JPS62168167A - Multicolor recording device - Google Patents

Abstract

PURPOSE:To reproduce an intermediate color in a short time by an inexpensive means by providing a developing means which is not in contact with a surface to be developed in a developing process for the 2nd and succeeding times. CONSTITUTION:An electrostatic recharging device 51 which uses the 2nd and the 3rd output controllable corona devices 7 and 10 for belt bodies is provided among plural developing devices 6, 9, and 12 which are arranged at the periphery of a photosensitive body 2 and use different color toner. The output of the recharging device 51 is controlled selectively to obtain monochromatic records that the respective developing devices 6, 9, and 12 have and records in intermediate colors obtained by combining their single colors selectively. Thus, records in colors more than the developing devices are obtained at low cost without using any optical means. Then a corona electrode 53 is connected to a high voltage power source 33 and brought under the switching control of a switching control part 54 so that this recharging device 51 has a selective charging function which holds a potential difference due to the 1st image exposure of the 1st LED array 5 as it is at an unexposed part where the potential is high and returns an exposed part where the potential low to the same potential with the unexposed part.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention (Field of Industrial Application) The present invention relates to a multicolor recording device capable of obtaining a multicolor recorded image using an electrophotographic method.

(Prior Art) Multicolor recording technology using electrophotography has a long history, and various methods have been proposed and disclosed. Among these technologies, laser oscillators and light emitting diodes (hereinafter referred to as L
(abbreviated as ED) using light emitting elements such as arrays,
Alternatively, there is one that uses an optical system that writes digitized optical information using a liquid crystal or an optical switching element that uses the Farade effect. The reason why these technologies are considered to be effective for multicolor recording is that, first, the light intensity of each color information is reduced by color separation of the original, which has traditionally been one of the major technical challenges in multicolor electrophotography. , there are no restrictions on process speed caused by a mismatch with the spectral sensitivity of the photoreceptor. Second, various S/
N improvement is possible. Thirdly, it is possible to perform many applied processes by linking with a computer, such as electrical image processing such as image information editing. In electrophotographic apparatuses that use these methods of writing digitized image information onto a photoreceptor, reversal development is generally performed to visualize the portion irradiated with the exposure beam light. This is because it is possible to reduce the load on the laser oscillator and LED serving as the light source, and to reduce the burden on the accuracy of the scanning optical system.

The basic method of multicolor electrophotography is to repeat the charging, image exposure, and development steps as many times as the number of colors to be used. The first method is to arrange each device for charging, image exposure, and development processes in the number of required colors, and the first method is to arrange only developing devices in the number of colors to be used, and the charging and image exposure devices are arranged in a photosensitive manner. It is broadly divided into the second method, which uses repeated rotation of the body. The first method is large in terms of equipment, but short in recording time, and is a highly promising method from a practical standpoint. Normally, when reproducing colors, various intermediate colors can be obtained by adjusting the mixing ratio of three primary colors (cyan, magenta, and yellow), but controlling these adjustments is relatively difficult. The reason for this is that when a second toner image is formed on the first toner image once formed on the photoreceptor, when exposure is performed to control the adhesion amount, the corona-charged toner image is damaged by the electrostatic charge on the photoreceptor. This is because the phenomenon of loss of binding force and scattering becomes noticeable. This causes smearing of character images, etc., making it unusable, and many devices generally avoid this by using the second method described above.

However, as described above, it is necessary to solve these problems in order to realize a practical multicolor recording device.

(Problems to be Solved by the Invention) The present invention has been made to solve various problems related to the reproduction of intermediate colors by conventional exposure control. An object of the present invention is to provide a multicolor recording device which can reproduce intermediate colors in a short time by an inexpensive means without using a multicolor recording device, and which does not cause color mixture.

[Structure of the Invention] (Means for Solving the Problems) The present invention is a multicolor recording device that records a multicolor image on an image carrier by repeating each step of charging, image exposure, and development multiple times. In the second and subsequent charging steps, there is a mode in which the potential pattern generated by the first image exposure on the image carrier is re-charged to a substantially uniform potential without performing full-surface exposure;
The device has a means for selectively controlling a mode in which recharging is not performed, and is provided with a developing means that is not in contact with the surface to be developed at least in the second and subsequent developing steps.

(Function) By controlling the recharging means, it is possible to selectively obtain a single color record on each developing means surface °q and an intermediate color record formed by mixing these single colors. Furthermore, since a non-contact developing means is used, multicolor recording without color mixing is possible. Therefore, it is possible to reproduce intermediate colors in a short time using inexpensive means without using the conventional method of producing 11 intermediate colors by controlling the exposure amount, and moreover, it is possible to perform multicolor recording without color mixture.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows a multicolor recording apparatus according to the present invention.

That is, 1 is a main body of the apparatus, and approximately in the center of the main body 1, a photoreceptor (image carrier) 2 in the form of a drum-like combination of selenium and tellurium, for example, is rotatably disposed. The photoreceptor 2 is rotated by a drive unit (not shown) at a predetermined timing based on a signal from an image power unit 3 provided on the left side of the main body 1 to which an external device is connected (at a peripheral speed of, for example, 160 [ars/s]). A first charging corona device 4 and a first charging corona device 4 are arranged around the photoreceptor 2.
LED array 5, first developing device 6, second charging corona device 7, second LED array 8, second developing device R9, third charging corona device 10. Third LED array 11, third developing device 12, pre-transfer corona device 13, transfer corona device 1
4, a peeling guide 15, a static elimination lamp 16, and a fur brush cleaning device 17 are arranged in this order along the rotation direction Z of the photoreceptor 2. Here, the first charging roller device 4 has a desired voltage (for example, approximately 6.5 [KV]).
After the photoreceptor 2 starts rotating, the surface of the photoreceptor 2 is uniformly charged to, for example, 1000 [V]. Second. Activation or inactivation of the third charging corona devices 7 and 10 is selected by either an instruction from an external device or a manual operation from the operation panel 18. The first to third LED arrays 5, 8, 11 have their light emitting points scan-controlled in accordance with image signals from an external device.
The surface of the photoreceptor 2 is imagewise exposed to record a desired signal as an electrostatic latent image. The first to third developing devices 6, 9.12 are
Each contains cyan toner, magenta toner, and yellow toner, and reversely develops the electrostatic latent image on the surface of the photoreceptor 2 (that is, the first to third LED arrays 5 and 8°11 (the exposed areas are developed).

In the lower right side of the figure of the main body 1, there are an insertion slot 20 for a cassette 19 for storing recording paper, a cassette holder 21, and an insertion slot 2.
A paper feed roller 22 feeds out the recording paper one by one by rolling contact with the recording paper in the cassette 19 inserted into the cassette holder 21 via the paper feed roller 22. A paper feed section 25 is provided, which includes a pair of registration rollers 23 and a guide plate 24, which feed paper to a transfer position between the photoconductor 2 and the transfer corona device 14 in synchronization with the rotation of the photoconductor 2. In addition, in the upper right side of the figure of the main body 1, there is a paper ejection port 26 for ejecting recording paper on which an image has been recorded to the outside of the main body 1, and a paper ejection port 26 that protrudes from the paper ejection port 26 to the outside of the main body 1. Paper output tray 27 that receives recording paper
, and a pair of paper ejection rollers 28 disposed inside the main body 1 of the paper ejection port 26. Further, a fixing device 30 is provided adjacent to the paper ejection roller 28 , and between the fixing device 30 and the peeling guide 15 , the recording paper to be peeled off from the photoreceptor 2 by the peeling guide 15 is attached to the fixing device 30 . A pair of rollers 31
A conveyor belt 32 is stretched between them.

In addition, 33 in the figure is the first to third charging corona device 4,
7.10 is a high-voltage power supply, and 34 is a printed circuit board in which a processing circuit for processing signals from the image input section 3 and the like are incorporated.

In such a configuration, when the photoreceptor 2 is rotated in the direction of arrow Z in the figure, the surface of the photoreceptor 2 is uniformly charged by the first charging corona device 4, and then imagewise exposed by the first LED array 5. An electrostatic latent image is formed on the surface of the photoreceptor 2. This electrostatic latent image is developed by the first developing device 6, and cyan toner is adhered thereto. After development by the first developing device 6, the photoreceptor 2 is recharged by the second charging corona device 7, or image-wise exposed by the second LED array 8 without being recharged, to form an electrostatic latent image. This electrostatic latent image is developed by the second developing device 9, and magenta toner is attached thereto. After development by the second development device 9,
The photoreceptor 2 may be further recharged by the third charging corona device 10, or may not be recharged and may be charged by the third LED array 11.
An electrostatic latent image is formed by imagewise exposure. This electrostatic latent image is developed by the third developing device 12 and yellow toner is applied thereto. After development by the third developing device 12, the photoreceptor 2 to which the cyan toner, magenta toner, and yellow toner are attached is returned to a uniform charge amount by the pre-transfer corona bag it 13.

On the other hand, in synchronization with the rotation of the photoreceptor 2, the paper feed section 2
5, the recording paper is supplied to the transfer position and brought into contact with the photoreceptor 2, and the toner images of the respective colors are transferred onto the recording paper by the transfer corona device 14. After the transfer, the recording paper is peeled off from the surface of the photoreceptor 2 by a peeling guide 15, and transported to a fixing device 30 by a transport belt 32, where the transferred toner image is fixed. After regular feeding, the recording paper is discharged onto the paper discharge tray 27 via the VR paper slot 26 by the paper discharge roller 28. On the other hand, the photoreceptor 2 from which the recording paper has been peeled is irradiated with light by the charge removal lamp 16 to remove the charge, and is then cleaned by the fur brush cleaning device 17 and prepared for the next recording.

Next, the first to third charging corona devices 4, 7, 10, the first to third LED arrays 5, 8, 11, and the first to third developing devices 6, 9, which are the main parts of the present invention.
．． 12 will be explained in more detail.

As described above, the photoreceptor 2 is first uniformly charged by the first charging corona device 4, then imagewise exposed by the first LED array 5 to form an electrostatic latent image, and this electrostatic latent image is further transferred to the first The developing device 6 performs reversal development and cyan toner is attached.

After this reversal development by the first developing device 6, the second charging corona device 7 is selectively activated or deactivated by either an instruction from an external device or a manual operation from the operation panel 18. FIG. 2(a) shows the first developing device 6.
When the second charging corona device U7 is activated, the photoreceptor 2 is again set to the desired potential (for example, the first charging corona device U7 is activated). It is charged to the original potential Vo) by the device 4.

That is, as shown in FIG. 2(b), the portion A that has undergone the first charging, image exposure, and development steps by the first charging corona device 4, the first LED array 5, and the first developing device 6.
4 (40 in the figure indicates cyan color 1.6-) is the potential vR,
The second charging corona device 7 returns the voltage to the original potential Vo. On the other hand, the portion B that did not receive the first image exposure (the portion where no electrostatic latent image was formed) hardly changes even when recharging by the second charging corona device 7, and maintains the original potential Vo. be done. Then, when imagewise exposed by the second LED array 8, the cyan toner 40 on the photoreceptor 2
The surface potential of the photoreceptor 2 is selectively attenuated (an electrostatic latent image is formed) in the portion B to which is not attached. Therefore, when the image is developed by the second developing device 9, magenta toner is attached to the portion where the electrostatic latent image is formed (the portion where the surface potential of the photoreceptor 2 is attenuated more than Vo).

On the other hand, when the second charging corona device 7 is inactive, the photoreceptor 2 is subjected to image exposure by the second LED array 8 while maintaining the surface potential state shown in FIG. 2(a). Therefore, in the photoreceptor 2, in addition to the portion A to which the cyan toner 40 is attached, the portion where the electrostatic latent image is formed by image exposure is in a potential state lower than Vo, and the second developing device 9 When developed, magenta toner is attached to the areas to which the cyan toner 40 is attached and to the areas where the electrostatic latent image is formed.

That is, in this embodiment, if recharging is not performed by the second charging corona device 7, the developed color on the photoreceptor 2 will be two colors, blue and magenta, which are a mixture of cyan and magenta. When recharging is performed, the developed colors on the photoreceptor 2 become two colors, cyan monochrome and magenta monochrome.

Furthermore, even when the ':j53 charging corona device 10 is activated or deactivated, the third LED array 1
Image exposure and development steps are performed by the first and third developing devices 12.

Therefore, in this embodiment, the second. 1. Activate or deactivate the third charging corona device 7.10. By controlling the control and also controlling the operation of the first to third developing devices 6°9.12, it is possible to combine seven colors obtained from three colors as shown in FIG. result,
Multicolor recording using any three colors from among these seven colors is possible. Note that the alphabet letters in the figure were used as symbols corresponding to the respective colors. Here, examples of recorded colors obtained by activating (on) or inactivating (off) the first to third charging corona devices 4, 7, and 10 are shown in the table below.

In addition to the table above, there are also the order of colors of each phenomenon device,
It goes without saying that a combination of activation (on) or deactivation (off) of the developing device itself is also possible, and various combinations of colors to be reproduced can be set. Further, the colors used are not limited to cyan, magenta, and yellow, and by selecting and using various colors in advance, a color reproduction range that more closely matches the purpose can be obtained.

The order of these processes can be controlled by using these processing circuits (built into the printed circuit board 34) to control instruction signals from the image input section 3 connected to the operation panel 18 or an external device (for example, a computer). The program is set, and the second and third charging corona devices 7, 10
The operation of the high-voltage power supply 33 connected to the controller is controlled, and the relationship between the content of these electrical controls and color reproduction is programmed in advance.

Next, the second. The charging device 51 used as the third charging corona device 7.10 will be described in detail with reference to FIG. As shown in FIGS. 2(a) and 2(b), this charging device 51 charges the potential difference generated by the first image exposure by the first LED array 5 to the non-exposed portion B where the potential is high (where an electrostatic latent image is formed). The exposed area A (where an electrostatic latent image is formed), which has a low potential, is held as it is (the unexposed area), and the exposed area A (where an electrostatic latent image is formed) is made conductive in order to have a selective charging function that returns it to the same potential as the unexposed area B. It consists of a cylindrical shield 52 and a corona electrode 53 provided within the cylindrical shield 52, and the corona electrode 53 is connected to the high voltage power source 33. Note that 54 in the figure is a switching control section that performs switching control of the high voltage power source 33.

The output of the high voltage power supply 33 is, for example, 400 to 1000
It is an AC voltage with a frequency of about Hz, and has a voltage waveform as shown in Figure 5, and also has an eccentric component represented by VDC in the figure, and can be adjusted independently with the voltage peak value VAC. It has become.

By using such a charging device 51 as the second charging corona device 7, the portion A of the photoreceptor 2 that has undergone the first charging, image exposure, and development steps, as shown in FIG. The potential vR returns to the original potential Vo, for example, as shown by the dashed line in FIG. Charging only such a specific area (portion A), so-called selective charging, is achieved by changing the output voltage of the high-voltage power supply 33.
This is possible by appropriately combining the values of c and VDC and adjusting them to a predetermined potential.

In addition, in this example, VAC is approximately 7 [KV], vDC
uses approximately 1 [KV], and VO is 1000 [V]
, VR is operating normally at 150[v].

Also, the second. As the third charging corona device 7.10,
In addition to the charging device 51 shown in FIG.
A charging device 55 as shown in the figure can also be used. This charging device 55 includes a conductive shield 56 and a conductive shield 56.
6 and two corona electrodes 57 provided in the shield 5
Conductive mesh grid 58 provided in the discharge opening of 6
It is a scorotron charging device consisting of. Then, a predetermined DC voltage is applied to the grid 58 from the DC power supply 59, a corona generation voltage is applied to the corona electrode 57 from the high voltage power supply 60, and the applied voltage value is adjusted in the same manner as in the above method. It is possible to perform selective charging.

Next, the first to third developing devices 6, 9, and 12 used in this embodiment will be explained. Generally known developing devices can be used as the first to third developing devices 6, 9, and 12, but when reproducing an unfixed toner image on the photoreceptor 2, a new one can be used. If there is exchange of toner, problems due to color mixing will occur in the recorded image or in the developing device, so a preferred method is one that does not cause this color mixing. Also, the first to third
The developing devices used as the developing devices 6, 9, and 12 have slightly different structures depending on their mounting positions, but the basic elements are the same.

FIG. 7 shows an example of a developing device used as the first to third developing devices 6, 9.12.

That is, 71 is a casing, and this casing 71 houses the photoreceptor 2.
An opening 72 is nailed in the part facing the.

A portion of the inside of the casing 71 is exposed through the opening 72 and is placed in a non-contact state with the photoreceptor 2 .
A centric cylindrical roll (developing roll) 73 that is closely opposed to each other while maintaining a development gap of 0 to 400 [μm'Il], and a fur brush 7 that is in rotational contact with this developing roll 73.
4.75 are arranged. Further, the other end of an elastic blade 76, one end of which is in contact with the developing roll 73, is supported on the inner wall near the opening 72 of the housing 71. The developing roll 73 and fur brushes 74 and 75 are rotationally driven by a motor (not shown), and a developing bias voltage is applied to the developing roll 73 from a bias power supply 77. Note that toner 78 is accommodated within the housing 71.

In such a configuration, when the developing roll 73 and the fur brushes 74.75 are rotated, the toner 78 is rubbed by the fur brushes 74.75, becomes triboelectrically charged, and is attracted to the surface of the developing roll 73. Forms a thin layer of toner. The formed toner thin layer is regulated to an appropriate thickness by an elastic blade 76 and conveyed to the development gap. The thin toner layer that has reached the development gap is ejected onto the surface of the photoreceptor 2 from the portion where the ejection initiation electric field has been reached. That is, development is performed by an electric field formed by the electrostatic latent image potential of the photoreceptor 2 and the development bias power source. As described above, this developing device has no mechanical contact with the photoreceptor 2, so it is possible to transfer mixed colors and recorded images to the next developing process (second stage).
(Developing process using the developing device 9 or the third developing device 12)
It is suitable for multicolor development without causing any disturbance.

As explained above, according to the above embodiment, a recharging device whose output can be controlled is provided between the stages of developing devices using different color toners disposed around the photoconductor, and the recharging devices of these recharging devices are provided. By selectively controlling the output, it is possible to selectively obtain a single color record of each developing device and a different intermediate color record by combining the monochrome colors of each developing device in a short time. Therefore, it is possible to record more color reproductions than the number of developing devices without using optical means, and it is also possible to obtain a product with excellent functionality at a low price and without changing the structure. Furthermore, since a non-contact developing device is used as the developing device, clear multicolor recording without color mixing is possible.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and the reproducibility can be changed depending on, for example, the number and color of developing devices, and whether or not image exposure is performed at each station.

Further, in the embodiment described above, a multicolor recorded image can be obtained by one rotation of the photoreceptor, but the present invention is not limited to this. May be transcribed. Further, the recharging device is activated (on) -
It goes without saying that the output value may be strengthened or weakened within a range that does not cause any problems, instead of taking only the two values of inactivation (off).

[Effects of the Invention] As detailed above, according to the present invention, intermediate colors can be reproduced in a short time by inexpensive means without using the conventional method of reproducing intermediate colors by controlling the exposure amount, and moreover, it is possible to reproduce intermediate colors in a short time by controlling the exposure amount. It is possible to provide a multi-color recording device that does not require

[Brief explanation of drawings]

The drawings show one embodiment of the present invention. Fig. 1 is a vertical diagram of a multicolor recording device, Fig. 2 is a diagram explaining the action of the recharging means, and Fig. 3 is a combination of colors. A diagram explaining
Fig. 4 is a block diagram of the recharging means, Fig. 5 is an output voltage waveform diagram of the recharging means in Fig. 4, Fig. 6 is another block diagram of the recharging means, and Fig. 7 is a block diagram of the developing means. It is. 2... Photoreceptor (image carrier), 4... First charging corona device (charging means), 5, 8.11... First to third LED array (image exposure means), 7.10...
Second and third charging corona devices (recharging means), 6.9.
1st section: first to third developing devices (developing means). Applicant's representative Patent attorney Takehiko Suzue d Figure 2 (a) Figure 2 (1) Figure 4 Figure 5 Figure 6 Figure 7

Claims (1)

[Claims] (1) A multicolor recording device that records a multicolor image on an image carrier by repeating each step of charging, image exposure, and development multiple times; In an apparatus having a means for selectively controlling a mode in which the potential pattern generated by the second imagewise exposure is recharged to a substantially uniform potential without performing full-surface exposure, and a mode in which recharging is not performed; at least from the second time onwards; 1. A multicolor recording device comprising a developing means that does not come into contact with a surface to be developed in the developing step.