JPH0256568A - color recording device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to color recording devices such as color printers, color facsimiles, and color copying machines, and particularly relates to color recording devices such as color printers, color facsimiles, color copying machines, etc. The present invention relates to a color recording apparatus that forms a color image on a transfer paper using a superimposition transfer method in which images of each color separation are superimposed by reciprocating the image.

(Prior art) After forming an electrostatic latent image corresponding to each color by performing image exposure on a photoreceptor for each color separation of the original image, the photoreceptor is exposed for each color separation using a developer corresponding to each color. The latent image formed on the top is visualized, and the resulting developed image for each color separation is transferred to a predetermined transfer position by a transfer paper conveyor belt that can reciprocate and stop. Transfer it onto paper.

When the above-mentioned transfer paper conveyance belt moves forward (forward rotation), the transfer paper is passed through the transfer section to perform the transfer, and when the transfer paper conveyance belt moves backward (reverse rotation), the transfer paper is returned to the pre-transfer position and stopped/timed. This operation is repeated for each color transfer, and after the final color transfer is completed,
There is known a color recording device using a superposition method in which the transfer paper is conveyed to a fixing device and the image transferred to the transfer paper is fixed to obtain a color image corresponding to the original image. (See Publication No. 186282).

Here, the color recording apparatus described in the above publication is provided with a transfer paper separation static eliminator (13) for separating the transfer paper after the final color transfer from the transfer paper conveyance belt.
This transfer paper separation static eliminator (13) is arranged near the drive roller (2) for driving the transfer paper conveyance belt that supports the most downstream end side of the transfer paper conveyance belt (1), and separates the transfer paper at the armpit. The charge was removed to separate it from the transfer paper conveyance belt.

(Problem to be Solved by the Invention) By the way, as in the color recording device described in the above publication, the transfer paper separation static eliminator (13) is simply placed near the drive roller (2) for driving the transfer paper conveyance belt. Then, the following problems arise.

When the size of the transfer paper is large, when the transfer paper conveyance belt (1) moves forward, the leading edge of the transfer paper separates from the transfer paper conveyance belt (1) at a portion corresponding to the drive roller (2), and when the transfer paper conveyance belt (1) moves backward, the leading edge of the transfer paper separates from the transfer paper conveyance belt (1). The transfer paper conveyance belt (1) is reciprocated so that the trailing edge of the paper is separated from the transfer paper conveyance belt (1) at a portion corresponding to the driven roller (3).
As the corona application in step 2) is repeated two or three times depending on the number of transfers, when the electrostatic adhesion between the transfer paper and the conveyor belt becomes very strong, the leading and trailing edges of the transfer paper will be It may not be possible to separate it from the belt (1) and it may become entangled, resulting in a conveyance failure. Therefore, in order to prevent this, the transfer separation static eliminator (13) is operated not only when the transfer paper is separated and discharged at the end of the final color transfer process, but also during the reciprocating movement of other transfer processes to separate the transfer paper. There is a way to make it easier, but in the position where the transfer and separation static eliminator (13) is arranged like the color recording device described in the above publication, the static electricity is removed from the transfer paper only from the leading edge to the position of the separation static eliminator (13). The charged potential of the transfer paper and the transfer paper conveyance belt differs between the charge-eliminated area and the non-eliminated area up to the trailing edge of the paper, and the transfer efficiency during the first transfer process is lower than that of the above-mentioned charge-eliminated area. A problem arises in that transfer image unevenness occurs in the subsequent region up to the trailing edge of the paper.

In addition, in the above method, the charge is not removed from the trailing edge of the paper, so there remains the problem that conveyance failure during the backward movement cannot be resolved at all.

The present invention has been made in view of the above circumstances, and even when a color image is obtained by overlapping color-separated images by repeating the transfer process multiple times, a uniform transfer image can be obtained over the entire surface of the transfer paper. It is an object of the present invention to provide a color recording device in which transfer paper conveyance defects in a transfer paper conveyance section can be prevented.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides electrostatic latent image formation for forming an electrostatic latent image corresponding to each color for each color separation on a photoconductor rotated at a constant speed. a development process in which the latent image formed on the photoreceptor for each of the above color separations is visualized using a developer corresponding to each of the above colors, and a reciprocating operation to visualize the image visualized in each of the above color separations. and the transfer process of transferring the image to the transfer paper conveyed to a predetermined transfer section by a transfer paper conveyance body capable of stopping operation are repeated sequentially, and one sheet of transfer paper is reciprocated multiple times by the transfer paper conveyance body to be exposed to light. In the color recording device, the images of each color separation on the body are superimposed and transferred, and after the final color transfer is completed, the transfer paper is conveyed to a fixing device, and the image transferred to the transfer paper is fixed to obtain a color image. A charger is installed on the upstream side of the transfer section, and the charger operates as a paper suction means when feeding transfer paper to the transfer paper conveyance body during forward movement, and as a paper charge removal means during return movement after image transfer. It is characterized by functioning as a working charger that absorbs paper and removes static electricity.

In addition, in the above color recording device, when necessary in the transfer process before the final color transfer process, a paper separation static eliminator installed on the downstream side of the transfer section removes electricity from the leading edge of the transfer paper as it moves forward, thereby transferring the image. It is characterized in that during the subsequent return movement, the trailing edge of the paper is charged by a charger that is installed upstream of the transfer section and is used for both paper adsorption and charge removal.

In addition, in the above color recording device, in the transfer process before the final color transfer process, the charge removal area by the paper separation static eliminator and the paper adsorption/static charge removal charger is the paper leading edge side and paper trailing edge side outside the image transfer area of the transfer paper. It is characterized by being a region.

(Function) In the color recording device configured as described above, the charger for paper adsorption and neutralization installed on the upstream side of the transfer section is used as a paper adsorption means when feeding transfer paper to the moving transfer paper transport body. It operates as a paper static eliminator during the return movement after image transfer, and when necessary in the transfer process before the final color transfer process, the transfer paper is removed by a paper separation static eliminator installed downstream of the transfer section. Charges are removed from the leading edge of the transfer paper during forward movement, and charge is removed from the rear end of the paper during return movement after image transfer by the above-mentioned paper adsorption and charge removal charger installed upstream of the transfer section, and the charge removal area is By setting the leading edge and trailing edge areas of the transfer paper outside the image transfer area, the leading edge of the paper is reliably neutralized during forward movement, and the trailing edge of the paper is reliably neutralized during backward movement. This prevents the leading edge and trailing edge of the transfer paper from being caught during movement, thereby preventing poor conveyance.

In addition, since the above-mentioned static elimination for preventing conveyance defects is performed only on the leading edge side and the trailing edge side of the paper outside the image transfer area of the transfer paper, uneven charging does not occur in the image transfer area of the transfer paper.
The occurrence of transferred image unevenness is prevented.

(Example) Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a schematic configuration diagram showing an example of a color recording device suitable for implementing the present invention, FIG. 2 is a timing chart showing the basic operation of the same color recording device, and FIG. 3 is a drive of the same color recording device. The control systems are shown in FIGS. 1 and 3, where 1 is a photoreceptor belt (hereinafter referred to as "PC belt"), and 2 is a belt for supporting and rotating one end of the PC belt 1. 3 is a PC driven roller for rotatably supporting the other end of the PC belt 1, 4 is a charger for charging the PC belt 1, and 5 is a color charger for the PC belt 1. Optical writing units for forming corresponding electrostatic latent images, numerals 7, 9, 11, 13, developing devices for developing latent images corresponding to each color, numerals 6, 8, .
10.12 is a developing roller installed in each of the developing units 7, 9, 11, and 13; 14, 33, and 34 are transfer sheets; and 15 is a paper feeder for feeding the transfer paper 14 into the recording apparatus. Paper rollers, reference numeral 16 is a registration roller, reference numeral 17 is a transfer paper transport belt which is a transport means for transporting the fed transfer paper 14 to the transfer section and fixing section, and reference numeral 18 is one end side of the transfer paper transport belt 17. 19 is a driven roller that rotatably supports the other end of the transfer paper conveyance belt 17. Reference numeral 20 moves the transfer paper conveyance belt 17 toward and away from the PC belt 1. 21 is a transfer corona for transferring the developed image on the PC belt 1 to the transfer paper 14; 22 is a charge-eliminating corona for discharging the transfer paper conveyance belt 17; 21 is a transfer corona for transferring the developed image on the PC belt 1 to the transfer paper 14;
Reference numeral 3 denotes a transfer paper adsorption charger for electrostatically adhering the transfer paper 14 to the transfer paper conveyance belt I7, and functions as a charger for both paper adsorption and charge removal to remove electricity from the transfer paper during return movement when necessary. Further, reference numeral 24 is a transfer paper separation static eliminator for separating the transfer paper electrostatically attracted to the transfer paper transport belt 17, and reference numeral 25 is a static eliminator for removing paper powder, developer, etc. attached to the transfer paper transport belt 17. Transfer paper conveyor belt cleaner for, code 2
Reference numeral 6 denotes a filter paper path switching member for changing the conveyance direction of the transfer paper after transfer, reference numeral 27 refers to a paper leading edge guide plate, reference numeral 28 refers to a paper trailing edge guide plate, and reference numeral 29 removes residual toner on the PC belt 1 after transfer. PC belt cleaner for, code 30 is PC
A static eliminator 31 is used to remove static electricity from the belt 1, and a fixing device 31 is used to fix the image transferred to the transfer paper.

Reference numeral 31a denotes a pair of fixing rollers of the fixing device 31, and reference numeral 32 denotes a paper discharge tray for discharging the transfer paper after the image is fixed.

Reference numeral 35 is a color image reading device for reading a color image of a document, reference numeral 36 is a PC drive motor for rotationally driving the PC drive roller 2, and reference numeral 37 is a PC drive motor 3.
Encoder 6, reference numeral 38 a rotation detection sensor attached to the shaft of the PC drive roller 2, reference numeral 39 a transfer drive motor for moving the transfer paper conveyance belt 17% moving roller IFHJg, reference numeral 40 detects the rotation of the transfer drive motor 39. Reference numeral 41 indicates a main control circuit for controlling a servo control drive circuit 42 for the PC drive motor 36 and a servo control drive circuit 43 for the transfer drive motor 39, respectively.

The main control circuit 41 includes a well-known CPU and RAM.
It consists of a storage device consisting of a ROM, an I10 port, an input/output interface, a counter circuit, etc. The ROM of the storage device is pre-stored with control programs and control data according to various copying processes. has been done.

First, the copying operation of the color recording apparatus having the basic configuration shown in FIGS. 1 and 3 will be explained.

In FIGS. 1 to 3, when a print operation start signal (see FIG. 2(a)) is issued by the print switch, control by the main control circuit 41 is started, and an ON signal for the PC drive motor is output. The PC belt 1 is rotated clockwise at a linear speed vP by the PC drive roller 2 which is rotationally driven by the PC drive motor 36. still,
The PC belt 1 is passed between the PC driving roller 2 and the PC driven roller 3. Simultaneously with the rotation of the PC belt 1, a transfer paper conveyance belt 17 made of a dielectric belt is passed between the drive roller 18 and the driven roller 19.
The transfer drive motor 39 first rotates in the normal direction (see Fig. 2 (g),
(h), (j)) is started, and the linear velocity VF is increased in the forward direction.
It is rotated by. In addition, the PC belt 1 and the transfer paper conveyance belt 1
7 has its running speed controlled so that it rotates under the condition of VP=VF.

After the toner on the surface of the PC belt 1 is removed by the cleaning device 29, the static electricity is removed by the static eliminator 30 to bring the surface potential to approximately Ov.After this, the entire surface of the PC belt 1 is uniformly charged by the charging device 4. be done.

As the static eliminator 30, a light irradiation type, a static eliminating corona applying type, or a combination of both may be used. Furthermore, in the case of the well-known negative-positive process, toner is attached to uncharged areas on the surface of the PC belt 1, so the charger 4 must uniformly charge the entire surface of the PC belt 1. . Further, charging by the charger 4 is uniformly performed by corona discharge, but a slight amount of ozone is generated during this discharge. This ozone decomposes in a short time when the discharge is stopped, but the PC belt 1
It may adversely affect the surface and reduce the clarity of the image. Therefore, a fan or the like is installed to send air from behind the charger, or the ozone is removed by suction to prevent the influence of ozone. is installed, as shown in Figure 2 (
As shown in d), a detection pulse is generated each time this roller rotates. In the example shown in Figure 2,
At the timing of the third pulse of the rotation detection sensor, control of the semiconductor laser (hereinafter referred to as LD) of the optical writing unit 5 is started, and optical writing based on the 7 image data of the yellow image is started. An electrostatic latent image is formed on the PC belt 1 at the middle point E. Note that other types of optical writing units such as other types of lasers, LED arrays, LCD arrays, etc. may be used as the optical writing unit.

The image data to be written is sent to the color image reading unit 3.
5, for example, read the three color separated lights of blue, green, and red, and based on the intensity level of each color light,
Yellow (Y), magenta (M), and cyan (C) are produced by performing known image calculation processing.

This is black (Bk) image data with each word written on it. Note that apart from the color image reading unit 35, other color image processing systems (for example, a color facsimile r
Writing may be performed based on image data output from a Howard processor, personal computer, etc.).

A yellow (Y) developer 7 and a magenta (M) developer 9 that visualize the electrostatic latent image. Cyan (C) developer 11. The black (Bk) developing device 13 usually includes a respective developing roller 6,
8.10.12 is placed in a position where it does not come into contact with the PC bevel 1 surface. Then, only from just before the latent image surface of the corresponding color reaches the position of each color developing roller to just after passing through it,
The developing device of the corresponding color is pressed and moved so that its developing roller faces the photosensitive surface so as to be in contact with the photosensitive surface by a predetermined amount.

Further, as shown in FIGS. 2(n) to 2(p), only the developing device facing the photosensitive surface starts to be driven in order to have a developing function.

Now, as mentioned above, first, seven latent images are formed on the photosensitive surface, so the Y developing device 7 is brought into contact with the photosensitive surface at the right timing and is driven. )
), visualize this.

After this, the PC belt 1 proceeds to the transfer process,
At this time, the transfer paper conveyance belt 17
The vertical position of the belt contact/separation switching roller 20 is switched so that it contacts and separates from the belt surface at the transfer portion of the PC belt 1 wound around the PC belt 1 .

Next, when the printing operation starts, the transfer paper conveying belt 17
is driven at speed VF, and then the belt contact/separation switching roller 20 is moved to the upper position to press the transfer paper conveyance belt 17 to contact the PC belt 1 (see FIG. 2 (1)).

Then, the transfer paper 14 is fed by the paper feeding roller 15 at a timing according to the number of pulses of the encoder 37 of the PC interval motor 36 (see FIG. 2(q)). The advance of the transfer paper is stopped by the registration roller 16, and then conveyed toward the surface of the transfer paper conveyance belt 17 at a timing that matches the position of the image formed on the PC belt 1 (see Fig. 2). (r)).

The conveyed transfer paper is transferred to a corona charger 23 for adsorbing the transfer paper.
The sheet is corona charged with a predetermined polarity (see FIG. 2 (X)) and brought into close contact with the transfer sheet conveying belt 17.

This prevents misalignment with the belt during transfer or conveyance. At this time, the belt contact/separation switching roller 2o functions as a counter electrode for corona discharge of the transfer paper adsorption charger 23. Prior to the transfer process of the negative color, the transfer paper conveyance belt 17 is completely neutralized by corona discharge by a static eliminator 22 (see FIG. 2(w)). At this time, the transfer paper conveyance belt 17 is A cleaning process is performed by a cleaner 25.

Now, the tips of the 7 visualized images on the PC belt 1 are
When the transfer point T reaches the TS point, which is a predetermined distance from the transfer position T, the transfer immediate motor forward rotation start signal S is inputted from the main control circuit 41 to the control drive circuit 43 of the transfer drive motor 39 (Fig. 2 (h) )reference).

However, at the time of start S, it is already rotating in the forward direction (see Fig. 2).
(see j)), and the normal rotation operation continues. The output timing when the transfer drive motor starts normal rotation S is as follows:
This is actually the point in time when the leading edge of the transfer paper reaches the RT point, which is the manual position at a distance Q1 from the transfer position T. At this time, P
The leading edge of the 7 images on the C belt 1 is a distance m fl from the transfer position T
In the control example shown in FIG. 2, the PC drive roller 2 rotates four times from the Y image data writing start timing (point E), and further p
This is the point at which the a motor 36 has rotated by the number of pulses Po of the encoder 37 (FIG. 2(d)).

(see (e), (f), (h)).

When time t has elapsed since the start signal S□, the leading edge of the 7th image and the leading edge of the transfer paper have both moved a distance Q1 and reached the transfer position T, and the 7th image is transferred due to the corona discharge from the transfer corona charger 21. (See Figure 2(s)). Time t at this time.

The number of pulses of the encoder (PC) 37 of the PC drive motor 36 is P, and the encoder (T) of the transfer drive motor 39 is
The number of pulses of 40 is PT□ (Fig. 2(e)).

(see (k)). Here, as the resolution of both encoders, if the belt movement length per pulse is the same, then P = PT, and if the ratio of the two is α,
Pl and PT have values corresponding to the coefficient α.

The following description will be made assuming that the condition P=PT1 is satisfied. Incidentally, the number of pulses of the encoder (PC) 37 is inputted to the control circuits 41 and 42.

Now, as the 7 image transfer process progresses, the leading edge of the transfer paper is separated from the transfer paper conveyance belt 17, guided to the paper path switching member 26 placed at the solid line position, and guided to the paper leading edge guide plate 26.
Proceed to 7. Then, 7 more image transfer steps proceed.
When the trailing edge of the transfer paper passes the transfer position T by a length of Q2,
That is, as shown by reference numeral 34 from the start point 81, the transfer paper has a length Ω1+UP(
When the transfer paper size)+Q is moved, a transfer drive motor reverse rotation signal (see FIGS. 2(i) and (j)) is generated to rotate the motor in the reverse direction. Simultaneously with or prior to this reversal signal, the belt contact/separation switching roller 20 is moved to the lower position to move the transfer sheet conveyance belt 17 away from the PC belt 1.

By reversing the transfer drive motor 39, the transfer paper conveyance belt 17 and the transfer paper supported by it are caused to run in the reverse direction in the direction of the right arrow in FIG. 1 at a speed VR (>VF). At this time, the belt 17 is caused to quickly return the distance traveled in time 11+1° at time t. At this time of return, the trailing edge of the transfer paper is separated from the transfer paper conveyance belt 17 and advances to the upper surface of the paper trailing edge guide plate 28, and the transfer paper is accurately moved by a predetermined distance indicated by reference numeral 33 (paper leading edge is at the RT point) and stops, and waits for time t4 (see FIG. 2 (j)) in preparation for the next M image transfer.

On the other hand, on the PC belt 1, the process of forming a two-color M image has already been performed during the transfer of the seventh image of the negative color.

That is, the writing unit 5 based on the M image data
Formation of an electrostatic latent image by optical writing by controlling and driving the PC starts when the moving roller 2 has made an integral number of revolutions, in the illustrated example, has made four revolutions (see Fig. 2). f), (g)). In addition, the developing device is 7
However, the Y developing device 7 was contacted and driven only in the image area.

Before the M image area of the two-color front reaches the Y developing device 7, the P
Figure 2 (m)
), instead of this, the developing roller 8 of the M developing device 9 is
It is brought into contact with and driven by one surface of the C belt (see FIG. 2(n)) in preparation for visualization of the M image.

When the leading edge of the M image reaches the TS point, the transfer opening motor is rotated by 4 rotations of the PC roller 2 and the number of pulses P0 of the pcyA dynamic motor encoder 37 from the M image data writing start timing. A rotation start signal S2 (see FIG. 2(h)) is input to the control drive circuit 43. At the same time or with a slight delay, the belt contact/separation switching roller 20 is moved to the upper position and presses the transfer paper conveyance belt 17, and the transfer paper conveyance belt 17 is moved to the PC belt 1 before the leading edge of the transfer paper reaches at least the T point. bring into contact.

Now, at time t from the timing of the normal rotation start signal S2 signal, the PC belt 1 moves to P as in the case of the previous seven images.
The number of pulses of C drive motor encoder (pc) 37 is P□
, the moving distance of the PC belt 1 is . Therefore, during this time t, the transfer paper also rises from the speed O to VF (=VR), and during this time, the pulse number is the same as the pulse number from the first color timing S to the time t□.
In this case as well, position control is performed so that P engineering = PT yu so that Tl. As a result, at time t1, the leading edge of the transfer paper has moved a distance Q distance, and the 7 images of the negative color and the M image of the two-color edge are aligned on the transfer paper. 'After that, the same process as described above is repeated for each color, and finally the process proceeds to the process following writing of Bk image data.

In the Bk image transfer process, the paper path switching guide plate 26 is moved to the chain line position in FIG. The fixing device 31 is separated from the conveyor belt 17.
will be transported towards. and.

When the transfer of the Bk image, which is the last step, is completed, the transfer drive motor 39 continues to rotate in the normal direction to convey the transfer paper (see FIGS. 2(j), (u), (v), and (y)). . The transfer paper on which the toner image is fixed by the fixing roller pair 31a of the fixing device 31 is discharged onto the paper discharge tray 32 as a color print. At this time, the transfer paper conveyance belt 17 is uniformly neutralized by applying a static eliminating corona from the timing when the trailing edge of the image area of the -th copy passes through the static eliminator 22 . Then, when the final copy is ejected, each motor, fixing device, and paper feeding system are stopped.

Here, as shown in FIG. 2, when performing a repeat operation, after writing the Bk image data on the -th sheet, the process proceeds to the writing process of the Y image data on the second sheet, and at the same time, the operation of the transfer paper conveying belt 17 is controlled. Also, repeat the same operation from the beginning of the -th sheet. After the transfer, the PC belt 1 is moved to a cleaner 29.
The residual toner is removed by the static eliminator 30, and the residual charge is removed by the static eliminator 30, and the final color print is sent to the charger 4. Finally, the final color print is ejected to the paper ejection tray 32, and is transferred to the PC belt 1. After the paper conveyance belt 17 is cleaned and neutralized, it stops operating and returns to its initial state.

In the above explanation, the order of image formation is as follows: Y image, M image - 30
Image=>Bk image, and the arrangement of the developing units is Y, M, C, and Bk in order from the top, but the invention is not limited to this.

In addition, we have mentioned a method in which electrostatic latent images of each color are optically written using an LD or the like using image data of each color that has undergone digital image processing. Color recording may also be performed by irradiating and forming an image.

Furthermore, one or more of the explanations were about full-color printing by overlapping four colors, but when overlapping two or three of these colors, image formation and transfer of the necessary colors are performed two or three times. , it is sufficient to finish the recording operation, and the operation is controlled accordingly.

Further, in the case of monochrome image recording, the developing device of that color is brought into contact with and driven by the PC belt 1 until a predetermined number of sheets are completed, and the transfer paper conveyance belt 17 remains in contact with the PC belt. In this case, the paper path switching guide plate 26 is held at the position indicated by the chain line in FIG. 1 and guides the transfer paper toward the fixing device 31. Therefore, in repeat recording, the print creation speed is 4/3 times as fast as in 4-color recording, and 2/3 times faster in 3-color recording than in 4-color recording.
Processing is twice as fast when using color, and four times faster when using single color. Further, the color of the developer is not limited to the four colors mentioned above, and blue, green, red, and other desired colors can be used in combination as necessary.

Now, the basic configuration and copying operation of the color recording apparatus have been explained above based on FIGS. 1 to 3. In the configuration shown in FIG. Transfer paper separation static eliminator 2 for separating from 17
4 was disposed at the position of a drive roller 18 for supporting the downstream end of the transfer paper conveyance belt 17 for moving the transfer paper conveyance belt.

However, if the transfer paper separation static eliminator 24 is simply disposed near the drive roller 18 for idle movement of the transfer paper conveyance belt 17, the same problem as in the case of the recording apparatus shown in the prior art will occur.

That is, when the size of the transfer paper is large, when the transfer paper conveyance belt 17 moves forward, the leading edge of the transfer paper separates from the transfer paper conveyance belt 17 at a portion corresponding to the drive roller 18, and when the transfer paper conveyance belt 17 moves backward, the trailing edge of the transfer paper separates from the transfer paper conveyance belt 17. The transfer paper conveyance belt 17 is reciprocated so as to be separated from the transfer paper conveyance belt 17 at a portion corresponding to the driven roller 19, but in such a case, the corona application by the transfer corona charger 21 is applied twice depending on the number of transfers. When the electrostatic adsorption force between the transfer paper and the conveyor belt 17 becomes extremely strong as the process is repeated three times, the leading and trailing edges of the transfer paper cannot be separated from the transfer paper conveyor belt 17 and become entangled, resulting in a conveyance failure. may occur. Therefore,
In order to prevent this, there is a method of operating the transfer separation static eliminator 24 not only when separating and discharging the transfer paper at the end of the final color transfer process, but also during the reciprocating movement of other transfer processes to facilitate separation of the transfer paper. However, with the arrangement position of the static eliminator 24 for transfer separation as shown in FIG. The charging potential of the transfer paper and the transfer paper conveyance belt 17 differs between the above charge removal area and the subsequent trailing edge of the paper, and the transfer efficiency during the 9th transfer process is lower than that between the above charge-eliminating area and the trailing edge of the paper thereafter. A problem arises in that unevenness occurs in the transferred image depending on the region.

In addition, the above method does not remove static electricity from the trailing edge of the paper at all.
The problem remains that it is ineffective against poor conveyance during backward movement.

Therefore, in the present invention, in the color recording apparatus having the configuration shown in FIG. In this way, it operates as an IS device for paper suction,
During the return movement after the completion of transfer for each color during the transfer process for each color separation, the transfer paper and the transfer paper conveyance belt 17 are operated as a static eliminator that eliminates static electricity 6 In other words, in the present invention, the transfer paper adsorption charger 23 functions as a paper adsorption/discharge charger that performs adsorption/separation charge removal of the transfer paper as necessary, and ensures that the trailing edge of the transfer paper is reliably neutralized and separated when the transfer paper returns. This prevents conveyance defects when the transfer paper moves backward.

Further, in addition to the above configuration, in the present invention, even in transfer processes other than the final color transfer process, when necessary, the leading edge side of the transfer paper is charged by the paper separation static eliminator 24 when the transfer paper moves forward. With this configuration, during the forward movement during each transfer process, the leading edge of the transfer paper is neutralized by the paper separation static eliminator 24, and during the backward movement, the trailing edge of the transfer paper is subjected to the above-mentioned paper adsorption and static elimination. Since the charge is removed by the paper adsorption charger 23 which functions as a dual-purpose charger, the edge of the transfer paper is reliably separated from the transfer paper conveyance belt I7 during both forward and backward movement, and the edge of the transfer paper is reliably separated from the transfer paper conveyance belt I7. Entanglement is prevented,
Transport defects are almost completely prevented.

Next, the above-mentioned paper that can be used for both adsorption and static elimination for $1! A specific configuration example of the paper adsorption charger 23 functioning as a container is shown in FIG. 4 and will be described.

In FIG. 4, the paper adsorption charger 23 is an alternating current (AC)
High voltage output circuit (including trigger circuit) and direct current (DC)
It is connected to a high voltage supply power source 44 configured with a high voltage output circuit (including a trigger circuit), and is provided to be able to apply an AC voltage for static elimination and a DC voltage for charging. .

Here, both the trigger force for the AC component output of χ2 shown in FIG. Then, the paper adsorption charger 23 has an AC component and a DC component as shown by the broken line in FIG.
In this case, the paper adsorption charger 23 functions as an IF electric device for paper adsorption.

Next, turn off the trigger for the DC bias component of χ.
When only the trigger human power for outputting the AC component of χ2 is applied, an AC component voltage whose center value is zero potential is applied to the paper adsorption charger 23, as shown by the solid line in FIG. The paper adsorption charger 23 is operated as a charge remover for removing charge from the transfer paper.

In contrast to the paper adsorption charger 23, an AC component voltage as shown by the solid line in FIG. 5 is applied to the paper separation charge eliminator 24 when necessary, so that it performs only the charge removal operation. ing.

Next, the operation of the color recording apparatus according to the present invention will be explained based on the timing chart shown in FIG.

1 and 3 to 6, as shown in the timing chart of FIG. 6, in the present invention, when feeding transfer paper, the AC of χ2 shown in FIG.
Both the component output trigger power and the DC bias component trigger power of χ are applied to the paper adsorption charger 23 to operate it (see FIG. 6 (χ1) and (χ2)), and the transfer paper 14 is operated.
is attracted to the transfer paper conveyance belt 17. In the transfer process, the image is transferred to the transfer paper, and the paper separation static eliminator 24 is activated only before and after the leading edge of the transfer paper reaches the paper separation static eliminator 24 (see FIG. 6(y)). ),
To facilitate separation of paper at the leading end of the transfer paper by a drive roller 18 section.

Next, after the first transfer operation is completed, the transfer paper conveying belt 17
When the transfer paper is moved back to the pre-transfer position by reversing the transfer paper, timing is taken only before and after the rear end of the transfer paper reaches the paper adsorption charger 23, and the paper adsorption charger 23 is charged with an AC component of χ3. The output trigger is operated only by human power (see Fig. 6 (χ2)), eliminates static electricity from the transfer paper and the transfer paper conveyance belt 17, and facilitates separation of the paper by the driven roller 19 at the rear end of the transfer paper during return movement. Make it.

Here, the areas where the static electricity is removed at the timing at the front and rear edges of the transfer paper are areas up to about 5 mm from the front and rear edges of the transfer paper, respectively, and only the area outside the transfer area of the actual color image is Make sure to eliminate static electricity. If the static elimination area is set in this way, the image area will not be affected by static elimination, so the charged potential in the image area of the transfer paper and transfer paper conveyance belt will be kept uniform, and the transfer efficiency in the first transfer process will be uniform. As a result, the entire image within the image area is uniformly and evenly transferred to the transfer paper, and an image with no transfer unevenness is obtained.

Regarding paper separation, the leading edge and trailing edge of the transfer paper are separated into layers, and the subsequent areas are separated and conveyed as they are, so no conveyance defects occur.

In addition, in order to prevent the charge-eliminating areas at the leading and trailing ends of the transfer paper from digging into the image area, a paper separation static eliminator 249 is used.
It works effectively if the paper adsorption charger 23 has a narrowed opening.

Now, in the second and subsequent transfer steps, the same repeating operation as the first time is performed, and hereafter, the transfer paper conveying belt 1
7, the paper separation static eliminator 24 and the paper adsorption charger 23 as a static eliminator are operated, and during the final color transfer and paper ejection process, the paper separation static eliminator 24 operates from the leading edge of the transfer paper. It is operated to uniformly eliminate charges in the entire area up to the rear end (see FIG. 6(y)).

In the above description, the voltage applied to the charger 23 for both paper adsorption and charge removal is assumed to be rAC component + DC bias component when adsorbing transfer paper, and only rACAC component is applied during charge removal, but this is not limitative. It is sufficient to apply appropriate voltages that are effective for paper adsorption and charge removal, respectively.

Furthermore, although the voltage application to the two-paper separation static eliminator 24 has been described as an AC component, in this case as well, it is not limited to the AC component, and any suitable static neutralization voltage that is effective in paper separation may be applied. .

In addition, in the timing chart shown in FIG. 6, static electricity is removed from the leading and trailing edges of the transfer paper during the reciprocating movement in all transfer processes, but this is also done within the range that can achieve the purpose. It is sufficient to perform static elimination as many times as necessary, and there is no need to perform it in every transfer process. For example, the static elimination operation can be set to be performed during the second and subsequent transfer steps, when the application of transfer corona during transfer is repeated and the electrostatic adhesion between the transfer paper and the transfer paper conveyance belt is considered to be particularly strong. be.

(Effects of the Invention) As explained above, in the color recording apparatus according to the present invention, the #F electric device installed upstream of the transfer section and used for both paper adsorption and static elimination acts on the moving transfer paper conveyance body. When the transfer paper is fed, it operates as a paper suction means, and when it moves back after image transfer, it operates as a paper static elimination means, and when necessary in the transfer process before the final color transfer process, it is installed on the downstream side of the transfer section. The leading edge of the transfer paper is neutralized by the paper separating static eliminator when the paper moves forward, and the trailing edge of the paper is removed during the backward movement after image transfer. By configuring the structure to eliminate static electricity,
During forward motion, the leading edge of the paper is reliably neutralized, and during backward motion, the trailing edge of the paper is securely neutralized, preventing the leading and trailing edges of the transfer paper from getting caught during reciprocating motion, thereby preventing conveyance defects. Ru.

In addition, since the above-mentioned static elimination for preventing conveyance defects is performed only on the leading edge side and the trailing edge side of the paper outside the image transfer area of the transfer paper, uneven charging does not occur in the image transfer area of the transfer paper.
The occurrence of transferred image unevenness is prevented.

Therefore, according to the present invention, in a color recording device that obtains a color image by repeating transfer a plurality of times, it is possible to prevent transport failure of the transfer paper during reciprocating movement of the transfer paper and to stabilize the transport performance. Moreover, it is possible to obtain a uniform and even transfer image over the entire surface of the transfer paper.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing an example of a color recording device suitable for implementing the present invention, FIG. 2 is a timing chart showing the basic operation of the same color recording device, and FIG. 3 is a drive of the same color recording device. A perspective view including a block diagram showing a control system, FIG. 4 is a schematic configuration diagram of a charger for both paper adsorption and static elimination according to the present invention, and FIG. 5 is a voltage waveform applied to the charger having the configuration shown in FIG. FIG. 6 is a timing chart showing an example of the operation when the present invention is applied to the color recording apparatus shown in FIG. 1... Photoconductor, 2... Photoconductor driving roller, 5...
・・Optical writing unit, 7.9.11.13・・・・
Developers for each color, 14.33.34...transfer paper,
17...Transfer paper conveyance belt, 18...Transfer paper conveyance belt drive roller, 23...Charger for both paper adsorption and charge removal, 24...Paper separation charge remover, 31...・Fixing device, 35... Color image reading device, 36...
・Photoconductor drive motor, 37.40...Encoder, 3
9...Transfer drive motor for driving the transfer paper conveyance belt,
41... Main control circuit, 42... Servo control drive circuit for photoreceptor drive motor, 43... Servo control drive circuit for transfer drive motor, 44... Charger for paper adsorption and neutralization. High voltage supply power. U40 Type D

Claims (1)

[Claims] 1. An electrostatic latent image forming process in which an electrostatic latent image corresponding to each color is formed for each color separation on a photoconductor rotated at a constant speed, and a developer corresponding to each color is used. A developing step is performed to visualize the latent image formed on the photoreceptor for each of the color separations, and a transfer paper conveying member capable of reciprocating and stopping the image developed for each of the color separations in a predetermined manner. The transfer process of transferring the image to the transfer paper conveyed to the transfer unit is repeated sequentially, and the transfer paper is moved back and forth a plurality of times by the transfer paper conveyance member to overlay and transfer the images of each color separation on the photoreceptor. , in a color recording device that conveys the transfer paper to a fixing device after completing the final color transfer and fixes the image transferred to the transfer paper to obtain a color image, a charger is installed upstream of the transfer section, The charger functions as a paper adsorption means when feeding transfer paper to the forward-moving transfer paper transport body, and functions as a paper adsorption/discharge charger that operates as paper charge removal means during return movement after image transfer. A color recording device featuring: 2. In the color recording apparatus according to claim 1, when necessary in the transfer process before the final color transfer process, static electricity is removed from the leading edge of the transfer paper when the transfer paper moves forward by a paper separation static eliminator installed on the downstream side of the transfer section. A color recording device characterized in that, during the backward movement after image transfer, the trailing edge of the paper is charged by a charger that is installed upstream of the transfer section and is used for both paper adsorption and charge removal. 3. In the color recording apparatus according to claim 2, in the transfer process before the final color transfer process, the charge-eliminating area by the paper separation charge eliminator and the paper adsorption/charge-eliminating charger includes the paper leading edge side and outside the image transfer area of the transfer paper. A color recording device characterized in that the area is on the trailing edge side of the paper.