JPS63217372A - Image forming device - Google Patents

Abstract

PURPOSE:To obtain a sharp multicolor image having no color mixture by fixing a toner image which is formed except in final image forming operation, etc., temporarily on a recording medium. CONSTITUTION:A latent image formed on a photosensitive drum 2 as a recording medium by a 1st exposure 3 is developed by a developing device 4 with toner of specific color to become a visual image, which is fixed temporarily on the drum 2 by a pressure roll 5. Then the final image forming operation by 2nd exposure 6 is performed and the resulting latent image is developed with specific-color toner by a developing device 7. This temporary fixing process make plural latent images and toner equal in polarity to simplify the image forming process, thereby forming the sharp multicolor image having not color mixture.

Description

[Detailed Description of the Invention] (Industrial Application Field) Undeveloped fJI is a multicolor or multicolor image in one recording cycle.
The present invention relates to an image forming apparatus.

(Prior Art and its Problems) Various image forming apparatuses that can obtain multicolor images in one recording cycle have been proposed in the past. First, as an electrophotographic apparatus, a plurality of i
) Is there any known device that is equipped with an electric appliance, an exposure device, and a developing device? This device requires a plurality of strip removers, so there is a tendency for the device to become larger. In addition, as a developing method for chromatic toner, a secondary magnetic brush is generally used, or in the L device, a magnetic brush of the second stage or later developing device is used, or a magnetic brush is already formed on the photosensitive tram L-. This has the disadvantage that it not only disturbs the toner image, but also that the toner gets mixed into the developing device, causing color mixing in the image.

To solve this problem, we set the magnetic brush in a non-contact state with respect to the photosensitive drum and applied an AC bias to disturb the developer! The method of terminating, JP-A-56-1
No. 44452-publication. however,
With this method, it is difficult to set the development bias (?), the distance between the development sleep and the photosensitive drum, etc., and it is important to note that the toner or latent image may be coated in one minute or one image or be rough. 151 people have been found.

In addition, in a conventional apparatus that can obtain a multicolor image in one recording cycle, image formation must be performed by changing the polarity of a plurality of static images and the polarity of a plurality of toners corresponding to each required color image. This made the image forming process complicated.

Furthermore, in methods other than electrophotography, a dielectric material is used as a recording medium, and a charge pattern corresponding to image information is formed on the dielectric material using a multi-stylus, digital ion charger, etc., and this is used in a developing device to form toner 'IIf'. Is there a way to visualize it? Even with this method, the above-mentioned image disturbance,
Problems such as color mixing were unavoidable.

(]1) The unreleased 11 was made in consideration of the actual situation as follows,
! ! An object of the present invention is to provide an image forming apparatus capable of obtaining multicolor or multiple images without color mixture.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a plurality of image forming means around a recording medium, and forms a plurality of toner images on the recording medium by the image forming means. In the image forming apparatus configured as above, a means for temporarily depositing the toner image formed by the image forming means on a recording medium is provided next to each image forming means except the final image forming means. It is characterized by

(Function) By temporarily depositing the first toner image, it is possible to avoid the first toner image from being disturbed or causing color mixing by the image forming means of the second and subsequent stages.

(Example) Hereinafter, embodiments of the present invention will be described based on the drawings.

FIG. 1 shows a two-color electrophotographic apparatus as a first embodiment, in which a photosensitive drum (electrostatic latent image holder) 2 is uniformly charged by a primary charger l, and a first J light After a first electrostatic latent image (negative latent image) is formed by 3, reverse development is performed by a first developing device 4 to form a first toner image.

Reference numeral 5 denotes a pressure roll for temporarily adhering the first toner image to the photosensitive drum 2, which increases the contact area between the toner 31 constituting the first toner image and the photosensitive drum 2 as shown in FIG. 2(B). As a result, the adhesion force of the toner 31 to the photosensitive drum 2 increases. In addition, in FIG. 2, 32 is a photosensitive layer,
33 is a substrate.

Next, the photosensitive tram 2 is exposed to a second static image by a second exposure 6.
After the tt latent image (negative latent image) is formed, it is developed by a second developing device 7, and a second toner image having a different color from the first toner image is formed. In this second development, the first toner image comes into contact with the magnetic brush of the second developing device 7, but as described above, the pressure roll 5 tends to increase the adhesion of the first toner image to the photosensitive drum 2. Therefore, the first toner image is not disturbed, and the possibility of the first color toner getting mixed into the second developing device 7 and causing color mixing is avoided. be done.

Thereafter, each of the two-color toner images is transferred onto a transfer material 9 by a transfer device 8 and fixed via a fixing roll 10. h
l! , residual toner on the optical drum 2F is cleaned by a cleaner 11, and residual charge is removed by an eraser lamp 12.

As a conventional two-color image forming method using electrophotography, as disclosed in Japanese Patent Application Laid-open No. 54-81855 and Japanese Patent Application Laid-Open No. 56-87060, two-color image formation is possible by forming a three-level latent image. How to obtain images and JP-A-55
As disclosed in No. 137538 and No. 57-2047, the first color is formed as a negative latent image, this is developed into a visible image by reversal development, and the second color is formed as a positive latent image. Although there is a method of obtaining a two-color image by regular development, it is unlikely that the present invention can be applied to either of these methods.

Furthermore, the present invention is not limited to two-color image formation, but can also be applied to image formation with three or more colors, and can also be applied to multi-color image formation using monochrome toners.

In particular, even if the polarity of the first electrostatic latent image and the second electrostatic latent image are the same, and the charged polarity of the first developed toner and the second developed toner are made the same, the first toner image may be disturbed. Since the second toner image can be obtained without the need for the second toner image, the single image forming process can be simplified.

Next, a second embodiment of the present invention will be described with reference to FIGS. 3 to 5. In this embodiment, a dielectric sheet 41, which is a conductive material coated with a dielectric material, is used as a recording medium, and an image forming apparatus 50 as shown in FIG. 4 is used as one image forming stage F. The image forming device 5
0, conductive magnetic toner 51 is conveyed through a non-magnetic cylinder 53h by a rotating magnet 52 and passed through a recording electrode 54J consisting of a large number of recording elements made of magnetic material, while having an insulating layer 56 on the surface. A voltage is applied between the conductive layer 57 of the recording medium 55 and the recording electrode 54 to cause toner 51 to adhere to the recording medium 55 to form an image.

To explain the image forming process with reference to FIG. 3, the image forming device W
The dielectric sheet 41 is
A first toner image is formed on a recording medium 55 (corresponding to the recording medium 55 in FIG. 4), and then heat is applied to the first toner image by a flash lamp 43, which is a temporary attachment means. Due to this heating, the surface of the toner 51 of the first toner image on the flash lamp 43 side is melted, and adjacent toner particles are bonded to each other as shown in FIG. 5(B).

Next, a second toner image is formed by the second developing device 44 having the image forming device 50. At this time, since the toners of the first toner image are combined with each other as described above, the second developing device 44 44, it does not peel off. Therefore, the il toner image is not disturbed, and color mixing due to toner contamination does not occur.

Thereafter, the two toner images are transferred and fixed onto the transfer material 9 by the transfer/fixing roll 45, and the toner remaining on the dielectric sheet 41 is removed by the cleaner 11.

A third embodiment of the present invention will be described with reference to FIG.

In this embodiment, a dielectric sheet 41 similar to that of the second embodiment is used as a recording medium, and a digital ion charger disclosed in JP-A-54-78134 is used as a latent image forming means. To explain the formation process, first, the dielectric sheet 4 is heated by the first digital ion charger 71.
A first latent image is formed on the M1L toner image by forming a first latent image on the M1L toner image and developing it in the first developing device 73 to form a first toner image. Apply the voltage and make it temporarily adhere.

Next, a second latent image is formed by the second digital ion charger 72 and developed by the second developer 74 to form a second toner image, but the first toner image is completely different from the second embodiment. Similarly, since it is temporarily attached, the second development! ! 74 and 1? ! Thereafter, the two toner images are transferred and fixed onto the transfer material 9 via the transfer/fixing roll 45 without being peeled off even when rubbed. The toner remaining on the dielectric sheet 41 is removed by the cleaner ti.
will be removed.

Note that a commonly used electrostatic recording needle '+'l (pole) may be used as the latent image forming means.

Further, as the temporary attachment means in the second and third embodiments, the pressure roll 5 of the first embodiment may be used instead of the French lamp 43.

(Effects of the Invention) As described in 1-1 above, according to the present invention, a clear multicolor or multiple image without image disturbance or color mixture can be obtained. In particular, the polarity of the plurality of electrostatic latent images and the developing toner can be changed.

The image forming process is simplified.

4. The internal theory fJ+ of the 14th page FIG.
11 composition, 2nd ['14 (A) and (B) are the same, explanatory diagrams showing the state of assumed toner adhesion, and 3rd UA is the mechanical configuration of the second embodiment [:4. Figure 4 shows an enlarged cross section 14 of the image forming device.
, 5f4 (A), (a) are the same diagrams showing the hypothetical adhesion state of toner. 614 is a schematic configuration diagram of the third embodiment.

1...Obi'lli, vessel, 2...kI! -, optical tram, 4, 7, 42° 44.73.74... developer, 5.
...Pressure roll.

4t...dielectric sheet, 43...flash lamp,
50...Image forming device, 71.72...Digital ion band commercial equipment.

Patent Applicant Canon Co., Ltd. Agent, Patent Attorney: Yama Ryo - Figure 1 Figure 2 Values, (B) Figure 5 IA) 7Z Type Z CB)

Claims (5)

[Claims] (1) In an image forming apparatus configured such that a plurality of image forming means are provided around a recording medium and a plurality of toner images are formed by the image forming means on the recording medium, each of the image forming means except the final image forming means An image forming apparatus characterized in that a means for temporarily depositing a toner image formed by the image forming means on a recording medium is provided next to the image forming means. (2) The image forming apparatus according to claim 1, which uses a photoreceptor as a recording medium and uses a charging exposure and developing device as an image forming means. (3) As an image forming means, a recording electrode consisting of a large number of recording elements and a device for conveying developer to the recording electrode are provided, and a toner image is formed on a recording medium according to a signal applied to the recording electrode. An image forming apparatus according to claim 1, wherein the image forming apparatus is configured to form an image. (4) The image forming apparatus according to claim 1, which uses a dielectric material as a recording medium, and uses an electrostatic latent image forming device and a developing device that apply a charge onto the dielectric material as image forming means. (5) The polarity of the electrostatic latent images of the first stage and the second stage and subsequent stages in the plurality of image forming means is the same, and the charged polarity of the developed toner of the first stage and the second stage and subsequent stages is set to be the same. An image forming apparatus according to claims 1 to 4, which are the same.