JPS6397986A - Electrophotographic recording device - Google Patents

Abstract

PURPOSE:To almost uniformly destaticize the surface of a latent image carrier with destaticizing light with normal intensity by providing a light source which performs before-transfer or before-cleaning destaticizing by using infrared light that is never absorbed by toner. CONSTITUTION:Light emitting diodes which emit light beams with light emission distributions close to near infrared rays as the destaticizing light are employed as light sources for a before-transfer electrostatic destaticizer (PTL) 22 and a before-cleaning destaticizer (PCL) 24. All of color toner particles have nearly 100% light reflection factors in the near infrared range and the destaticizing light beams emitted by the PTL22 and PCL24 are transmitted through the respective color toner particles without being absorbed internally and reach the surface of a photosensitive drum 15. Consequently, an image part is destaticized almost equally to a no-image part and a toner remaining area is also destaticized almost equally to a nonremaining area.

Description

[Detailed Description of the Invention] (Technical Field) The present invention relates to an electrophotographic recording device, and particularly relates to an electrophotographic recording device in which a latent image carrier is entirely exposed to static eliminating light before transfer or cleaning. .

(Prior Art) Generally, in an electrophotographic recording apparatus, a latent image formed on a latent image carrier is developed and visualized by a developing device, and the visible image is transferred to a recording material. After the transfer, the toner remaining on the latent image carrier is cleaned by a cleaning device, and the next recording operation is performed.

On the other hand, in such a visible image transfer type electrophotographic recording apparatus, operations called pre-transfer exposure and pre-cleaning exposure have been frequently performed. Is this possible prior to visible image transfer and cleaning? This is an operation in which the surface of the latent image carrier holding the J2 image is uniformly irradiated with neutralizing light to reduce the latent image charge that attracts the visible image toward the latent image carrier.

This makes it possible to improve the efficiency of transferring a visible image onto a recording material and the efficiency of cleaning residual toner.

However, since the static eliminating light in such pre-transfer exposure and pre-cleaning exposure is exposed from above the visible image, the static eliminating light is absorbed into the toner due to the filter effect of the toner that forms the visible image. , it is often not possible to obtain a sufficient static elimination effect. In addition, if the static elimination effect becomes uneven as described above, the background potential in the next recording cycle will become uneven from the beginning, and the area where the static elimination effect was insufficient due to the formation of the image area in the previous recording cycle. However, there is also the problem that the latent image functions as a latent image even in the next recording cycle, causing an afterimage there.

In order to solve this problem, it may be possible to increase the intensity of the static eliminating light to minimize the influence of the toner filter effect, but in this case, the powerful static eliminating light may cause fatigue of the latent image carrier. This results in a deterioration of electrostatic properties and a decrease in charging potential.

(Objective) Therefore, an object of the present invention is to provide an electrophotographic recording device that can obtain a sufficient static elimination effect with an appropriate amount of static elimination light.

(Structure) In order to achieve the above object, the present invention is characterized in that a light source having an emission distribution in the infrared region is used as a static elimination light source.

In an electrophotographic recording device having such a configuration,
Since the static eliminating light emitted from the static eliminating light source toward the latent image carrier has an emission distribution in the infrared region, it is possible for the static eliminating light to be formed by various color toners and black toners that have very low light absorption in the infrared region. The static elimination light almost completely passes through the visual image, and a sufficient static elimination effect is produced not only in the non-image area but also in the image area.

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a laser color electrophotographic copying stone to which the present invention is applied. This duplication unit has an image scanner section 1 and a printer section 2.

A document 4 is placed on a document table 3 provided on the upper surface of the image scanner section 1, and a document illumination lamp 5 forming an exposure optical system and a reflection mirror are placed directly below the document table 3. 6.7° 8 and an imaging lens 9 are installed. Further, within the image scanner section 1, there is provided a part of an image processor that receives the light that has passed through the exposure optical system and obtains an image signal for each color. A prism 11 and a light receiving element (COD) 12.13°14 are shown.

The printer part 2 is provided with a photosensitive drum 15 as a latent image carrier so as to be rotationally driven in the direction of arrow A. As this photoreceptor drum 15, an OPC photoreceptor is adopted. Further, around the photoreceptor drum 15, there is a charger 16, a laser writing section 17, each reliable developing device 18°19.20, and a pre-transfer static eliminator (PTL) 2.
2. Transfer drum 23, pre-cleaning static eliminator (PCL)
24, a cleaning device 25, etc. are arranged in close proximity.

The transfer drum 23 is rotated in the direction of arrow B. A recording paper serving as a transfer material fed from a paper feed cassette 26 is wound around the transfer drum 23, and a transfer charger 27, a separation charger 28, a separation claw 29, etc. are arranged close to each other. Furthermore, a fixing device 31 and a paper discharge tray 32 are installed behind the transfer drum 23.

Further, each of the light sources of the pre-transfer static eliminator (PTL) 22 and the pre-cleaning static eliminator (PCL) 24 is a light emitting diode (LED) whose static elimination light emitted from each of these light sources has an emission distribution in the near infrared region. has been adopted. That is, the static eliminating light emitted from the light emitting diodes used as the light sources of the pre-transfer static eliminator (PTL) 22 and the pre-cleaning static eliminator (PCL) 24 is as follows:
The emission wavelength has an emission distribution curve as shown in Figure 3, and the intensity of the emission wavelength is 880 in the near-infrared region.
It is distributed in a convex shape with a peak at nm.

In such an embodiment, an optical image of a document 4 placed on a document table 3 of an image scanning section 1 passes through various exposure optical systems to a light receiving element (COD) of a part of an image processor.
)12.13.14, and the light image is color separated (R
, G, B) and then read and processed into image signals for toner development of each color.

These image signals for toner development of each color are modulated into optical signals by the laser writing section 17 of the printer section 2. When the photosensitive drum 15 as a latent image carrier is irradiated with laser light as an image signal in a predetermined scanning manner, an electrostatic latent image is formed for each image signal. These electrostatic latent images are respectively developed and visualized by developing devices 18, 19, and 20 for each color toner (cyan C1 magenta M1 yellow Y).

In this case, the PC photoreceptor employed as the photoreceptor drum 15 has high sensitivity characteristics as shown in FIG. That is, this oPC photoreceptor has a laser completion and pre-transfer static eliminator (PTL) 22 as an image signal,
It has a sensitivity distribution that can sufficiently cover each emission wavelength of the static elimination light (3) emitted from the pre-cleaning static eliminator (PCL) 24, and can satisfactorily sense each of these lights.

The developed visible image will be sequentially transferred for each color to the recording paper wrapped around the transfer drum 23 by the attraction electric force of the transfer charger 27, but before each transfer, pre-transfer removal is performed. Static elimination light is emitted from the electric appliance (PTL) 22 to perform static elimination. This charge removal operation reduces the latent image charge that attracts the visible image, and improves the efficiency of transferring the visible image onto the recording paper. In this case, the emission wavelength intensity of the static eliminating light emitted from the light source (LED) of the pre-transfer static eliminator (PTL) 22 is distributed in the near-infrared region with a peak of 880 nm (see Figure 3).
. On the other hand, as shown in FIG. 2, the spectral reflectance of each color toner is approximately 10
It has a light reflectance close to 0%. Therefore, the static eliminating light emitted from the pre-transfer static eliminator (PTL) 22 is transmitted to all of the colors I to Luna forming a visible image without being absorbed internally, and reaches the surface of the photoreceptor drum 15. I will reach it. As a result, the image area receives substantially the same static elimination effect as the non-image area.

After the transfer, the toner remaining on the photoreceptor drum 15 is removed from the photoreceptor drum 15 by the cleaning device 25 after being subjected to the neutralization effect by the neutralization light emitted from the pre-cleaning static eliminator (PCL) 24 . The static eliminating light emitted from the pre-cleaning static eliminator (PCL) 24 also has an emission distribution in the near infrared region, similar to the pre-transfer static eliminator (PTL) 22 described above. Therefore, the static eliminating light emitted from the pre-cleaning static eliminator (PCL) 24 is
All of the remaining color toners reach the surface of the photosensitive drum 15 without being absorbed. As a result, the toner remaining area receives the same static elimination effect as the non-residual area.

<Effects> As described above, the electrophotographic recording device according to the present invention has the following effects:
Since it is equipped with a light source that performs static elimination before transfer or cleaning using infrared light that is not absorbed by the toner, the static elimination light emitted from the static eliminator is absorbed internally by all of the toner of each color. The light reaches the surface of the latent image carrier without being damaged, and the surface of the latent image carrier can be almost uniformly neutralized even with a normal intensity of charge eliminating light. Therefore, it is possible to avoid a situation in which the life of the latent image carrier is shortened by strong static elimination light, and it is also possible to prevent the afterimage phenomenon caused by non-uniform static elimination, thereby improving transfer efficiency. and the cleaning performance can be improved satisfactorily.

[Brief explanation of the drawing]

Fig. 1 is an explanatory longitudinal cross-sectional view of a laser color electrophotographic copying machine to which the present invention is applied, Fig. 2 is a diagram showing the spectral reflectance of each color toner, and Fig. 3 is the emission of static elimination light emitted from a static elimination light source. A diagram showing the distribution, FIG. 4 is a diagram showing the spectral sensitivity of the OPC photoreceptor. 15... Photosensitive drum, 22... Pre-transfer static eliminator, 2
4...Static eliminator before cleaning. Figure 7 Procedural Amendment Document June 11, 1988 Patent Application No. 243600 2 Name of Invention Electrophotographic Recording Device 3 Relationship with the case of the person making the amendment Name of patent applicant Name (674) Representative for Ricoh Co., Ltd. 4 Address: 4-5-4 Kyodo, Setagaya-ku, Tokyo
"Detailed Description of the Invention" column. --- In the 9th line of page 4 of the specification, the phrase "black toner" is corrected to "black toner that does not use carbon black pigment as a coloring material."

Claims (1)

[Claims] 1. Supplying toner to the latent image formed on the latent image carrier and developing it to obtain a visible image, and cleaning before or after transferring this visible image to a recording material. In the electrophotographic recording apparatus, the entire surface is exposed to the static eliminating light emitted from the static eliminator, wherein the static eliminator is equipped with a light source that emits static neutralizing light having an emission distribution in the infrared region. Recording device. 2. The electrophotographic recording apparatus according to claim 1, wherein the light source of the static eliminator is composed of a light emitting diode.