JP3069406B2 - Color image copying machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color image copying apparatus and, more particularly, to reading of an original and image formation in a copying apparatus for a large original.

[0002]

2. Description of the Related Art The size of an input document and the size of an output copy in a copying machine as general-purpose office equipment are overwhelmingly large up to A3, and larger sizes are called large format. In the method of reading a large-size document, it is usual that a document inserted between a pair of rollers by hand is read after being held on a holding drum serving as a document mounting table. However, recently, the thickness of a document has become so thick that the above-described method of inserting a roller and holding a drum cannot be applied, and a flat plate (hereinafter, abbreviated as a bed) has to be used as a document mounting table. Has also occurred.

[0003]

Regardless of whether the original is held in a drum type or a bed type for reading the original, the reading of large-format originals and the image formation are performed in comparison with those up to A3 size. Takes a significantly longer time. In particular,
For forming a full-color image, compared to the case of a single-color image,
Approximately four times the time is required for the four colors of yellow, magenta, cyan, and black, so that the time is further increased.

The present invention solves the above-mentioned problems of the prior art, shortens the time required to read an original, shortens the time required to form a copied image, and shortens the time required for the copying process. It is something to offer.

In order to solve the above-mentioned problem, a color image copying apparatus according to the present invention employs a color image copying apparatus which is capable of detecting a relatively moving original image.
A reading sensor that reads out the reflected light of each color by color separation
And a photoelectric conversion device that amplifies a signal from the sensor.
Has the number corresponding to the number of color separations, and
The reading length of the original image in the moving direction
Each photoelectric conversion is arranged at intervals that are almost equally divided by the number of decompositions.
Process the output electrical signals from the device as image signals for each color.
Image processing device and the signals of each color output from this processing device.
Image signal comprising a signal delay device for mutually delaying signals
And a receiver for receiving an output from the image signal generator.
Image forming apparatus for forming an image of the color
It is arranged around the formed body at intervals of approximately equal division by the number of color separations.
Function of each device so that the required original copy image can be obtained.
A control device including a timing circuit for controlling
And the document image is read, and the number of color separations is almost equal in the length direction.
This divided image is simultaneously processed by each corresponding sensor.
And read each divided image on the image forming body.
Documents are formed almost simultaneously at the equally divided positions, and
It is configured to combine and reproduce as a photographed image. further,
The developed image reading means converts the original image into yellow
Color, magenta, cyan, and black.
And features.

[0006]

By adopting the above means, in the color image copying apparatus according to the present invention, the time required for reading the original image and the time required for forming the copied image can be reduced by the conventional method as long as the structure of the claims is adopted. Can be reduced to about one-fourth.

That is, the divided images are read almost simultaneously by the four sets of reading devices, and the corresponding copied images are also divided into four to form images almost simultaneously for each divided image, so that the time required for copying is greatly reduced. It has the function of being performed.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a basic diagram for explaining a document reading process in a color image copying apparatus according to the present invention. (A) and (b) correspond to a case where the shape of the document table is a bed shape and a drum shape, respectively. In common to both, P indicates the entire original image, and P _i (i = 1 to 4) indicates a portion divided in the reading length direction. The bold D indicates the length direction of the reading of the original,
Odd numbers indicate a light source for illuminating the original image, and even numbers indicate an optical reading sensor that receives the light source light reflected from the original surface. D and subscripts a, b
Correspond to the above figures (a) and (b), respectively. When the original is fixed and the light source and the reading sensor are moved, the divided partial view (P _i ) of the original image may not have the same size as the gist of the present invention. In the case where the mounting table is moved and each of the reading elements is fixed, the reading table is equally divided in the D direction.

The meaning of the above description is as follows. Conventionally, a document image is read by a set of document image reading devices including one light source and one reading sensor. On the other hand, in the present invention, yellow, magenta, cyan, and black (Y, The surface of a document divided into four sections in the length direction substantially uniformly corresponding to the four colors (M, C, Bk) is read almost simultaneously by four sets of reading devices. The read image signal is
Then for the image forming to be described, are accumulated stored, color signals Y~Bk each P _i is being output with a delay. FIG. 2 is a view for explaining a basic mechanism when the present invention is applied to an image forming process in a dry electrophotographic system.

(A) and (b) show a case where a corona discharge is used to charge a photoconductor PC and a laser beam is irradiated on the surface of the PC to write an image. The method of applying an electric bias between the body and the developing material is adopted, and the method of writing an image corresponds to the case of irradiating the back surface of the PC with LED light. The suffixes a and b in each figure correspond to figures (a) and (b). Symbols P _i and Y～Bk, are as previously described.

Rp is a driving roller that also serves as a support necessary for rotating the belt-shaped PC, and supports and rotates the transfer paper TP mounted on the belt-shaped transfer paper transport belt, similarly to Rt.・ It is a roller for transportation. Rm is PC
Roller for assisting or facilitating image transfer from TP to TP. In FIG. 5, N represents corona charging, L represents laser light, Ma represents a developer unit for supplying toner, and (Ea, Eb) represents a cleaner. Bold letters Dp and Dt indicate the rotation directions of the photosensitive drum and the transfer belt, respectively. V means the power supply for generating the bias voltage between the PC and M described above. The set of N, L, and Ma in (a) and the set of LED and Mb in (b) are provided for each of Y to Bk, that is, four sets each. The illustration of the set is omitted.

Next, the basic mechanism of image formation according to the present invention comprising the above basic elements will be described. FIG.
In both (a) and (b), the PC is composed of four parts of approximately equal length and the rest. The isometric portions correspond one-to-one to Y to Bk, and the read signal of the original described in FIG. 1 is written almost simultaneously for each of the four colors Y to Bk, and the entire image of the original is printed while the PC makes one round. Is written to form a full-color image. The TP is driven at the same time when the formation of all the images is completed, and captures all the images from the PC in a single rotation. E works immediately after the end of the transfer to contribute to the initialization. In the above description, the explanation of the functions and mechanisms of the color image copying apparatus according to the present invention is not limited to the illustration of these constituent parts or means unless it is necessary to explain the structure and materials directly or indirectly. Description is omitted at all. The same applies to the following.

Next, the flow of an image signal when a document image is divided and read, and at the same time a corresponding divided image is formed will be described.

FIG. 3 shows a color signal when a document is divided and read in a time series in correspondence with the divided image (P _i ). In the part (P _i ) where the document is read by dividing,
... Bk are simultaneously color-separated and stored, and color signals are delayed and sent out in a different order for each divided screen. On the other hand, in the image forming section, for example, in the case of the above-described electrophotographic method, the photosensitive member serving as the latent image forming section is read for each color and divided into substantially equal length portions corresponding to the length of the divided screen. Of the color signals delayed from each other as described above, only signals of the same color are output. At this time, contrary to the case of reading, the signals corresponding to the inner divided images of the same color are output after being mutually delayed. Table 1 shows this in more detail.
And 2.

That is, Table 1 (a) is a table of FIG. 3 as it is, and t _i (i = 1 to 4) corresponds to the time required for each signal to be completely output.

Table 1 (b) shows the output order of the separated color signals for each divided image for each time as in (a). On the other hand, Table 2 similarly shows the order of development in the image forming unit as described above, which corresponds to the case of the electrophotographic system.

[Table 1]

It should be noted that the gist of the present invention is not limited to the electrophotographic system, but is a well-known color image copying apparatus based on an ink jet system, a thermal transfer system, and a silver halide photographic system. It can also be applied to At that time, the signal sequence shown in Figure 3 and Table 1 and 2, concisely may each P _i Y, M, C, in the order of Bk, thus, the development process i.e. positive image forming process of Y~Bk In this case, all colors are colored in the order of P1 to P4. However, four sets are required with the functional configuration unique to each of the above methods. The number of the four sets comes from the fact that four sets of developing units are formed corresponding to the four colors Y to Bk in the dry electrophotographic system.

[Table 2]

[Table 3] T1 = t0−t0 (= 0) T2 = t1−t0 T3 = t2−t0 T4 = t3−t0 (where t _i (i = 0 3) is the time given in FIG. 3)

[Table 4] T1 = t0−t0 (= 0) T2 = t1−t0 T3 = t2−t0 T4 = t3−t0 (where t _i (i = 0 3) is the time given in FIG. 3)

Table 3 shows Y to B in the case of the above-mentioned electrophotographic system to which the signal trains shown in FIG.
in which the color signal of the k showed whether it is necessary to delay the extent mutually each P _i, as can be seen from the description of FIGS. 1 and 2,

Approximately T2 = T3 = T4 (= t4−t3).

On the other hand, FIG. 4 and Table 4 show time series of color signals and their mutual delay times when the present invention is applied to cases other than the electrophotographic system. As is clear from the diagram, and a T'i ≠ T'j (i, j ≧ 1), the delay time between colors next phase Y~Bk at a particular P _i part, is constant in each other . Conversely, for P _i and P _j (i ≠ j), the delay times may be different from each other. That is, as given by the equation immediately above.

As will be understood from the above description, in the full-color image copying apparatus according to the present invention, the image forming time is greatly reduced as the image reading time is greatly reduced as compared with the conventional one. You. Simply put, it is about a quarter of what it was before. In addition, in the case of an electrophotographic copying machine, only one photosensitive drum is required.

In the electrophotographic system described in JP-A-59-181362 and the like, when the color is superimposed on the surface of the photoreceptor drum, the circumference of the photoreceptor has four equal lengths and the remaining portion has the same length. The effect of dividing into and will be described with reference to FIG. FIG.
(A), (b) In common, Y, M, C, and Bk have the same meanings as described at the beginning of this section, and other symbols also have the same meaning as in FIG. Is exactly the same as T indicates that an image is transferred from the photoconductor onto the transfer paper.

FIG. 3A shows that all the original images are read only once by a set of reading sensor units, the color signals of Y to Bk are simultaneously decomposed and stored as digital signals, and sequentially (for example, Y, M, This corresponds to a case in which writing is performed in the order of C and Bk) as a conventional example. At this time, the peripheral length Lc of the drum-shaped or belt-shaped photoreceptor to be used is represented by the following equation.

L'c = Lp + L't + L'0 (1) (in the case of the conventional example: FIG. A) Lc = Lp + Lt (2) (in the case of the present invention: FIG. B) where Lp: reading of the entire original image L't, Lt: Minimum length required for transfer L'0, L0: Limit perimeter for arranging four sets of units required for development process

Since L0 is included in Lp, (2)
It does not appear explicitly in the formula. Since approximately L't = Lt,
From the expressions (1) and (2), the following expression is sufficiently established. That is, Lc <L'c (3)

As in the above example, a large-format full-color copier is
When trying to function in a dry electrophotographic system using only one photoreceptor, the perimeter of the photoreceptor is originally unavoidable to be longer than that for a normal size or a black and white type. As shown, it is considered that the invention example in which the circumference of the photosensitive member can be shortened even a little has higher industrial value.

As a typical example of controlling the functions of the color image copying apparatus according to the present invention understood by the above description, a case of a dry electrophotographic system is shown in FIG. First,
When the start button of the copier is pressed, reading of the document image starts, and a timing circuit as a kind of CPU starts working. P _i (i = 1 to 4) means the divided image signals up to the above, and the four arrows from each symbol correspond to the simultaneous color separation of the image signal into four colors of Y to Bk. .

The image signal generation circuit converts the analog color signal read by a reading sensor represented by a CCD and subjected to simultaneous color separation into a digital signal, and outputs it in the form of various image processing. In the delay circuit, the image signal is delayed for each P _i in correspondence with Y to B k as shown in FIG. 3 and Tables 1 to 3, and a laser beam as a light source for writing a latent image on the photosensitive member is provided. Or input to a light signal generating circuit from a light emitting diode. Four thick arrows are Y ~ B
It corresponds to four colors of k. The optical signal generation circuit corresponds to the exposure circuit in the Carlson process circuit, and the timing circuit controls the Carlson process from driving and charging of the photosensitive drum to charge elimination. In this sense, this timing circuit is a kind of CPU, and can usually be constituted by a microcomputer or the like.

When the copying system is an electrophotographic system other than the electrophotographic system, such as an ink jet system, a thermal transfer system, or a silver halide photographic system, the circuit shown in FIG. 6 is partially modified as follows. That is, in the case of the ink jet system or the thermal transfer system, the optical signal generating circuit, the photosensitive drum driving circuit, and the Carlson process circuit are eliminated, and the driving circuit for ejecting the ink jet and the heat signal generating circuit to be added to the transfer ribbon are replaced with the circuit shown in FIG. The position of the optical signal generating circuit at 6 is entered. In the silver halide photographic method, the Carlson process circuit and the photosensitive drum driving circuit are not required. Needless to say, the functions of the delay circuit and the timing circuit at this time are as described in the description of FIG. 4 and Table 4. In addition, it is easy to understand that practical images take the least time when T _i in FIG. 4 and Table 4 are substantially equal to each other.

[0030]

As can be easily understood from the above description, the color image copying apparatus according to the present invention can reduce the time required for the conventional image formation to about one-fourth. It has an objective value.

[Brief description of the drawings]

FIG. 1 is a basic diagram of a document reading process. (A) When the document placing table is in a bed shape. (B) When the document placing table is in a drum shape.

FIG. 2 is a diagram showing a basic mechanism of image formation. (A) When corona discharge is used to charge a photosensitive member and laser light is used to write an image. (B) Instead of charging the photosensitive member, a bias between the photosensitive member and the developing member is used. When using the LED back exposure method for writing images

FIG. 3 is a time series diagram of color signals (1).

FIG. 4 is a time series diagram of a color signal (2).

FIGS. 5A and 5B are explanatory diagrams of a photosensitive drum circumferential length; FIG.

FIG. 6 is an explanation of a basic operation circuit symbol in an embodiment of the copying apparatus according to the present invention.

[Explanation of symbols]

1a, 1b, 3a, 3b, 5a, 5b, 7a, 7b Light source 2a, 2b, 4a, 4b, 6a, 6b, 8a, 8b Reading sensor

Claims (2)

(57) [Claims] 1. A reading sensor for reading reflected light from a relatively moving document image by separating the light into respective colors, and a photoelectric conversion device for amplifying a signal from the sensor correspond to the number of the color separations. A sensor for reading each color is arranged in the moving direction at intervals obtained by substantially equally dividing the reading length of the document image by the number of color separations, and an output electric signal from each of the photoelectric conversion devices. And an image signal generating device comprising a signal delay device for mutually delaying the signals of the respective colors output from the processing device, and an image processing device for processing the image signals of the respective colors as image signals of the respective colors. An image forming apparatus that forms an image of the color in response to the output is arranged around an image forming body such as a photoreceptor at intervals substantially equally divided by the number of color separations, and the functions of the respective apparatuses are copied as required. Image obtained A control device including a timing circuit for controlling the original image so as to divide the original image substantially uniformly in the reading length direction by the number of color separations, and simultaneously read the divided image by the corresponding sensors and read the divided image. A color image copying apparatus configured to simultaneously form each divided image on the image forming body at the equally divided positions and to synthesize and reproduce as a document copy image before division. 2. A color image according to claim 1, wherein said developed image reading means corresponds to the original image in four colors of yellow, magenta, cyan, and black.
Copying equipment .