JPH02120762A - Multicolor image forming device - Google Patents

Abstract

PURPOSE:To form a multicolor image by arranging plural units including an electrostatic charger, an electrostatic latent image forming means, a fixation means and a full surface irradiating means on the circumferential surface of a transfer paper carrying drum, providing a transfer means inside the drum and providing a reference position control means for a transfer paper and a developed image. CONSTITUTION:In an image forming unit 20, a photosensitive material 24 and an image carrier 21 are electrostatically charged by the electrostatic charger 25, a latent image is written on the material 24 by an optical system 26 and developed by a developing device 27. The developed image is fixed by a flash fixation device 28 and irradiated by a full surface irradiating lamp 29 to form the image. Then, a residual toner cleaner 17 performs cleaning. The transfer paper is supplied to the carrying drum 10 from a paper supply part 40 by an electrostatic tack corotron 44 and the image is transferred by a transfer corotron 22 to the transfer paper, which is separated by a separation corotron 45 and fed to a fixation part 48. The unfixed toner image is fixed on the transfer paper 15 by a heating roll 48 and a pressurizing roll 49 and the paper is ejected to a tray. With such a constitution, copying in full color, printing and multiple transfer are rapidly performed en bloc.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a multicolor image forming apparatus, and more specifically, for example, a multicolor image forming apparatus that can perform high-speed full color printing using an electrostatic printing plate on which a printed image is fixed. The present invention relates to a multicolor image forming apparatus that can selectively perform normal copying, printing, and printing in full color.

[Prior Art] Conventionally, an electrostatic printing plate is formed by fixing a visible image formed by toner on the photosensitive layer of an image-bearing sheet member having a photoconductive photosensitive layer, and this printing plate is charged to perform printing as required. A printer that exposes the entire surface of the 11th printing plate to light to form an electrostatic image, develops this electrostatic image with toner, and transfers this toner image from the printing plate to a transfer member to repeatedly obtain printed matter. It has been known.

A conventional printer of this type includes, for example, as shown in FIG. A charger d for pre-charging the surface of a flexible electrostatic image bearing sheet member; and an electrostatic latent image forming means e for forming a latent image according to image information on the charged electrostatic image bearing sheet member. , a developing means f (developing and cleaning device) for converting the latent image formed on the electrostatic image bearing sheet member into a visible image, and a transfer means for transferring the visible image on the electrostatic image bearing sheet member onto transfer paper. q, a fixing means for fixing the visible image on the electrostatic image bearing sheet member as necessary, and an entire surface irradiation means i for re-exposing the fixed image fixed by the fixing means. Ru. In FIG. 10, reference numeral j represents a transfer paper peeling means, k represents a paper feeding section, and ri represents a conveyance belt.

To obtain a single copy from a different type of original using a conventional printer configured as described above, the operation button is set to copy mode, and the image-bearing sheet member charged by m N B d is electrostatically charged. After a latent image of the document is formed by the latent image forming means e, the developing means develops the toner image, and this toner image is transferred to transfer paper fed from the paper feeding section, and then the fixing device (not shown) to obtain a copy.

In addition, in order to obtain a large number of copies, that is, printed matter, from the persimmon original, the operation button is set to print mode, and the electrostatic latent image forming means e
writes a latent image of the original on the image-bearing sheet member, and develops this with a developing means f to form a visible toner image;
This visible image is fixed by a fixing means on an electrostatic printing plate (
master), and then this master is recharged by the charger 16, exposed to light by the entire surface irradiation means i to form an electrostatic image, and after this electrostatic image is developed with toner by the developing means f,
A copy is obtained by transferring this visible image onto a transfer paper by a transfer means Q and fixing it by a fixing device.
By repeating the above steps, that is, the master charging step, the entire surface exposure step, the toner development step, the transfer process, and the fixing step, a large number of copies can be continuously obtained.

After copying a large number of sheets, the take-up roll m in the image carrier C is rotated to take up the image-bearing sheet member, which is an electrostatic printing plate, and a new image-bearing sheet is placed on the circumferential surface of the cylindrical drum 8. Part 1 is stretched and prepared for the next process.

[Problem to be solved by the invention] This type of conventional li! ji image forming device is white/black 11! It was aimed at "color" peas, and only produced flat color copies without replacing the developing means. Therefore, it has been impossible to make Victorian (full color) color copies in print mode.

This invention was made in view of the above circumstances, and its purpose is to provide a multi-color copying system that can selectively set normal copy mode and print mode, and quickly obtain not only single-color copies but also Victorian full-color copies. The present invention aims to provide an image forming apparatus.

[Means for Solving the Problems] In order to achieve the above object, the multicolor image forming apparatus of the present invention has a flexible electrostatic image bearing sheet member stretched around the circumferential surface of a cylindrical drum so as to be windable. At least a charger, an electrostatic latent image forming means, a developing means, and optionally a fixing means for fixing a visible image formed on the electrostatic image carrying sheet on the circumferential surface of an image bearing member formed by A plurality of image forming units each having an entire surface irradiation means for recharging the fixed image fixed by the above are arranged at appropriate intervals on the circumferential surface of the flexible transfer paper carrying drum. A transfer means is disposed inwardly facing each image carrier, and is formed on the leading edge of the transfer paper carried by the transfer paper carrying drum and the image carrier at the transfer position of each of the image carriers. It is equipped with a control means for matching the front end reference position of the microscope image.

In this invention, the flexible electrostatic image bearing sheet 1 to member are stretched around the circumferential surface of the cylindrical drum so that they can be wound up by an appropriate winding means, and after being charged by a charger, the flexible electrostatic image bearing sheet 1 to the member are Any photosensitive material may be used as long as a latent image corresponding to predetermined image information is written by the electrolatent image forming means.
Depending on the type of electrostatic latent image forming means, for example, zinc oxide (Zo
O) Optical semiconductors or dielectric materials such as organic photoreceptors using sensitized zinc oxide, phthalocyanine pigments, or square lylium pigments can be used.

Further, the electrostatic latent image forming means may be of any type as long as it forms a latent image of predetermined image information onto the electrostatic image bearing sheet member, and for example, it may receive a signal from a predetermined document reading means. A gas laser, laser diode, or light emitting diode (LE) is used to write the signal onto the electrostatic image bearing sheet member.
In addition to the optical system such as D), when an M1-shaped material is used as a sensitive material, a writing means using ions can be used. Furthermore, as means for inputting signals to the electrostatic latent image forming means, in addition to the above-mentioned document reading means, for example, a magnetic tape into which predetermined image information is inputted in advance, a computer image output unit, etc. may be used. can. Note that when an optical system is used as the electrostatic latent image forming means, since the gas laser and the laser diode have different emission wavelengths, it is necessary to use a sensitive material that can correspond to the emission wavelengths.

Further, two or more of the above-mentioned developing means are disposed. For example, when the multicolor image forming apparatus of the present invention is used as a full-color printer, four color developers of yellow magenta, cyan, and black are used. It is preferable.

Furthermore, the control means includes control for aligning the leading edge of the transfer paper carried by the transfer paper carrying drum at the transfer position of each of the image carriers with the leading edge reference position of the visible image formed on the image carrier. Any means is fine,
For example, the leading edge position of the transfer paper held by the transfer paper carrying drum and the leading edge reference position of the visible image formed on the image carrier are detected, and the position is determined based on the time it takes for the leading edge position of the transfer paper to reach the transfer unit. By controlling the angular velocity of the image carrier, the leading edge position of the transfer paper and the leading edge reference position of the visible image can be matched. In this case, in order to align the transfer positions, it is necessary to synchronize the image carriers so that their angular velocities match.

Note that it is necessary to set the control reference position of each control means in consideration of the arrangement position of each image forming unit, but if the image forming units are arranged at equal intervals, the phase of the control reference position of each control means will be the same. This is preferable because it can be set to .

In addition, the transfer paper carrying drum has flexibility, and
Any device may be used as long as it has the function of conveying the transfer paper. For example, an insulating mesh or an insulating synthetic resin film is pasted on the opening provided on the circumference of the cylindrical base, and the cylindrical base is It can be formed by having a gripper that can be opened and closed on the circumferential surface of the base.

Function] In the multicolor image forming apparatus according to the present invention, when obtaining a single copy from a different type of original, etc., by setting the normal copy mode, the electrostatic image bearing sheet member charged W1 by the charger can be set to the normal copy mode. Predetermined image information is written on the electrostatic latent image forming means to form a latent image, a visible image is formed with toner from the developing means, this visible image is transferred onto the transfer paper by the transfer means, and the transfer The unfixed visible image on the transferred paper is fixed by a fixing unit. In addition, when making multiple copies from the same type of original, the surface of the flexible electrostatic image-bearing sheet member is charged in advance by a charger as in the normal copy mode, and then a latent image based on predetermined image information is formed. An electrostatic latent image is written on the electrostatic image bearing sheet 1 to member from the electrostatic latent image forming means. Next, the electrostatic latent image is sequentially developed with toner by a developing means to form a visible image, and these visible images are sequentially fixed by a fixing means for fixing the original plate to form a printing original plate. Then, after each printing master plate is recharged,
Developed with toners of different colors to form different colored developed images on the original printing plate, and each developed image is sequentially transferred onto a sheet of transfer paper while being aligned by rotation of the transfer drum of the transfer means. The unfixed images on the transfer paper are fixed all at once by a fixing unit.

[Examples] Examples of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a schematic sectional view of an example of a multicolor image forming apparatus according to the present invention.

The multicolor image forming apparatus of the present invention includes a plurality of image forming units 20 (four units are not shown in the drawing) arranged at equal intervals on the circumferential surface of a flexible transfer paper carrying drum 10, and a plurality of image forming units 20 that carry a transfer paper. A transfer corotron 22, which is a transfer means, is disposed facing the image carrier 21 of each image forming unit 20 inside the drum 10, and a transfer paper carried by the transfer paper carrier drum 10 at the transfer position of each image carrier 21. It is equipped with a control means (not shown) for aligning the leading edge of the paper 15 with the leading edge reference position of the visualized image formed on the image carrier 21.

As shown in FIG.
4 (hereinafter referred to as a sensitive material) is stretched such that it can be wound up, and a charger 25 that charges the surface of the sensitive material 24 in advance.
, an optical system 26 which is an electrostatic latent image forming means for writing a predetermined number of latent images according to image information on the charged photosensitive material 24; A developing device 27 is a developing device for fixing the developed image on the photosensitive material 24 as needed, a flash fixing device 28 is a fixing device for fixing the developed image on the photosensitive material 24, and the printing original plate fixed by the flash fixing device 28 is re-charged. After that, the entire surface is irradiated by a lamp 29 for irradiating the entire surface. In this case, the image carrier 21 has a slit portion 30 formed in a part of the outer periphery of a cylindrical drum 23 made of, for example, aluminum, and a take-up reel 31 and a photosensitive material 24 are wound inside the cylindrical drum 23. The photosensitive material 24 pulled out from the reel 32 is wrapped around the outer peripheral surface of the cylindrical drum 23 via guide rolls 33 and 33, and can be wound onto the take-up reel 31 side. A scroll drive mechanism is provided. In this case, a clutch mechanism (not shown) is interposed between the reel 32 and the winding portion 31, so that a constant tension is constantly applied to the sensitive material 24, and the material is stretched around the outer peripheral surface of the cylindrical drum 23. There is. Note that the circumferential length of the image carrier 21 is desirably at least the length in the longitudinal direction of the maximum size (for example, A3) of the transfer paper 15 used.

The material layer of the sensitive material 24 differs depending on the correlation with the emission wavelength of the optical system 26, but in the embodiment, the optical system 26 uses a polygon mirror 26a to emit the oscillated light of the He-Ne gas laser (wavelength: 632. 8 nm), sensitized zinc oxide (ZnO) is used. The sensitive material 24 using this sensitized zinc oxide is, as shown in FIG. It has a four-layer structure including an under layer 36 made of PVA), casein, etc., and a photoconductive surface layer 37 made of sensitized zinc oxide particles bound with a binder.
Its thickness is approximately 100-odd μm. In addition, the photoconductive surface layer 3
The structure of the sensitized zinc oxide particles constituting 7 is as shown in FIG. An n-type basic dye 38C (for example, methylene blue, crystal violet, brilliant green, malachite green, etc.) for He-Ne lasers is added to the surface of a general zinc oxide sensitive material on which type acidic dye 38b is adsorbed.
is adsorbed to form an npn type sensitive material structure. According to the sensitive material using sensitized zinc oxide configured in this way,
As shown in Figure 6, compared to general zinc oxide sensitive materials,
It is significantly sensitized to the e-Ne laser firing wavelength of 632.8 nm.

Note that the developing device 27 of each image forming unit 20 is as follows:
For example, it is formed by four developing devices containing four color developers of yellow, magenta, cyan, and black.
Each developing device 27 includes a developer supplying roll 27a, a developer stirring paddle 27b, and a pair of upper and lower developing rolls 27.
c, 27d are arranged. Here, the developing roll 27
The reason why the upper and lower portions c and 27d are arranged as a pair is to enable efficient toner supply in response to the high-speed rotation of the image carrier 21.

On the other hand, as shown in FIG. 7, the transfer paper carrying drum 10 has an insulating mesh 13 stretched over an opening 12 formed on the circumferential surface of the cylindrical base 11, and a Gripper 1 that partially grips the leading end of transfer paper 15
4 is attached so that it can be opened and closed by a cam mechanism (not shown). The cylindrical base 11 is rotatably supported on a fixed shaft 16 fixed to a frame (not shown) on the apparatus main body side.

Note that the charger 2 disposed on the circumferential surface of the image carrier 21
A cleaning unit 17 for cleaning toner remaining on the photosensitive material 24 is disposed on the front side of the photosensitive material 24 .

On the other hand, a feed roll 41 is disposed in the paper feed section 40 that supplies the transfer paper 15 to the transfer paper carrying drum 10 side. After being put on standby, it is supplied to the transfer paper carrying drum 10 side via the guide chute 43, and is conveyed over the transfer paper carrying drum 10 by electrostatic attraction by the electrostatic tack roller 1-ron 44. Further, after the transfer paper 15 conveyed by the transfer paper carrying drum 10 is transferred by the transfer corotron 22,
The paper is separated from the transfer paper carrying drum 10 by the separation corotron 45 and transferred to the fixing unit 41 via the discharge chute 4G.
The unfixed developed image, that is, the unfixed toner image, on the transfer paper 15 is fixed by the heating roll 48 and the pressure roller 49, and then the paper is discharged onto the paper discharge tray 50. It has become.

Note that the position of the leading edge of the transfer paper 15 conveyed by the transfer paper carrying drum 10 and the reference position of the leading edge of the developed image formed on the photosensitive material 24 on the image carrier 21 are aligned FO! Control for this can be performed by adjusting the angular velocity of the drive motors 51 of both image carriers 21.

η, as shown in FIG. 3, from the image carrier sensor 52 that detects the angle θ2 between the front end reference position A of the visible image formed on the photosensitive material 24 of the image carrier 21 and the transfer position T. The signal from the transfer paper carrying drum sensor 53 that detects the angle θ1 between the leading edge position of the transfer paper 15 conveyed by the transfer paper carrying drum 10 and the transfer position is input to the control unit 54, and the transfer By inputting the rotation signal of the paper carrying drum motor 55 to the control section 54, the control section 54
The angular velocity of the image carrier drive motor 51 is controlled based on the time taken by the rotation of the transfer paper carrying drum 10 to reach the transfer position of the transfer paper leading edge position. The front end reference position A of the microscope image is made to match at the transfer portion tlT.

Next, the mode of operation of this invention will be explained.

■ Copy mode To obtain full-color prints through normal copying, first set the operation mode of the device (not shown) to "copy mode", and the original will be printed in four colors: yellow magenta, cyan, and black (for blackboards). The decomposed signals are input to the optical system 26 of each image forming unit 20 as modulation signals. At this time, the charger 2 is placed on the photosensitive material 24 on the cylindrical drum 23.
5, it is uniformly negatively charged to about -6oO to -800V. Next, based on the decomposed No. 1g, the multi-optical system 2
6, an electrostatic latent image is formed on the photosensitive material 240, and the developer 21 for each color forms a visible image corresponding to yellow, magenta, cyan, and black. 15 is conveyed to each transfer section by the transfer paper carrying drum 10, thereby obtaining a full color print in "copy mode".

In this way, the unfixed visible image transferred onto the transfer paper 15 is fixed by the heating roll 48 and pressure roll 49 of the fixing unit 41, so that the unfixed image can be transferred from different kinds You will get 1 full color print.

◎Print Mode Next, the case where a large number of printed materials are obtained from the same type of original will be explained with reference to the process schematic diagrams in FIGS. 8(a) to 8(f) and the time chart in FIG. 9.

First, when the operation mode (not shown) of the apparatus is set to "Master plate making 7-mode" or "Print 1-mode J", as in the above-mentioned "copy mode", the image forming unit 20 is stretched over the cylindrical drum 23 of each image forming unit 20. An electrostatic latent image of each color is formed on the photosensitive material 24, and this electrostatic latent image is
A device 27 converts the image into a visible image. Then, each microscopic image is fixed by the flash fixing device 28 to form a master plate 56 (see FIG. 8(a)). By setting the process speed slower than the normal "copy mode" during master plate making, high-definition halftone image quality can be obtained.

Next, the master 56 visualized by the process speed described above is recharged (-like charging) 57 by the charger 25.
After that, the entire surface is exposed using the lamp 29 for irradiating the entire surface (
(see FIG. 8(b)), the charge on the master 56 is retained by the light shielding effect, but the charge on the other sensitive material 24 is removed, and an electrostatic charge 958 according to the master 56 is formed. (See Figure 8(C)). Toner 59 of each color is deposited on the master 56 of each color by each developer 27 in the same manner as in the "r copy mode" for this electrostatic charge image 5B (see FIG. 8(d)).

On the other hand, the transfer paper 15 is conveyed by a feed roll 41 and is held by a registration roll 42 while forming a curl on the transfer paper 15. Based on a reference signal from a sensor (not shown), the leading edge of the transfer paper 15 is moved to support the transfer paper. The transfer paper 15 is gripped by the gripper 14 of the drum 10 and sent out from the registration roll 42, and the transfer paper 15 and the insulating mesh 13 on the transfer paper carrying drum 10 are electrostatically attracted and conveyed to the transfer section by the electrostatic tack corotron 44. be done.

Then, while synchronizing the leading edge of the transfer paper with the reference position of the leading edge of the master 56 in each transfer section, the developed image of each color on the photosensitive material 24 of each image forming unit 20 is sequentially transferred onto the transfer paper 15 by the transfer corotron 22. Multiple transcription occurs (Figure 8)
(see (e)). Therefore, the transfer paper 15 conveyed by the transfer paper carrying drum 10 is sequentially transferred by the image carrier 21 of each image forming unit 20 to obtain a full color print.

After the transfer, the charge on the transfer paper 15 is removed using a separate corotron 45.
The fixing unit 4 is
The unfixed visible image 60 on the transfer paper 15 conveyed to the 7th side is fixed all at once by the heating roll 48 and the pressure roll 49 of the fixing unit 47, and is then discharged onto the discharge paper l/ray 50 (8th (See figure (f)).

A large number of full-color prints can be obtained by sequentially repeating the above-mentioned series of steps, that is, the charging step, the exposure step, the developing step, and the transfer step.

After obtaining the desired full color print in this way,
In each image forming unit 20, a master plate-formed photosensitive material 24 is wound into a cylindrical drum 23 by a scroll mechanism, and a new photosensitive material 24 is fed out and stands by for the next copying or printing.

[Effects of the Invention] Since the present invention is configured as described above, the following effects can be obtained.

1) Since an image forming unit capable of master plate making is arranged around the transfer paper carrying drum, full-color copying and printing can be performed selectively, and multiple transfers can be quickly performed all at once. , and the cost can be reduced.

2) Since charging and writing of an electrostatic latent image can be omitted in the print mode, power consumption can be reduced and speed can be increased.

3) Since master plate making can be performed at low speed in print mode, it is possible to improve the image quality of the master plate and the image quality of prints.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view of a multicolor image forming apparatus according to the present invention, FIG. 2 is a sectional view of an image forming unit according to the present invention, FIG. The figure is an enlarged cross-sectional view of the electrostatic image-bearing sheet according to the present invention, and FIG. i Enlarged cross-sectional view of zinc oxide particles, No. 6
The figure is a characteristic curve diagram showing the relationship between the emission wavelength and sensitivity of ordinary zinc oxide and sensitized zinc oxide that form the electrostatic image bearing sheet, and Figure 7 is a perspective view of the transfer drum according to the present invention. 8(a) to f) are process explanatory diagrams during printing according to the present invention, FIG. 9 is a time chart during the printing process, and FIG.
The figure is a schematic cross-sectional view of a conventional image forming apparatus. Description of symbols (10)...Flexible transfer paper carrying drum (11)...
Cylindrical base (12)...Opening (13)...Insulating mesh (14)...Gripper (20)...Image forming unit (21)...Image carrier (22)...・Transfer means (transfer corotron) (23)・
... Cylindrical drum (24) ... Electrostatic image bearing sheet member (sensitive material) (25)
... Charger (26) ... Electrostatic latent image forming means (optical system) (27)
...Developing means (developing device) (28) ...Fixing means (flash fixing device) (29)
...Full surface irradiation means (full surface irradiation lamp) (54)...
・Applicant for permission from the Control Department Person: Fuji Xerox Co., Ltd. Person: Satoshi Nakamura, Patent Attorney 1m (3 people included) Funeral map! +) Condolence diagram I Kanuka α Osamu luminescence wavelength (rm)

Claims (1)

[Claims] At least a charger, an electrostatic latent image forming means, a developing means, and, if necessary, are arranged on the circumferential surface of an image carrier formed by a flexible electrostatic image-bearing sheet member stretched around the circumferential surface of a cylindrical drum so that it can be wound up. A plurality of image forming units each including a fixing means for fixing a visible image formed on the electrostatic image bearing sheet and an entire surface irradiation means for recharging the fixed image fixed by the fixing means. A transfer means is arranged at appropriate intervals on the circumferential surface of the transfer paper carrying drum, and a transfer means is disposed inside the transfer paper carrying drum to face each image carrier, and the transfer position of each image carrier is arranged. A multicolor image forming apparatus comprising: a control means for aligning the leading edge of the transfer paper carried by the transfer paper carrying drum with the leading edge reference position of the visible image formed on the image carrier. .