JPS63305662A - Image reader - Google Patents

Abstract

PURPOSE:To upgrade the accuracy of positioning and the resolution and to increase the drive speed constituting the titled reader having a member to color-decompose an optical image from an original, two solid-state image pickup elements, and an image forming member, fixing the two solid-state image pickup elements and the image forming member, and making the color-decomposing member replacable. CONSTITUTION:A dichroic prism 5A is such a one whose reflecting beam of light is green G in color and the transmitting beam of light is red R in color, while a prism B is such a translucent prism whose reflecting beam of light is colorless BK and the transmitting beam is blue B. First, the prism 5A is present in the image forming optical path, and the information about a red R image is outputted from a CCD image sensor 4A while from that 4B, the information about a green G image is outputted. Thereafter, the prism 5A is saved from the optical path and the translucent prism 5A enters the optical path, hence, from the 4A, the information about a blue B image is outputted while, from the 4B, the information about a colorless BK image is outputted. Thus, image information whose colors are B, G, R, and colorless can be obtained. Therefore, the positioning of the solid-state image pickup elements is made easier, also, there is no need for containing three kinds of filters in one picture element like with a color CCD. As a result, the resolution is remarkablly upgraded and the lowering of drive speed can be suppressed.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to an image reading device used in a color image forming apparatus, and particularly an image reading device that forms and reads an image of a document on a solid-state image sensor, which is used in a color image forming apparatus suitable for image formation using electrophotography. It is related to.

[Background of the invention]

2. Description of the Related Art In recent years, image forming apparatuses that use a full-color original image (original) to form a full-color copy using electrophotography have begun to appear. Multicolor images are useful not only for reproducing figures, still lifes, landscapes, and the like from manuscripts, but also for figures, tables, and the like, since it is easy to incorporate a large amount of information into a single recorded image. Under the above circumstances, various methods and apparatuses for forming multicolor images have been proposed. For example, a plurality of latent image forming means and a plurality of developing means are arranged around a rotating drum-shaped photoreceptor, and by repeating latent image formation and development, visible images of different colors are formed on the drum-shaped photoreceptor. A method of forming layers in layers and transferring them all at once to recording paper (
JP-A-52-106743, JP-A No. 56-14445
No. 2 Publication, No. 58-79261 Publication. 61-170754) is shown. Further, one latent image forming means and a plurality of developing means are arranged around the rotating drum-shaped photoreceptor, and a latent image is formed and developed for one color each time the photoreceptor rotates. Multiple rotations form a multicolor visible image on the photoreceptor, which is then
A method of simultaneously transferring onto recording paper (Japanese Unexamined Patent Publications No. 60-76766, No. 60-95456, No. 61-17075)
Publication No. 4) is shown. In the former method, when the colors to be reproduced are full colors consisting of yellow, magenta, cyan, and further black if necessary, the latent image forming means and the developing means are provided with the same number of photoreceptors as the types of colors mentioned above. The photoreceptor must be arranged around the photoreceptor, which increases the diameter of the photoreceptor and increases the size of the device. Furthermore, when forming a latent image, in order to guarantee alignment (renost) of each color separation latent image, control and equipment are required to ensure extremely high writing accuracy of latent image forming means such as lasers, LEDs, and LCSs. Since only one scan is required, either the reading registration is good or a large capacity image memory is required. In the latter method, since there is only a single latent image forming means, the apparatus can be made smaller than in the former method, and in particular, since the latent image forming means is commonly used, it is advantageous in guaranteeing latent image registration. However, the photoreceptor must be rotated the same number of times as the types of colors, which slows down the speed of multicolor image formation. On the other hand, reading scanning requires image memory (in one case, reading scanning is performed 3 to 4 times, and in contrast to the former method, the registration of the reading means becomes a problem. It solves the above-mentioned problems with conventional image formation, allows image formation to be performed at high speed without increasing the size of the device, maintains clear color images without color shift, and significantly reduces memory capacity. An application has been filed for a reduced color image forming apparatus (Japanese Patent Application No. 61-294290).The above color image forming apparatus has two sets of image forming means, and at least one of these is repeatedly used. Therefore, compared to image formation by one rotation of the image carrier (1 means 1 movement), or image formation by 3 to 4 rotations (1 means 3 to 4 movements), the image forming apparatus must be small and high-speed. In addition, by synchronizing with the image reading means, color images can be formed efficiently with a small memory capacity.Furthermore, many multicolor modes such as single color and two color can be efficiently handled. It has the advantage that single-color or two-color printing can be performed by one reading scan and one rotation or one movement of the image carrier. Conventional color image reading devices (color scanners) As shown in Fig. 19, the colors are separated into blue, green, and red using a guichroic prism or a guichroic mirror, and then the light is input to a CCD image sensor, which is three solid-state image sensors, or as shown in Fig. 20). Color CC
A method using a D image sensor was used. In the figure, reference numeral 27 is a document holding plate that brings the document 21 into close contact with the document table; 28m, 28b=28c are reflecting mirrors that reflect light when the document 21 is illuminated by the illumination lamp 22; the light is reflected by this group of reflecting mirrors; The light is lens 30
The colors are separated by a guichroic prism 29 and then sent to a CCD image sensor 24a. A green image, a blue image, and a red image are formed on 24b and 24c,
converted into an electrical signal. Note that the arrows indicate the illumination lamp 22 and the reflecting mirror groups 28a and 28b.
. It shows the direction in which 28c is moved for sub-scanning. FIG. 20 is a diagram showing a color CCD, in which the color CCD shown in FIG. 20 is directly provided without providing the gicroic prism 29 after the lens 30 of FIG. 19 to obtain an electrical signal of an image. In the figure, 24 is a color CCD image sensor, and sensor elements 43 are densely arranged in the − dimension.
, a blue, green, and red mosaic filter [45] disposed on the surface of the sensor element 43 group, and a transfer section (CCD shift register) 47, and a color C
The image of the original 21 formed on the sensor element 43 of the CD image sensor 24 is photoelectrically converted by the sensor element 43 . The electric signal obtained by the charge conversion is φ3. Driven by the two-phase drive pulse 46 of φ2, the transfer unit (CCD shift register) 47 is main scanned in the direction of the arrow X, and the output 48
is output to. CCD image sensors 24a and 24b shown in FIG.
The same applies to the signal outputs of , 24c.

[Problems to be solved by the invention]

Blue (B) by a conventional image reading device as described above. The method of obtaining three color signals of green (G) and red (R) at once is effective for an image forming apparatus having three sets of writing systems, but as described above, it is effective for an image forming apparatus having two sets of image forming means. Since only two sets of information can be used effectively with the equipment that we have, one set of information is wasted and not only does the equipment become expensive, but also three sets of information can be used effectively.
It is difficult to precisely align individual CCDs. Further, the color CCD image sensor shown in FIG. 20 has problems such as a decrease in pixel density, poor resolution, and a decrease in driving speed. SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and provide an economical image reading device that is high speed, has excellent resolution, and is suitable for an image forming apparatus having a 2IIL writing system.

[Means to solve the problem]

The above object is to provide an image reading device that is layered with a member that color-separates an optical image from a document, two solid-state image sensors, and an image-forming member, while the two solid-state image sensors and the image-forming member are fixed; This is achieved by an image reading device whose members are replaceable.

【Example】

Hereinafter, the present invention will be explained in detail with reference to illustrated examples. FIG. 1(a) is a diagram showing the configuration of an embodiment of the present invention.
Figure (b) is an enlarged perspective view of the color separation portion shown in Figure 1 (,). The diagram shown in FIG. 1(a) is the same as the conventional image reading device shown in FIG. 19 except for the color separation portion after the lens 2, so a detailed explanation will be omitted. In FIG. 1(b), 2 is a lens which is an image forming member, 4
^. 4B! ! Line-shaped CCD image sensor, 5^, 5B
5^ is a guichroic prism which is a color separation member, and 5^ has a guichroic reflective surface that makes the reflected light green (G) and the transmitted light magenta (N), and the exit surface 5^ of the transmitted light.
A is a guichroic prism coated with a red filter layer so that the reflected light is green (G) and the transmitted light is red (R); 5B is a translucent prism, for example, and the transmitted light exit surface 58a is a semi-transparent prism; It is a semi-transparent prism coated with a blue (B) filter layer so that the reflected light becomes Wc colored (BK) and the transmitted light becomes blue (B). Initially, there is a guichroic prism 5Δ in the imaging optical path, and the CCD image sensor 4^ outputs information regarding a red (R) image, and the fiilccD image sensor 4B outputs information regarding a green (G) image. Next, the guichroic prism 5^ retreats from the optical path, and the translucent prism 513 enters the optical path, and the CCD image sensor 4^ outputs blue (B).
Image information, achromatic color (B
K) Image information is output. In this way, image information of B, G, R, and achromatic colors are obtained, and the prisms 5^ and 5B return to their original positions and prepare for the next image formation. In another embodiment shown in FIG. 2, a prism 5C that simply divides the optical path into two is fixed, and a filter plate 6^, which is a color separation member, is movable between the translucent prism 5C and the CCD image sensors 4^ and 4B. and 6B are provided. The filter plate 6^ is made of, for example, a support of a transparent parallel plane plate, and has a filter layer in which the upper half is red (R) and the lower half is green (G), and the filter plate 6B is, for example, also has a blue (B) filter layer in the left half. It consists of a filter layer, and can first obtain information on a green image and a red image, then a blue image and an achromatic image. Other embodiments shown in FIGS. 3 and 4 are side views showing a case where a light converging element array such as a cell-hoc lens 7-ray is used as an imaging member, and in the figure, 3 is a light converging element array. Array, 4^, 4B is a contact image sensor, 5^, 5
B, 5C are prisms or semi-transparent prisms that split the transmitted light and reflected light as shown in Fig. 1, 6
^, 6B are filters having the same characteristics as the filters 6^, 6B shown in FIG. The example shown in Figure 3 is dichroic prisms 5^ and 5B.
The prism 5 is rotated around the beam 7 to position either the prism 5^ or the prism 5B in the optical path, and the first prism 5^ is in the optical path and the red (R) image and Green (G) image information is output from the contact type image sensors 8^ and 8B, and then a prism 5B enters the optical path, and a blue (B) image and an achromatic BK image are output from the contact type image sensors 8^ and 8B. information is now output. The embodiment shown in FIG. 4 is a prism 5 that simply divides the optical path into two.
C is fixed, and the filter plates 6^ and 6B move left and right or up and down, first providing information on the red (R) and green (G) images, then on the blue (B) and achromatic (BK) images. Information is obtained from contact image sensors 8^ and 8B. Note that the output order of each color information is not limited to that shown above, and the order in which the prisms 5^ and 5B enter the optical path may be changed, or the dichroic prisms 5^, 5
The output order may be changed by changing the spectral characteristics of B, and a filter plate 6B and a semi-transparent prism 5B may be used to obtain achromatic light.
Needless to say, a correction filter layer may be provided so that the overall characteristics including the spectral sensitivity characteristics of the image sensors 4B and 8B approximate the visibility. Next, a color image forming apparatus including the image reading device described above will be described. 5(a) and 5(b) are schematic configuration diagrams showing an example of a recording device using the image reading device of the present invention, FIG. 6(a),
(b) and (c) are schematic configuration diagrams of a laser beam scanner for image exposure, FIG. 7 is a partial sectional view showing an example of a developing device, and FIGS. 8 to 11 are respective illustrations of implementation of the method of the present invention. In the 70-chart, Figure 12.13 is an image forming circuit diagram, and Figure 14.15 is a time chart of image formation. In the recording apparatus shown in FIG. 5(,), 1 is a drum-shaped image carrier having a photoconductive surface layer of Se or the like and rotating in the direction of the arrow; 11 and 12 uniformly cover the surface of the image carrier 1; Charging devices 21 and 22 are image exposure units for each color of a color image, 31 to 22;
34 is a developing device in which toners of different colors such as yellow, magenta, cyan, and black are used as developers; 13 and 41 are toner images of a plurality of colors formed on the image carrier 1 by superposition. 14 is a transfer device; 61 is a pre-transfer charger and a pre-transfer exposure lamp which are provided as necessary to make it easy to impart a color image to the transfer body P or to make it easy to separate the transfer body P; A fixing device 42.15 for fixing the toner image transferred to the transfer body P is a static elimination lamp and a static elimination corona discharger, respectively, and one or both of them are used in combination. Reference numeral 16 denotes a separation electrode, and 51 contacts the surface of the image carrier 1 after the color image has been transferred to remove residual toner on the surface, until reaching the surface where the first development has been performed. This is a cleaning device having a cleaning blade that separates from the surface of the image carrier 1 and a seven-hoo brush. Further, in FIG. 5(b), optical static elimination is performed using a lamp 71 in order to stabilize the potential of the photoreceptor before charging. Here, the chargers 11 and 12 are used as shown in the figure, which can provide stable charging with less influence from previous charging, especially when the chargers 11 and 12 charge the surface of the image carrier 1 which is already charged. It is preferable to use a scorotron corona discharger such as the one shown in FIG.
may be the same as in ordinary monochrome electrophotographic copying machines, in which the slit exposure is filtered for each color using a filter, but in order to record clear color images, the sixth
It is preferable to perform image exposure using a laser beam scanner as shown in Figures (a), (b), and (c), and then reversely develop the resulting latent image. FIG. 6(a) for forming image exposure 104
By using a laser beam scanner such as that shown in FIG. 3B, it is possible to easily form electrostatic images for each color with good positional accuracy, as will be described later, and therefore it is possible to record clear color images. The laser beam scanner in FIG. 6(a) is a He-Ne laser beam scanner.
A laser beam emitted from a laser 121, such as a laser, is turned on and off by an acousto-optic modulator 122, and is deflected by a mirror scanner 123 consisting of an octahedral rotating polygon mirror rotated by a drive motor 130 to form an image f- Image exposure 104 is performed by scanning the surface of the image carrier 1 at a constant speed through two θ lenses 124. Note that 125 and 126 are mirrors, and 127 is a lens for optimizing the diameter of the beam incident on the imaging f-theta lens 124 for irradiating the beam onto the image carrier 1 with an appropriate diameter. In addition, as a laser beam scanner,
The structure shown in FIG. 6(b) is also suitable. A laser beam generated by a semiconductor laser 221 is transmitted to a polygon mirror 223 rotated by a drive motor 230.
．． , is rotated and scanned from the center, passes through an f-theta lens 224, has its optical path bent by a reflecting mirror 237, and is projected onto the surface of the image carrier 1 to form a bright line 239. 234 is an index sensor for detecting the beam position in order to control the start of beam scanning, and 235 and 236 are cylindrical lenses for correcting the inclination angle. 238a, 238b,
A reflecting mirror 238e forms a beam scanning optical path and a beam detection optical path. Also, the patent application filed by the applicant in 1986-23
When using a laser beam scanner and an optical deflector 223 such as an etched insulating plate, such as a crystal plate, as described in the 9469 specification, reciprocating scanning becomes possible, unlike scanning using a rotating polygon mirror. When such reciprocating scanning is employed, the optical scanning system may have a configuration as shown in FIG. 6(c). That is, by arranging the index sensors 234 and 234' in the forward and backward directions of the scanning direction,
Since the start and end of scanning of the laser beam (which can also be called the start of scanning since the beam returns) can be detected, corresponding image information can be recorded on the image forming body 1. In FIG. 6(c), 238e and 238c' indicate reflecting mirrors. When scanning is started, the beam is directed to the index sensor 234.
, and modulation of the beam by the IJil color signal is started by a modulator (not shown). The modulated beam goes up to the charger 11 or 12 and scans over the image carrier 1 which has been uniformly charged in advance. laser beam 1
A latent image corresponding to the first color is formed on the drum surface by the main scanning by 04 and the sub-scanning by rotation of the image carrier 1. Further, the image exposure 104 is not limited to the laser beam as described above, but is, for example, an LE light beam.
It may be obtained using a D, CRT, liquid crystal, or optical 7-eyeper transmitter, and it may be a recording device in which the image carrier is in the form of a belt. Furthermore, the developing devices 31 to 34 preferably have a structure as shown in FIG. 7. In the fjS7 diagram, 131 is a developing sleeve made of a non-magnetic material such as aluminum or stainless steel, 132 is a magnet body provided inside the developing sleeve 131 and has a plurality of magnetic poles in the circumferential direction, and 133 is formed on the developing sleeve 131. a layer thickness regulation blade that regulates the thickness of the developer layer;
134 is a scraper blade that removes the developer layer after development from above the developing sleeve 131; 135 is a developer reservoir 13;
137 is a toner hopper; 138 is a toner replenishing roller that has a gate on its surface through which the toner enters and replenishes toner from the toner hopper 137 to the developer reservoir 136; 139 is a protective resistor 140; This is a power source for applying a bias voltage including an oscillating voltage component in some cases to the developing sleeve 131 via the power source to form an electric field that controls the movement of toner between the developing sleeve 131 and the image carrier 1. It is shown that the developing sleeve 131 and the magnet body 132 each rotate in the direction of the arrow, but even if the developing sleeve 131 is fixed, the magnet body 132 is fixed, or the developing sleeve 131 and the magnet The magnetic bodies 132 may rotate in the same direction, but when the magnetic bodies 132 are fixed, the magnetic flux density of the magnetic pole facing the image carrier 1 is usually made larger than the magnetic flux density of the other magnetic poles. In order to make the magnetization stronger,
Two magnetic poles of the same polarity or different polarities are placed close to each other. In such a developing device, the magnetic pole of the magnet body 132 is usually 500.
It is magnetized with a magnetic flux density of ~15011 μs, and its magnetic force creates a developing puddle 13 on the surface of the developing sleeve 131.
6 is adsorbed, and the thickness of the adsorbed developer is regulated by a layer thickness regulating blade 133 to form a developer layer, and the developer layer is rotated in the same direction as the rotation arrow direction of the image carrier 1 or The surface of the developing sleeve 131 moves in the opposite direction (the same direction in the figure) and develops the electrostatic image on the image carrier 1 in the development area where the surface of the developing sleeve 131 faces the surface of the image carrier 1, and the remaining part is developed by the scraper blade 134. The surface of the sleeve 131 is removed and returned to the developer reservoir 136. The development is repeated at least for the second and subsequent development to superimpose the color toner images.
Non-contact development is preferably performed under non-contact development conditions so that the toner attached to the image carrier 1 during the previous development is not displaced during the subsequent development. When the layer is separated from the image carrier 1 with no developing bias applied, a superimposed bias of direct current and alternating current is applied to the developing sleeve 131 to cause the toner to fly under an alternating electric field and transfer it to the image carrier 1. Refers to the development method in which it is deposited on top. FIG. 7 shows a state in which development is performed under non-contact development conditions. Furthermore, the developing units 31 to 34 are made of non-magnetic material that does not require the toner to contain a black or brown magnetic material, which makes it possible to obtain toner with a clear color and to easily control the charging of the toner. It is preferable to use a so-called two-component developer consisting of a mixture of toner and a magnetic carrier. In particular, when the magnetic carrier is a styrene resin, a vinyl resin, an ethylene resin, a ronone-modified FI1G resin, an acrylic resin, a polyamide resin, For resins such as epoxy resins and polyester resins, triiron tetroxide, γ-ferric oxide, chromium dioxide, manganese oxide, 7
It consists of fine particles of a ferromagnetic or paramagnetic material such as elite, manganese-copper alloy, etc., dispersed therein, or the surface of the particles of the magnetic material is coated with the above-mentioned resin. Resistivity is tOSΩC- or more, preferably 10'
It is preferable to use an insulating carrier with a resistance of 3Ωt3Ta or more.If this resistivity is low, when a bias voltage is applied to the development input-1131, charge is injected into the carrier particles, causing the carrier particles to be deposited on one surface of the image bearing member. Problems such as easy adhesion and insufficient application of bias voltage arise. In particular, when carriers start to adhere to the image carrier 1,
Adversely affects the tone of color images. In addition, the resistivity is determined by placing the particles in a container with a cross-sectional area of 0.50 cm2 and tapping, then applying 1
This value is obtained by applying a load of "kg/am" and reading the current value when applying a voltage that generates an electric field of 100OV/c- between the load and the bottom electrode. If the diameter is less than 5μ, the magnetization will be too weak, and if it exceeds 50μ, the image will not be improved, breakdown or discharge will easily occur, and high voltage will not be able to be applied.
- or less, and if necessary, a fluidizing agent such as hydrophobic silica may be appropriately added as an additive. The toner is preferably a resin with various pigments and, if necessary, a charge control agent, etc., and has an average particle size of 1 to 20 μm.
The average charge amount is 3 to 300 μe/g. Particularly preferred is one of 10 to 100 μe/g. When the average particle size of the toner is less than 1 μm, it becomes difficult to separate from the carrier, and when it exceeds 20 μm, the resolution of the image decreases. When a developer made of a mixture of an insulating carrier and toner as described above is used, the bias voltage applied to the developing sleeve 131 shown in FIG. There is a risk of leakage (this can be done easily).In addition, in order to more effectively control the development movement of toner by applying such a bias voltage, it is necessary to set the A magnetic material such as that used in a magnetic carrier may be contained within a range that does not impair color clarity.The above is the structure of the developing device and developer preferably used in the method of the present invention. This is not limited to, but includes JP-A-50-30537 and JP-A-55-1865.
No. 8-18659, No. 56-144452, No. 58-
116553 to 116554 may be used, and it is more preferable to use the developing devices and developers described in Japanese Patent Laid-open Nos. 58-57446 and 58-96900 to 96903, which were previously filed by the applicant of the present application. , 58-979
No. 73, No. 60-192710-11, No. 60-14
No. 537, No. 60-14539, No. 60-17606
It is preferable to use non-contact development conditions using a two-component developer as described in each specification of No. 9, especially JP-A No. 60-1.
In the developing device disclosed in No. 76069, the magnet body in the developing sleeve is fixed, and the developing device performs development in the thin part of the developed M layer between the magnetic poles. It is preferable that high developing performance can be obtained by forming a block, and the fact that the magnet body is not rotated is also advantageous for deviceization, especially for image forming apparatuses having multiple developing devices. However, these image exposure positions must be determined using index markers (one, multiple if necessary) for the registration storage 5 provided at fixed positions on the image carrier
This can be easily and accurately performed by position detection and image exposure timing control using a conventional 7-oto sensor that detects pulses of an encoder rotating with the image carrier (not shown) and the like every time the image carrier rotates. No color shift occurs in the resulting image. In the case of a laser optical system, a polygon is also used as a light scanning means, as disclosed in Japanese Patent Application Laid-Open Nos. 58-181566 and 57-6471.
No. 8, VF11 as a position control method and a multiple laser beam forming method using polygons according to Publication No. 59-53866.
Image shift can be particularly accurately prevented by using the technique disclosed in Japanese Patent No. 150068/1983 or by using a plurality of laser beam forming methods using an optical modulator. Further, as described above, in the above recording method, the toner image formed on the image carrier 1 is transferred directly from the image carrier 1 to the transfer body PI: 11X by the transfer device 14 without using a transfer drum. - Since it is designed to capture images, the device can be made smaller without causing color shift. With the recording apparatus as described above, the methods shown in FIGS. 8 to 11 can be carried out. Note that FIGS. 8 to 11 all show the stage up to the second development. Figure 8 shows that an electrostatic image is formed by an electrostatic image forming method in which the exposed part of the image becomes the background part and the non-exposed part becomes an electrostatic image, and during development, toner charged to the opposite polarity is attached to the electrostatic image. An example is shown in which this is done. This is shown in Figure 5 (
According to the recording apparatus of a), the charger is applied during the first rotation to the surface of the image carrier 1 which is in an initial state where the electric potential is 0 after being neutralized by the electric charge remover 15.42 and cleaned by the cleaning device 51. 11, and the charged surface is subjected to imagewise exposure 21 for each color so that the potential other than the electrostatic image area becomes approximately O, and the potential obtained thereby is The developing device 3 generates an electrostatic image approximately equal to the potential of the first charging.
First development is performed by a developer using a developer of a color toner corresponding to image exposure 21 among images 1 to 32, and toner T charged to the opposite polarity is attached. A second charge is uniformly applied again by the charger IZ, and the charged surface is subjected to a second image exposure 22 for a color different from the curve, so that the potential other than the electrostatic image area becomes approximately 0. Then, the obtained electrostatic image is developed a second time using one of the other developing devices 33 to 34 using a developer of a corresponding color toner. Next, the transfer pretreatment 13.41, the transfer pole 14, the static eliminator 15゜42, and the cleaning l & it 51 are made inactive, and 2
The 3rd and 4th electrostatic image formation and development are repeated during the rotation, and when the 4th development is performed and a color image in which color toner images are superimposed is formed, it passes. The pre-transfer charger 13 and the pre-transfer exposure lamp 41 are operated until the color image is transferred to the image carrier 1 by the transfer device 14.
The transferred color image is transferred to a transfer body P that is sent in synchronization with the rotation of the image carrier P, and the transferred color image is fixed on the transfer body P by a fixing device 11. The surface of the image carrier 1 to which the color image has been transferred is
．． In this embodiment, one cycle of color image recording is completed by being neutralized by the cleaning device 42 and returning to the initial state by being cleaned by the cleaning device 14. That is, charging for each electrostatic image formation is performed twice by the chargers 11 and 12, and image exposure is also performed twice by two exposure devices created by the laser beam scanner of #12, for example. , the recording device can be made small and inexpensive, and can perform high-speed recording. In the embodiment shown in FIG. 8, development is carried out by a developing method in which an electrostatic image is developed with a toner that is charged with opposite polarity, so it is easy to increase the development density of each color, and therefore it is easy to produce clear colors. Images can be recorded. In addition, since potential remains in the dead toner image and color mixing is likely to occur, in order to avoid color mixing, it is recommended to set the DC bias during development to a higher value in later stages. Correspondingly, it is preferable to set the charging potential higher in sequence, and a means for aligning the polarity of the toner is required during transfer. Figures 9 to 11 show that an electrostatic image is formed by an electrostatic image forming method in which the exposed area becomes an electrostatic image with a lower potential than the background area, and development causes the electrostatic image to have the same polarity as the background area potential. An example of reversal development performed by adhesion of charged toner is shown. The embodiment of FIG. 9 using the recording device of FIG.
The surface of the image carrier 1 in the same initial state as shown in the figure is uniformly charged by the charger 11 at one viewing port, and the image exposure 21 for each color is projected by the laser beam scanner in FIG. 6 onto the charged surface. Then, a first image exposure is carried out so that the potential of the electrostatic image area becomes approximately O, and the obtained electrostatic image is transferred to a developer of a color toner corresponding to the image exposure 21 of the developing units 31 to 32 (however, In this case, unlike the example shown in Fig. 1
1 and 12, a second image exposure is performed by projecting an image exposure 22 of a different color at a position shifted from or at the same position as the projection position of the previous image exposure 21, thereby The obtained potential is approximately 0
The electrostatic image is developed by one of the other developing devices 33 to 34 using a developer of the corresponding color toner, and 2
The third and fourth electrostatic image formation and development are repeated on the circulation opening, and thereafter one cycle of color image recording is completed in the same manner as described with reference to FIG. In this example, even if an electrostatic image with a potential of approximately 0 is developed and toner T, which is charged to the same polarity as that of the image carrier 1, adheres to the electrostatic image, the potential is changed to approximately the background area as shown in the figure. Since the potential is not equal to the potential, when developing the electrostatic image formed later with different color toner T, the electrostatic image area to which the toner T has adhered is not exposed or written. figure,
Toner T' accumulates and adheres. Therefore, by utilizing the fact that toners of different colors tend to overlap each other, it is possible to obtain a monochrome image or a multicolor image with excellent clarity. In the example of Fig. 10, the electrostatic image is formed after the electrostatic image area that was developed first, whereas the example of Fig. 19 actively overlaps the electrostatic image at the position where the electrostatic image was previously formed. This is an example of smoothing by recharging to prevent color mixing in which even a small amount of toner of different colors adheres during development. In the example shown in FIG. 10, the steps from the initial stage to the first development are the same as those shown in FIG.
, perform a second image exposure on the charged surface, perform a second development step b1, and repeat the third and fourth electrostatic image formation and development in the same manner. This example differs from the example shown in FIG. 9 in that the example shown in FIG. In this way, in the example of FIG. 10, in which the surface of the image carrier 1 is uniformly charged again after the previous development to perform the subsequent electrostatic image formation and development, it is different from the example of FIG. Similarly, an electrostatic image can be formed over the position where an electrostatic image was previously formed, and unless the image position where the previous toner adhered is exposed, later toner of a different color will hardly adhere. This effect can be obtained. The example shown in FIG. 11 is an example in which the subsequent toner of a different color is particularly prevented from adhering to the image position where the previous toner was adhering. This example is the same as the first development in Figure 10 until the first development, but after the first development, Figure I:IS5 (
As shown in b), the image carrier 1 is exposed using the exposure lamp 71.
Either uniformly expose the surface to light and then charge it a second time with the charger 12, or first charge it evenly for the second time with the charger 12 and then apply a weak light with the exposure lamp 71 shown by the phantom line. After that, a second image exposure and a second development are performed, and the electrostatic image formation and development are repeated a third time and four times at tJS. Here, if you uniformly expose it first after development,
The photoconductor, including the area to which toner has been developed, is uniformly exposed to approximately O potential, and by performing a second charging, the potential of the area to which toner has adhered is compared with that of the remaining electrostatic image. The difference in potential from the portion where formation is performed becomes smaller, and the surface of the image carrier 1 can be uniformly charged. It also gives favorable results to photoreceptors having optical memory. In each of the above examples, a developer made of a mixture of toner and an insulating carrier is used in the developing units 31 to 34.
Preferably, development is performed under non-contact development conditions. As mentioned above, this prevents the mixing of toners of different colors, and also makes it easy to apply an appropriate bias voltage for toner control to the developing sleeve 131 of the developing device.
Even when using an electrostatic image forming method or a developing method as shown in the examples of FIGS. 9 to 11, in which an image exposure device such as a laser beam scanner is advantageously used, it is possible to produce color images with high development density and excellent clarity. Can be recorded. Next, the outline of the color image forming system according to the present invention will be explained in the first part.
This will be explained using Figure 2. This image forming method uses the process shown in FIG. The recording device, dot pattern memory, and image forming process are controlled and driven by control signals from the CPU. For example, the exposure system (lamp 2,
As the mirrors 38m, 38b, 38c) move, the image sensors 4A and 4B move B and G in the lateral direction of the original M1.
, R and 1 achromatic color, and outputs an analog video signal. After A/D conversion, this signal undergoes shading correction to remove color information and distortion caused by the optical system, etc., and is temporarily input to a buffer memory for each B,
G, R, and achromatic colors are made to correspond to the same image position. In addition, in order to improve the color separation characteristics of the color separation filter, it is preferable to provide a notch filter for cutting off light between B and G, and between G and R. An interference filter is preferably used as the notch filter, and for example, a notch filter having spectral characteristics as shown in FIG. 17 is used. As shown in FIG. 18, the notch filter 1 is installed before and after the lens system or between the lenses in the lens system 170, and is used before and after the light converging element in a contact color image sensor. Next, the B, G, R, and uncolored signals from the buffer memory are converted into Y, M, C, and 1 black (complementary color conversion), and after gradation correction is performed, they are converted to a pattern generator.
(pc). Here, it is changed into a digital dot pattern signal based on a dither method, for example, and stored in a page memory for each color. These image data are outputted to the recording device through a line memory required as a buffer in synchronization with the rotation of the image forming body, where writing and image formation are performed. In FIG. 12, the M dot pattern is passed through a selector for selecting color information at the one-rotation port of the image forming body, and the Y dot pattern is transferred to the first latent image forming means and the second latent image forming means, respectively, through a delay circuit that guarantees the distance between the two image forming means. C is output from the latent image forming means, and when the image forming body of the next second rotation comes to the same position.
The BK dot pattern is delayed from the dot pattern and is outputted from the page memory from the first latent image forming means and the second latent image forming means, respectively, in synchronization with the write timing. FIG. 13 shows a case where the image memory is significantly reduced. Image reading device of the present invention as shown in FIG. 12! Image data is input to the pattern generator (PC) by the first scan by the color scanner. Here, for example, the M dot pattern signal is changed into a digital dot pattern signal based on a dither method, and the M dot pattern signal that is written first is written and imaged almost synchronously with the reading through a line memory required as a buffer. . On the other hand, the Y dot pattern signal, which is inputted secondly, is outputted to the recording device via a delay circuit that guarantees the distance between the two image forming means, and is outputted to the C dot pattern when the zero-order image forming body rotates. The dot patterns in B are scanned again by the color scanner in accordance with the writing timing, while the dot patterns in B are sequentially taken out via a delay circuit. The color scanner scans in synchronization with the rotation of the image forming body. In FIGS. 12 and 13, the delay circuit is an image memory that functions as a shift register. This image memory compensates for the difference in writing timing between the two image forming means. In the normal color mode, a developing device having a color toner corresponding to image data operates. Regarding the image forming apparatus shown in FIGS. 5(a) and 5(b), developing devices 31 and 32 having magenta toner and cyan toner correspond to the case of developing image data outputted without passing through a delay circuit, and yellow and yellow toners are used. This corresponds to the case where a developing device having a black F toner develops image data outputted through a delay circuit. Note that the image forming means 21
corresponds to the first image forming means, and the image forming means 22 corresponds to the second image forming means. The first and second latent image forming means have different recording positions on the photosensitive drum. Therefore, it is necessary to accurately shift the timing of sending data from the delay circuit. The timing deviation is determined by counting the first horizontal synchronization signal, and when the specified number of times is reached, the second image signal (color information) is determined.
Send out. In addition to such means, it is also possible to set the rotational state or time of the drum using a drum encoder or the like. In the method described in FIG. 13, it is necessary for the reading system to return to the next writing point, and furthermore, it is necessary to align the image on the image forming body. Since it is extremely difficult to do this mechanically, it is recommended to prepare the necessary line memory as a buffer for each screen. (at the start) document table, read the position of the light source or the end of the document as a reference position and store it in the buffer memory, and correspond to the M reference toner image position formed on the drum as the external write timing. When a signal is detected and the writing is performed from the second rotation onwards, the images can be aligned with high precision. This superimposed toner image is easily transferred by the action of the pre-transfer charger 13 and the exposure lamp 41. After that, the transfer paper P is transferred onto the transfer paper P supplied from the cassette by the action of the transfer electrode 14, and the transfer paper P is separated by the action of the separation electrode 16 and transferred to the fixing device 6.
1, heat fixing is performed. The surface of the image forming body 1 after transfer is covered with a cleaning device including a static eliminator 15 and a cleaning blade! 51, residual toner is cleaned and prepared for the next image formation. As explained above, in the present embodiment 111, each color's doratono (turn) is written in synchronization with the read image signal, so the buffer memory is sufficient and a large-capacity frame memory is not required. This greatly contributes to cost reduction.The reference signals EF+* Elv Ec and Ek are used for toner density control, charging potential, exposure intensity, development/
The reproducibility of color images is greatly improved by using the standard density pattern for feedback. Figures 14 and 15 are timing charts of the system described in Figures 12 and 13.
It can be obtained by rotating the image forming body twice. As described in the process shown in FIG. 9, the same latent image can be developed multiple times without recharging to obtain a single color image. In this case, the image forming means 21 in FIG.
Developing and transferring using 34 developing devices selectively or in plurality 1. For example, to create a green monochrome image, Y
Development is performed using toner and C toner. At this time, the charger 12 and the image forming means 22 are not operated. Of course, when operating the developing devices 33 and 34, the charger 12 and the image forming means 22 may be operated. 2. Description of the Related Art In an image reading apparatus, there are cases where it is desired to display a specific area in a two-color mode, for example, M or C in a black document. At this time, by trimming, a specific color area is specified and the image forming device 21
Image formation in a specific area by , development by the developing devices 31 and 32 with a specific color, recharging (12), image formation in a specific area by the image forming device 22, and development by the developing devices 33 and 34 in a specific color, resulting in one reading. A two-color image can be obtained by scanning and rotating one image forming scan. Output data from the six selectors is divided into the same black data according to the trimmed area to form a first latent image and a second latent image. Output to means. In the case of M and black, after charging and image exposure by the image forming device 21, development with M toner is performed, and after recharging, image exposure is performed by an RA 22 manufactured by Image Formation Co., Ltd., and development is performed in black. Alternating arrangement of two image forming means and a plurality of developing devices in this manner is not limited to only color image formation, but is a configuration that can effectively utilize various mors. The image forming body is configured to rotate, but in order to overlap images by multiple rotations, it is necessary to make the image forming body larger than the image size. If the image size includes A-3, A-4゜B-
Even small images such as 5 are printed at the same speed, resulting in extremely poor efficiency. In such a case, it is preferable to form a plurality of images on the image forming body. (Japanese Patent Application Nos. 60-86321 and 80-86322) Accordingly, the reading scan repeats scanning according to the document and then returning to the starting position.
In the time chart shown in FIG. 15, two more reading scans are performed during the first reading scan. This changes the timing of charging, image exposure, and development, but the delay time between the two image forming means remains the same. As can be seen from the processes shown in FIGS. 8 to 11, the electrostatic image (latent image) forming means is
r & will be done. Next, the image reading apparatus according to the present invention and the image forming embodiments shown in FIGS. 8 to 11 will be described in more detail as Examples 1 to 3, respectively. ¥! JLfLL (Example of FIG. 8) The image reading device shown in FIG. 1(,) and FIG. 1(b) and the color image forming device as shown in FIG. 5(,) were used. Color image formation was performed by the method shown in FIGS. 10, 13, and 15. The image carrier 1 has an OPC (organic photoconductive layer) surface layer, and its peripheral speed is 90
m5/see. The surface of the image carrier 1 was charged at 1,600 cm by a charger 11 using a scorotron corona discharger.
The charged surface was subjected to a first image exposure of magenta color image information using a semiconductor laser beam scanner 21 at a density of 11 points/l. As a result, the background potential of the exposed portion of the image carrier 1 is -50V.
In contrast, an electrostatic image was formed in which the potential of the non-exposed area was -soo v. This electrostatic image is transferred to a developing device 31 as shown in FIG.
The image was developed for the first time. The developing device 31 contains a carrier made of resin-coated spherical 7-elite with an average particle diameter of 30 μm and a magnetization of 30e+*u/g-resistivity of 10'4ΩC or more, and a styrene-acrylic resin containing 10 parts by weight of magenta pigment. A developer consisting of a non-magnetic toner having an average particle size of 10 .mu.m including a charge control agent was used under conditions such that the ratio of toner to developer was 15 wt%. The average charge amount of the toner is 10 μc/g. Further, the outer diameter of the developing sleeve 131 is 20su+,
The rotation speed is 1100 rp, the surface magnetic flux density of the developing sleeve of the NSS magnetic pole of the magnet body 32 is 100 (lus), the rotation speed is 100 Qrp+e, the thickness of the developer layer in the developing area is 0.41
, the gap between the developing sleeve 131 and the image carrier 1 is 0.6--
, the developing sleeve 131 is supplied with a DC voltage of 100V and 3V.
kHz. Non-contact development conditions were used in which a superimposed voltage of AC voltage of 1000 V (effective value) was applied. While the developing device 31 was developing the electrostatic image, the other developing devices 32 to 34 shown in FIG. 7 were kept in a non-developing state. It connects the developing sleeve 131 to the power source 13.
This is achieved by separating the developing sleeve 131 from the developing sleeve 131 to create a 70-ting state, or by actively applying a DC bias voltage having the same polarity as the charging of the image carrier 1 and the opposite polarity to the charging of the toner to the developing sleeve 131. . Since the developing devices 32 to 34 are also designed to perform development under non-contact development conditions like the developing device 31, there is no need to remove the developer layer on the developing sleeve 131. The developing device 32 uses a developer having a configuration in which the toner in the developer is changed to a toner containing yellow pigment instead of magenta pigment.
, a developer was used in which the toner was changed to a toner containing @7talosi72 as a cyan pigment, and a developer was used in the developing device 34 in which the toner was changed to a toner containing carbon black as a black pigment. A developer was used. Of course, color toners based on other pigments or dyes can be used, and the order of the colors to be developed and the order of the developing devices can also be appropriately selected. The surface of the image carrier 1, which had been subjected to the first development, was re-charged to -650V by acting on the Suflotron corona charger 12. A second image exposure of yellow image information is performed on the charged surface by the laser beam scanner 22, and then the developing sleeve 131 is exposed to a DC voltage of 150 cm and 3 k.
The second magenta toner is developed by the developer 33 under non-contact development conditions in which a superimposed voltage of AC voltage of 100 Hz and 100 OV is applied.
Second development was performed. Mainly, the pine grain is charged twice and the cyan image information is image exposed by the laser beam scanner 21, and the ant toner is developed thirdly by the developer 32, and the charging and black image information is image exposed and developed by the laser beam scanner 22. The fourth development of the black toner with container 34 was repeated. In the development after the second development, the amplitude of the DC bias component and AC component of the voltage applied to the developing sleeve 131 is adjusted appropriately according to the change in the surface potential of the image carrier 1, the development characteristics, and the color reproducibility. The frequency, selection time of time selection conversion, etc. can be changed. In particular, the absolute value of the charging potential is gradually increased (1), while the absolute value of the DC bias is gradually increased (1).
(This has the effect of preventing color mixing of the toners.) Once a four-color image is formed on the image carrier 1 after being developed four times, it is transferred to the pre-transfer charger 13 and the transfer an
The light lamp 41 facilitates the transfer, the transfer device 14 transfers the image onto the transfer body P, and the fixing device 12 fixes the image. Appropriate exposure by the pre-transfer exposure lamp 41 also has the effect of making it easier for the transfer body P to separate from the image carrier 1. The image carrier 1 to which the color image has been transferred is neutralized by the static eliminator 15 and the static eliminator lamp 42, and residual toner is removed from the surface by contact with the cleaning blade or sponge roller of the cleaning device i51, and color image formation is performed. One cycle of color image recording is completely completed at the point when the surface has passed through the cleaning device 51. The color image recorded by the above method was clear with sufficient density for each color, but slight mixing of toner colors was observed in areas where the toners of each color closely adhered to each other. . The timing of the image forming process is shown in the timing chart of FIG. The screen signal read by the CCD image sensor 4 is not stored in the dot pattern memory, and the M pattern and Y pattern signals are recorded without passing through the page memory or via the line memory as necessary. ! The output from the device, however, the external C and B turn signals are delayed by a shift register (delay circuit) with a capacity that is large enough to fit between the image forming devices, and are sequentially taken out in accordance with the timing of image forming. It will be done. Therefore, the first M
The toner image and Y toner image are obtained by the image reading and i! S
F is formed synchronously. In this image forming process, since image formation is performed by two reading scans and two rotations of the image forming body 21, and reading and writing are performed synchronously, high-speed recording is possible and a page memory corresponding to multiple sheets is possible. Capacity savings are expected. LUG-(Example of combined use of Figure 9 and tjS10) Figure 1 (
A color image forming apparatus as shown in FIG. 5(a) and FIG. 5(a) was used. Obtain a two-color image from a single-color image. A case is shown in which the original is a monochromatic black image, and specific areas are made green and other areas are made red by trimming. The image carrier 1 had a long-wavelength sensitized Se photoreceptor surface layer, and its peripheral speed was 120 mm/sec. The surface of this image carrier 1 is charged to +800V by a charger 11 using a suflotron corona discharger, and a laser beam scanner 2 shown in FIG. 2 uses a semiconductor laser on the charged surface.
A first imagewise exposure was carried out using No. 1 at a density of 12 dots/square. As a result, an electrostatic image was formed on the image carrier 1 in which the potential of the exposed portion was +50 V compared to the potential of the background portion of +800 V. This electrostatic image is first processed by a developing device 31 as shown in Figure @S.
Reversal development was performed twice. The developing conditions for the developing device 31 containing magenta toner were such that the average particle size of the developer carrier was 30 microns, the ratio of toner to developer was 20 wt %, and the average charge amount of the toner was 15 microcog. +s to developing sleeve 131
Example 1 except that a superimposed voltage of a DC voltage of oo v and an AC voltage of 1.5 kHz, 700 V (effective value) was applied.
The same as Further, the conditions of the other developing devices 32 to 34 were the same as in Example 1 except for the bias voltage. However, in this case, the bias voltage that keeps the developing device in a non-developing state, which does not participate in development, has the opposite polarity to the toner charging.
The charging of the image carrier 1 also has the opposite polarity. The second image exposure by the laser beam scanner 22 is not performed on the surface of the image bearing member 1 which has been developed by the first magenta toner without the action of the charging device 12, and then by the developing device 33. A second development of yellow toner was performed. As a result, a red toner image was formed on the same latent image. After recharging to +5 oov by the charger 12 in the second rotation, image exposure is performed tj42 times by the laser beam scanner 21, and similarly, a third development of cyan toner is performed by the developer 32, and a fourth development of yellow toner is performed by the developer 33. Development was repeated to form a green toner image on the same latent image. In the development after the second development, the amplitude of the DC bias component and AC component of the voltage applied to the developing sleeve 131 is adjusted appropriately according to the change in the surface potential of the image carrier 1, the development characteristics, and the color reproducibility. The frequency, selection time of time selection conversion, etc. can be changed. In this example, it is particularly effective to gradually increase the DC bias each time to improve the color reproduction of the toner. After the 4th development is performed and a two-color image is formed on the image carrier 1, the rest is transferred and fixed to the soft photographic medium P as in Example 1, and the image carrier 1 is destaticized and cleaned. This completed one cycle of color image recording. The timing of the image forming process is partially different from the timing chart of FIG. Only the BK pattern signal is used as the image signal read by the CCD image sensor 4. The B pattern signal to be converted into a red image is outputted to the recording device through the first image forming means without passing through the page memory or via the line memory if necessary. In this image forming process, the first red toner image is formed almost synchronously with the first image reading. Since green toner image formation is performed during two reading scans and the second rotation of the image forming body 21 in the same manner as the first time, and reading and writing are performed synchronously, no delay circuit is used. 'MJLILL <Example of combined use of FIGS. 9 and 10] A color image forming apparatus as shown in FIGS. 1(a) and 5(a) was used. Obtain a two-color image from a single-color image. This shows a case where the original is a monochromatic black image, and by trimming, certain areas are magenta and other areas are black.The image bearing member 1 has Se feeling and body surface debris, and its peripheral speed is 120-1ee. And so. The surface of the image carrier 1 is charged to a charger 11 using a scorotron corona discharger to +soo v, and a semiconductor laser is used for the charging diagram, and a laser beam scanner 21 shown in FIG. The first image exposure was carried out at a density of . As a result, an electrostatic image was formed on the image carrier 1 in which the potential of the exposed portion was +50 V compared to the potential of the background portion of +800 V. This electrostatic image was first developed using a developing device 31 as shown in FIG. The developing conditions for the developing device 31 containing magenta toner were such that the average particle size of the developer carrier was 30 μg, the ratio of toner to developer was 20 wt %, and the average charge amount of the toner was 15 μcog. +6 to developing sleeve 131
Example 1 except that a superimposed voltage of a DC voltage of 00 V and an AC voltage of 1.5 kHz, FOOV < effective value) was applied.
The same as *The conditions of the other developing devices 32 to 34 were also the same as in Example 1 except for the bias voltage. However, in this case, the bias voltage that keeps the developing device in a non-developing state, which does not participate in development, has the opposite polarity to the toner charging.
The charging of the image carrier 1 also has the opposite polarity. A charger 12 is applied to the surface of the image carrier 1 which has been developed with magenta toner once in MS, and then image exposure is performed twice in PIS by a laser beam scanner 22.
Next, a second development of black toner was performed using the developing device 34. As a result, a two-color toner image consisting of magenta and black was formed. In the development after the second development, the amplitude of the DC bias component and AC component of the voltage applied to the developing sleeve 131 is adjusted appropriately according to the change in the surface potential of the image carrier 1, the development characteristics, and the color reproducibility. The frequency, selection time of time selection conversion, etc. can be changed. In this example, it is particularly effective to gradually increase the DC bias each time to improve the color reproduction of the toner. Once the two-color image is developed and formed on the image bearing member 1, the rest is transferred and fixed to the pine photographic body P as in Example 1, and the image bearing member 1 is neutralized and cleaned to form a color image. One cycle of image recording has been completed. In this case, the image carrier forms a two-color image in one rotation. As for the timing of the image forming process, only the first half shown in the timing chart of FIG. 14 is used. CCD
Only the BK pattern signal is used as the image signal read by the image sensor 4. BK converted to M image
The pattern signal is output to the recording device via the page memo 1 or via the line memory if necessary.
Each pattern signal of BK output as a black image is delayed by a shift register having a capacity comparable to that between the image forming apparatuses, and is sequentially taken out in accordance with the timing of image formation. Therefore, the first M toner image is formed almost synchronously with the image reading. In this image forming process, since image formation is performed by one reading scan and one revolution of the image forming body 21, and reading and writing are performed synchronously, high-speed recording is possible. The color image recorded in the above manner was as clear as in Example 1. Example of m<@” figure) Using the same device as in Example 1 and using the Se photoreceptor used in Example 2, the developing sleeve 131 of the developing device was
The voltage applied to +600 V DC voltage and 1000 H
z, a superimposed voltage of AC voltage of 500 V (effective value), and the surface potential of the image carrier 1 is set to 700 V by the charger 12.
Color image recording was carried out under the same conditions as in Example 1, except that charging was performed and reverse image formation was used. The recorded color image is better than that according to Example 1.
Color mixing of the toners in areas where the color toners adhered closely to each other was reduced, resulting in a more vivid image. In addition, according to this example, as mentioned earlier, Y%
In order to overlap toner images made of M%C, BK) toner, it is desirable that the previous image exposure position and the subsequent image exposure position overlap. In this case as well, in order to form an electric latent image by imagewise exposure, it is desirable that the previously formed toner image has translucency to the imagewise exposure light, and the order in which the colors are developed is determined so that the color image is clear. It is necessary to carefully decide the order of the colors to be developed, as this will have a considerable effect on the color quality. [(Example shown in FIG. 11) When using the ttlffif shown in FIG. . The voltage applied to the developing sleeve 131 of the developing device is +600.
A superimposed voltage of a DC voltage of V and an AC voltage of 2 kHz, 500 V- (effective value) is used, and the surface potential of the image carrier 1 is charged to +FOOv before each image exposure after the second image exposure. The charging by the container 11 or 12 and the surface potential are approximately O■
A color image was recorded under the same conditions as in Example 4, except that uniform weak exposure was performed using an exposure lamp 71 (illustrated in a hypothetical manner) that lowered the exposure. If uniform exposure is too strong, optical fatigue of the photoreceptor increases. The recorded color image was extremely clear, with no color mixing of the toners even in areas where the toners of each color closely adhered to each other. This embodiment is effective for photoreceptors suffering from optical fatigue. According to the above embodiment, by using two sets of devices to repeat electrostatic image formation four times, the recording device can be made small and low cost, the recording speed is relatively fast, and each image exposure can be synchronously controlled. The excellent effect of easily and accurately being carried out is obtained, and each development is carried out by a developing method in which a toner charged to the opposite polarity is attached to the electrostatic image, which makes it relatively easy to control the development density. This can also be done by a developing method in which a toner charged to the same polarity is attached to an electrostatic image using a laser beam scanner as an image exposure device. When carried out under contact development conditions, an excellent effect can be obtained in that a color image with sufficient development density and excellent clarity can be recorded. Also, the arrangement of the developing device and the order of development can be changed in other ways.
For example, black toner development is performed first, then Y and M. It is also possible to form a color image by sequentially performing any of steps C. This case is effective for color images where priority is given to black image components. Furthermore, the Y, H, and C developing devices and the order of development may be determined in accordance with the color reproduction of the toner. In addition to the embodiments described above, various modifications are possible based on the idea of the present invention. For example, when it is not necessary to form a color II image, for example, when forming a black image, the charger 11 or 12
It is possible to form a latent image by any combination of either the laser beam scanner 21 or 22. When the photosensitive layer of the image carrier 1 has large darkening blades, it is preferable to form a latent image by a combination of the charger 12 and the laser beam scanner 22 and develop it by the developer 34. This is because the short time (short distance) between the exposure and development steps can be utilized. When forming a monochrome image using one color (a), yellow, magenta, and cyan toner, the combination may be selected using the same concept. In the case of two or three colors, it goes without saying that any combination can be selected depending on the necessity or performance. Further, by appropriately selecting a combination of image exposure and a developing device, it is also possible to form images of various colors. In addition, by performing image exposure using separate image information from the laser beam scanners 21 and 22, it is possible to perform image synthesis on the image carrier 1. As mentioned above, the present invention is not limited to a recording device in which the image bearing member is a drum, and is not limited to a recording device in which a color image is transferred to a transfer member. . That is, the present invention can also be applied to an image forming body mounted on a substrate such as electrofax paper, on which a color image is fixed without being transferred. In this case, a pre-transfer charger, a pre-transfer exposure lamp, a transfer device, and even a cleaning device are not required. Of course, the pre-transfer charger, pre-transfer exposure lamp or static eliminator can be omitted even when transferring, and the transfer can be either direct pressure transfer or transfer via an intermediate transfer body, and the fixing can be done by heat roller fixing. Of course, it is not limited to. The image reading device according to the present invention is preferably used in electrophotography, but can also be applied to image forming technology using thermal transfer technology. FIGS. 16(a) and 16(b) each show an example of the thermal line head T.
The present invention requires that the I2 set is provided in a direction perpendicular to the paper, and in this case, the image forming means is a line head. For example, there is an M between the thermal line head TH and the paper.
, C, Y, and BK thermal ink ribbons TR are interposed to perform image formation. In FIG. 15(a), the thermal ink ribbon TR is moved in a direction perpendicular to the line of the thermal line head TO. In FIG. 15(b), the color is changed by moving in the line direction and switching up and down. The recording medium is moved by reciprocating up and down, or by being fixed above and below the drum and rotating. When using thermal transfer technology, a thermal line head A (TH-^), a charger 12, a laser beam scanner 22, and a developer 33, 34 are used instead of the charger 17, laser beam scanner 21, and developer 31, 32. Instead, a hood B (TI-B) is provided to the thermal line to perform image recording equivalent to latent image formation and development in electrophotography, and the image carrier 1 is attached to a recording material or a support for the recording material. It will be equivalent. The image carrier 1 corresponds to a recording material or a support for the recording material. As explained above, the recording apparatus shown in FIGS. 5(a) and 5(b) has the following effects. (1) Since a plurality of latent image forming means are used and at least one of them is used repeatedly, image formation can be performed by one rotation or one movement of the image carrier, or by three to four rotations or three to four times. Compared to iii image formation by moving the image forming apparatus, a color image forming apparatus with a smaller size and higher speed can be obtained. (2) By synchronizing with the H image reading means, color III images can be formed efficiently with a small memory capacity. (3) Many multicolor modes such as single color, two color, and color can be efficiently handled. Monochrome or two-color printing can be performed by one reading scan and one rotation or one movement of the image carrier.

【Effect of the invention】

As explained above, the present invention has a configuration in which four sets of color information can be obtained using two sets of solid-state image sensors.
It is easier to align the solid-state image sensor, and unlike color CCDs, there is no need to accommodate three types of filters in one pixel, so the resolution is excellent, and two sets of writing systems can be written at high speed without reducing drive speed. It is possible to obtain an economical image reading device suitable for an image forming apparatus having the above.

[Brief explanation of drawings]

Figures 1 (,) and (b) are a schematic configuration diagram and a partially enlarged perspective view of one embodiment of the present invention; Figure 2 is an enlarged perspective view of a main part showing another embodiment of the present invention; Figure 3 and FIG. 4 is a side view showing still another embodiment of the present invention, FIGS. 5(a) and (b) are schematic diagrams of the configuration of the image forming apparatus, and FIGS. 6(a), (b), and (a). 7 is a schematic diagram of the configuration of a laser beam scanner for image exposure, FIG. 7 is a sectional view of main parts of a developing device, and FIGS. 8, 9, 10, and 11 are flow charts showing the process of image formation. 12 and 13 are circuit configuration diagrams for image formation, FIG. 14 and 15 are time charts for image formation, and FIG. 16 (a
), (b) is a schematic diagram of image formation using thermal transfer technology, Figure 17 is a graph showing the spectral characteristics of a notch filter, Figure #418 is a configuration diagram with a 7-touch filter installed in the lens system, and Figure 19 is a conventional diagram. FIG. 20 is a diagram illustrating a CCD line image sensor for reading images. In addition, in the reference numerals shown in the drawings, 1 ----- one image carrier 2 ----- one lens 3 ----- one light converging element array 4 A,
4 B-1----CCD image sensor 5A,
5B ------- Dichroic prism SC-1 ---- Bar 7 mirror prism 6 A, 6 B -
--- One filter plate 7 --- One wheel 8A, 8B --- One close-contact image sensor 11,
12 -------One charger 14------One transfer device 15---One static eliminator 21---One original 22---11---Illumination lamps 24a-24c------ -CCD image sensor 2
7 ---- One original presser plate 28a to 28c ---- One reflecting mirror 29 ---- Dichroic prism 42
----- One static elimination lamp 31, 32, 33, 34 -- One developing device 41 ----- One pre-transfer exposure lamp 51
------ Cleaning device 61 ----- Constant deposition device 71 -----, uniform exposure lamps 121, 221
-------Laser 122 -------Acousto-optic modulator 123, 223 -------Mirror scanner 124, 224 -------Imaging f-theta lens 1
25, 128. 237. 238m, 238b
--------Mirror 127, 235.236----Lens 131
+++HH-Developing sleeve 132 -+++++-
Magnet body 133 +-+--1 developer layer thickness regulating blade 1
34 ++++++-scraper blade 135
−＋＋−Returning body 136 +−＋＋＋−Developer reservoir 137
＋＋＋＋−−Toner hopper 138 −−−−−−
) Gner replenishing roller 139 +-+++-Power supply 140 -+++++-Protective resistor P +-+++-Transfer body T, T'--) Gner P II ------+-Exposed section D-
----1 non-exposed area. Applicant Roku Konishi Photo Industry Co., Ltd. Figure 1 (a) 2 L> 4A, 48: CCO image sensor 21: Jl cormorant 22: Teruguchi 8 run 27: 8 mNt hoe 28a to 28c reaction et. Figure 2 Figure 8 Figure 11 Figure 17 (nm) Figure 19 Figure 20

Claims (7)

[Claims] (1) In an image reading device comprising a member that color separates a light image from a document, two solid-state image sensors, and an image forming member, while the two solid-state image sensors and the image forming member are fixed,
An image reading device in which the color separation member is replaceable. (2) The image reading device according to claim 1, wherein the color separation member is provided between the image forming member and two solid-state image sensors. (3) Claim 2, characterized in that the color separation member comprises a member that splits an optical path into two directions and performs color separation.
The image reading device described in Section 1. (4) Claim 1 characterized in that the color separation member is composed of a member that serves both to divide optical paths in two directions and to separate colors.
The image reading device described in Section 1. (5) comprising means for creating color information based on color separation information input by the image reading device and a plurality of image forming means for outputting the color information onto the image forming body, the image forming body being 2. The image reading device according to claim 1, wherein the image reading device is used in a color image forming apparatus that forms a color image on an image forming body by rotating or moving the image forming body. (6) The present invention is used in a color image forming apparatus in which the output of at least one of the color information is delayed in accordance with the image forming position by the image forming means.
The image reading device described in Section 1. (7) The invention is used in a color image forming apparatus in which optical scanning of the image reading device and output of the color information onto the image forming body are repeated twice in synchronization. The image reading device according to item 6.