JPH071405B2 - Multicolor recorder - Google Patents

Description

The present invention relates to a multicolor recording apparatus using an electrophotographic recording system,
In particular, the present invention relates to a device structure capable of high-speed vivid multicolor recording without color mixture for a long period of time.

In recent years, with the diversification of information, the color of recorded information such as characters, symbols, and images has been changed as necessary, and color recording in which characters, symbols, images, etc. of different colors have been mixed is performed on the same recording paper. Is required, and various apparatuses or systems for multicolor recording have been proposed.

In electrophotographic recording, a photosensitive drum, which is generally an image carrier, is uniformly charged with electric charges, and an exposure corresponding to an information image to be recorded is performed on the photosensitive drum to form an electrostatic latent image, and then the electrostatic latent image is formed. The latent image is developed by a developing device to form a visible image with toner, and the visible image is transferred to a recording sheet for recording.

Therefore, a plurality of image forming units each including a latent image forming unit and a developing device are provided around the photosensitive drum, and each image forming unit forms a visible image with toner of different colors on the surface of the photosensitive drum. By transferring the visible image to a recording sheet,
Multicolor recording can be obtained.

In such an apparatus for performing multicolor recording with toners of different colors, the rabbit angle and the toner in the developer used in the previous development step are mixed in the developer in the next development step, and the mixed toner However, there is a problem that color mixing easily occurs in the visible toner image when the amount of accumulated toner is increased, and it is desired to eliminate such inconvenience.

[Conventional technology]

As a conventional apparatus for performing multicolor recording at high speed by the electrophotographic recording system, a multicolor recording apparatus or system for performing multicolor recording while the photosensitive drum makes one revolution has already been disclosed by the present applicant. 106743, JP-A-58-116553.

In order to simplify the explanation, the conventional multi-color recording apparatus based on the electrophotographic recording method is described with reference to the schematic diagram of the two-color recording apparatus in FIG. As shown in the level diagram, first, the entire surface of the photosensitive drum 1 composed of a photosensitive layer such as selenium (Se) is uniformly charged to the initial charging potential level Vs by the initial charger 2 as shown in FIG. I do.

Next, negative exposure corresponding to the first color information is performed on the surface of the photosensitive drum 1 by the first exposure unit 3 to attenuate the charging potential of the exposed portion to about 0v as shown in FIG. First
A latent image 21 is formed. Thereafter, the first latent image 21 is subjected to magnetic brush reversal development by the first developing device 4 using a two-component magnetic developer in which the toner of the first color and the carrier are mixed, and as shown in FIG. A first toner visible image 22 is formed.

Next, the potential of the 22th portion of the first toner visible image is recharged by the recharger 5.
Vt is the background potential Vs on the photosensitive drum 1 as shown in FIG.
Is recharged so that the potential becomes substantially the same as This process is for preventing the toner in the next development from adhering to the already formed first toner visible image 22.

Next, a negative exposure corresponding to the second color information is performed on the surface of the recharged photosensitive drum 1 by the second exposure unit 6, and the ninth exposure is performed.
As shown in the figure, a second latent image 23 is formed in which the charging potential of the exposed portion is attenuated to approximately 0v. Thereafter, the second latent image 23 is subjected to magnetic brush reversal development by the second developing device 7 using a two-component magnetic developer in which the toner of the second color and the carrier are mixed, and as shown in FIG. A two-toner visible image 24 is formed.

In this way, the first and second parts formed on the surface of the photosensitive drum 1
The visible toner images 22 and 24 are collectively transferred onto the recording paper 13 by the transfer device 8 and further fixed by the fixing unit 9 to record the information of two colors.

On the other hand, the toner remaining on the surface of the photosensitive drum 1 is neutralized by the AC static eliminator 10 and removed by cleaning by the cleaner 11, and all the charges on the surface of the photosensitive drum 1 are removed by the optical static eliminator.
The static electricity is erased by 12 and the next recording cycle starts.

In the above-mentioned recording apparatus, in order to prevent the first toner visible image 22 formed in the first developing step from being destroyed in the next second developing step, the second developing device 7 sets Toner of the second color is applied by applying a two-component magnetic developer using a microcarrier having a particle size of the carrier mixed with the toner of 5 to 100 μm, or by applying an AC bias voltage to the developing device 7. A soft-touch developing method such as non-contact developing, in which the toner is made to fly from the developer and is developed, is used.

Further, in order to prevent the color mixture of the second toner visible image 24 caused by the toner of the first color mixed and accumulated in the second developing device 7, the mixed toner of the first color is The method of separating from the two developers has already been proposed by the present applicant by Japanese Patent Application Laid-Open No. 58-105173.

That is, the above separating method is performed by the triboelectrification series of the first and second color toners 31 and 32 in the first developer and the second developer and the first carrier 33 and the second carrier 34 mixed with the toners 31 and 32, respectively. By selecting as shown in FIG.

The first and second color toners 31 and 32 are positively charged by frictional charging with the first carrier 33 and the second carrier 34, respectively. Further, when the toner 31 of the first color is mixed in the second developing device 7, the polarity is reversed to the negative polarity or becomes almost 0 due to the frictional charging with the second developer.

Further, the negative polarity first color toner 31 is electrostatically coupled to the positive polarity second color toner 32, and the apparent charge amount is substantially zero.
As a result, the binding force with the second carrier 34 is weakened, and the toners 31 and 32 of the first and second colors remain electrostatically coupled, or the first charge having a charge amount of about 0 is Color toner 31
Is scattered and separated from the developing roller in the second developing device 7 by centrifugal force, and the mixed toner 31 of the first color is not accumulated in the second developing device 7. Therefore, the above recording operation is repeated for a long time. Even if there is no color mixture, it is possible to stably record good two-color information.

As a structure for recording more color information in accordance with such a two-color recording structure, for example, as shown in FIG. 12, an initial charger 42, a first exposure section 43, and a developing unit are provided around a photosensitive drum 41. Unit 44, recharging unit 45, second exposing unit 46 and developing unit 47, recharging unit 48, third exposing unit 49 and developing unit 50, and further transfer unit.
54, a fixing device 55, an AC static eliminator 56, a cleaner 57, an optical static eliminator 58 are arranged in order, and the color of the toner of the developer used in each of the developing devices 44, 47 and 50 is changed to cyan, magenta and yellow. By performing the recording operation according to the two-color recording process, it is possible to realize good multicolor recording without color mixture.

[Problems to be solved by the invention]

By the way, in the above-mentioned multi-color recording apparatus, black character information is often recorded.
Recording is performed by mixing visible toner images of different colors.

However, even if the three color toners are mixed, the color does not become completely black. Therefore, a recharger 51, a fourth exposure section 52, and black toner are further included in the subsequent stage of the third developing section 50 in the recording apparatus. It has been attempted to arrange the developing section 53 using a developer.

However, if the image forming function for recording the black character information is added in this way, not only the complicated apparatus configuration becomes more complicated, but also the developing devices 50, 5 after the second developing unit 47 are further complicated.
The toners 61, 62, 63 and 64 of the so-called first to fourth colors in the so-called first to fourth developers for separating and removing the different color toner mixed in 2 to prevent color mixture, and mixing them respectively It is necessary to select the 1st to 4th carriers 65, 66, 67 and 68 to have the triboelectrification series shown in FIG. 13, and it is extremely difficult to procure or manufacture such toners and carriers. It was very difficult.

[Means for solving problems]

The above problems have at least two image carriers, one of which has a plurality of developing units, and the toner and the carrier used in the plurality of developing units are arranged so that triboelectrification series are alternately arranged. The toner of different colors, the plurality of developing units form images of a plurality of colors on the image carrier, and then collectively transfer the image. The other image carrier has a plurality of developing units. Then
The toner and the carrier used in the plurality of developing units are selected so that the triboelectrification series are alternately arranged, and the colors of the respective toners are made different, so that the plurality of developing units form the plurality of color toners on the image carrier. A multi-color recording apparatus for forming an image and then transferring the image so that it overlaps with the image transferred by the one image carrier, and as shown in FIG. 2, the arrangement of the triboelectric series is independently provided for each image carrier. It is solved by setting.

[Action]

That is, by providing a plurality of image carriers, the developing units of respective colors using the developer containing the toners of plural colors of cyan, magenta, yellow, and black are divided and arranged, and one image carrier When forming images of multiple colors on top and transferring them all at once, by providing the toner and the carrier of the developer that forms an image on the image carrier of multiple colors with a triboelectric charging series, one line of triboelectric charging series can be obtained. The number of toners and carriers that need to be arranged can be reduced, color mixing can be prevented even in a multicolor recording apparatus, and good printing can be stably performed.

〔Example〕

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

FIG. 1 is a schematic configuration diagram showing an embodiment of a multicolor recording apparatus according to the present invention.

The apparatus configuration of the present invention is a configuration in which two conventional two-color recording apparatus configurations shown in FIG. 4 are arranged side by side.

That is, 71 and 72 are image carriers, and selenium (Se) or S
It is composed of first and second photosensitive drums composed of a photosensitive layer such as eTe. The recording sheets 94 are arranged in parallel in the running direction.

An initial charger 73 is provided around the first photosensitive drum 71.
A first exposure unit 74 and a developing unit 75, a recharger 76, a second exposure unit 77 and a developing unit 78, a transfer unit 79, an AC static eliminator 80,
A cleaner 81 and an optical static eliminator 82 are arranged in this order, and also around the second photosensitive drum 72, an initial charger 83, a third exposure unit 84 and a developing unit 85, a recharger 86, a fourth charger. Exposure section 87 and developing section 88, and further transfer section 89, AC static eliminator 90, cleaner 91,
The optical static eliminator 92 is arranged in this order.

Further, each of the developers used in the first developing section 75 to the fourth developing section 88 contains, for example, toner in the order of yellow, magenta, cyan and black, and further, the carrier of each developer and the toner. Are two developing units disposed on the photosensitive drums 71 and 72, that is, a first developing unit 75 and a second developing unit 78.
And toners 101, 102 of the first and second colors and first and second carriers 103, 104 used in the third developing section 85 and the fourth developing section 88.
And the toners 105 and 106 of the third and fourth colors and the third and fourth carriers 107 and 108 are selected so as to have independent triboelectric charging series for each photosensitive drum as shown in FIG. The toners of the first and third colors mixed in the fourth developing section 78, 88 are separated and removed by polarity reversal or by attenuating the charge amount depending on the difference in order in the triboelectric charging series.

Therefore, in order to perform multicolor recording with the configuration of the recording apparatus, first, on the first photosensitive drum 71, the first exposure unit 74 and the developing unit 75 are used in accordance with the two-color recording method described in the conventional example. A first toner visible image (yellow) corresponding to the first color information and a second toner visible image (magenta) corresponding to the second color information are formed by the second exposure unit 77 and the developing unit 78. , The visible images are collectively transferred onto the recording paper 94 at the transfer section 79.

On the other hand, on the second photosensitive drum 72, the first photosensitive drum 71
The third toner visible image (cyan) corresponding to the third color information by the third exposure unit 84 and the developing unit 85, and the fourth exposure unit 87 and the developing unit 88 are operated at different timings from the side. A fourth toner visible image (black) corresponding to the fourth color information is formed, and the first toner visible image (yellow) and the second toner visible image (magenta) are transferred to these visible images. The recording sheet 94 is collectively transferred onto the recording sheet 94 at the transfer section 89.

After that, the multicolor toner image transferred onto the recording paper 94 is heat-fixed in the fixing unit 93, for example, whereby permanent multicolor recording without color mixture is obtained.

The second development and the fourth development during the recording process in this apparatus
In developing, in order to prevent the visible images of the first and third toners already formed on the first and second photosensitive drums 71 and 72 from being destroyed, the particle diameters of the second and fourth carriers 103 and 108 are set to 5 to 100 μm. And a soft touch developing method such as non-contact developing in which an AC bias voltage is applied to each developing portion to cause the toner to fly out of the developer and develop.

FIG. 3 shows an example of the second developing device and the fourth developing device for performing the second developing and the fourth developing.

The developing roller 111 includes a magnetic roller 112 and a non-magnetic cylindrical sleeve 113, and the developer 116 is conveyed to the photosensitive drum 71 (72) side by using the rotation of the magnetic roller 111 or the rotation of the sleeve 113 in combination. There is.

When the first and third toners are mixed, the polarities of the first and third toners are reversed and become negative due to frictional charging with the second and fourth toners while stirring in the second and fourth developing devices. . If the developer is further agitated in this state, the first and third toners whose polarities are reversed and the second and fourth toners having the positive polarity are electrostatically bound to each other. As described above, in the case where the first and third toners and the second and fourth toners are electrostatically bound to each other, the electrostatic force between the second and fourth carriers is weakened, and the second and fourth toners remain in the coupled state. 4 It becomes easier to leave the carrier. The toner in which the first and third toners and the second and fourth toners are electrostatically bound to each other, which is easily separated from the second and fourth carriers, is separated by the centrifugal force generated by the conveying force of the developing roller 111, By attaching an air suction / collection tool or the like for collecting these toners when separated, it becomes possible to efficiently collect the separated color toners.

〔The invention's effect〕

As is clear from the above description, according to the multi-color recording apparatus of the present invention, the main photosensitive drums have a plurality of continuous structures, and a plurality of developing units are separately arranged on each photosensitive drum. It is possible to reduce the number of developing units arranged on the photosensitive drum together with the toner, and thus reduce the number of toners and carriers that need to be arranged in a series of triboelectrification series. It is easy to procure or manufacture and has an excellent effect in practice.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a multicolor recording apparatus according to the present invention, and FIG. 2 shows an embodiment of a triboelectrification series of toner and carrier used in each developing section of the recording apparatus of the present invention. FIG. 3 is a longitudinal sectional view of an essential part showing an embodiment of a developing unit of a recording apparatus of the present invention, and FIG. 4 is a two-color recording apparatus applied to simplify the explanation of a conventional multicolor recording apparatus. 5 to 10 are diagrams showing the potential level on the photosensitive drum in each process for performing two-color recording, and FIG. 11 is a diagram showing toner and carrier used in each developing section for performing two-color recording. FIG. 12 is a diagram showing a triboelectrification series, FIG. 12 is a schematic configuration diagram showing an example of a conventional multicolor recording apparatus, and FIG. 13 is a triboelectrification of toner and carrier used in each developing section in the multicolor recording apparatus of FIG. It is a figure which shows a series. In the figure, 71 and 72 are first and second photosensitive drums, 73 and 83 are initial chargers, 74, 77, 84 and 87 are first to fourth exposure units, and 75, 78, 85 and 88 are first to first exposure units. 4th developing section, 76 and 86 recharger, 79 and 89 transfer section, 8
0,90 is AC static eliminator, 81,91 is cleaner, 82,92 is optical static eliminator,
93 is a fixing unit, 94 is a recording sheet, and 101, 102, 105 and 106 are first to first
Toner of the fourth color, 103, 104, 107, 108 are first to fourth carriers, 111 is a developing roller, 112 is a magnetic roller, 113 is a sleeve, and 114 and 115 are openings.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuhiko Sato 1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture, Fujitsu Limited (72) Inventor Junzo, Nakajima 1015, Kamikodanaka, Nakahara-ku, Kanagawa Prefecture, Fujitsu Limited ( 56) References JP-A-59-30561 (JP, A) JP-A-49-91233 (JP, A)

Claims (1)

[Claims] 1. At least two image carriers, one of which has a plurality of developing units, and toners and carriers used in the plurality of developing units are arranged such that triboelectrification series are alternately arranged. , And make the color of each toner different,
An image of a plurality of colors is formed on the image carrier by the plurality of developing units, and then transferred in a batch. The other image carrier has a plurality of developing units, and the toner and carrier used in the plurality of developing units are Select so that the triboelectrification series are arranged alternately, and make the color of each toner different,
A multicolor recording apparatus for forming images of a plurality of colors on the image carrier by the plurality of developing units, and then transferring the images so as to overlap the image transferred by the one image carrier, wherein the triboelectric series is arranged. Is set independently for each image carrier.