JPH06233060A - Color image forming device - Google Patents

Abstract

PURPOSE:To uniformize the resolving power of image pickup elements used in the image forming device read system consisting of plural image pickup elements of a multicolor image forming device or the like. CONSTITUTION:The color image forming device where picture data is separated into colors of blue, red, and green based on picture data and each separated color is exposed on an image carrier and respective images are developed with at least yellow, magenta, and cyan color developers to form a color image is characterized by providing a prism 22 for color separation of picture data, a lens 20 which makes picture data incident on the prism 22, and plural image pickup elements 23 to 25 which receive separated colors separated by the prism 22 and emitted from plural light-emitting surfaces and providing one or two crystal plates 29 and 30 between plural light-emitting surfaces and plural image pickup elements.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus for uniformizing the resolving power of an image pickup element used in an image forming apparatus reading system such as a color multicolor image forming apparatus.

[0002]

2. Description of the Related Art A multicolor image forming apparatus, in particular, a digital multicolor image forming apparatus is generally constituted by a color image processing apparatus such as an image reading section and an image writing section. A solid-state image pickup device such as a plurality of CCDs which separates a light image of a document surface into a plurality of lights by a light splitting means such as a prism installed behind the image forming lens system for reading and is received in each channel. The image is picked up at, the image signal corresponding to each color light is taken out, and this is input to the above-mentioned image writing section.

[0003]

As described above, a plurality of Cs are used.
In a color image reading apparatus using a solid-state image sensor such as a CD, as described above, after passing through a lens for color discrimination of each blue, red, and green, it is split into the above three colors by using a prism. However, due to the chromatic aberration of the lens, the MTF values at the resolutions of blue, red and green are different. So blue, red and green MT
In order to evenly balance the F value, it is intentionally used at a position where the MTF value is low. Therefore, there is a problem that the image resolution performance is deteriorated and the MTF values are not perfectly balanced, so that a pseudo color is generated at the edge of the copied recording paper.

The present invention was devised to solve the above problems. I.e. through the lens,
The purpose is to provide a crystal plate between the emission surfaces of the three colors separated into the blue, red and green by the prism and the solid-state image sensor to make the MTF values of the blue, red and green equal.

[0005]

In order to achieve the above object, the present invention relates to claim 1, wherein the image data is color-separated based on the image data, and then exposed on the image carrier for each separated color. In a color image forming apparatus that forms a color image by developing with a color developer of at least yellow, magenta, and cyan, a prism that separates the image data,
The prism is provided with a lens that inputs the image data, and a plurality of image pickup devices that receive the separated colors that are separated by the prism and are emitted from a plurality of emission surfaces, respectively. A crystal plate is provided on one or two emission surfaces between the elements, and the crystal plate is defined on the basis of the lowest resolution value among the blue, red and green. The present invention has been solved by arranging the quartz plate on one or two exit surfaces of the above, and further adhering the crystal plate to the exit surface of the prism with an adhesive.

[0006]

FIG. 1 shows an embodiment of the present invention.

FIG. 1 shows the basic structure of a multicolor image forming apparatus equipped with the color separation prism device of the present invention. A is an image reading system, B is a laser writing system unit, C is an image forming unit, and D is an image forming unit. Is a paper feeding unit, and a color image is formed by the following process.

In the reading system A, 11 is a document table, and the document D1 stored in the document table 11 is illuminated by a halogen lamp 13 mounted on a carriage 12 that slides in the horizontal direction. The movable mirror unit 15 includes a mirror 16 and
17 is attached, also slide horizontally,
In combination with the mirror 14 attached to the carriage 12, the optical image of the original is led to the lens reading unit 20.

The carriage 12 and the movable mirror unit 15 are driven via wires (not shown) connected to a stepping motor, and are slid in the same direction at speeds of V and 1 / 2V, respectively.

The lens reading section 20 includes a lens barrel 21 and
Color separation prism device 22 with built-in filter, CCD23,
It consists of 24 and 25. Further in FIG. 2, the mirror 1
The light image of the original transmitted by 4, 16 and 17 is focused by the lens reading unit 20 and a plurality of color separation filters F, F ₁ provided in the color separation prism device 22 are built in and sequentially transmitted through each filter. , Green, red, blue (below,
Decomposed light (G, R, B) is imaged on the light receiving surfaces of the CCDs 23, 24, 25 provided on the reading substrates 26, 27, 28.

The reading substrates 26, 27, 28 are fixedly provided on the machine frame A1 of the image reading system A.

Numerals 29 and 30 are exit surfaces 2 of the separated light which are separated by the color separation filters F and F ₁ of the color separation prism device 22.
It is a crystal plate adhered to 21, 222 with highly transparent adhesives 223, 224.

The reading system A constructed as described above
When exposing one surface of the document D1, the above-described scanning by the carriage 12 and the movable mirror unit 15 is performed four times, and in synchronization with this, an optical image is formed on the color separation prism device 22 from the lens reading unit 20. Is transmitted, and color conversion is performed by each of the color separation filters F and F ₁ incorporated as described above.

Thus, the optical image corresponds to the G, R, B and neutral (ND) filters, and the CCDs 23, 24, 25 are used.
Each image signal output from the above is subjected to signal processing in a signal processing unit (not shown). At that time, in the light images G, R, B, G
Passes through filters F and F ₁ and is received by CCD 23, and R
Is separated by the filter F ₁ and is received by the CCD 24 provided below the prism 22, and B is separated by the filter F and received by the CCD 25 provided below the prism 22. In this case, as described above, since the optical image passes through the lens reading unit 20 before the optical image reaches the prism device 22, the chromatic aberration of the lens occurs, and the resolving power of each of G, R, and B is M.
The TF values are different.

Therefore, in order to average the MTF values, the lowest MTF value of each color of Y, M, and C is used as a reference value.
Make the MTF values match. That is, as shown in FIG. 3, when the optical image G and the optical image B are low and the MTF values are the same, the crystal plate 2 is only on the emission surface 221 from which the optical image R is emitted.
By adhering 9 with the adhesive 223, the resolution of the optical image R is reduced, and the optical images G, R, and B are averaged. Further, as shown in FIG. 2, when the MTF values of the optical images R and B are high and the optical image Y is low, the crystal plates 29 and 30 are attached to the emission surfaces 221 and 222 of the optical images R and B by adhesives 223 and 224. The MTF values of the optical images G, R, B are averaged by reducing the resolution of the optical images R, B provided by adhering.

In the laser writing system unit B, the laser beam generated by the semiconductor laser (not shown) is rotationally scanned by the polygon mirror 32 rotated by the drive motor 31, passes through the Fθ lens 33 and the optical path by the mirror 34. The curved lines are bent and projected onto the peripheral surface of the image carrier 30 to which electric charges have been applied in advance by the charger 35 as a charging means to form a bright line.

On the other hand, when the scanning is started, the beam is detected by the index sensor, the modulation of the beam by the first color signal, for example, the G image signal is started, and the modulated beam is on the peripheral surface of the image carrier 30. To scan. Therefore, a latent image is formed on the peripheral surface of the image carrier 30 by the main scanning by the laser beam and the sub-scanning by the rotation of the image carrier 30.
This latent image is developed by the developing device 36Y loaded with yellow toner in the developing means, and a toner image is formed on the drum surface. The obtained toner image passes under the cleaning device 39, which is a cleaning means separated from the peripheral surface of the image carrier 30 while being held on the drum surface, and enters the next copy cycle.

That is, the image carrier 30 has the charger 35.
The second color signal output from the signal processing unit, for example, the image signal passing through the R color separation filter F ₁ is input to the writing system unit B ₁ and is processed in the same manner as the above-described image signal. Is written on the drum surface to form a latent image. The latent image is developed by the developing device 36M loaded with magenta toner as the second color.

This magenta toner image is formed in the presence of the previously formed yellow toner image.

Similarly, 36C and 36BK are developing devices having cyan color toner and black color toner, respectively, and correspond to a filter corresponding to the toner color and a neutral filter on the drum surface based on a control signal generated in a signal processing section. To form C and black toner images. AC and DC biases are applied to the sleeves of the developing devices 36Y to 36BK, non-contact development is performed by a two-component developer that is a developing means, and the image bearing member 30 which is grounded is first formed. The development is performed without destroying the toner image.

The color image thus formed on the peripheral surface of the image carrier 30 is sent from the paper feed section D by the paper feed belt 41 and the feed roller 42 in the transfer pole 40 provided as the transfer means. The image is transferred onto a recording sheet that is a recording medium. The recording paper on which the toner image has been transferred is separated from the drum surface by the separation electrode 43, and is carried into the fixing device 45 via the conveyor belt 44 to fix the image.

On the other hand, the blade 39A of the cleaning device 39 is attached to the image carrier 30 in which the recording paper is separated from the peripheral surface of the drum.
Removes the residual toner after contact with the toner. After the completion of the removal, the toner is separated from the peripheral surface of the drum again, and a new color image forming process is started.

[0023]

As described above, according to the present invention, when the reflected light of the document D1 is separated into at least G, R, and B by the color separation filter provided in the reading prism by the lens, the reading by the lens occurs. As for the chromatic aberration, the MTF value is adjusted by the crystal plate provided on the exit surface of the prism so that the pseudo color generated at the edge of the recording paper can be almost completely prevented. Highly versatile and vivid color copying is possible.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a multicolor image forming apparatus.

FIG. 2 is a configuration diagram in which a lens reading unit, a prism, and an image sensor are assembled.

FIG. 3 is a configuration diagram showing another embodiment of FIG.

[Explanation of symbols]

A image reading system B laser writing system C image forming unit D paper feeding unit D1 original 11 original table 20 lens reading unit 21 lens barrel 22 color separation prism 23, 24, 25 CCD F, F ₁ color separation filter 29, 30 crystal Board 223, 224 adhesive

Claims (3)

[Claims] 1. Based on image data, the image data is color-separated into blue, red, and green, and then exposed on an image carrier for each of the separated colors, and at least yellow, magenta, and cyan color developers are used. In a color image forming apparatus which develops and forms a color image, a prism for color-separating the image data, a lens for injecting the image data into the prism, and a separation separated by the prism and emitted from a plurality of emission surfaces Providing a plurality of image pickup elements for receiving each color, the plurality of emission surfaces,
A color image forming apparatus, wherein one or two crystal plates are provided between the plurality of image pickup devices. 2. The quartz plate is one of the other emission surfaces based on the lowest resolution value of the blue, red and green.
The color image forming apparatus according to claim 1, wherein the color image forming apparatus is provided on one emission surface or on two emission surfaces. 3. The color image forming apparatus according to claim 1, wherein the crystal plate is attached to the exit surface of the prism with an adhesive.