JPH0511563Y2 - - Google Patents

Description

[Detailed description of the invention] "Industrial application field" This invention is a multicolor recording device that records images of two or more colors using a method of forming an electrostatic latent image on a recording medium and developing it. Regarding.

``Prior Art'' Devices that form an electrostatic latent image on a recording medium using an electrophotographic method or an electrostatic recording method, develop this to obtain a toner image, and transfer it to recording paper include copying devices. As such, it has been adopted in various recording devices. Various types of devices have been developed that perform not only monochrome but also multicolor recording using this device.

FIG. 3 shows a schematic configuration diagram showing one example.

This multicolor recording device has a
Exposure section 2 and four developing devices 4a, 4b, 4c, 4
d, a cleaning device 5, and a charger 3.

Further, a transfer drum 6 is provided so as to circumscribe the photosensitive drum 1, and a recording paper 7 is wound around the outer periphery of the transfer drum 6. The exposure section 2 is
It is composed of an optical system for guiding a light image to the outer peripheral surface of the photosensitive drum 1, or an optical writing head using an LED array or the like. Developing devices 4a-4
d is a developing device that develops an electrostatic latent image using cyan, magenta, yellow, and black toners, respectively.

In such a multicolor recording device, when the photosensitive drum 1 rotates in the direction of the arrow, its outer circumferential surface is cleaned by a cleaning device, and then a constant charge is applied by the charger 3 to expose the exposed portion 2. An electrostatic latent image is formed. First, an electrostatic latent image corresponding to, for example, cyan is formed, and a cyan toner image is formed by the developing device 4a. This toner image is transferred to the recording paper 7 on the transfer drum 6.
transcribed into. Next, the outer peripheral surface of the photosensitive drum 1 is cleaned again by the cleaning device 5, and an appropriate charge is applied by the charger 3, and an electrostatic latent image corresponding to magenta color is formed in the exposure section 2. be done. This electrostatic latent image is developed by the developing device 4b and transferred onto the recording paper 7 again. Similarly, yellow and black toner images are printed on the recording paper 7.
When the images are superimposed and transferred, recording of a multicolor image on the recording paper 7 is completed.

Note that each toner image is transferred by moving the transfer drum 6 so that the corresponding parts of the images overlap each other.
This is performed by conveying and rotating the recording paper 7.

FIG. 4 shows an example of a multicolor recording apparatus having a different configuration from that shown in FIG.

This apparatus is provided with four photosensitive drums 1a to 1d on the conveyance path of the recording paper 7, each of which is configured to transfer a toner image onto the recording paper 7 by a transfer device 9. On the outer periphery of each photosensitive drum 1a to 1d, an exposure section 2, a charger 3, and a developer 4 are provided.
and a cleaning device 8 are provided, respectively. For example, in the photosensitive drum 1a, the electrostatic latent image formed by the exposure section 2 is developed by the developing device 4 to form a cyan toner image. This toner image is transferred to a recording paper 7 in a transfer device 9.
transcribed into. Other photosensitive drums 1b, 1c, 1d
The same applies to

``Problem that the invention aims to solve'' However, although the multicolor recording device shown in FIG. 3 has the advantage of having a relatively compact device configuration, the Since the transfer of one color is performed on each image, four rotations of transfer are required for four colors, which has the disadvantage of slowing down the process speed.

On the other hand, although the process speed of the multicolor recording apparatus shown in FIG. However, due to unevenness in the conveying speed, toner images do not overlap completely and accurately, resulting in so-called color misregistration.

In addition to the apparatus described in FIGS. 3 and 4, an electrostatic recording head is used to irradiate ions onto a recording medium made of an insulator instead of a photosensitive drum, thereby generating an electrostatic charge. Devices that form latent images have also been developed. In order to irradiate such ions, for example, Japanese Patent Application Laid-open No. 59-190854,
The electrostatic recording head disclosed in Japanese Patent Laid-Open No. 60-94357, Japanese Patent Application Laid-Open No. 60-89373, etc. is used. This electrostatic recording head controls the ion flow generated by discharge using an electrode array consisting of a large number of electrodes, guides the ion flow onto the recording medium, and forms an electrostatic latent image of the ions. be.

Using such an electrostatic recording head, it is possible to realize a device with a similar configuration, but there are the same problems as described above in terms of process speed and increasing the size of the device. It was hot.

The present invention was developed in order to solve the above-mentioned drawbacks of the conventional technology. It enables high-speed printing, has a relatively compact structure, and also performs high-speed, high-quality multicolor recording with little color shift. The object of the present invention is to provide a multi-color recording device that can perform a multi-color printing process.

``Means for Solving the Problems'' The multicolor recording device of the present invention uses a recording medium drum having an adhesive surface layer on its outer circumferential surface and an electrode array in which a large number of electrodes are arranged to direct the ion flow generated by electric discharge. a plurality of electrostatic recording heads that control and irradiate onto the recording medium drum to form electrostatic latent images on the outer circumferential surface thereof; and a plurality of electrostatic recording heads that develop the electrostatic latent images to form corresponding toner images. and a pressure roll that presses the toner image formed by these developers onto the adhesive surface layer of the recording medium drum immediately after the development.

"Function" As described above, when a recording medium drum having an adhesive surface layer on the outer circumferential surface is used, toner images of two or more colors can be recorded on the outer circumferential surface in a superimposed manner, and the process speed can be improved. can. Furthermore, the adhesion force between the developed toner and the recording medium is increased, and separation of the toner from the recording medium, which tends to occur during the subsequent electrostatic latent image writing process and development process, can be prevented. This enables high quality and reliable recording. Further, since a pressure roll is provided to press the toner against the adhesive surface layer, the effect is further enhanced.

Embodiment FIG. 1 is a schematic diagram of a multicolor recording apparatus according to the present invention.

This device includes four
three electrostatic recording heads 2a, 2b, 2c, 2d,
Six chargers 3a, 3b, 3c, 3d, 3f, 3
g, four developing devices 4a, 4b, 4c, 4d,
A cleaning device 8 is arranged. Also,
A transfer device 9 is provided circumscribing the recording medium drum 1, and the recording paper 7 is conveyed between the transfer device 9 and the recording medium drum 1.

The electrostatic recording heads 2a to 2d form electrostatic latent images corresponding to cyan, magenta, yellow, and black images, respectively. In addition, the developing device 4
In a to 4d, electrostatic latent images are developed using cyan, magenta, yellow, and black toners, respectively, to form toner images of the respective colors. Further, each charger is composed of a known corotron for charging the outer circumferential surface of the recording medium drum 1 to a preselected potential.
An adhesive surface layer 11 made of silicone rubber, for example, is provided on the outer peripheral surface of the recording medium drum 1.

FIG. 2 is an enlarged view of a part of this multicolor recording apparatus. Here, in FIG. 1, the charger 3
An enlarged view of only the portion extending from a to the charger 3b via the electrostatic recording head 2a and the developing device 4a is shown.

Here, a pressure roll is provided between the developing device 4a and the charging device 3b. This pressure roll is
With respect to the outer peripheral surface of the recording medium drum 1, arrow 12'
It is made up of circumscribed rolls that are pressurized in the direction of . Although not shown in FIG. 2, similar pressure rolls are provided immediately after the other developing units 4a, 4b, and 4c.

The multicolor recording apparatus having such a configuration records a multicolor image on the recording paper 7 in the following manner.

First, the electrostatic adhesion of unnecessary toner adhering to the outer peripheral surface of the recording medium drum 1 is weakened by the charger 3g, which corresponds to a pre-clean corotron. Next, the unnecessary toner is removed by the cleaning device 8, and the cleaning is completed. Then, the outer peripheral surface of the recording medium drum 1 is precharged to a predetermined potential by the charger 3a.

First, an electrostatic latent image is formed thereon by the electrostatic recording head 2a for writing a yellow image. This electrostatic latent image is developed by the developing device 4a, and a yellow toner image is formed on the outer peripheral surface of the recording medium drum 1. Next, the outer peripheral surface of the recording medium drum 1 is recharged to a predetermined potential by the charger 3b. Then, an electrostatic latent image is written by the electrostatic recording head 2b for writing a magenta image. This electrostatic latent image is developed by the developing device 4b, and a magenta toner image is formed on the outer peripheral surface of the recording medium drum 1. Then, it is charged again by the charger 3c, and a cyan toner image is formed by the electrostatic recording head 2c and the developer 4c. The same goes for the next step, and a black toner image is formed by the charger 3d, the electrostatic recording head 2d, and the developer 4d.

In this way, the recording medium drum 1 rotates in the direction of the arrow, and the four-color toner images formed one above the other by the above process pass under the charger 3f. This charger 3f functions as a so-called transfer corotron and uniformly adjusts the adhesion force of the toner image. These toner images are then transferred onto the recording paper 7 by the transfer device 9. This transfer device 9 is
It is pressed against the outer peripheral surface of the recording medium drum 1, and has heating means inside. Using this pressure and heat, the four-color toner image is transferred to the recording paper 7.
transfers well onto the surface.

Note that unnecessary residual toner adhering to the outer peripheral surface of the recording medium drum 1 is removed again by the charger 3g and the cleaning device 8. Since the outer circumferential surface of the recording medium drum 1 is formed of the adhesive surface layer 11, the cleaning device 8 may be a thermal roll that thermally removes toner.

In the recording apparatus having the configuration of this embodiment, toner images of four colors are sequentially superimposed and formed on the outer peripheral surface of one recording medium.

At this time, each toner adheres to the outer peripheral surface of the recording medium drum 1 with a strong force not only by so-called electrostatic attraction but also by adhesive force. Therefore, it is possible to prevent the toner in the toner image already formed from separating from the outer peripheral surface of the recording medium 1 due to the electric field formed by each electrostatic recording head or developing device.

Furthermore, the pressure roll 12 is used in the multicolor recording device of the present invention.
presses this toner image in the direction of arrow 12',
Improves the adhesion between the toner image and the adhesive surface layer. This action improves the adhesion of the toner image to the outer peripheral surface of the recording medium drum 1, and prevents the toner image from being disturbed by subsequent electrostatic latent image formation and development processing. can do. The pressure roll 12 is, for example, a roll coated with tetrafluoroethylene to prevent toner from adhering to its outer peripheral surface.

"Modification" The multicolor recording device of the present invention is not limited to the above embodiments.

The chargers disposed on the outer peripheral surface of the recording medium drum 1 may be added or omitted as necessary. Furthermore, the pressure rolls do not necessarily have to be installed behind all the developing units.
Of course, there is no need to provide a pressure roll behind the last developing device 4d unless there is anything that will cause the toner image to be disturbed thereafter. It goes without saying that according to the present invention, it is possible to perform multicolor recording by freely combining two or more colors.

"Effects of the invention" According to the multicolor recording device of the invention described above,
Since a multicolor toner image can be formed in one revolution of the recording medium drum and transferred to recording paper, high-speed recording can be achieved. In addition, since an adhesive surface layer is formed on the outer circumferential surface of the recording medium drum and the toner image is pressed onto this layer using a pressure roller, the developed toner image does not require special energy for adhesion of the toner image. It is possible to reliably prevent scattering, and it is possible to perform high-quality, highly reliable, and economical recording with a relatively simple configuration. Furthermore, in the present invention, since the toner images are pressed in order, the relationship of overlapping colors is clear. In this way, since color mixing does not occur between toners of different colors, good color reproduction can be achieved.

[Brief explanation of the drawing]

Fig. 1 is a schematic block diagram showing an embodiment of the multicolor recording device of the present invention, Fig. 2 is a schematic block diagram showing an enlarged part of the multicolor recording device of the present embodiment, and Fig. 3 is a conventional recording device. FIG. 4 is a schematic configuration diagram showing an example of another conventional recording apparatus. 1... Recording medium drum, 2a to 2d... Electrostatic recording head, 3a to 3g... Charger, 4a to 4d...
...Developer, 7...Recording paper, 8...Cleaning device, 9...Transfer means, 11...Adhesive surface layer,
12...Crimp roll.

Claims (1)

[Claims for Utility Model Registration] A recording medium drum having an adhesive surface layer on its outer circumferential surface, and an ion flow generated by electric discharge that is controlled using an electrode array having a large number of electrodes and irradiated onto the recording medium drum. a plurality of electrostatic recording heads that form electrostatic latent images on their outer peripheral surfaces; developing devices that develop the electrostatic latent images and form corresponding toner images; 1. A multicolor recording apparatus, comprising: pressure rollers disposed at respective sides of the rollers for pressing a toner image formed by development onto the adhesive surface layer.