JPH05127486A - Image forming device - Google Patents

Abstract

PURPOSE:To improve the ability to separate a form from a photosensitive body by means of the simple configuration by employing toner which is decolorized by the specific-wavelength light, as the toner for development. CONSTITUTION:The device is provided with a carrying belt 19 which carries a form on which an image transferred to a fixing device 20, a form ejecting roller 21 which ejects the sheet on which the image is fixed an erasing halogen lamp 22 which is provided above the carrying belt 19 and emits the specific- wavelength light to decolorize toner on the front end part of the sheet carried by the carrying belt 19. Below a contact glass 1, a strip-like black plate is provided at the end on the side where an exposure lamp 3 starts exposing an original. A developing device 10 uses toner (decolorization toner) which is decolorized when receiving the light of the erasing halogen lamp 22, for example, the toner containing cyanine-based dye obtained by the reaction of the cyanine-based dye with the ammonium salt of organic boron.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as an electrophotographic copying machine for forming an image by using a photoconductor.

[0002]

2. Description of the Related Art Conventionally, in such an image forming apparatus, when a toner image on a photoconductor is transferred onto a paper and then the paper is separated from the photoconductor, the paper having a poor separability is used. It is known that a toner having the same color as that of the paper is adhered onto the photoconductor corresponding to the leading end of the paper to improve the separability of the paper (see, for example, Japanese Patent Laid-Open No. 1-92768). ).

[0003]

However, in such a conventional image forming apparatus, in addition to the original developing device for developing the electrostatic image on the photoconductor, the toner of the same color as the paper is selected and exposed. Since a special device for developing the body is required, there is a problem that the configuration of the image forming apparatus and its control become complicated. The present invention has been made in view of such circumstances, and provides an image forming apparatus capable of improving the separability of a sheet from a photoconductor without complicating the configuration and control of the apparatus. Is.

[0004]

SUMMARY OF THE INVENTION The present invention is an image forming apparatus configured to develop an electrostatic latent image formed on a photoconductor with toner and transfer the developed image to a sheet. The developing toner is provided with an irradiation unit for irradiating a predetermined region of the photosensitive member corresponding to a portion with image light, and an irradiation unit for irradiating the front end of the sheet with light of a specific wavelength. The present invention provides an image forming apparatus, which is a toner that is decolorized by the above light.

[0005]

Since the prevention means prevents the image light from being irradiated onto the predetermined area of the photoconductor corresponding to the leading edge of the paper, the toner adheres to the predetermined area during development of the photoconductor to improve the separability of the paper. .. Further, the toner transferred to the leading edge of the paper is decolorized by the light emitted by the irradiation means.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on the embodiments shown in the drawings. This does not limit the invention. FIG. 1 is an explanatory view of the configuration of an electrophotographic copying machine showing an embodiment of the present invention, in which 1 is a contact glass for placing a document, 2 is a document cover, 2a is a document holding mat, and 3 is a document exposed. Exposure lamp, 4 is an imaging lens,
Reference numerals 5 to 7 denote mirrors that guide the image light from the document exposed by the exposure lamp 3 to the imaging lens 4.
Is moved in the direction of arrow A to scan the document, the mirror 5
7 to 7 are moved so that the optical path length from the document to the imaging lens 4 is always constant.

Reference numeral 8 is a mirror for reflecting the light from the imaging lens 4 to form an image light on the photosensitive drum 9, and 10 is an electrostatic latent image formed on the photosensitive drum 9 by the image light. A developing device, a transfer roller 11 for transferring an image from the photosensitive drum 9 onto a sheet, a cleaning unit 12 for removing residual toner on the photosensitive drum 9, and a main charger 13 for uniformly charging the photosensitive drum 9. Is.

Further, 14 and 15 are sheet feeding cassettes, 16 is a conveying path for conveying sheets from the sheet feeding cassette 14 or 15 to the photosensitive drum 9, and 17 is a conveying path 16 for rotating the photosensitive drum 9. A registration roller that determines the paper feed timing for the registration roller 18 and a registration switch 18 that is provided in the vicinity of the registration roller 17 and detects that the paper has reached the registration roller 17.

Numeral 19 is a conveyor belt for conveying the transferred sheet to the fixing device 20, and numeral 21 is a sheet ejection roller for ejecting the fixed sheet. An erasing halogen lamp 22 is provided on the conveyor belt 19 and emits light of a specific wavelength to decolorize the toner on the leading edge of the sheet conveyed by the conveyor belt 19. Further, the developing device 10 includes a toner that is decolorized when receiving the light of the erasing halogen lamp 22 (hereinafter referred to as a toner that disappears), for example, a cyanine-based dye obtained by reacting a cyanine-based dye with an ammonium salt of organic boron. Toner is used.

FIG. 2 is an enlarged view of a portion B of FIG. 1. A strip-shaped black plate 23 is provided on the lower surface of the contact glass 1 at the end portion where the exposure lamp 3 starts exposing the original.

FIG. 3 is a block diagram showing a main part of the control circuit of the embodiment shown in FIG. 1, where MC is a control unit incorporating a microcomputer, KB is a keyboard for inputting various copying conditions, and TC is a copying process. A timer counter for management, PS1 is a primary paper feed drive unit for driving the primary paper feed system from the cassette 14 or 15 to the registration roller 17, PS
Reference numeral 2 denotes a secondary paper feed drive unit that drives a secondary paper feed system from the registration roller 17 to the paper discharge roller 21, PS3 denotes an optical system drive unit that drives an optical system such as the exposure lamp 3 and mirrors 5 to 7, and JS. Is a jam detection sensor that detects a paper jam (paper jam), and DP is a display unit that displays various copying conditions and conditions.

The control unit MC receives outputs from the keyboard KB, the registration switch 18, and the jam detection sensor JS, and receives a timer counter TC, an erasing halogen lamp 22, a primary paper feed drive unit PS1, and a secondary paper feed drive unit PS2. ,
The output is provided to the optical system drive unit PS3, the display unit DP, and the like.

The operation in such a configuration will be described with reference to the flowchart shown in FIG. First keyboard KB
When "copy start" is input from the
S1 is driven to convey the sheet from the cassette 14 or 15 to the registration roller 17 (step 101). If no jam occurs at this point, formation of an electrostatic latent image on the photosensitive drum 9 is started (step 103).
That is, the optical system drive unit PS3 is driven to perform exposure scanning of the document by the exposure lamp 3, and an electrostatic latent image is formed on the photosensitive drum 9. At the same time, the timer counter T
When C starts timing (step 104) and a predetermined time elapses, the registration roller 17 is driven to start secondary paper feeding (step 105). The electrostatic latent image formed on the photosensitive drum 9 is developed into a toner image by the developing device 10 and transferred onto a sheet by the transfer roller 11 (step 106).

By the way, since the black plate 23 is provided at the exposure start position of the contact glass 1 as shown in FIG. 2, even if the black plate 23 is irradiated by the exposure lamp 3, the light is absorbed, Photoconductor drum 9 corresponding to the black plate 23
The upper area is not exposed, and toner that disappears like a band adheres to the area. Therefore, the leading end of the sheet comes into contact with the belt-shaped toner-attached portion, so that the sheet transferred by the transfer roller 11 is very smoothly transferred onto the photosensitive drum 9.
Separate from.

Further, a belt-shaped toner image as shown in FIG. 5 is formed on the leading end of the sheet separated from the photosensitive drum 9. Therefore, at the same time when the transfer roller 11 starts the transfer onto the paper, the timer counter TC starts counting time (step 107), and when the time when the leading edge of the paper arrives under the erasing halogen lamp 22, the erasing halogen is reached. The lamp 22 is turned on (step 108).

The leading edge of the paper is a halogen lamp 22 for erasing.
When the timer counter TC measures the time for passing under (step 109), the erasing halogen lamp 22 is turned off (step 110). At this point, the paper is discharged by the paper discharge roller 21 when no jam occurs. When a jam occurs in steps 102 and 111, the copying machine stops its operation (step 1
13), "Jam display" is performed on the display portion DP.

In this way, the image formed by the stripped toner on the leading edge of the sheet, which is formed to improve the separability, is erased, and the image corresponding to the original is copied to the other portion of the sheet. ..

[0018]

According to the present invention, it is possible to improve the separability of the paper from the photoconductor with a simple structure.

[Brief description of drawings]

FIG. 1 is a structural explanatory view showing an embodiment of the present invention.

FIG. 2 is an enlarged view of part B in FIG.

FIG. 3 is a block diagram showing a control circuit of the embodiment.

FIG. 4 is a flowchart showing the operation of the embodiment.

FIG. 5 is an explanatory diagram showing a toner adhesion state on the front end of the paper according to the embodiment.

[Explanation of symbols]

 1 Contact Glass 3 Exposure Lamp 9 Photosensitive Drum 10 Developing Device 11 Transfer Roller 19 Conveyor Belt 22 Erasing Halogen Lamp 23 Black Plate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Keiichi Nagahashi 1-2-2 Tamatsukuri, Chuo-ku, Osaka Mita Industrial Co., Ltd.

Claims (1)

[Claims] 1. An image forming apparatus configured to develop an electrostatic latent image formed on a photoconductor with toner and transfer the developed image to a sheet, and a predetermined photoconductor corresponding to the leading edge of the sheet. The developing toner is provided with a preventing means for preventing the image light from being irradiated onto the area, and an irradiation means for irradiating the front end of the paper after transfer with light of a specific wavelength.
An image forming apparatus comprising a toner that is decolorized by light having the specific wavelength.