JPH0212274A - Color image forming device - Google Patents

Abstract

PURPOSE:To prevent the occurrence of significant color slurring by keeping the position of a sheet edge almost constant without interposing a fixing stage between 1st- and 2nd-color transfer bodies when an image of two colors is composed and printed on one side. CONSTITUTION:A 1st endless transfer belt device 3 electrostatically attracts a sheet, which is carried to a photosensitive body 110 comprising a 1st image producing unit 1 to transfer an image thereon. Then, the sheet is moved to a 2nd endless transfer belt device 16 through a sheet route switching gate 13 set in a sheet receivable state from the 1st endless transfer belt device 3, electrostatically attracted and further carried. An image created by a 2nd image producing unit 2 and an image transferred by the 1st image producing unit 1 are superposed and transferred onto the sheet. At the end of transfer, the sheet is fed to a fixing device 31 from the 2nd endless transfer belt device 16, and is fixed, whereby a composed image on one side of the sheet can be obtained. Thus, color slurring is minimized to attain high quality multicolor printing.

Description

[Detailed description of the invention]

[Industrial Field of Application 1] The present invention relates to a color image forming apparatus, and more particularly to a color double-side forming apparatus capable of synthesizing multicolor images. [Prior Art] Conventionally, in order to form a color image in a copying machine, etc., one photoreceptor and a plurality of developing devices for developing latent images formed on the photoreceptor are used. Two devices are known. [Problems to be Solved by the Invention] When performing a multicolor image (image composition) using the above-mentioned conventional color image forming 1iff, one sheet of paper on which the image has been fixed is stored in an intermediate tray, and the paper is transferred through the intermediate tray. By refeeding the paper, it was necessary to synthesize the lζ image, which was developed with the color of the pond.This caused the problem of poor work efficiency.Also, in the conventional system; Then, feed the paper to the fixing device as per the national standard, refeed the paper from the intermediate tray, and transfer the paper to the intermediate tray.
It is carried out. For this reason, the size of the ffJ paper changes due to heating during color 1iljifII fixed tube, and the (p position) on the paper tends to shift when re-feeding. Even if this method is carried out, there is a problem that the color shift is large during transfer and it is difficult to form a clear multicolor image. It is an object of the present invention to provide a color image forming apparatus that can combine multicolor images more quickly and efficiently, minimize color shift, and obtain high quality multicolor printing. [Problem] Means for Solving the Problem] The color image forming apparatus of the present invention includes a photoconductor, an exposure device that exposes the photoconductor to form a static 1°h latent image, and +
IQ&! arranged along the outer periphery of the photoreceptor, each 514
a first image forming unit and a second free-standing image forming unit each having a developing Qit'ff with a 1-ner of a color that has changed;
In order to transfer the image on the photoreceptor visualized by the first image forming unit 1- onto a sheet of paper supplied from a paper feeder, the sheet is transferred to the photoreceptor at @112'.
J-ru m I HQ turn"i! Held H place, +XI
A second endless transfer unit that adsorbs the paper to the photoreceptor and transports it in order to transfer the image on the photoreceptor visualized by the image forming unit onto the paper. belt! A, the first endless transfer belt device on the downstream side of the photoconductor constituting the first image forming unit, and the 27111th end transfer belt of the photoconductor constituting the second image forming unit; A paper path gJ special gate section located between the devices and selectively receiving the paper from the first endless transfer belt device and transferring it to the second endless transfer belt device; A fixed W device receives the paper from the endless transfer belt device and fixes the m II+ transferred to the R paper, and a fixed W device is installed downstream of the fixed n device and selectively discharges or reverses the paper to 2. A paper ejecting and reversing device for supplying the paper to the non-window transfer belt in the i position. [Effect J first image formation], electrostatic latent terms of colors corresponding to the knit and second image formation (each photoreceptor of the Rin unit) are formed. Then, each electrostatic latent image is formed differently. Six toners of different colors are developed by the present I'1 device, and seven latent images are turned into chain threads.In synchronization with these processes, the paper is transferred from the paper feed S!i!ff to the first endless It is supplied to the transfer belt arrangement.

[First endless rotating belt V4V! 1, the paper is electrostatically attracted and conveyed to the photoreceptor constituting the first image forming unit. In this way, an image is transferred onto the paper by the first image forming unit. Next, the paper is transferred from the first endless transfer belt device to the second endless transfer belt device via a paper path cutter H gate section set in a paper receiving state, and the paper is electrostatically attracted to the second image forming unit. Then, the image created by knitting and the image transferred by the first image forming unit are transferred onto the paper. After the transfer, the paper is sent from the second endless transfer belt 8i to the fixing device and fixed, thereby producing 15 images combined on one side of the paper. After fixing, the paper is discharged through the paper discharge and reversing device 9
゜When the double-sided image forming mode is selected, the paper path cutter H gate section is set to a state in which it does not receive paper from the first endless transfer belt, and does not discharge the paper.
k reversing device is a paper reversing type rFM1. : Set. 1st
An image is transferred to one side of the paper by the image forming unit, and the paper with this transferred image is transferred to the first non-permeable transfer belt.
It is sent from the device to the fixing device and fixed. After the image is stabilized in this way, it is sent to the paper ejecting and reversing device.
Here, the leading edge of the paper is detected, and for a certain period of time tI'f,'A
Thereafter, the paper is reversely driven and supplied to the second endless transfer belt device C. Next, the image created by the second image creation unit is transferred to the other side of the paper. Thereafter, the sheet is fed from the second endless transfer belt device to the constant M Hfiff and conveyed out from the sheet ejection and reversal position V4. [Example] Hereinafter, the present invention will be explained based on an example. (First Embodiment) In the color image forming apparatus of the present invention, two image forming units 1 to 1 (a first image forming unit I- and a first image forming unit I- and a second image forming unit Fig. 1 is a schematic configuration diagram of an embodiment in which two image forming units) are arranged side by side, and Fig. 2 shows the cross-sectional structure of the transfer belt of the endless transfer belt device.
As shown in the figure. The color image forming device d of the present invention includes a first image forming unit 1, a second image forming unit 2, and a first endless transfer unit that transfers the image formed by the first image forming unit 1 onto a sheet of paper. a belt assembly 113, and a second endless transfer belt device 1 that transfers the image formed by the second image forming unit 2 onto a sheet of paper.
6, paper path cutting line gate section 13, and fixing device ff31
, and a paper ejecting/inverting head 32. As shown in FIG. 1, the first and second image forming units 1.2 have almost the same configuration, so the first image forming unit 1 on the right side will be explained as a representative. The first image forming units 1 to 1 include a photoreceptor] 10, a laser exposure section (exposure device) 101, a Wt electric charger 130 arranged along the outer periphery of the photoreceptor 110, and a (developing 4f
fl 20, sleeve roller 121, magnet [1
- roller 122, supply roller 123 and screw 124
f! will be accomplished. The laser exposure section light s 101 is generated by a laser diode (not shown) that emits a radar beam of a specific wavelength, a polygon scanner 102 that is rotationally driven by a motor, and a "θ lens 103.
, reflective mirrors 104 and 105, and a photoreceptor 1101.
A static sin image is formed. As mentioned above, the second image forming unit 2 arranged on the left side of FIG.
The other configurations except for the color of the toner inside are completely the same as the first image forming unit 1. The transfer belts 3a and 168 of the belt device 3.16 have a structure in which a dielectric layer 41 is laminated on a conductive layer (rubber material>40) as shown in FIG. 2. The transfer belt 3a116a has a function of attracting and conveying the paper P, and sequentially transferring the image transferred onto each photoreceptor 110, 210 onto the paper P, and is driven by a drive (not shown). The transfer belt 3a of the first endless transfer belt unit 13 is rotated in the direction of the arrow G in FIG. 1 by the power from the source.
0, a driving roller 7, and a driven roller 2.5 that follows the roller 17 while applying tension to the belt 3a.
, 6, ~)t is supported by roller 8 and circulates in the direction of arrow Q in FIG. Worked. Said rotation 7 Nubert 3a
A static elimination brush 9 is provided along the transfer belt 3a upstream of the roller 8 to defrost the transfer belt 3a. The roller 8 removes the dots attached to the surface of the transfer belt 3a.
It is disposed opposite to an elastic blade 10 that constitutes a cleaning device 11 provided for cleaning etc. What about this transfer belt 3a? l) It has the function of electrostatically adsorbing and transporting the paper P that is given an electric charge of opposite polarity to the charge of the drain by the electric device 12 and is being conveyed from the right direction (direction of arrow F in FIG. 1). There is. Second endless transfer belt! A position 16 is #transformation 7 of the structure described above.
The Abelt 16a and the transfer belt 16a are connected to the photoreceptor 21.
A roller 17 that faces and presses against the roller 1, and a driving roller 18
, while applying tension to the transfer belt 16a and applying tension to the transfer belt 16a.
ff le slave slave ---y 15.19.20.26.
28 # and supported by the roller 24 in the direction indicated by the arrow G in FIG.
One vote is driven in the downward direction. A static elimination brush 21 is provided upstream of the roller 2/1 and along the transfer belt 16a to eliminate static electricity from the transfer belt 16a. The cleaning device η23 is arranged opposite to the elastic blade 25 that constitutes the cleaning device η23. The transfer belt 16a is given a charge of opposite polarity to that of the toner by a charger 27, and has the function of electrostatically attracting the conveyed paper r). The paper path cutting H gate section 13 connects the first φless transfer belt device 3 and the second image forming belt downstream of the inter-track photoreceptor 110 constituting the first image forming unit 1. 1
between the second endless transfer belt device 16 on the upstream side of the photoreceptor, which selectively comprises the first endless transfer belt ! The function of receiving the paper P from the station 3 and transferring it to the first endless transfer belt device 16 is shown in FIG. The solid line in FIG. 1 is located at the i? Y(
14-A) and the two-dot chain line position! ! ! It is movable to (14-8). Fixer fi! If31 consists of a pair of rollers 31a and 31b arranged on both sides of the paper P path. The roller 31a is a heating roller. This fixing device 31 is disposed at a position where it can receive the paper P guided by the guide 29 from the first endless transfer belt V4 position 3 and the second endless transfer belt device 16, and the image transferred to the paper P is It has the ability to become established. Na J3, as mentioned later, is set in J! It is preferable that the rollers 31a and 31b of i31 be movable by a means not shown to a position where they are pressed together and a position where they are separated depending on printing needs. The paper ejecting and reversing device 32 is used for fixing)! A pair of transport rollers 32a and 32b that are installed downstream of the i-buyer 31 and are disposed on both sides of the path of the paper 1) and are reversible in the forward and reverse directions;
Fixing device: Detects the tip of the working arm (1) sent from N31, and adjusts the length of the paper P just before the trailing edge of the paper P passes through the transport rollers 32a, 32b to be handled, the transport roller 32a,
It consists of a detection means 37 consisting of a light emitting element 35 and a light receiving element 36 provided for reversing the paper P, and guides 38 and 39 for the paper P. In addition, the conveyance roller 32a132
When b is driven in reverse, the roller 31 of the constant tl device 31
It is preferable that a and 31b be moved to separate positions. In the middle 111, the paper [] is inverted 1 while keeping the rollers 31a and 31b pressed by 1 diameter! If the rollers 31a, 3
Not only is it necessary to switch 1b to the reversed state, but there is also a possibility that problems unfavorable in terms of image quality may occur, such as crushed print on the paper P passing between the O-ra 31a and 31b, and curling of the paper P. This is because there is. The color of the toner in each of the developing devices Ft125 and Ft225 can be selected from black or other colors (Ff, green, red, brown, etc.). Next, the operation of the color image forming apparatus according to the present invention will be explained. (Single-sided multicolor (two-color) composite printing) In this single-sided multicolor composite printing mode 1 to 1, the paper path 1 and the gate part 13 are connected to the first endless transfer belt l-device 3 as shown by the solid line in FIG. 1ff when it touches the transfer bells 1 to 3a of
f(14-A). Further, in the paper ejecting/reversing device 32, the conveying rollers 32a and 32b are rotationally driven in the direction to eject the paper, and the detection means 37 is set to the OF-"state. In this state, the color image forming apparatus is not operated. When you start it,
First of all, the first image on the right @ ``Ray set inside knit 1''
The laser beam output from the laser beam diode at the tip 101 enters the lζ polygon scanner 102, which has a plurality of mirror surfaces.Next, the laser beam is horizontally deflected and passes through the f/θ lens 103 and the reflecting mirror 104. ．．
105, the photoconductor 110 is illuminated with 0.1 shi, and the photoconductor 11
A static M latent image is formed on the surface of 0. Next, developing VA station 1
25, the static ffi latent image is visualized. At the same time as these, paper 1 is supplied from a paper feeder (not shown). The supplied IaP is conveyed in the direction of the arrow in FIG.
As described in J, since the surface layer is composed of the dielectric layer 41 charged to a predetermined potential by the charger 12, the M1Ps are electrostatically attracted one after another and transported in the direction of the arrow G toward the first photoreceptor 110. do. In this way, an image formed on the photoconductor 110 of the first image forming unit 1 from the right by the laser exposure section 101 and developed by the developing device 125 is transferred to the photoconductor 110.

[] - transfer belt 3 at the f [contact part with roller 4]
The image is transferred to paper P via a. As a result, the negative color image is first transferred. The post-transfer MP is suctioned and conveyed in the direction of arrow Q in FIG.
is guided to the second transfer belt 16. The transferred sheet 1) is sent to the photoreceptor 210 of the second image formation unit by the seven-node belt 16a. Note that, in the same manner as the first image forming unit 1, an image visualized by the -b developing device 225 is formed on the second photoreceptor 210 by the second image forming J unit 2. In this way, at the pressure contact portion between the roller 17 and the photoreceptor 210, the images formed on the two photoreceptors 210 (1) are transferred onto the paper P via the transfer belt 16a, and a two-color image is formed on the paper P. be done. After passing through the second image forming unit 2, the sheet 1] is guided and conveyed to the drive roller 18, and guided to the fixing device ff31 via the sheet guide 30.29. Here, the roller 31a1
31b. After a certain period of time n, the paper is driven by the conveyance rollers 32a and 32b of the paper ejection/reversal @ station 32, guided by guides 38 and 39, and ejected. In this way, one process of single-sided multicolor (two-color) composite printing can be completed more quickly and without causing large color deviations, printing deviations, etc. In this case, after separating the paper P at the switching gate section 13 for the transfer belt 3a and at the roller 10 for the rolling belt 16a, the charge on the surface is eliminated by the static elimination brush 9.21, and the elastic It is crushed by the body blade 10.25 and conveyed again to the charger 12.27. (Double-sided printing) During this double-sided printing, one paper path and the gate section 13 are filled from the transfer belt 3a as shown by the two-dot chain line in FIG.
IJII t, switched to position (14-8)
Further, the detection means 37 of the paper ejecting and reversing device is set to the ON state so that the paper P can be detected and transported and the detection means 32a and 132b can be reversed. When the image forming apparatus is set to the double-sided printing mode, an image is transferred to the paper P by the first image forming unit 1 using the same process as the single-sided multicolor (two-color) printing. After the first color image is transferred, the paper P is conveyed in the direction of arrow G in FIG. Therefore, the paper P is transferred to the transfer belt 3a as it is.
The paper is attracted and conveyed by the paper guide 29 , separated from the transfer belt 3 a by the curvature of the drive roller 7 , and sent to the fixing device 31 along the paper guide 29 . After fixing, the leading edge of the paper P is detected by the detection means 37, which is a combination V of the light emitting element 35 and the light receiving element 36, and the paper is divided into lengths according to the length of the paper P. : Immediately before the sheet 1 is detached, when the feed rollers 32a and 32b are reversed, the sheet 1 is reversely driven. This moment, it's constant! i431 roller 3
1a and 31b are in a separated state, and 8t1) is a fixing device by the conveyance rollers 32a and 32b in a reversed state! 31
1 and is conveyed along the guide 30 in one direction in FIG. Then, it is attracted to the transfer belt 16a between the guide line 28.5 and the guide line 28.5 on the tangential extension of the guide 30. Then, the paper is sucked and fed by the transfer belt 16a,
The image formed on the photoconductor 210 by the second radar exposure unit 201 (202 to 205) and the developer 81225 is transferred to the paper P at the roller 17, and is further conveyed and separated at the roller 19. It is fixed by the fixing device 31 via the guide 30.29 (in this state, the roller 31
a and 31b are returned to the pressure contact position). After the paper has been fixed, it is ejected by the transport sheets 32a and 32b of the paper ejecting and reversing device 32. At this time, the detection means 37 has returned to the OFF state and does not operate. In this case, it is necessary for the second image to be placed on the photoreceptor 210 from the end of the page, but this can be done relatively easily by having a 1-page division memory. It is. (Second Embodiment) In the Can-1i11i image forming apparatus of the present invention, the schematic structure of the second example in which the Rayleigh exposure section is shared is shown in the third example.
Not shown. Second fruit M! In example i, the laser exposure section 301 of the 1st J unit and the 2nd unit 1''''2' is shared, and both units 1-2' have only one laser exposure section 301. The structure is different from the first embodiment.The first and second image forming units 1' and 2' have the same structure as the image forming unit 1.2 shown in the first embodiment. However, as in the first embodiment, the current t! & device 125.22
Inside 5, drains of different colors are housed. In the case of this second embodiment, the laser exposure unit 301 includes two radar diodes that output radar beams with different wavelengths, a polygon ski 1Pner 302, a 1':・θ lens 303, and a lens that transmits light of a specific wavelength. A filter 304 coated with a multilayer film that reflects light of a specific wavelength.
and reflecting mirrors 305 and 306. 2f
The radar beams having different wavelengths outputted from the laser diode i41 pass through a polygon skinner 302 and an F/θ lens 303, and then enter a filter 306 coated with a multilayer film. The filter 304 causes the Rade beam of a specific wavelength to be reflected by the reflection mirror 305 and irradiates the first photoreceptor 110 . The Radhe beam that has passed through the polar filter 304 is reflected by a reflecting mirror 306 and irradiates the second photoreceptor 210 . It goes without saying that the reflecting mirror 305.
The position δ of 306 is selected so that the image is focused on the photoreceptor 110 on the 1st. The other structural members and the operations of the first and second non-astease transfer bells 1 to 1.2 are the same as in the first embodiment, and therefore their explanations will be omitted. In this embodiment, by sharing the laser exposure section 301, the structure of the first and second image forming apparatuses 1' and 2' is simplified, and the overall cost of the color image forming apparatus is reduced. It is possible to reduce the [Effects of the Invention] According to the color image forming apparatus of the present invention, when forming a single-sided two-color composite mark 1f4, there is no predetermined distance between the transfer of the first color and the second color. Therefore, there is no risk of deformation of the paper caused by the first color image transfer pattern or heating by the fixing unit, and the position of the paper edge is kept substantially constant, so that large color misregistration does not occur. Further, since double-sided printing of the single-sided multicolor composite mark If4, etc. can be performed continuously without re-feeding the paper, the printing work can be performed quickly and efficiently.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing a first embodiment of a color image forming apparatus according to the present invention, and FIG. 2 is a cross-sectional configuration of an endless transfer belt unit in the color image forming apparatus according to the present invention; It is a diagram. FIG. 3 is a schematic configuration diagram showing a second embodiment of a color image forming apparatus according to the present invention, in which exposure and exposure are combined into a single configuration. 1.1'...First image i'r 1l-1 days 1-2.
2-...Second image creation unit 3...First edge transfer belt 1-device 38116a...Transfer belt 16...Second endless transfer belt mounting 13...Paper path 1 unit Gate Part 2.5.6.15.19.20, 26.28... Driven roller 7.18... Drive "1-ra 4.17... []-ra 31... Fixing device 31 a , 3 l b-UJ-7 32... Paper discharge differential reversing device 32 a, 32 b-@feed [1-ra 29.30.3
8.39...Guide 101.201.301...Laser exposure section ('IK optical device) 110.210...Photoconductor 125.225...Currently*@crystal

Claims (1)

[Claims] (1) Each has a photoconductor, an exposure device that exposes the photoconductor to form an electrostatic latent image, and a developing device that is arranged along the outer periphery of the photoconductor and has toner of a different color. a first image forming unit and a second image forming unit; to transfer the image on the photoreceptor visualized by the first image forming unit onto a sheet of paper fed from a paper feeding device;
a first endless transfer belt device that adsorbs and conveys the sheet of paper to the photoreceptor; a second endless transfer belt device that attracts and conveys the paper to a photoconductor; the first endless transfer belt device on the downstream side of the photoconductor constituting the first image forming unit; and the second image forming unit. a paper path that is located between the second endless transfer belt devices on the upstream side of the photoreceptor constituting an image forming unit and selectively receives the paper from the first endless transfer belt device and transfers the paper to the second endless transfer belt device; a switching gate unit; a fixing device that receives paper from the first endless transfer belt device and the second endless transfer belt device and fixes the image transferred to the paper; installed downstream of the fixing device; A color image forming apparatus comprising: a paper ejecting and reversing device that selectively ejects or reverses the paper and supplies it to a second endless transfer belt device.