JPH03100678A - Image forming device - Google Patents

Abstract

PURPOSE:To clearly reproduce a color original by providing a filter traveling means which automatically faces a filter which eliminates highly sensitive wave length light color of reflecting light to a lens. CONSTITUTION:The filter 21 is provided on an end tip side of the lens 17 and the device is of a constitution so that it interferes selectively with a light path according to the type of the original. This filter 21 is fixed to a metal plate 50, and the metal plate 50 is provided with feeding holes 52 which engage with teeth of a gear 51 at a specified pitch. The filter traveling means 56 is constituted so that by operating a driving motor 53, a gear 54 is rotated, and by rotating the gear 51 which engages with it, the filter 21 is slid on a guiding member 55. Therefore, when a red color original switch 71 is turned ON, a lamp 72 on a control panel 70 is lit, the gears 54 and 51 are rotated so that the filter 21 is automatically traveled to a position facing the lens 17. Thus, the color original can be reproduced well.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to an image forming apparatus such as an electronic copying machine, and more specifically, the present invention relates to an image forming apparatus such as an electronic copying machine. The present invention relates to an image forming apparatus that forms an image on a photoreceptor through an optical system that includes the image forming apparatus.

(Prior Art) Normally, in electronic copying machines, etc., the light that scans a document is not reflected from black areas but is reflected from white areas. The light is guided to a photoreceptor through an optical system and exposed to light to obtain black and white contrast, that is, an electrostatic latent image.

In this way, black and white originals can be reproduced using the method described above, but for color originals, the scanned light becomes wavelength light of each color and is irradiated onto the photoreceptor, so high sensitivity is required for that wavelength. There is a problem in that the photoreceptor having such a color is exposed to light, making it difficult to distinguish it from a white part.

For example, in the negatively charged organic photoreceptor (minus OPC) that has been widely used recently, the sixth
It has a spectral sensitivity as shown in the figure, with a red wavelength of 600
Shows high sensitivity at ~650 nm. Therefore, when a red original is used, there is a problem in that it is difficult to distinguish it from white parts, resulting in poor reproducibility.

(Problems to be Solved by the Invention) As described above, conventional image forming apparatuses have a problem in that it is difficult to clearly reproduce color originals.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an image forming apparatus that has a simple configuration and is capable of clearly reproducing color originals.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above problems, the present invention irradiates light onto a document, and directs the reflected and emitted light onto a photoreceptor through an optical system including a lens. The image forming apparatus for forming an image is configured to include a filter for removing the high-sensitivity wavelength light color of the reflected light, and a filter moving means for automatically moving the filter against the lens.

(Function) That is, according to the present invention, color reproduction is improved by arranging a filter that cuts off the high-sensitivity wavelength light color of the photoreceptor to face the lens. Further, in the case of a black and white original, there is no filter, making it possible to prevent a decrease in the amount of light.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 2 shows an electronic copying apparatus, in which a drum-shaped photoreceptor 2 having an organic photosensitive layer on its surface as an image carrier is provided in the center of the apparatus main body 1 so as to be rotatable in the direction of arrow A. There is. A charging device 3 that uniformly charges the surface 2a of the photoreceptor is arranged above the photoreceptor 2, and a developing device 4, a transfer device 5, a peeling device 6, and a cleaning device 7 are arranged in this order.

Furthermore, in the upper part of the apparatus main body 1, light is irradiated onto the original placed on the original placing table 10, and the reflected light r is guided between the charging device 3 and the developing device 4, and the original is placed on the original placing table 10. Exposure device 1 that forms an electrostatic latent image corresponding to image information on photoreceptor 2
1 is placed.

This exposure device 11 irradiates light onto an original placed on an original placing table 10 using an exposure lamp 13 whose back is surrounded by a reflector 12, and transmits the reflected light to a first mirror 14.
, second mirror 15, third mirror 16, lens 17, fourth
Optical system 2o consisting of mirror 18, slit 19, etc.
The structure is such that the light is guided to the photoreceptor 2 by. The exposure lamp 13 whose back is surrounded by the reflector 12 and the first mirror 14 are mounted on a first carriage (not shown), and the second mirror 15 and third mirror 16 are mounted on a second carriage (not shown). Along with being there,
The first carriage is moved at a constant speed in the right direction (direction of arrow B) in the figure by a carriage moving means (not shown), and the second carriage is moved in the same direction at half the speed. It is possible to scan with the image fixed.

Further, a filter 21, which will be described later, is arranged on the rear end side (or the front end side) of the lens 17, and is configured to be selectively interposed in the optical path depending on the type of document.

Further, paper feed cassettes 25 and 26 containing sheets of paper P such as plain paper are installed on the right side of the main body 1 of the apparatus, and the paper cassettes 25 and 26 are arranged so that the sheets are sequentially fed one by one through the paper feed means 27. It has become.

Paper feed rollers 2 are provided downstream of the paper feed means 27 and 27, respectively.
8 and a separation roller 29, and is arranged so that only one sheet of paper P is sent out. 2 and the image transfer unit 35 of the transfer device 5, and are fed into a conveyance path 37 that leads to a paper discharge tray 36 mounted on the left side of the apparatus main body 1.

An aligning roller pair 38 is provided on the upstream side of the conveyance path 37, and a fixing device 39 and a paper ejection roller pair 4 are provided on the downstream side.
0 is set.

When copying a document, the photoreceptor 2 rotates in the direction of the arrow, and the surface 2a of the photoreceptor 2 is uniformly charged by the charging device 3. Thereafter, the image information is exposed by the exposure device 11, and the charge on the surface 2a of the photoreceptor 2 is selectively removed to form an electrostatic latent image.

Next, by facing the developing device 4, this electrostatic latent image is visualized with a charged developer (toner) attached thereto.

Meanwhile, in synchronization with the image forming operation on the photoreceptor 2, the paper P is taken out from the paper feed cassette 25 or 26 and sent to the image transfer section 35 via a pair of aligning rollers 38. The toner image on the photoreceptor 2 is transferred onto the paper P by the action of the transfer device 5.

Note that the toner on the photoreceptor 2 that has not been completely transferred is cleaned by the cleaning device 7, and the next cycle begins.

Further, as mentioned above, if the photoreceptor 2 has a spectral sensitivity of -oPc as shown in FIG.
It shows high sensitivity to red light of m.

Therefore, depending on the reflected light, the area may be exposed to light, making it difficult to distinguish it from the white area. Therefore, in the present invention, by interposing a filter 21 having a transmittance that cuts red light as shown in FIG. 3 in the optical system 2o, it is possible to form a good image of a red original. It has become.

The filter 21 is fixed to a metal plate 50 as shown in FIGS. 1 and 4, and the metal plate 50 has feed holes 52 that engage with the teeth of a gear 51 at a predetermined pitch.

Then, by operating the drive motor 53, the gear 5
4 and the gear 51 that meshes with the gear 51 constitutes a filter moving means 56 in which the filter 21 slides on the guide member 55.

Further, the drive motor 53. Filter 21, lens 17
is mounted on the third carriage 60.

This third carriage 60 has a guardrail 6 on one end side.
1, and the other end is connected to a nut member 63 that is fitted onto the screw shaft 62. When the copy magnification is changed, the screw shaft 62 is driven by the motor 64, so that the screw shaft 62 moves integrally. It is configured to do this.

The drive motor 53 of the filter moving means 56 is electrically connected to a red original switch 71 provided on a control panel 70, as shown in FIG.

Normally, the filter 21 is located at a position that does not face the lens 17, and when the red original switch 71 is turned on, the lamp 72 on the control panel 70 lights up and the gear 5
4 and 51 are rotated, and the filter 21 is automatically moved to a position facing the lens 17.

Therefore, when copying a black-and-white original, the amount of light is not reduced because the filter 21 is not located at a position facing the lens 17.

Furthermore, when copying an original with red parts, by turning on the red original switch 71 on the control panel 70, the filter 21 faces the lens 17 and the red original can be reproduced well.

Note that the present invention is not limited to the above-mentioned embodiment, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

[Effects of the Invention] As explained above, according to the present invention, when a color original is used, color reproducibility is improved by installing a filter that cuts the high-sensitivity wavelength wave color of the photoreceptor in the optical path of reflected light. It is possible to obtain images with clear contrast. Further, in the case of a black and white original, since the filter is removed, a decrease in the amount of light can be prevented.

Furthermore, the presence or absence of a filter can be selected by operating the control panel, and the filter is automatically installed, making it easy to use.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of the filter mechanism mounted on a lens moving carriage, FIG. 2 is a schematic configuration diagram of an electronic copying device, FIG. 3 is a diagram showing the transmittance of the filter, FIG. 4 is a perspective view of a filter mechanism showing an embodiment of the present invention, FIG. 5 is a plan view showing an operating section of the filter mechanism, and FIG.
The figure is a diagram showing the spectral sensitivity of a photoreceptor. 2... Photoreceptor, 17... Lens, 20... Optical system, 21... Filter, 56... Filter moving means,
r...Reflected light, D...Document.

Claims (1)

[Claims] In an image forming apparatus that irradiates light onto a document and uses the reflected light to form an image on a photoreceptor through an optical system including a lens, the filter removes the high-sensitivity wavelength light color of the reflected light; An image forming apparatus comprising a filter moving means that automatically moves the filter against the lens.