main routine (steps 503 and 504).

On the other hand, when the multicolor mode is selected, flag I is set to 0°. This flag reset is performed in the main routine.

In the multicolor copy mode, a counter N that counts the number of drum index interruptions is incremented by an interruption of the index signal.

Counter N is set as soon as the copy switch is turned on.
It has been cleared by the main routine (step 510).

When the counter N is incremented, the presence or absence of the flag C is checked (step 511).

Flag C is set during continuous copying, and is set in the main routine when the optical scanning system reaches the home position. Then, it is reset by inputting an index signal thereafter.

For the sake of explanation, let's first take a single copy as an example.

In this case, the process moves to step 512, and the presence or absence of flag A is checked.

Flag A is a flag for detecting the presence or absence of previous rotation, and is set to 1° while one rotation is possible.

This setting is performed by the main routine program when the copy is turned on.

Since the copy start causes a pre-rotation process, the process moves to step 513 and the number N of index signals is checked. This check can be performed by determining the contents of the counter N.

Since the initial value is O, the process moves to step 504, but
Once the four index signals have been counted, light ''7: scanning can be started, the counter N is reset, then the flag A is reset, and the counter DN is reset (steps 514 to 517).

The processing here corresponds to the period To shown in FIG.

For the next step, flag = ○, flag C = 0
．． Since flag A=O, the presence or absence of flag B is checked in step 520.

Flag B is a flag for checking the presence or absence of post-rotation processing, and is i"1" for post-rotation processing.

This can be set at the start of the final scan of the optical system.

When optical scanning is started in step 514, flag B=O, so the process moves to step 521, where the first color latent image and development processing are executed, and when the drum rotates by a predetermined angle (the first (corresponding to period T1 in Fig. 30), the optical system performs a return scan and returns to the Bauhm position after a certain period of time (periods T2 and T3).

Then, since the time when N=6 corresponds to the first rotation of the drum, when N=6 is detected, scanning of the scanning optical system is started and the counter N is reset (step 52).
1-523). Thereafter, it is checked whether the optical scan is the final color scan (step 524), and if not, the drum counter DN is reset in step 525.

When N=6 is detected again, the third color copy mode is entered (corresponding to period T4 in FIG. 30), so this copy mode is detected in step 524 and flag B is set.
is set (step 525). Since flag B=1 for the third color (u), the process now moves to step 530 and the index signal is monitored.

Even after the copying of the third color is completed and the drum rotates once, the drum continues to rotate. This rotation continuation period becomes a post-rotation processing period (period T5).

Then, when the drum index counts up to N=15 counting from the beginning of period T4, the end of the post-rotation process is detected, the main motor is stopped, and counters N and DN are reset at the same time. At the same time, the flag - is set and the state before copying is restored (steps 531 to 534).

Note that when in continuous copy mode, flag C=1
Therefore, the start of the first optical scan in this copy mode is performed in step 540. Then, counters N and DN are reset, and the flag is reset to O, as in the one-sheet copy operation (steps 541 to 543). After that, the flag becomes 0, so the process is performed in the same steps as for one-sheet copying.

and copying starts as shown in Figure 30.
When N=4, the first color copy is executed, and N=4.
This copy mode is updated every 6. After that, N
When =15, the post-rotation processing operation is also completed, and a standby state is entered for the start of the next copy.

Now, paying attention to the contents of the count of the index signal during the post-rotation process, the numbers shown at the bottom of the figure are the total value of the index signals from the start of the post-rotation and the pre-rotation. On the other hand, the number written in the upper row is the count value of the index signal when it is reset every time N=6 and every time the slave drum rotates once.

Therefore, the position corresponding to the first color at the time of first copying is the position of the number "1" in the upper row. However, the first color of the second copy is actually the number "2" in the upper row.
” position.

Thus, the drum start positions of the first and second copies do not match. In other words, the copy start position is undefined. This means that the copy start positions are averaged without being biased.

Note that counting the number of indexes includes counting by measuring time.

Further, the pre-rotation process can be set at a position where an index signal corresponding to the minimum processing time can be obtained. This is because a plurality of index signals are provided to detect drum rotation. The same applies to the processing time setting for post-rotation processing. Therefore, in either case, the minimum processing time can be set.

Above, an example was shown in which the image formation start timing is controlled based on the drum index signal.However, for controlling processes that do not affect the registration of other image formations, other pulses such as 2g generated pulses are used instead of the drum index signal. This may be done by counting.

FIG. 31 shows an example of a timer interrupt processing routine 550 for adjusting write timing.

This interrupt processing is performed at regular intervals based on a reference timer. When this interrupt processing starts,
The flag of the vertical valid area signal (V-VALID) is checked, and when this flag is set, the count value of the counter of the vertical valid area signal (V-VALID) reaches the scan start count value indicating the start point of laser writing. A match is checked (step 55).
1,552).

In other words, when the index signal is obtained, the vertical valid area signal (V-VALID) start counter starts, and when the count value reaches a predetermined value (count value corresponding to the run-up period), image data is written by the Rage. starts. Therefore, after the count value of the counter matches the scan start count value, the vertical valid area signal (V-VALID) is output to the timing circuit 10.
2, the vertical valid area signal (V-VALID
) flag is reset (step 5538554
), proceed to the next step.

Here, if the reference timer is restarted based on the drum index signal, the period from when the index signal is obtained to the end of the run-up period will always be constant regardless of the drum rotation speed, and the drum index will be constant. 7 signal does not change even if the interrupt method differs each time. This makes it possible to always match the leading edge position of the document with the rotational position of the drum, that is, with the writing timing of image data.

If the flag of the vertical valid area signal (V-VALID) is not set or if the count value of the counter of the vertical valid area signal (V-VALID) does not match the scan start count value, the process immediately proceeds to step 555.

In step 555, the count value of the prohibition counter is checked. This step 555, as described above,
This step is for inhibiting the input of a signal other than the index signal even if a signal other than the index signal is input, so that the laser writing start point does not malfunction due to noise generated during the run-up period.

Therefore, the set count value of this prohibition counter is set to a count value corresponding to the run-up period or the period before the next index signal.

After the count value of the vertical valid area signal (V-VALID) start counter matches the count value of the prohibition counter, the optical system can be started, so the index interrupt flag is reset after this state. At the same time, the index interrupt prohibition is canceled (steps 556 and 557).

Thereafter, the vertical valid area signal (V-VALID) start counter is incremented, processing other than registration is executed, and the process returns to the main routine (steps 558+559).

The control program described above is related to the first microcomputer 201.

Next, the control program for the second microcomputer 251 will be explained in detail with reference to FIG. 32 and subsequent figures. The second microcomputer 251 is mainly used to drive and control the optical system.

FIG. 32 shows a flowchart of the main routine of the optical system. When this control program starts, the second
The CPU provided in the microcomputer 251 is initialized, the memory is cleared, the optical system home position search is started, and then the warm-up measurement timer is started and the warm-up is started. (Step 601~
604).

When warming up is started, a check is made to see if the warming up is complete, and if not, a check is made to see if the one quarter warming up time has arrived, and if the warming up is not completed even after the time has elapsed, a trouble is displayed. (step 605~
607).

When the warming-up is completed, the warming-up timer is stopped, and at the same time, the light source (such as a fluorescent light) that illuminates the document 1 is turned off (step 608
, 609).

Next, the presence or absence of copy mode is checked, and if it is in copy mode, the light source is turned on, and the amount of light reflected from the document 1 is monitored, and if the amount of light is insufficient! - If the error message is displayed and there is no abnormality on the monitor, a ready flag is set, a ready flag is sent to the second microcomputer 251, and optical scanning is initialized (steps 610 to 615).

When the initialization of optical scanning is completed, the pulse count check flag is checked, and if the flag is set, the forward movement of the optical system is checked, and when the optical system is in forward movement, it is checked whether the optical system has advanced by a predetermined distance as described above. The determination is made based on the pulse count value (steps 616 to 618).

If the above-mentioned count value is not reached, the pulse interval time is set, and then the excitation pattern is set, and the current value is set to a predetermined value. Thereafter, the pulse count check flag is reset and the process returns to step 616 (steps 619 to 622).

When the predetermined number of pulses are counted, the optical system has moved forward to the maximum movement position in the sub-scanning direction, so in this case, the movement of the optical system is completed and the forward movement flag is set (step 623). .624).

Retraction of the optical system can be determined in step 617. When in the retraction mode, the set pulse number is checked in the same way as described above, and if not, the pulse interval time is set and the excitation pattern is set, followed by step 622. (Steps 630-632).

When the set number of pulses is reached, the retraction (return) of the optical system is completed, the home position signal is transmitted from the second microcomputer 251 to the first microcomputer 201, and then the copy mode is determined again. be done. This copy mode determination is a step of determining whether or not continuous copying is to be performed; in the case of single copying, the light source is turned off and the process returns to step 610. In the case of continuous copying, the process returns to step 612 (step 6
33-636).

FIG. 33 is an example of an optical system drive control program 650, in which when the interrupt processing routine of the exemplary pattern switching timer of the pulse motor 253 starts, the drive circuit 252 of the pulse motor 253 that drives the optical system is At the same time as the excitation pattern switching signal is sent, the current value to the pulse motor 253 is switched (step 65).
1,632), then a timer is set, the pulse count value is incremented, and then a flag for pulse count check is set, thereby returning from this control routine to the main routine (steps 653 to 655). .

Further, FIG. 34 shows an example of a scan start interrupt processing program 660 that is executed when a start signal for scanning start is sent from the first microcomputer 201 side and a scan start interrupt processing routine is called. When the scan start interrupt processing starts, the ready state is determined, and if it is not in the ready state, a trouble display is displayed, and if it is in the ready state, the timer count value is set, and then the excitation pattern and current value are set. Then, after the ready flag is reset, the pulse count check flag is set (steps 666 and 66).
7). When the pulse count flag is set, the process exits from this processing routine and returns to the main routine.

By the way, when a plurality of drum indexes are provided, in addition to the above-mentioned features, the smaller the paper size used, the shorter the copying time during continuous copying becomes. In other words, the smaller the paper size, the more copies can be made per unit time.

This is due to the following reasons.

In other words, when multiple drum indexes are provided, as shown in Figure 35, the colors must be overwritten for the first to third colors, so the images are always written back to the same drum position. There is a need.

However, when the third color is completed, there is no need to return to the first image writing position again, and the next copy operation can be started from the first index No. 49 after the completion of the fortune-telling operation for the third color. (Figure 35B)
-D).

Therefore, as in the case of one drum index,
Regardless of the paper size, the drum is always rotated to the initial position,
There is no need to wait for the next copy operation, and the copy time can be reduced accordingly. As a result, the copying time becomes shorter as the number of copies increases.

Note that in order to reduce the copying time depending on the paper size, the paper size to be used is detected in the multicolor copy mode and in the paper size detection circuit 203 (see FIG. 19), and the paper size is detected. The output may be supplied to the first microcomputer 201. This is because the first microcomputer 201 generates necessary command signals.

The command signal is, for example, the count r in step 521 shown in FIG. 29 when copying the final color according to the paper size.
I1. This is a signal for changing N, etc.

In addition, although the above example illustrates the case where the number of index signals obtained during one rotation of the drum is set to six, the number is not limited to this number, and the configuration can be configured so that more index signals can be detected. You may.

When there are two drum indexes, rlN=1.1 in the pre-rotation processing step 513 in FIG. 29, and N 4! in the rotation processing step 521 in FIG. Similar control can be performed by setting N=3 and N in the post-rotation processing step 530 to N=3.

In addition, when the number of drum indexes is 30, N in step 513 is N=16, and N in step 521 is N=3.
0, and N in step 530 was set to N=45, and control was performed.

Similarly, if the number of drum indexes is 60, N in step 513 is N=31, N in step 521 is N=31, and N in step 521 is N=31.
60, the N of the step 530 was set to N=150, and control was performed.

In any of these cases, since the pre-rotation process requires extra time, fatigue on the surface of the photoreceptor can be made uniform.

It goes without saying that the length of the front rotation and rear rotation processes can be changed as appropriate depending on each device.

[Effects of the Invention] As explained above, according to the present invention, since a plurality of drum index signals are generated during one rotation of the drum, the optical operation start position on the drum is not fixed. That is, the optical operation start position on the drum can be averaged. As a result, it is possible to prevent partial deterioration of the drum photoreceptor, and it is possible to achieve a longer lifespan of the drum.

Roughly speaking, when configured as described above, detection of processing times for pre-rotation processing and post-rotation processing can be set arbitrarily. Therefore, since the processing time can be set to the minimum in both cases, it is possible to easily reduce the total copying time and the continuous copying time corresponding to differences in paper size.

Furthermore, according to the above-described configuration, when a color image is recorded by overwriting images several times, images corresponding to each color can be recorded from the leading edge of the document, resulting in good color registration. Image recording can be achieved. Therefore, it has the feature that color image recording with improved image quality can be easily achieved.

In this case, since the start of writing is controlled based on the rotation of the drum, the registration will not deteriorate even if the load on the drum fluctuates.

Therefore, the present invention is extremely suitable for application to a colorless copying machine, in which a desired color image is recorded by overwriting several times as described above.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the entire color image forming apparatus according to the present invention to provide a general explanation of the apparatus, FIG. 2 is a cross-sectional view of essential parts showing an example of a color copying machine that can be used extensively in the present invention, and FIG. 4 is a sectional view showing an example of a developing device, FIG. 5 is a block diagram showing an example of an image reading device, and FIG. 6 is used to explain image reading. A diagram showing the relationship between processing timings, Figure 7 is an explanatory diagram of the image reading system, Figure 8 is a spectrum diagram of color signals, Figure 9 is a diagram explaining color separation, and Figure 10 is an example of a color separation map. 11A is a block diagram showing an example of a color separation circuit, FIG. 11B is a block diagram showing an example of a color selection circuit, and FIGS. 12 and 13 show color signals and their recording relationships. 14 is a block diagram of the binarization circuit, FIG. 15 is a diagram for explaining the interpolation method, FIG. 16 is a diagram showing an example of an interface, and FIG. 17 is a diagram showing the peripheral circuit of the output device. 18 and 19 are block diagrams of circuits associated with the first and second microcomputers, FIG. 20 is a schematic configuration diagram showing the relationship between the image forming body and the drum index, and FIG. 21 is a block diagram of the circuit associated with the first and second microcomputers. Its plan, 2nd
2 to 24 are waveform diagrams for explaining the color recording processing operation, and FIGS. 25 to 29 and 31 to 34 are waveform diagrams for explaining the color recording processing operation. Flowchart showing an example, Part 3
0 is a waveform diagram for explaining the operation of FIG. 29, FIG. 3S is a waveform diagram for explaining the operation in continuous copy mode, and FIGS. 36 and 37 are waveform diagrams for explaining the operation of the present invention. 0... Image reading device 20... Color A No. 3 forming means 30... Binarization circuit 40... Interface circuit 61... Image forming body (drum) 95... Index element 96... ...Index detecting means 100...Output device 200.250...First and second control unit Patent applicant Konica Co., Ltd. Current moat Fig. 8 A [3 Length (nm) - + Fig. 11 B 1fD etc. Fig. 14 Fig. 30: 2 tang, lLf hia Fig. 15 Fig. 21 Fig. 7b Fig. 33 Fig. 34

Claims (12)

[Claims] (1) In a color image forming apparatus that forms a color image by rotating the image forming body multiple times and repeating at least latent image formation and development processing, a color image forming apparatus that corresponds to a plurality of predetermined positions on the image forming body means for generating a reference signal; and controlling the start timing of an image forming cycle using the reference signal corresponding to any one of the predetermined positions, and using the reference signal corresponding to any one of the other predetermined positions. 1. A color image forming apparatus, comprising means for controlling the start timing of another image forming cycle. (2) The color image forming apparatus according to claim 1, wherein the latent image is formed by a laser beam. (3) A claim characterized in that it has a plurality of developing means and a plurality of transfer means, and the plurality of color images are formed on an image forming member by the said developing means, and then transferred onto an image support member. 1st
color image forming device. (4) The color according to claim 1, comprising means for reading an image, and signal processing means for inputting a signal from the reading means and generating a signal for forming a latent image. Image forming device. (5) Claim 4, characterized in that the reading means is comprised of means for decomposing light from an original into light of a plurality of colors, and means for photoelectrically converting the decomposed light.
color image forming device. (6) The color image forming apparatus according to claim 5, wherein the signal processing means includes means for generating a color separation signal from a photoelectrically converted signal and means for generating a multi-value signal from the color separation signal. (7) The color image forming apparatus according to claim 4, wherein the start timing control means controls the start of reading based on a reference signal. (8) The color image forming apparatus according to claim 1, wherein the reference signal generating means includes a disk-shaped drum index element. (9) The color image forming apparatus according to claim 4, wherein the timing control means controls the start of latent image formation based on a reference signal. (10) The color image forming apparatus according to claim 1, wherein the timing control means includes means for counting reference signals. (11) A photoreceptor drum is used as the image forming member, and means is provided for obtaining the rotation of the photoreceptor drum by comparing a counted number from the counting means with a predetermined number, and the detection result thereof is provided. 11. The color image forming apparatus according to claim 10, wherein timing control is performed based on the following. (12) The image forming body cycle is to rotate the image forming body a plurality of times to form an image, and the control means includes:
2. The color image forming apparatus according to claim 1, wherein the start timing of image formation for each rotation is controlled by a reference signal corresponding to any one of the positions.