JPH055553Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention relates to an exposure device for a color copying machine.
In particular, the present invention relates to an improvement in an exposure apparatus that employs a so-called full-surface exposure method.

[Prior Art] As a conventional exposure apparatus of this type, there is one shown in FIG. 5, for example. This has a housing 1 with a closed cross-sectional structure, and an opening is provided at the top of the housing 1, and a platen 3 made of glass or the like on which a copy document 2 is placed is attached to the opening. is provided with a flash illumination means S for instantaneously illuminating the platen 3, and further includes a lens mounting hole provided at approximately the center of the bottom of the housing 1, and an imaging lens 4 mounted in the lens mounting hole. It is something. The flash illumination means S includes, for example, a pair of flash light sources 5a and 5b installed at opposing parts of the bottom of the housing 1, and a pair of flash light sources 5a and 5b installed on the non-platen 3 side of each flash light source 5a and 5b, respectively. a reflector 6a that reflects light directed toward the non-platen 3 side from each flash light source 5a, 5b toward the entire surface of the platen 3;
6b is provided. This type of exposure device instantly illuminates the entire surface of the platen 3 with the flash illumination means S, and directs the entire original image of the copy document 2 on the platen 3 to a predetermined photosensitive belt 7 via the imaging lens 4. It has come to be projected on

By the way, when applying the above-mentioned exposure device to a color copying machine, it is necessary to separate the original image light from the copy original 2 into color components for color copying. As shown in FIG. 5, below the imaging lens 4, a color separation filter 8 corresponding to the color components for color copying is installed.
a, 8b, 8c are arranged, and the color separation filters 8a, 8b, 8c are arranged with respect to the original image optical path of the copy original 2.
The color separation filters 8a, 8b, and 8c are provided so as to be removable and removable, and the color separation filters 8a, 8b, and 8c are placed on standby at a position separated from the original image optical path of the copy original 2 during black-and-white copying.
During color copying, the color separation filters 8a, 8 are activated according to the illumination timing of the flash illumination means S.
It is conceivable to move the light beams b and 8c sequentially into the optical path of the original image of the copy document 2. In this case, the original image light from the copy original 2 is separated into color components for color copying by the color separation filters 8a, 8b, and 8c and sequentially projected onto the photosensitive belt 7. For this reason, each developer (not shown) develops a projected image corresponding to each color component each time with complementary color toner, and then sequentially transfers each toner image onto a sheet of transfer paper (not shown). If you do this, you will get one color copy.

[Problems to be Solved by the Invention] However, in the exposure device of such a conventional color copying machine, the color separation filters 8a, 8b, 8c are connected to the copy document 2 according to the illumination timing of the flash illumination means S. Since the color separation filters 8a, 8b, and 8c must be positioned in the original image optical path, not only does the positioning control of the color separation filters 8a, 8b, and 8c become complicated, but also the
Since the color separation filters 8a, 8b, 8c temporarily stop at each positioning point, the color separation filters 8a, 8b, 8c
Even if the moving speed of the printer is set to a certain level of speed, it is relatively difficult to sufficiently increase the color copying speed.

This invention was made in order to solve the above technical problems, and it is possible to easily separate the original image light from the copy original into colors without complicated control, and to achieve a sufficient color copying speed. It is an object of the present invention to provide an exposure device for a color copying machine, which can be used in a black-and-white copying mode easily while maintaining good copy image quality.

[Means for Solving the Problems] That is, this invention includes a transparent platen that constitutes a placement surface for a copy document, a mode selection means for selecting either a color copy mode or a black and white copy mode, and a mode selection means for selecting either a color copy mode or a black and white copy mode, and a A flash illumination means instantly illuminates the entire surface of the copy document on the platen at a predetermined illumination timing according to the mode selected by the selection means, and a flash illumination device forms an original image of the illuminated copy document on a predetermined portion of the photoreceptor. The image lens includes an image lens and a color separation means for separating the original image light of the copy original into arbitrary color components for color copying, and is configured to sequentially expose the original image of the copy original to the photoreceptor for each color component. The color separation means includes a rotating shaft disposed near the imaging lens to block the original image optical path of the copy document and deviated with respect to the original image optical path. and a rotary plate having holes opened at predetermined angular intervals corresponding to the original image optical path position, and a rotary plate that is fitted into a plurality of adjacent holes of the rotary plate and converts each transmitted light into each color component for color copying. a color separation filter for separating; a light attenuation filter fitted into the hole of the rotary plate; an initial position setting means for setting the initial position of the rotary plate so that the light attenuation filter is disposed at the original image optical path position; An actuator rotates a rotary plate at a constant speed, and the actuator is driven under the condition that a color copying mode is selected by the mode selection means, and the color separation filters are used as original images in synchronization with the illumination timing of the flash illumination means. The present invention is characterized in that it is provided with drive control means that are sequentially arranged at optical path positions and hold the actuators in a non-operating state under the condition that the black and white copying mode is selected by the mode selection means.

[Operation] According to the above-mentioned technical means, when the color copying mode is selected by the mode selection means, the drive control means drives the actuator to rotate the rotary plate at a constant speed, and the illumination of the flash illumination means is activated. The color separation filters of the rotating plate are sequentially arranged at the original image optical path position in synchronization with the timing. Therefore, without positioning and stopping each color separation filter, the original image light of the copy document on the platen is sequentially separated into colors by each color separation filter.

Furthermore, when the black and white copying mode is selected by the mode selection means, the drive control means holds the actuator in a non-operating state, so the rotating plate does not rotate and the original image light of the copy original illuminated by the flash illumination means is initially The light passes through a light attenuation filter set at a certain position. Therefore, in the black-and-white copying mode, the light intensity of the original image of the copy document is appropriately attenuated by the light intensity attenuation filter, even if the illumination light intensity of the flash illumination means is not particularly controlled.

[Example] This invention will be described in detail below based on the example shown in the attached drawings.

In the embodiment shown in FIGS. 1 to 4, the exposure device of the color copying machine adopts a so-called full-surface exposure method, and its basic structure includes a housing 1 with a closed cross-sectional structure, and a top portion 1a of the housing. A transparent platen 3 is attached to a rectangular opening formed in the housing 1 to form a placement surface for the copy original 2, while a flash illumination means S is disposed inside the housing 1, and a flash illumination means S is disposed inside the housing 1. An imaging lens 4 is attached to a hole opened approximately in the center of 1b, and a color separation means C is disposed near the bottom of the imaging lens 4 to separate the original image light of the copy original 2. It separates the original image into red, green, and blue color components for color copying, and sequentially exposes the original image of the copy document 2 to the photosensitive belt 7 for each color component.

In this embodiment, the flash illumination means S includes, for example, as shown in FIG. From the flash light source 10 to the platen 3
a shade 11 that blocks direct light directed toward the user; a blocker 12 installed below the flash light source 10 that blocks light directed substantially directly downward from the flash light source 10; and a diffuse reflection coated on the entire inner wall of the housing 2. The light from the flash light source 10 is irradiated into the housing 1 through the gap between the shade 11 and the blocker 12, and after being diffusely and multiple-reflected by the diffuse reflection layer 13, a substantially uniform light intensity distribution is produced. It is designed to reach the platen 3 as well.

The imaging lens 4 is fixed to the upper half of a stepped cylindrical lens case 20 and is attached to the hole in the housing bottom 1b via the lens case 20, and is attached to the lower half of the lens case 20. The portion is formed to have a larger diameter than the aperture of the imaging lens 4,
A light quantity correction filter 21 for correcting the cosine fourth law characteristic of the imaging lens 4 is attached to the lower end opening of the lens case 20. A cutout opening 22 is provided approximately at the center of the lens case 20 in the vertical direction and extends approximately semicircumferentially.

Further, the color separation means C has a rotating plate 30 disposed substantially horizontally near the bottom of the imaging lens 4, as shown in FIGS. 2 and 3 in particular. The rotary plate 30 is arranged to protrude from the notch opening 22 into the lens case 20 so as to block the original image optical path B of the copy document 2.
is disposed outside the lens case 20 so as to be offset from the original image optical path B of the copy original 2. For example, four filter mounting holes 32 are opened at predetermined angular intervals, e.g., every 90 degrees, around the rotating plate 30 at a portion corresponding to the original image optical path B. Color separation filters 35, 36, and 37 that separate the transmitted light into each color component, red, green, and blue for color copying, and a light amount attenuation filter 38 that attenuates the amount of transmitted light are inserted, respectively. Furthermore, a drive motor 40 as an actuator is fixed to the upper half of the lens case 20 via a support bracket 41, and the shaft of the drive motor 40 serves as the rotation shaft 31 of the rotation plate 30. It is connected and fixed to the center of 30.

Furthermore, the rotary plate 30 is rotated at a constant speed by the drive motor 40, and the rotary plate 30 is configured to rotate along the original image optical path B.
The initial position is such that the light amount attenuation filter 38 is located at the corresponding position, and the color separation filters 35, 36, and 37 are sequentially arranged in accordance with the illumination timing of the flash illumination means S. A through hole 50 is formed near the peripheral edge of the rotary plate 30, and a light emitting element 52 and a light receiving element 53 as a position sensor 51 are installed on the rotary plate 30 at a portion corresponding to the through hole 50. The position sensor 51 detects whether or not the rotary plate 30 is at the initial position depending on the presence or absence of the amount of light received by the light receiving element 53. and again,
In this embodiment, the light emitting element 52 emits light in conjunction with a color copying switch (not shown), and the position sensor 51 detects the initial position of the rotary plate 30 when the position sensor 51 first detects the initial position of the rotary plate 30. The drive motor 40 is operated, and then the operation of the drive motor 40 is stopped when the initial position of the rotary plate 30 is detected.

In FIG. 1, reference numeral 60 is a pre-charger for pre-charging the photosensitive belt 7, and 61, 62, 63 and 64 are for charging each latent image formed based on each color component for color copying relative to each of the above-mentioned color components. 65 is a transfer unit to which the toner image on the photosensitive belt 7 is transferred. A paper 66 rotates in synchronization with the photosensitive belt 7 and wraps the transfer paper 65 appropriately to transfer the toner image onto the transfer paper 65. A transfer roll 67 cleans residual toner on the photosensitive belt 7. It's a cleaner.

Therefore, according to the exposure device of the color copying machine according to this embodiment, when the color copying switch is operated during color copying, the light emitting element 52 of the position sensor 51 emits light. At this time, since the position sensor 51 is arranged corresponding to the through hole 50 of the rotating plate 30, the light from the light emitting element 52 passes through the through hole 50 and enters the light receiving element 53, The position sensor 51 is the rotary plate 30
Detect the initial position of. Then, as shown in FIG. 4, the drive motor 40 is actuated by the output pulse of the position sensor 51, and the rotation plate 3
0 starts rotating at a constant speed. In this state, if the flash illumination means S is operated three times at every desired timing period T, the color separation filters 35, 36, and 37 are sequentially arranged in the original image optical path B of the copy document 2. It turns out. In this case, the illumination time t of the flash illumination means S
1 is sufficiently shorter than the time t2 during which each of the color separation filters 35, 36, 37 is placed in the original image optical path B, so that each of the color separation filters 35, 36, 37 Even if the original image light of the copy original 2 is moving within the color separation filter 35, 36, 37, the original image light of the copy original 2 will surely pass through each color separation filter 35, 36, 37. As a result, first, in accordance with the first illumination timing of the flash illumination means S, the original image light of the copy original 2 is transmitted through the red color separation filter 35 and projected onto the photosensitive belt 7, and the projected image is After the toner is developed by the cyan developer 61, it is transferred to a transfer paper 65 fixed to the transfer roll 66. Next, in accordance with the next illumination timing of the flash illumination means S, the original image light of the copy original 2 passes through the green color separation filter 36 and is projected onto the photosensitive belt 7, and the projected image is the magenta color image. developer device 6
After the toner is developed in Step 2, the toner is transferred onto the transfer paper 65 fixed to the transfer roll 66 in an overlapping manner. After this,
In accordance with the final illumination timing of the flash illumination means S, the original image light of the copy original 2 passes through the blue color separation filter 37 and is projected onto the photoreceptor belt 7, and the projected image is converted into the yellow developed image. After the toner is developed in a container 63, the toner is transferred onto a transfer paper 65 fixed to the transfer roll 66 in an overlapping manner. Thereafter, the rotating plate 30 rotates to the initial position, and stops at the initial position based on the output of the position sensor 51. At this stage, if the multilayer toner image on the transfer paper 65 is fixed, the color copy image is stably held on the transfer paper 65, and one color copying process is completed.

In addition, in the above-mentioned exposure apparatus, a black-and-white copying switch (not shown) may be operated during black-and-white copying. At this time, the drive motor 40
If the rotary plate 30 is kept in an inoperative state, the rotation plate 30 is placed at the initial position, so that the original image light of the copy document 2 changes in the light intensity according to the illumination timing of the flash illumination means S. The projected image is transmitted through an attenuation filter 38 and projected onto the photosensitive belt 7, and the projected image is developed with toner in a black and white developer 64, and then transferred to a transfer paper 6 fixed to a transfer roll 66.
The black and white copying process of 1 is completed after a predetermined fixing process. In this step, the light intensity of the original image of the copy document 2 is attenuated to some extent by the light intensity attenuation filter 38 before reaching the photosensitive belt 7, so that the light intensity of the projected image on the photosensitive belt 7 is less than that in the case of color copying. The situation where the number of images becomes unnecessary is effectively avoided, and the quality of the copy image based on the above-mentioned projected image will not become thinner due to overexposure.
The above-mentioned copy image quality is always kept good.

Note that the location of the rotary plate 30 is not limited to that shown in the above embodiment, and for example, the rotary plate 30 may be disposed below the light amount correction filter 21 or inside the housing 1. There is no harm in doing so. Also,
In the above embodiment, the original image light of the copy document 2 is color-separated into three predetermined colors, but the invention is not limited to this. You can also do it. Furthermore, regarding the arrangement relationship of the color separation filters 35, 36, and 37,
It is not limited to those shown in the above embodiments, and may be selected as appropriate. Furthermore, the specific structure and support means of the actuator that drives the rotary plate 30 may be appropriately modified in design other than those shown in the above embodiments. Further, it goes without saying that the specific structure of the flash illumination means S can be changed as appropriate as long as it illuminates the entire surface of the platen 3. Furthermore, in the above embodiment, this invention is applied to a type in which the cosine fourth law characteristic of the imaging lens 4 is corrected by the light intensity correction filter 21, but the illuminance distribution on the three platen surfaces Of course, this invention can be applied to a type in which the cosine fourth law characteristic is corrected in advance.

[Effects of the invention] As explained above, according to the exposure device of the color copying machine according to this invention, the original image light of the copy original is removed without positioning the color separation filter with respect to the original image optical path of the copy original. Since it is possible to perform color separation during color copying, the color separation can be performed extremely easily without complicated control. In addition, according to this invention, there is no need to position and stop the color separation filter at a predetermined position as in the conventional case, so it is possible to shorten the time required for color separation of the original image light of the copy document, and accordingly,
Color copying speed can be reduced.

Furthermore, according to this invention, the light intensity of the original image of the copy document can be appropriately attenuated by the light intensity attenuation filter without having to particularly control the illumination light intensity of the flash illumination means in the black-and-white copy mode. In some cases, it is possible to effectively prevent deterioration of copy image quality due to overexposure and maintain good copy image quality without particularly controlling the amount of light. Therefore, it is possible to easily support not only the color copy mode but also the monochrome copy mode.

[Brief explanation of the drawing]

Fig. 1 is an explanatory cross-sectional view showing one embodiment of the exposure device for a color copying machine according to this invention, Fig. 2 is an enlarged explanatory view of the main part of Fig. 1, and Fig. 3 is a view from the middle direction of Fig. 2. 4 is a timing chart showing the operation of the exposure device according to the embodiment, and FIG. 5 is a cross-sectional explanatory view showing an example of the exposure device of a conventional color copying machine. Explanation of symbols, B... Original image optical path, C... Color separation means, S... Flash illumination means, 2... Copy original, 3... Platen, 4... Imaging lens, 7...
Photosensitive belt, 30...Rotating plate, 35,3
6, 37... Color separation filter, 40... Drive motor (actuator).

Claims (1)

[Scope of utility model registration request] A transparent platen forming a surface for placing a copy original, a mode selection means for selecting either a color copy mode or a monochrome copy mode, and a copy original on the platen according to the mode selected by the mode selection means. A flash illumination means for instantaneously illuminating the entire surface at a predetermined illumination timing, an imaging lens for forming an illuminated original image of a copy document onto a predetermined portion of a photoreceptor, and a light source for color copying using the original image light of the copy document. In the exposure device of a color copying machine, the color separation means is configured to sequentially expose the original image of the copy document to the photoreceptor for each color component, the color separation means comprising: Disposed near the imaging lens to block the original image optical path of the copy document, and provided at predetermined angular intervals corresponding to the rotation axis deviated from the original image optical path and the position of the original image optical path. A rotating plate having holes, a color separation filter that is fitted into a plurality of adjacent holes of the rotating plate and separates each transmitted light into each color component for color copying, and an amount of light that is inserted into the holes of the rotating plate. an attenuation filter, an initial position setting means for setting the initial position of the rotary plate so that the light intensity attenuation filter is disposed at the original image optical path position, an actuator for rotating the rotary plate at a constant speed, and the mode selection means. The actuator is driven under the condition that the color copy mode is selected, and the color separation filters are sequentially arranged in the original image optical path position in synchronization with the illumination timing of the flash illumination means, while the black and white copy mode is selected by the mode selection means. 1. An exposure device for a color copying machine, comprising: drive control means for maintaining an actuator in an inoperative state under selected conditions.