JPH0355585A - Electrophotographic printing device - Google Patents

Abstract

PURPOSE:To compensate excellent print quality irrelevantly to the thickness and structure of a printing medium and to reduce the amount of ozone which is produced by corona discharge by providing a control part which operates according to a printing medium kind signal and controls the operating current of a separation charger. CONSTITUTION:A printing medium kind detecting means 7 which detects the kind and thickness of the printing form 3 and sends the printing medium kind signal is arranged by a printing medium supply means 4 and the control part 8 which receives the printing medium kind signal and controls the current for operating the separation character 6 is mounted. Consequently, the excellent print quality is secured irrelevantly to the thickness and structure of the printing form and the amount of ozone which is produced by the corona discharge is reduced to preclude environmental destruction.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an electrophotographic printing device, and particularly to an electrophotographic printing device suitable for using various print media.

[Conventional technology]

Conventionally, in the development process of this type of electrophotographic printing device, there has been a transfer charger that transfers an image formed on the surface of an electrostatic latent image carrier onto a print medium, and a print that transfers the image by this transfer charger. A corona charger is used as a separation charger that separates the medium from the electrostatic latent image carrier.

The transfer charger transfers an image onto the print medium using electrostatic force by applying direct current corona discharge of a predetermined polarity to the print medium from the opposite side of the electrostatic latent image carrier across the print medium. In addition, the separation charger generates a corona discharge of opposite polarity to the transferred print medium downstream of the transfer charger to neutralize the static electricity on the print medium that was charged during transfer, thereby reducing the electrostatic potential. Smooth separation from the image carrier.

[Intelligence B to be Solved by the Invention] However, in the above conventional example, the current value supplied to the corona charger, which is a separate charger, is fixed at a constant value, so it is usually used as a printing medium. If this separation current is set for relatively thin high-quality paper, there is a problem in that poor separation is likely to occur for thick paper such as postcards or double-layer printing media such as envelopes. On the other hand, if a separation current is set for thick paper such as a postcard or a double-layered printing medium such as an envelope, there is a drawback that it adversely affects the transfer charger and good print quality cannot be guaranteed. Furthermore, since the amount of ozone (03) generated by the corona discharge of the corona charger is large, there is a problem that it may lead to environmental destruction.

[Object of the Invention] The object of the present invention is to improve the disadvantages seen in the conventional examples, to guarantee good print quality regardless of the thickness and structure of the print medium, and to eliminate ozone (O, ) An object of the present invention is to provide an electrophotographic printing device that can reduce the amount of printing.

[Means for Solving the Problems] The present invention provides an electrostatic latent image carrier that forms an electrostatic latent image on its surface by irradiation with light and is rotationally driven by an external force, and a surface of this electrostatic latent image carrier. a developing device for visualizing the electrostatic latent image by supplying a developer to the electrostatic latent image; a printing medium supply means for supplying a printing medium between the developing device and the electrostatic latent image carrier;
It has a transfer charger that transfers the image formed on the surface of the electrostatic latent image carrier onto a printing medium, and a separation charger that separates the printing medium to which the image has been transferred by the transfer charger from the electrostatic latent image carrier. There is. A print medium type detection means for detecting the type of print medium and outputting a print medium type signal is attached to the print medium supply means, and operates based on this print medium type signal to control the operating current of the separation charger. The method is to equip it with a control unit. This is intended to achieve the above-mentioned purpose.

[Operation] Light is irradiated onto the electrostatic latent image carrier to form an electrostatic latent image on the surface. The developing device supplies developer to the surface of the electrostatic latent image carrier to visualize the electrostatic latent image. The print medium supply means supplies a print medium between the developer and the electrostatic latent image carrier. At this time, the print medium type detection means detects the type of the supplied print medium and issues a print medium type signal to the control section.

The transfer charger applies a current of a predetermined polarity to the supplied printing medium from the back side to transfer the image formed on the surface of the electrostatic latent image carrier onto the printing medium. The printing medium to which the electrostatic latent image has been transferred by the transfer charger is applied with a current of opposite polarity to that during transfer by the separation charger, neutralizing the static electricity remaining on the printing medium and separating it from the electrostatic latent image carrier. However, at this time, the control section controls the amount of current to be applied to the transfer charger based on the print medium type signal previously transmitted by the print medium type detection means, and uses a current with a strength corresponding to the print medium. Activate the separate charger.

[Embodiments of the invention] Hereinafter, one embodiment of the present invention will be described based on FIG.

In the embodiment shown in FIG. 1, there is an electrostatic latent image carrier 1 which forms an electrostatic latent image on its surface by light irradiation and is rotationally driven by an external force, and a surface of this electrostatic latent image carrier 1. A developing device 2 supplies a developer to visualize an electrostatic latent image, a printing medium supply means 4 supplies a printing medium 3 between the developing device 2 and the electrostatic latent image carrier 1, and A transfer charger 5 that transfers the image formed on the surface of the image carrier 1 onto the printing medium 3; and a separation charger 6 that separates the printing medium 3 onto which the image has been transferred by the transfer charger 5 from the electrostatic latent image carrier 1. have. A print medium type detection means 7 that detects the type of print medium 3 and issues a print medium type signal is provided in the print medium supply means 4, and is operated based on this print medium type signal to operate the separate charger 6. It is equipped with a control section 8 that controls the current.

The control section 8 includes a transfer medium type recognition mechanism 8A that receives a print medium type signal from the print medium type detection means 7, and a separation current value determination mechanism 8A that determines the current to be passed through the separation charger 6.
B, and a separation current generating mechanism 8C that causes this current to flow through the separation charger 6 to operate the separation charger 6. In the embodiment shown here, a photosensitive drum 20 is used as the electrostatic latent image carrier 1, a laser scanner 21 is used as a light source for irradiating light onto the photosensitive drum 20, and a developing device 2 that uses magnetic toner is used. ing. As the printing medium 3, printing sleeves 22 having various thicknesses and structures can be considered.

Next, the operation will be explained based on FIG.

A photosensitive drum 20 serving as an electrostatic latent image carrier 1 whose surface is uniformly charged by a charger 23 is rotationally driven by an external force (not shown). The surface of the photosensitive drum 20 is line-scanned by a laser scanner 21 while blinking a point image of light in accordance with input data. The exposed surface of the photosensitive drum 20 is discharged and an electrostatic latent image is formed. Then, magnetic toner is uniformly supplied from the developing device 2 to the surface of the photosensitive drum 20 to visualize and develop the electrostatic latent image formed on the surface of the photosensitive drum 20.

The toner image developed on the surface of the photosensitive drum 20 is transferred by a transfer charger 5 to a printing sheet 22 as a printing medium 3 supplied by a printing medium supplying means 4.
By applying a charge opposite to that of the magnetic toner from behind, the toner is attracted and transferred onto the printing sleeve 22.

When the printing medium supply stage 4 supplies the printing paper 22,
A print medium type detection stage 7 installed in the print medium supply means 4 detects the type of the printing gill 22 and issues a print medium type signal to the transfer medium type recognition mechanism 8A of the control section 8.

The printing paper 22 on which the toner image has been transferred is applied with a current of opposite polarity to that during transfer by the separation charger 6 to neutralize the static electricity remaining on the printing sleeve 22 during transfer and is separated from the photosensitive drum 20. However, at this time, the control unit 8 determines the amount of current that the separation current value determining mechanism 8B causes to flow through the transfer charger 5 based on the print medium type signal previously transmitted by the print medium type detection means 7, The separation charger 6 is actuated by passing a current having a strength corresponding to the printing cap 22 from the separation current generation mechanism 80.

The separated printing paper 22 is sent to a fixing device (not shown),
The toner image is fixed on the printing plate 22 by pressure and heat. After the transfer, the toner remaining on the photosensitive drum 20 is removed by a cleaner 24, and the charge on the surface of the photosensitive drum 20 is removed by an eraser (not shown) to complete the printing operation.

[Effects of the Invention] As described above, in the present invention, the printing medium type detection means that detects the type and thickness of printing paper and issues a printing medium type signal is disposed in the printing medium supplying means, and the printing It is equipped with a control section that receives a media type signal and controls the current that operates the separate charger. This ensures good print quality regardless of the thickness or structure of the printing paper, and also eliminates ozone (0) generated by corona discharge.
It is possible to provide an unprecedented and excellent electrophotographic printing device that can prevent environmental damage by reducing the amount of 3).

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the entire printing process according to an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Electrostatic latent image carrier, 2... Developing device, 3... Printing medium, 4... Printing medium supply means, 5... ...Transfer charger, 6...
- Separation charger, 7...Print medium type detection means, 8...Control unit.

Claims (1)

[Claims] (1) an electrostatic latent image carrier that forms an electrostatic latent image on its surface by irradiation with light and is rotationally driven by an external force;
A developing device that supplies developer to the surface of the electrostatic latent image carrier to visualize the electrostatic latent image, and a printing medium that supplies a printing medium between the developer and the electrostatic latent image carrier. supply means;
a transfer charger that transfers the image formed on the surface of the electrostatic latent image carrier onto the printing medium; and a separation charger that separates the printing medium to which the image has been transferred by the transfer charger from the electrostatic latent image carrier. In the electrophotographic printing apparatus, a print medium type detection means for detecting the type of the print medium and outputting a print medium type signal is provided in addition to the print medium supply means, and is operated based on the print medium type signal. An electrophotographic printing apparatus characterized in that the electrophotographic printing apparatus is equipped with a control section for controlling an operating current of the separation charger.