JPS58220161A - Transfer device - Google Patents

Abstract

PURPOSE:To prevent scattering of toner from a transfer material at the time of separation, and to enable destaticization of the surface of a holder of the transfer material, by corona-discharging from a pair of corona dischargers arranged near a separating claw. CONSTITUTION:Corona discharge is applied with the pair of corona chargers 5, 6 sandwiching the support 2 of a transfer material 3 arranged near the separating claw 7 to the transfer material 3 to be separated from the support 2. As a result, the tone is separated from the transfer material 3 without scattering, and at the same time the surface of the support 2 is destaticized to carry out good multiple transfer or the like without offset. An exclusive destaticizer for the support 2 can be dispensed with, thus permitting simplification of the structure of the transfer device and reduction of its size.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an apparatus for supporting a transfer material on a transfer material support, applying a transfer corona from the back side of the transfer material support, and transferring an image on the image carrier onto the transfer material. Regarding.

Conventionally, in this type of apparatus, it is known that corona charging is applied in advance from the transfer material side, from the back side of the transfer material support, or from both sides in order to easily separate the transfer material from the transfer material support.

However, it is difficult to always obtain good separation because the separation conditions differ depending on whether the humidity is high or low, or when the transfer material is paper or a film for an overhead glossier.

Further, when the toner image is separated, the toner image on the transfer material tends to be disturbed and scattered. In particular, the rotational d1 function is used to support a transfer material on a transfer material support, apply a transfer corona from the back side of the transfer material support, and transfer the image on the image carrier multiple times onto the transfer material to obtain multiple images. In a multiple transfer device, the toner in the top layer may scatter or move backward in the direction in which the transfer material moves.

In addition, in order to prevent charge-up of the transfer material support after each transfer, to facilitate cleaning of the transfer material support, or to statically clean the transfer material support, It is also known to apply corona charging from the surface or back surface or both sides 1 of the support. However, in such a configuration example, one or two additional chargers are required, and the high voltage generator for this becomes expensive. In addition, the location of the transfer material must be placed after the transfer material is separated and before the transfer material support is cleaned or before the transfer material is fed, so there are restrictions when placing the charger. There was a drawback that the device had to be large.

Furthermore, in a multi-transfer type transfer device, it is known that corona charging is applied from the surface, back, or both sides of the transfer material support in order to prevent charge-up of the transfer material support every time one sheet of transfer is completed. When the transfer material support is a high-resistance perforated screen, the electrostatic adhesion between the transfer material and the transfer material support is weaker during the first copy or printing after a pause compared to when continuous copying or stamping. As a result, it was found that a transfer position shift occurred, and that this resulted in color shift in multicolor copy printing. This is especially likely to occur at low temperatures.

The present invention aims to eliminate the above-mentioned drawbacks of the conventional transfer device, and it is possible to prevent the toner image from scattering on the transfer material during separation, thereby saving the device and reducing space constraints due to corona generation. In addition to simplifying the design of the transfer device and downsizing the transfer device by eliminating the transfer device, the present invention aims to provide a transfer device that makes it possible to perform transfer with less unevenness due to transfer offset in multiple transfer. .

The first feature of the transfer device according to the present invention is to hold the transfer material on the transfer material support and apply a transfer corona from the back side of the transfer material support to transfer the image on the image carrier onto the transfer material. The transfer device has a separating claw for separating the transfer material from the transfer material support and a pair of corona chargers arranged on both sides of the transfer material support. The arrangement is such that corona irradiation is applied from the position where the transfer material is in close contact with the transfer material support to the position where it is separated by the separating claw.

The second feature of the transfer device according to the present invention is that the transfer material is supported on a transfer material support in the form of a perforated screen, and a transfer corona is applied from the back side of the transfer material support to transfer the image on the image carrier. In a transfer device for transferring onto a material, a pair of corona chargers are provided on both sides of a transfer material support and irradiate a position where the transfer material is separated from the transfer material support, and the corona charger is activated when the main body starts operating. and operates when the transfer material is separated.

This will be explained below with reference to the drawings.

FIG. 1 shows an embodiment of a transfer device according to the present invention. 1st
In the figure, 1 is an image carrier such as a photosensitive drum that electrostatically holds a toner image. 2 is a transfer material support made of polyester, triacetate, Teflon (trade name), nylon, polyethylene. For these, a sheet or a perforated screen containing a resistance value controlling agent is used. The toner image on the image carrier 1 is transferred to a transfer material 3 supported by a transfer material support 2 by the action of a transfer charger 4 on the back side of the transfer material support 2. At this time, the transfer material 3 and the transfer material support 2 are strongly attached to each other by electrostatic force. In order to separate the transfer material 3 and the transfer material support 2 that are strongly stuck together in this way, corona chargers 5 and 6 are provided on both sides of the separation claw 7 and the transfer material support. The separation claw 7 separates the transfer material 3 from the transfer material support 2 while neutralizing the charges on the transfer material 3 and the transfer material support 2 by the separation claws 7 and 5.

The corona charger 5 uses DC of the same polarity as the transfer charger 4, a superimposed AC on it, or an AC.
As the corona charger 6, a DC with a polarity opposite to that of the transfer charger 4, a superimposed AC on it, or an AC is used. These may be controlled by a grid.

In the above combination, the best results were obtained when both were set to AC and the phases were opposite to each other, that is, the phases were shifted by 180°. This is achieved by reversing the inputs to the AC Takada transformers.

The transfer material 3 separated from the transfer material support 2 as described above proceeds to the toner image fixing step.◎On the other hand, the charge distribution on the front and back surfaces of the transfer material support 2 is adjusted by this separation and charging step, and the charge distribution is eliminated. Thereafter, the surface is cleaned as necessary, and the process proceeds to the next transfer material conveyance and transfer step. before cleaning.

There is no need for charging to facilitate cleaning.

FIG. 2(a) shows the state when the toner image is transferred to the transfer material, and in the figure, 8 indicates the toner image transferred onto the transfer material 3. For convenience, the description will proceed assuming that the polarity of the toner is negative. A positive charge 9 is attached to the back surface of the transfer material support 2 by the transfer corona irradiation by the transfer charger 4 (FIG. 1). On the other hand, a toner image 8 of negative polarity is transferred to the surface of the transfer material 3 due to the action of this charge, but when the image carrier l (FIG. 1) separates from the transfer material 3, the negative charge is 1
0 is also attached. As a result, as shown in FIG. 2 (aλ), the back side of the transfer material support 2 is positively charged, and the surface of the transfer material 2 is negatively charged, and the charge density is high in the area where the toner image is present, and in the area where there is no toner image. becomes low, and the potential distribution is almost uniform and positively charged.

Next, when the chargers 5 and 6 are used to neutralize the charges from both sides of the transfer material 3 and the transfer material support 2, as shown in FIG.
As shown in b), in areas where there is no toner, the charge is removed from the front and back sides, so that the charge disappears, and in areas where there is toner, ten charges are attached to cancel out the charge of the toner. As a result, the surface potential becomes O almost uniformly. (Strictly speaking, there is some variation in the potential due to variations in charging, etc., but since it does not affect most people, we will proceed with the discussion assuming that it becomes 0.) If the transfer material 3 and the transfer material support 2 are brought into the above state, If the two are separated by a separation claw or the like, the negative toner will be pulled backward by the positive charge on the back side of the transfer material support 2, as shown in FIG. occurs, resulting in disturbance of the toner image. At this time, a potential of 9 turns is generated in the transfer material support 2 and the transfer material 3, and charges due to peeling discharge are generated on the back surface of the transfer material and the surface of the transfer material support.

According to the first feature of the present invention, the corona charger 5°6 irradiates corona from the position where the transfer material 3 is in close contact with the transfer material support 2 to the position where it is separated by the separating claw 7 during transfer phase separation. It is arranged like this. That is, since the action of the corona chargers 5 and 6 extends to the position where they are separated, as shown in FIG. 2(d), the charges that become unbalanced at the time of separation are always supplied in a balanced manner by the corona charges. Therefore, the charge on the transfer material support disappears, the toner charge on the transfer material is also neutralized, and stable separation can be performed.

As can be inferred from this, this charging also has the effect of cleaning the charge arrangement on the surface of the transfer material support 2. That is, in the case of FIG. 2(C), a new potential pattern is created on the transfer support by separation, which may cause a transfer ghost during the next transfer. However, in the present invention, such a step is not necessary.

Next, a case will be described in which the above-mentioned transfer device is configured as the above-mentioned multiple transfer type transfer device. As a transfer material support, polyester, triacetate, Teflon (trade name), nylon, polyethylene, glass fiber, paper, or materials containing these mixed with a resistance value control agent, 46
．． A perforated screen is used. When the operation starts, the corona charger 5.6 irradiates the front and back surfaces of the transfer material support 2. The irradiation continues while the transfer material support makes one revolution.

Thereafter, irradiation is performed when the transfer material is separated. Similarly to the above, the corona charger 5 uses DC of the same polarity as the transfer charger 4, or AC superimposed on it, or AC, and the corona charger 6 uses DC or AC of the opposite polarity to the transfer charger 4. or AC is used. These may be controlled by a grid. Above Q
'), 1jLl combination, the best results were obtained when both were set to AC and the phases were opposite to each other, that is, the phases were shifted by 180°.

This is achieved by reversing the inputs to the AC high voltage transformer. The transfer material support 2, whose front and back surfaces have been initialized by irradiation with a charger 5.6, supports the transfer material 3 on its surface and electrostatically attracts the transfer material 3 by charging as necessary.Then, the toner on the image carrier 1 is The image is transferred to the transfer material 3 supported by the transfer material support 2 by the action of a transfer charger 40 on the back side of the transfer material support 2. At this time, the transfer material 3 and the transfer material support 2 are strongly attached to each other by electrostatic force. Next, the transfer material 3 and the transfer material support 2 are separated by a separating claw 7 while neutralizing the electric charge charged on the transfer material 3 and the transfer material support 2 by the corona chargers 5 and 6 arranged on both sides of the transfer material support. Corona charger5.
6 is irradiated from immediately AiJ when the transfer material is separated until the separation is completed.

Here, it is necessary to irradiate the irradiation range of the corona chargers 5 and 6 from the part where the transfer material support 2 and the transfer plate 3 are attached to the part where they are separated.

Transfer material 1-j separated from transfer material support 2 as described above
) Proceed to the fixing process of the color image. On the other hand, the charge distribution on the front and back surfaces of the transfer material support is adjusted by this separation and charging step, and then the transfer material is transferred to the next step of transporting and transferring the transfer material.

There is no need to perform charging prior to cleaning to facilitate cleaning. In this case, the irradiation position of the corona charger and its effect are the same as described with respect to FIG.

In the above-mentioned multiple transfer type transfer device, during the continuous transfer process, the charge cleaning effect of the separation chargers 5 and 6 makes it possible to perform the next transfer without performing cleaning charging again. However, after being suspended in a low temperature environment,
As mentioned above, when the transfer material support material is a high-resistance perforated screen, the electrostatic adsorption force between the transfer material and the transfer material support during the first copy or printing after a pause is greater than during continuous copying or printing. As a result, problems occur such as transfer misregistration and color misregistration in multicolor copying and printing. In the corona charging means, the transfer material support 2
This is because the charges on the front and back surfaces cannot be completely removed. The front and back surfaces of the transfer material support 2 usually exhibit an unbalanced arrangement with different charge polarities and charge densities.

□Such an unbalanced arrangement is unlikely to occur at room temperature, but it tends to occur at low humidity. During continuous copying, the unbalanced ^i[J continues to be copied in a continuous manner, so the transfer conditions do not change, indicating a stable transfer state. However, at the time of break 1, although the screen itself has a high resistance, a certain degree of charge movement along the surface of the screen is circular, so it moves slowly to eliminate unbalanced charge arrangement, and the surface of the transfer material support The weight arrangement on the back side changes. As a result, the transfer conditions change, and as a result, the transfer position shifts, and in the case of multicolor copying, color shift occurs.

According to a second feature of the invention, the corona charger 5.6 is activated also at the start of operation of the body, thus eliminating the above-mentioned phenomenon.

Next, a copying apparatus implementing the above-mentioned transfer apparatus will be described. FIG. 3 shows a copying apparatus embodying the present invention. This is a copying apparatus capable of both monochrome copying and color copying. The operation during color copying will be described below.

In the figure, reference numeral 11 denotes an electrophotographic photosensitive drum having an insulating layer on its surface, which is rotatably supported and starts rotating in the direction of the arrow in response to a copy command. When the drum 11 rotates to a normal position, the reflected light image of the original placed on the original table glass passes through a lens, is separated into colors by a color separation filter, and is reflected onto the drum 11.

The drum 11 is neutralized by the static eliminator 12, and then the primary band sight device 1
3, after the band N (for example, plus) is applied, the left side is exposed to slit light. At the same time, AC or negative weight removal with the opposite polarity (for example, negative) is carried out using the 'f7 static eliminator 14, and then an electrostatic latent image of Hatake contrast is formed on the drum 1 by full exposure using the full exposure lander 15. .

The electrostatic latent image on the photosensitive drum 11 is then developed by a developing device 16.
It is visualized as a toner image. Developer 16 is yellow 1
It consists of four developing devices: 6 a% manta 16b1 cyan 16e and black 16d, and the specified developing device works according to the color separation filter used for fog light to create a toner image of the required color. can get. When making a color copy, development is first performed in the yellow developing device 16m.

The transfer material 17 is supplied from the cassette 18m or 18b, and is sent to the transfer material support, that is, the surface of the transfer drum 20 by the paper feed guide 19, and the transfer material 17 is fed to the surface of the transfer material support, that is, the transfer drum 20, at the leading end of the transfer material 17.
It is gripped by the click-ya 21.

As described above, while the yellow developing device 161L is performing development, the transfer drum 20 has separate chargers 28 and 29.
is activated to initialize the charge on the surface of the transfer drum 2o's surface IJ-722, and the cleaners 30 and 31 are also activated at the same time or before or after this, if necessary.

The transfer material gripped by the clipper 21 of the transfer drum 20 is conveyed while being wrapped around the screen 22 attached to the transfer drum as the transfer drum 20 rotates, and the transfer material 17 is passed between the transfer charger 23 and the photosensitive drum 11. While passing, the yellow toner image on the photosensitive drum 11 is transferred onto the transfer material, and the transfer material 17 is held on the screen surface by electrostatic attraction. At this time! The electrostatic adsorption force between the screen 22 and the transfer material 17 is further strengthened by the action of the i71 electrode 24.In the 1st transfer, the transfer material 17 is electrostatically adsorbed to the screen after the transfer charger 23, unlike before. Since the binding force is weak, the transfer material 17 is stretched against the photosensitive drum 11, causing color misregistration. To prevent this, a presser plate 25 is provided. The holding plate 25 and the paper feed guide plate 19 are arranged to move away from the transfer drum 11 after the first paper has passed through them. The screen 22 is the transfer material 1
Rotate while holding 7 and proceed to the next transfer.

A toner image is formed on the photosensitive drum 11 by the magenta developer 16b, and the transfer material 1 on which yellow has already been transferred is
A magenta toner image is transferred onto 7 by a transfer charger 23. Next, a toner image by cyan developer 16e is transferred thereon.

When the transfer of the color toner image onto the transfer material 17 is completed in this way, the transfer material 17 is separated from the transfer material support, that is, the screen 22 of the transfer drum 20, and sent to the fixing device 26, where the toner image is fixed. It is then ejected from the aircraft.

At the separation position where the transfer material 17 is separated from the screen 22, a separation claw 7 and a corona charger 5.6 shown in FIG.
Separation claws 27 and corona bands [vessels 28.
29 is placed. In the figure, 30 and 31 are cleaners that clean toner stains on the screen 22 from both sides 1111, and 32 is a cleaner that cleans the photosensitive drum.

When the leading edge of the transfer material 17 approaches the separation position, it clicks/ya 21
is released, the separation chargers 28 and 29 work, and the separation claw 2
7 approaches the screen 22 and separates the transfer material 17.

AC high voltages are applied to the separation chargers 28 and 29 in opposite phases to each other, so that a large static elimination effect can be obtained with a smaller applied voltage than when the charges are in the same phase. For example, if it is in phase, it is 8k
What would have to be applied is about 5 kV in the reverse phase.This has the effect of making the charger smaller, reducing the risk of spark discharge, and making the high-voltage transformer smaller.

The transfer device according to the present invention is used as a saw, and the separation charger 28,
As mentioned above, the irradiation range 29 covers the area from the position where the transfer material 17 is in close contact with the screen 22 to the position where it is separated from the screen 22. As a result, in addition to the effect described in the explanation of single-color copying, it is possible to prevent the toner in the uppermost layer from scattering and to prevent the toner in the uppermost layer from moving backward in the direction in which the transfer material advances.

The charger is attached in a direction away from the transfer material 17 and the screen 22 so that the charge is applied gradually in a weaker manner. This is to prevent the charging action from proceeding excessively even after the charges on the transfer material and screen are neutralized, and the separation of the transfer material and screen weakens the adhesion between the transfer material and toner, thereby preventing sudden fluctuations in the electric field. This is because it is not desirable.

The purpose of the present invention is further ensured by gradually weakening the electrification. In order to gradually weaken the electrification, it is possible to provide a grid and change the density of the grid, or to change the bias applied to the grid. be.

The separation chargers 28 and 29 do not work while the transfer material continues the transfer process, and are configured to operate from just before the separation process begins until the transfer material is completely separated (5). If it works while the transfer process continues, the adhesion force between the transfer material and the toner will weaken, and the toner of the color rifJ will be likely to be offset onto the photosensitive drum during the next transfer, which is undesirable.

In particular, when the transfer material support is a screen, the charge of the transfer corona not only charges the screen, but also attaches to the back side of the transfer material and charges it. It shows a transfer rate that is low. Therefore, it is not only unnecessary to keep the chargers 28 and 29 working all the time, but it is even harmful. That is, the transfer material support is used as a screen, and the separation chargers 28 and 29 are operated from just before the transfer material enters the separation process until the transfer material is completely separated, and the irradiation position is set so that the transfer material is in close contact with the transfer material support. By irradiating the area from the current position to the remote position, offset during multiple transfer can be reduced.

As mentioned above, the separation charger also has the function of cleaning the surface charge of the transfer material support. I'm interested in this effect.

It is possible to prevent charging of the screen, to make the transfer conditions of the transfer material the same, and to make the electrostatic adsorption force the same. It also has the effect of facilitating cleaning of toner stains on the screen in the next step.

This dynamic jetting can also be obtained when the transfer material support is a sheet, but in the case of a screen, the effect is remarkable because the charging is carried out through the holes in the screen, and the same charge arrangement is likely to occur on both the front and back surfaces. Conventionally, one or two chargers are inserted between the separation charger 28.29 and the cleaner 30.31 to prevent charging from rising on the transfer material support. As can be seen, it is not easy to insert a charger here because the space is small, and there is a restriction that the transfer device must be made larger. However, in the present invention, the charger can be omitted, so this is not possible. Never happened. The separated transfer material 17 is heated and fixed by a fixing device 26. The transfer screen is cleaned of toner stains from both sides by cleaners 30 and 31, and transfer of the next transfer material begins.

As explained above, according to the first feature of the present invention, the separation charger separates the transfer material from the position where it is immersed in the transfer material support to the position where it is separated from the transfer material support by irradiating it by z 1%. This can prevent the toner image on the transfer material from scattering or moving at times.Furthermore, it also has the effect of cleaning the charge on the surface of the transfer material support, which saves equipment and eliminates space constraints. This facilitates the design of the transfer device and downsizes the transfer device.Furthermore, it is possible to reduce the offset at the time of multiple transfers, making it possible to fill the transfer device.

According to a second feature of the invention, there is also a transfer device.

In addition to saving on the corona generating device and downsizing the transfer device, it is possible to prevent misalignment of the transfer position after a pause and misalignment during multicolor copy printing.

[Brief explanation of drawings]

FIG. 1 is a schematic side view showing a transfer device according to the present invention, and FIG.
Figure <tl) (b) (e) (d) is an explanatory view showing the state of charge on the transfer material and the transfer material support, and FIG. 3 is a side view showing a copying apparatus in which the present invention is implemented. 1... Image carrier 2... Transfer material support 3''.
...Transfer material 4...Transfer charger 5...Separation charger 6...Separation charger 7...Separation claw

Claims (1)

[Scope of Claims] 1. In a transfer device that carries a transfer material on a transfer material support and transfers an image on the image carrier onto the transfer material by applying a transfer corona from the back side of the transfer material support, It has a separating claw for separating the material from the transfer material support and a pair of corona chargers disposed on both sides of the transfer material support, and the corona chargers include:
A transfer device characterized in that the transfer device is arranged so that when separating the transfer material, corona irradiation is applied from a position where the transfer material is in close contact with a transfer material support to a position where the transfer material is separated by a separating claw. 2. Place the transfer material on the transfer material support in the form of a perforated screen.
! In a transfer device that transfers an image on an image carrier onto a transfer material by applying a transfer corona from the back side of a transfer material support, a transfer device is provided on both sides of the transfer material support to transfer the transfer material from the transfer material support. A transfer device comprising a pair of corona chargers that irradiate a position to be separated, and the corona chargers are activated when the main body starts operating and when the transfer material is separated.