JP2543047B2 - Transfer / transport equipment - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic copying machine, a printer, and a facsimile, and more particularly to a transfer / conveyance apparatus that significantly affects image quality and usability of a machine.

2. Description of the Related Art In recent years, transfer / transport devices have been used in image output and character output devices such as office automation, and are required to have high reliability. Demand is high. Further, from the viewpoint of colorization, it is desired to establish a transfer technique and a transport technique for obtaining stable image quality regardless of the type and physical properties of paper. However, the current transfer and transport technologies depend on the physical properties of copy paper and the environment. This is because the charging or static elimination technology using static electricity is not fully utilized. There is a demand for a transfer / transportation device using a charge removal technique.

Hereinafter, an example of the above-described conventional transfer / transport apparatus will be described with reference to the drawings.

FIG. 7 is a front view showing the structure of a conventional electronic copying machine. In FIG. 7, 1 is a photoconductor charger, 2 is a photoconductor drum as an electrostatic latent image carrier having a photoconductive material provided on the surface, 3 is an exposure device, 4 is a development device, and 5 is a copy paper supply. Reference numeral 6 denotes a copy sheet, 7 denotes a transfer charger, 8 denotes a charge removing / separating charger, 9 denotes a belt, 10 denotes a fixing device, and 11 denotes a photoconductor cleaning device. The operation of this apparatus will be described. The surface of the photosensitive drum 2 is positively charged uniformly by the photosensitive charger 1. After the surface of the photoconductor drum 2 is uniformly charged by the photoconductor charger 1, the surface of the photoconductor drum 2 is exposed by an exposure device 3 to form a charge pattern by light. After that, the developing device 4 uses the negatively charged toner to transfer the toner onto the surface of the photosensitive drum in accordance with the charge pattern to visualize the toner. After the visualization, the copy paper 6 supplied from the copy paper supply device 5 is transferred to the photosensitive drum 2 serving as an electrostatic latent image carrier.
Then, the transfer charger 8 is positively discharged from behind the copy sheet 6 to transfer the toner on the surface of the photosensitive drum 2 to the copy sheet 6. After the transfer, in order to discharge the charged copy paper 6 and separate it from the photosensitive drum 2, an AC high voltage is applied to the charge removing / separating charger 8 to discharge the AC to discharge the copy paper 6 and remove the copy paper from the photosensitive drum 2. 6 is separated. The separated copy paper 6 is conveyed to the fixing device 10 by the belt 9 and the fixing device 10 fixes the toner on the copy paper 6 (the toner remaining on the surface of the photoconductor drum 2 after transfer is the photoconductor cleaning device 11). (For example, recording materials and photosensitive resins edited by Japan Society for the Promotion of Science, P23-32, Proceedings of 55th Research Symposium of the Electrophotographic Society of Japan, P83-87) Problems to be Solved by the Invention In the above configuration, for transfer,
Due to the provision of the transfer charger, the copying paper must be charged and electrostatically adsorbed on the photoconductor drum, and this must be separated from the photoconductor drum by removing the charge of the copying paper by the charge removal / separation charger.
For this reason, in addition to the power supply for the transfer charger, a power supply for the neutralization / separation charger must be prepared. Furthermore, in order to ensure the transferability and the separability of the copy paper from the photosensitive drum, it is necessary to find the point that works best by adjusting the discharge efficiency between the transfer charger and the charge-separation separator. and,
This discharge efficiency is greatly affected by the environment, re-tuning is required according to environmental changes, and the tolerance range for reliability is extremely small.It is the charge of the copy paper itself that affects the transferability. There are many factors that affect the charging such as the physical properties, storage, transfer environment, etc., and it is quite difficult to control the charging of the copy paper itself. This means that it is difficult to control the charge removal of the copy paper if the paper is turned upside down, which affects the performance of separating the copy paper from the drum. That is,
The current transfer / transport system is a method and design depending on the copy paper, and therefore has a problem that the paper-passing property as a machine is reduced and reliability is deteriorated.

Means for Solving the Problems In order to solve the above problems, the present invention relates to an electrostatic latent image carrier that conveys a toner image and a toner image that is close to the electrostatic latent image carrier and that copies the toner image. An endless belt made of a material having a specific resistance of 10 ¹⁰ to 10 ¹³ Ω · cm, which is transferred to paper and conveys the copy paper, and the belt is stretched, or
The stretching means to be driven and located downstream of the movement of the belt,
Separation means which supports the belt from the inside and which is made of a conductive material and has a diameter of 20 mm or less and which is grounded; and charge applying means for supplying the belt with a charge having a polarity opposite to the charge polarity of the toner image. And the separating means is made of a material having a specific resistance of 10 ⁸ to 10 ¹⁰ Ω · cm.

Operation In the present invention, the toner image on the photosensitive drum is transferred to a copy sheet by the above-described configuration. First, the transfer / transport principle will be described. As shown in the conventional example, the image formed on the photosensitive drum has a photoconductive layer on its surface, and the conductive layer supporting the photoconductive layer is grounded. After the surface is uniformly charged, a charge pattern is formed on the photoreceptor surface by exposure. This is visualized by a developing device. The developing device is a device that charges a powder having a diameter of about 10 μm and transfers it to the photosensitive drum. In this case, when the photosensitive drum is positively charged, the developing device negatively charges the toner. Therefore, a positive charge and a negative charge are electrostatically attracted, and the latent image is visualized. In order to transfer the toner image on the photosensitive drum to the copy paper, it is necessary to apply an electric field that overcomes the above-mentioned electrostatic attraction between the photosensitive drum and the toner. In the present invention, this electric field is created by bringing the belt close to the photosensitive drum and charging the belt. The belt has a specific resistance of 10 ¹⁰ Ωcm
It is composed of a semiconductor material having a density of up to 10 ¹³ Ω · cm. By making the belt semiconductive, it does not show the high charge seen in a substance having a weak self-discharge effect, such as a dielectric substance,
Like low resistance, the charge leakage is fast and the belt itself is not charged, and the charge is not generated by injecting charge into the copy sheet to charge it and forming an electric field to overcome the inquiries between the photosensitive drum and the toner. Hold the load. When the copy sheet is inserted between the belt and the photoconductor drum, the copy sheet is polarized by the electric charge of the belt and the electric field formed between the photoconductor drum. That is, when the belt is positively charged, a negative charge is induced on the belt side of the copy sheet and a positive charge is induced on the photosensitive drum side. The induced charge of the copy paper causes the negatively charged toner to be transferred to the copy paper, and at the same time, the copy paper is electrostatically attracted to the belt. There are two main reasons for separating the copy sheet from the drum. First, since the copy sheet is attracted to the belt by polarization, the charge of the belt and the polarization charge of the copy sheet are attracted (in this case, the positive charge of the belt and the polarized negative charge of the copy sheet). But,
It is larger than the attraction between the ground potential surface of the photoconductor drum (the exposed portion is at substantially the same potential as the conductor layer supporting the photoconductive layer) and the polarization charge (in this case, positive charge) of the copy sheet. Second, if the belt has a specific resistance of 10 ⁹ Ω · cm or less, injection of electric charges into the copy paper occurs, but the specific resistance is 10 ¹⁰
When a semiconductor belt having a conductivity of up to 10 ¹³ Ω · cm is used, electric charges are not injected into the copy paper, and repulsion of the same electric charge between the copy paper and the belt caused by the injection does not occur. For this reason, an effective attraction between the polarization charge and the belt charge occurs. The conveyance force of the copy sheet is generated by the attraction between the polarization charges of the copy sheet as long as the belt holds the charge. However, since the belt is a semiconductor, the leakage of electric charges is slower than that of a conductive material, and the electric charge leakage speed changes depending on the conveying speed of the belt and the conveying distance until the copying paper is separated from the belt. When the paper separates from the belt, the charge carried by the belt is different. Therefore, at this point, the copy sheet undergoes a rapid change in the electric field to cause a charging phenomenon. As described above, the degree of the separation charging differs depending on the transport speed and the transport distance. Also, the polarity is different from the charge of the belt, and if the belt is positively charged, the separated charge becomes negative, and if the belt is negatively charged, the separated charge becomes positive. Normally, the polarity of the charge held by the belt and the polarity of the toner are different polarities, so an attractive force is generated.However, the separation charging has a different polarity from the charge of the belt, that is, the same polarity as the toner, and thus becomes a repulsive force. This causes image disturbance. The degree of separation charging varies depending on the resistance of the copy paper, and the higher the resistance, the easier the separation charging occurs. Several methods are conceivable in order to suppress this separation charging as much as possible and to prevent image disturbance. For example, there are a method of removing electricity while the copy sheet is being conveyed by the belt, and a method of removing electricity when the copy sheet is separated from the belt. However, it is necessary to completely neutralize the copy paper conveyed by the belt or to give the copy paper a neutralization charge equivalent to the separation discharge at the time of separation, so that the capacity determined by the thickness and the water content of the copy paper can be reduced. Very difficult unless detected by some method. Usually, the separating means for separating the copy sheet from the belt is made of a conductor and is directly grounded or grounded via a resistor. As in the present invention, the belt resistance is set to 10 ¹⁰ to 10 ¹³
If the separation means has a diameter of 20 mm or less, even if the copy paper reaches the separation position, the belt retains a considerable charge, and the time for the copy paper to separate along the outer diameter of the separation means is further increased. It becomes extremely short. When the separating means is made of a conductive member and grounded, the apparent potential is about 0 V, but as described above, the toner image on the copy paper is abrupt because of a short time in the vicinity of the separating means of about 0 V. Receive a large electric field change. Therefore, the separating means can be made of a material of 10 ⁶ to 10 ⁸ Ω · cm, and the amount of charges flowing from the ground can be adjusted to prevent the toner image on the copy sheet from being disturbed.

The copy paper separated from the belt uses a guide member from a position close to the belt in order to guide the toner image to the fixing means for fixing the toner image to the copy paper. When a copy sheet comes into contact with this member, the capacity of the guide member affects the toner image and disturbs the toner image.

In the invention of the present application, unlike the conventional idea of eliminating static electricity from a copy sheet, the same polarity as that of the transfer charger used when the toner image is transferred from the electrostatic latent image carrier to the copy sheet in the area from the belt to the guide member is used. A corona discharger is operated to create an electric field to prevent the toner image from being disturbed due to a change in capacity when the copy sheet comes into contact with the belt or the guide member. Furthermore, for the purpose of adjusting the area to which the electric field of the corona discharger is applied at the time of separation, the guide member is made of the same electrically conductive material and grounded, or made of a material of 10 ⁶ to 10 ⁸ Ωcm and grounded. It is possible to remarkably enhance the effect by connecting the resistor or grounding via a resistor.

Hereinafter, a transfer / transport apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing the structure of a transfer / transport device according to the first embodiment of the present invention. In FIG. 1, reference numeral 20 is a belt having a specific resistance of 10 ¹⁰ to 10 ¹³ Ω · cm in order to obtain semiconductor characteristics. The belt 20 has elasticity in order to ensure running stability. For example, rubbers such as urepan rubber and chloroprene rubber, and urethane resin, which is slightly inferior in elasticity, are used. The thickness of the belt 20 is about 0.3 to 0.6 mm. Even if a dielectric layer having a thickness of about 1/10 or less of the thickness of the belt 20 is provided on the belt surface, the electrical characteristics are not significantly affected. Reference numeral 24 denotes a separation shaft for separating the copy paper 6, which is made of a conductive material and has a diameter of 20 mm or less and is used as a ground plate 37 in order to stabilize the separation performance of the copy paper 6 from the belt 20. Ground.
26 is a transfer shaft for stretching the belt 20, 28 is a stretching shaft for stretching and driving the belt, 29 is a belt charger for charging the belt, 30 is a belt drive device, and 34 is the belt 20. Is a pressing spring for pressing the photosensitive drum 2 against the photoconductor drum 2, 36 is a discharging charger, 37 is a ground plate for grounding the separation shaft, and 38 is a guide plate.

The operation of the transfer / transport apparatus configured as described above will be described below with reference to FIGS.

FIG. 2 shows a front view. First, the surface of the photosensitive drum 2 is uniformly charged by the photosensitive charger 1. A post-charging exposure device 3 creates a latent image, and a developing device 4 visualizes it with toner. The belt 20 includes a separation shaft 24, a transfer shaft 26, and a stretching shaft.
The belt 20 is stretched between 28, and the belt 20 is in contact with the photosensitive drum 2. The voltage of the high voltage power supply applied to the belt charger 29 is adjusted so that the belt 20 is positively charged by the belt charger 29 and the surface potential of the belt 20 becomes approximately +3000 V on the belt charger 29. When the specific resistance of the belt 20 is 10 ¹⁰ to 10 ¹³ Ωcm,
The surface potential on the belt 20 between the belt charger 29 and the separation shaft 24 is about + 2500V. When the copy paper 6 is supplied from the copy paper supply device 5 and inserted between the photoconductor drum 2 and the belt 20, the copy paper 6 is formed by the ground surface of the photoconductor 2 and the belt 20 formed by the charged charge of the belt 20. The copying paper 6 is polarized by the action of the lines of electric force from the photosensitive drum 2 to the photosensitive drum 2,
Electrostatically adsorb to 20. At this time, the charged particles are transferred to the copy paper by the action of this polarization charge. Copy paper 6 is belt 20
Although it is conveyed to the separation shaft 24 while being electrostatically adsorbed on the belt, as described above, the charge leakage is slow and the belt 20 shows a high charge due to the relation between the conveying speed and the conveying distance. If the distance between the shaft 26 and the separation shaft 24 is about 120 mm, the belt 20
Shows a surface potential of +2000 to + 2500V near the separation axis. When the copy sheet 6 is conveyed and separated from the belt 20 by the separation shaft 24, a separation charging phenomenon occurs. Copy paper 6
In the copying paper 6 left at room temperature and normal humidity, the separation charging potential reaches -5 to -6 Kv if the belt 20 is positively charged and the degree of charging is the same as that described above, although it depends on the resistance of the belt. The discharging charger 36 is provided for the purpose of preventing the toner image on the ejection sheet from being disturbed by this separation charging, and the discharging charger 36 discharges both the separation shaft 24 and the guide plate 38 provided in the vicinity thereof. Arrange as possible. The polarity of the discharge is also opposite to that of the belt 20, and the belt charger
Discharge with the same polarity as 29. That is, the transfer charger
The same power supply as 29 can be used. The static eliminator 36 suppresses the separation charge development of the copy paper 6, and the charge polarity of the copy paper 6 does not become the same as that of the charged particles, that is, the charge is approximately 0 V or slightly positively charged (in this case, the charged particles are charged). Is a negative charge)
It should be Therefore, the discharge from the discharging charger 36 is 10μ.
A or more is sufficiently effective. Separation shaft 24 is a static elimination charger
It is necessary to use a grounding plate 37 for grounding, which is made of a conductive material that functions as a counter electrode to assist the discharge of 36. Separation axis
It is also necessary to form the conductive layer 24 so that the charge of the belt 20 is leaked. If the guide plate 38 is made of a conductive material and is grounded, it can also serve as a counter electrode that assists discharge of the charge eliminating charger 36. This is effective when the opening portion of the static eliminator charger 36 cannot be sufficiently obtained. The copy paper 6 separated from the belt 20 is conveyed to the fixing device 10 through the guide plate 38 and the toner image is fixed.

As described above, according to the present embodiment, the transfer conveyance is carried out by the belt method, and the charge-eliminating charger is installed at the time when the copy paper is separated from the belt, so that the separation charge is generated at the time when the copy paper is separated from the belt. Disturbance of the toner image on the copy sheet can be prevented.

A second embodiment of the present invention will be described below with reference to the drawings.

FIG. 3 is a perspective view showing the vicinity of the separation shaft of the transfer / conveyance apparatus showing the second embodiment of the present invention. Reference numeral 20 is a belt, and 24 is a separation shaft. The above is the same as the configuration of FIG. First
The difference from the configuration shown in the figure is that the static eliminator 43 is provided on the guide plate 40 having a conductive property.

The operation of the transfer / conveyance apparatus configured as described above will be described below.

An electric charge is applied to the belt 20 by the belt charger 29, and the copy sheet 6 is electrostatically attracted to the belt 20 to convey the copy sheet 6. As described above, when the copy sheet 6 separates from the belt 20, separation charging occurs. As the static eliminator, for example, pure cotton cloth, silk, polyethylene, polyamide carbon fiber or the like is used. Pure cotton cloth and silk are materials that are hardly charged when they have a certain amount of water content and have an electric resistance of 10 ⁶
At about 10 ⁸ Ω · cm, the internal water content contributes to charge leakage and is effective in eliminating static electricity. Polyethylene and polyamide have a long carbon chain in the molecular structure, and carbon fibers connected in series show an extremely high effect on static elimination. The copy paper 6 separated from the belt 20 holds the charge by the separation charging as described above. If the guide plate is made of a conductive material and is grounded, charges may rapidly flow in order to cancel the charge on the copy sheet 6, and it may be difficult to hold the toner image. In particular, it is difficult to hold a toner image on thin paper or the like, which is considered to have a large capacity change after being separated from the belt 20.
Therefore, a substance having a specific resistance of 10 ⁶ to 10 ⁸ Ω · cm is provided on the guide plate 40 to prevent the above-mentioned drawbacks and prevent a rapid inflow of charges from the ground, and the effect of the electric field by the static eliminator 36 is reduced. You can fully pull it out. FIG. 4 shows the guide plate 45.
The substance itself is composed of a substance having a static elimination function, and examples of the material include phenol resin. Phenol resin is also an effective neutralizing material. As described above, this prevents rapid charge transfer, suppresses changes in the electric field, and stably holds the image. In addition, various conductive substances, particularly metals such as iron, copper and aluminum, greatly charge themselves and the other party by friction. This includes not only the problem of slipperiness of the surface but also the problem of contact potential difference caused by the difference in work function when the metal and the insulator such as the copy paper 6 are brought into contact with each other. Especially copy paper 6
It is considered that the physical properties change depending on the water content, etc., and the contact potential difference changes, especially when it is extremely dry.
The contact potential difference also becomes large, the mutual charge transfer amount also becomes large, and they are charged. Phenol is thought to serve to lower this contact potential difference than metals. This suppresses the contact potential difference to be lower because the contact potential difference is closer to the insulator than the metal, thereby preventing charging. In this sense, phenolic resin is a very effective material. By providing the guide plate with the charge removing function as described above, the effect of the electric field by the charge removing charger can be enhanced and the separation charge after separation from the belt of the copy sheet can be suppressed.

FIG. 5 is a perspective view showing the vicinity of the separation shaft of the transfer / conveyance apparatus showing the third embodiment of the present invention. Reference numeral 20 denotes a belt, and reference numeral 24 denotes a separation shaft which is grounded. Reference numeral 38 denotes a guide plate, which has the same configuration as that shown in FIG. The difference from the configuration of FIG. 1 is that a static eliminator 43 is provided on the separation shaft 24.

The operation of the transfer / transport device configured as described above will be described below.

It has been mentioned many times that the copy paper 6 electrostatically attracted on the belt 20 is separated and charged when it is separated from the belt 20. This separation charging was caused by the belt 20 showing high charging even on the separation shaft 24. Also, as described in the second embodiment, the separation shaft 24 made of a conductive material does not sufficiently contribute to the neutralization of the belt 20 even though it is grounded. Further, the belt 20 made of a semiconductor material having a specific resistance of 10 ¹⁰ to 10 ¹³ Ω · cm is characterized in that it is difficult to transfer an electric charge to a material in contact with the belt. Therefore, in order to enhance the static elimination effect of the belt 20, a material having a high static elimination effect is used for the separation shaft. Static eliminator 43
Is effective as a contact with a charged object,
It is a material that causes the movement of charges from this object. or,
As described above, the charging caused by the contact potential difference is suppressed and the charging due to the contact is prevented. That is, it should be a discharge path inserted between a charged body and a large-capacity one (for example, the earth) that releases electric charges, and an electrostatic resistance of a certain size (first Figure 6 has the National Conference of the Static Society of Japan, Proceedings P2 to P6). It is thought that it will be about 10 ⁸ to 10 ¹⁰ Ω · cm, although it is not in a strict sense, if it is taken into consideration with the resistance in electric power engineering. This value matches the specific resistance value that effectively functions as the static eliminator 43 described in the second embodiment. Phenol resin is an effective material. The separation charging of the copy sheet occurs in accordance with the amount of charge on the separation axis of the belt 20. Separation shaft 24 has a diameter of 20 mm
Since it is made of the following conductive material and is grounded, the belt 20 holding the charge and the copy paper 6 are suddenly separated from the belt 20, so that a rapid electric field change occurs, and the toner image on the copy paper 6 is formed. Therefore, it is possible to suppress the disturbance of the toner image after the copy paper 6 is separated from the belt 20 by increasing the charge removal function of the separation shaft 24. As the static eliminator, in addition to the pure cotton cloth, silk, polyethylene, polyamide, and carbon fiber shown in the first embodiment, a belt material, for example, a synthetic rubber such as urethane rubber, is used. A substance that can change is considered. When the fluorine-based material is wound around the separation shaft 24, the belt 20 tends to be positively charged because the fluorine-based material itself is easily negatively charged. If the belt 20 is positively charged, it tends to be charged rather than discharged.
When 20 is negatively charged (unlike in the case of the first embodiment of the present invention, when positively charged charged particles are transferred to the copy paper 6), it functions as a static eliminator. The static eliminator can function not only by removing electric charges but also by utilizing positive charging between materials.

As described above, by providing the static elimination function on the separation shaft, it is possible to suppress the separation electrification after the copying paper is separated from the belt.

FIG. 6 is a front view showing a transfer / transport unit of the transfer / transport apparatus according to the fourth embodiment of the present invention. 20 is a belt, 24 is a separation shaft, 26 is a transfer shaft, 28 is a tension shaft, 29 is a transfer charger, 32
Is a ground plate, and the above is the same as the configuration of FIG.
The difference from the configuration shown in FIG. 1 is that the static eliminating material 43 is provided on the belt 20.

The operation of the transfer / transport device configured as described above will be described below.

In the present invention, it has been described that the transfer of the toner image on the copy sheet and the separation of the copy sheet 6 from the photosensitive drum 2 are achieved by the polarization of the copy sheet 6 by the belt 20 holding the electric charge. However, the surface potential of the belt 20 is +2000 to +2500 V immediately above the separation shaft 24, and is expected to be higher at a position where the toner image is transferred from the photosensitive drum 2. For this reason, when the copy paper 6 has a high insulation resistance such as OHP paper, a micro-discharge occurs in a minute gap in the separation portion where the photoconductor drum 2 and the copy paper 6 are separated, and the surface charge of the photoconductor drum 2 is reduced. Moving to the copy sheet 6, the copy sheet may take on a true charge. In this case, the charge may be removed until the copy sheet 6 is separated from the belt 20. Sixth
In the figure, the belt 20 is provided with a static eliminator 43. As described in Embodiments 2 and 3, the role of the static eliminator 43 is to help remove the charge between the grounded conductive material and the charged material. Here, the effect of the static eliminator 43 is utilized between the belt 20 and the copy paper 6. That is, a substance that adjusts the contact potential difference between the copy paper 6 and the belt 20 is interposed between the copy paper 6 and the belt 20 so that charge transfer can be efficiently performed, and thus the charged copy paper 6 is charged.
Can be discharged. As shown in the third embodiment, the charge removing material 43 on the belt 20 may be a material in consideration of the difference in charging series from the copying paper 6, and examples thereof include polyester fiber and acrylic fiber. These materials tend to be negatively charged on the copy paper 6 and positively charged on the copy paper. Naturally, pure cotton cloth, polyamide and the like having a high static elimination function are effective. Further, although not shown in the drawing, these static eliminating materials 43 are mixed in the belt 20, and like the above-mentioned static eliminating materials 43 are provided on the surface of the belt 20,
By adjusting the contact potential difference between the contacting copy paper 6 and the belt 20, the charge of the copy paper 6 charged efficiently can be released from the belt 20. In this case, the electric charge flows from the copying paper 6 to the static eliminator 43, and from the static eliminator 43 to the member grounded via the conductive material originally kneaded with the belt 20.
As described above, the static eliminator 43 has a specific resistance of 10 ⁶ to 10 ⁸ Ωcm, and the kneading to the belt 20 reduces the actual resistance of the belt 20.
It must be 10 ¹⁰ Ω · cm or more. As a result, even if the charge removal function is strong and the charge leaks quickly, a large amount of charge is supplied on the transfer charger 29, so that it is possible to form an electric field sufficient to transfer the charged particles onto the copy paper 6. That is, the belt 20 has a reduced charge holding ability due to the kneading of the charge removing material 43, and the charge holding on the separation shaft 24 is reduced, so that the separation charge of the copy paper 6 can be prevented. However, in this method, if the charge eliminating function is too high, there is a possibility that the electric charge, which is the source of the attraction force between the copy sheet 6 and the belt 20, may be lost, and the carrying force is lost. This also applies to the case where the charge removing material 43 is attached on the belt 20, and in this case, a dielectric layer for controlling charging may be provided on the uppermost layer of the belt 20. The charge control needs to be considered in consideration of the combination of these materials, the transport speed, the transport distance, and the like. For example, when the distance between the transfer speed 105 mm / S transfer charger 29 and the separating shaft 24 is about 120 mm, the charging on the separating shaft 24 becomes almost zero when a pure cotton cloth is attached on the urethane rubber belt. However, the charge of the belt 20 is lost during the conveyance, and the conveyance force is lost. Therefore, a belt made of polyamide on pure cotton cloth
It is improved by using 20.

As described above, by providing the belt with the charge removing function, it is possible to suppress the separation charge after the copy paper is separated from the belt.

EFFECTS OF THE INVENTION As described above, the present invention is made of a material having a specific resistance of 10 ¹⁰ to 10 ¹³ Ω · cm which is close to the electrostatic latent image carrier, transfers the toner image onto a copy sheet, and conveys the copy sheet. The endless belt and the stretching means that stretches or drives the belt, is located downstream of the belt movement, and is made of a conductive material and has a diameter of 20.
The grounding separation means having a size of 10 mm or less, and the charge providing means for supplying the belt with a charge having a polarity opposite to the charging polarity of the toner image, and the separation means is a material having a specific resistance of 10 ⁸ to 10 ¹⁰ Ωcm. With the transfer / conveyance device characterized in that, it is possible to obtain a good transfer / conveyance device without disturbance of the toner image.

If the diameter of the separating means is 20 mm or less in order to surely separate the copying paper from the belt, the electric field will be changed suddenly. Therefore, by forming the separating means from a material of 10 ⁸ to 10 ¹⁰ Ω · cm, the change in the electric field can be alleviated and the disturbance of the toner image on the copy paper can be prevented.

[Brief description of drawings]

FIG. 1 is a perspective view of a transfer / transport apparatus according to the first embodiment of the present invention, FIG. 2 is a front view of FIG. 1, and FIGS. 3 and 4 are views of the transfer / transport apparatus according to the second embodiment. 5 is a perspective view of the vicinity of the separation shaft, FIG. 5 is a perspective view of the vicinity of the separation shaft of the transfer / conveyance device in the third embodiment, and FIG. 6 is a front view showing the transfer conveyance unit of the transfer / conveyance device in the fourth embodiment. FIG. 7 is a front view of a conventional transfer / conveyance device. 20 ... Belt, 24 ... Separation axis, 26 ... Transfer axis, 28 ... Stretching axis, 29 ... Transfer charger, 30 ... Belt drive, 32 ...
… Grounding plate, 34 …… Pressing spring, 36 …… Static discharge charger, 38 ……
Guide plate, 43 .... Static elimination material.

Claims (1)

(57) [Claims] And 1. A latent electrostatic image bearing member for carrying the toner image, proximate to the electrostatic latent image bearing member, transferring the toner image to the copy sheet, resistivity of 10 ¹⁰ to convey the copy sheet ~ 10 ¹³
An endless belt made of a material of Ω · cm, a stretching means for stretching or driving the belt, a downstream of the movement of the belt, supporting the belt from the inside, and a conductive material A separating means having a diameter of 20 mm or less, which is grounded, and a charge applying means for supplying a charge having a polarity opposite to the charging polarity of the toner image to the belt, and the separating means has a specific resistance of 10 ⁸ A transfer / transport device characterized by being made of a material of up to 10 ¹⁰ Ω · cm.