JPH04133084A - Transfer device - Google Patents

Abstract

PURPOSE:To prevent the occurrence of the meandering and biasing of a dielectric belt by engaging a protrusion provided on both side end of the dielectric belt as a transfer means with the opening part of a housing means. CONSTITUTION:Ribs 11b are formed on both side ends of the transfer belt 11, and simultaneously, the ribs 11 of both side end parts of the transfer belt 11 are engaged with both side end edges 4b of the opening parts 4a of the housing member of a transferring/carrying unit 4. On the other hand, a member having a high elastic modulus can be disposed on both side end parts of the belt 11. Both end parts of the belt 11 can be formed thicker than the other parts of it. Further, the width of the belt 11 is formed larger than the roller width of a driving roller 9, etc., and both ends of the belt 11 are turned and inserted into the outside of respective rollers, as the case may be.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention uses a dielectric belt as a transfer means. The present invention relates to transfer devices such as facsimiles and printers.

(Prior Art) Conventionally, image information (toner image) of a document held on an image information carrier (hereinafter referred to as photoreceptor) is transferred onto a recording medium made of plain paper (hereinafter referred to as transfer paper). A device using a dielectric belt made of a semiconductor material with an electrical resistance of 10' to 101 JΩ was proposed by the applicant for a transfer device of an image forming apparatus using the so-called Carlson process, and is already known. (Unexamined Japanese Patent Publication No. 53-9683
Publication No. 8).

An image forming apparatus using this dielectric belt as a transfer device uses a transfer charger consisting of a corotron that uses corona discharge as a means to transfer the toner image held on the photoreceptor, and transfers the toner image. A separation charger that removes the electrostatic attraction force of the transfer paper is used as a means for peeling the transferred transfer paper from the photoreceptor, and a separation charger is used as a means for transporting the transfer paper separated from the photoreceptor to the suction conveyance bell 1. The conventional general image forming apparatus used has
The following drawbacks can be overcome.

In other words, in the conventional general image forming apparatus described above, the transfer paper needs to have an electric charge in order to transfer the toner image on the photoreceptor onto the transfer paper, and on the other hand, it is necessary to separate the transfer paper from the photoreceptor. In order to do this, it is necessary that the transfer paper be sufficiently neutralized.

Moreover, in the conventional general image forming apparatus described above, these contradictory actions need to be performed in extremely close locations.

For this reason, if the voltage applied to the transfer charger is increased to increase the amount of charge applied to the transfer paper, the transfer of the toner image to the transfer paper will be ensured, but the charge removal from the transfer paper by the separation charger will be insufficient. In this case, there is a risk that the transfer paper will not be separated from the photoreceptor and will remain stuck there.

On the other hand, in order to prevent such separation defects, contrary to the above, if the action of the separation charger is strengthened, the static elimination action of this separation charger will extend to the charging range of the transfer charger, so that the transfer by this transfer charger will not be possible. The transfer effect of the toner image onto the paper becomes insufficient, and the toner image is easily transferred.

As is clear here, in order to achieve good transfer of the toner image onto the transfer paper and reliable separation of the transfer paper from the photoreceptor, the strength of the action of the transfer charger and the separation charger must be individually stable. It is necessary to make adjustments to achieve this, but their stable region is narrow and the adjustment process is extremely difficult.

Further, in the conventional general image forming apparatus described above.

The transfer paper itself holds the charge necessary to transfer the toner image on the photoreceptor, and the transfer paper is brought into direct contact with the photoreceptor.

For this reason, as described above, if the charging charger and the neutralization charger are arranged close to each other, the transfer paper becomes an electrical resistor that connects the transfer charger as a charge supply source and the separation charger as a charge absorption source. The amount of charge held by the transfer paper changes depending on the electrical resistance value of the transfer paper.

Therefore, in order for the transfer paper to have the charge necessary for transferring the toner image, it is necessary to adjust the amount of charge applied by the transfer charger each time according to the magnitude of the electrical resistance of the transfer paper.

However, as is well known, there are many types of transfer paper used in this type of image forming apparatus, and their electrical resistance values vary depending on the type.

Furthermore, even if the type of transfer paper is constant, its electrical resistance value will vary greatly depending on the environment in which it is placed, especially humidity conditions. Accordingly, it is virtually impossible to adjust the amount of charge applied by the transfer charger each time.

Therefore, in this type of image forming apparatus, it is extremely difficult to ensure good toner image transfer on all types of transfer paper under all environments.

Further, in order to transfer a toner image onto a transfer paper, it is necessary to apply an electric charge so that the surface potential of the transfer paper is usually 2 KV or more.

For this reason, in the above-mentioned conventional image forming apparatus, when the transfer paper having a high potential as mentioned above comes into direct contact with the photoreceptor, dielectric breakdown occurs in the photosensitive layer of the photoreceptor, which shortens the life of the photoreceptor. Furthermore, although the separation charger in this type of image forming apparatus can remove the electric charge held by the transfer paper, it cannot actively separate the transfer paper from the photoreceptor.

Therefore, in this type of image forming apparatus, the peeling action of the transfer paper from the photoreceptor is performed by the rigidity of the transfer paper.
If the rigidity of the transfer paper is low or if the rotational speed of the photoreceptor is too fast, poor separation or paper jams are likely to occur, resulting in a reduction in the productivity of the apparatus.

Furthermore, in this type of image forming apparatus, the transfer paper separated from the photoreceptor is conveyed by suction, so it is difficult to transfer paper that is relatively small in size and has a small suction area, curled transfer paper, etc. When the conveyance force is not obtained, the transfer paper often becomes jammed between the photoreceptor and the fixing device.

On the other hand, in an image forming apparatus using a dielectric belt as a transfer device, for example, as described in Japanese Patent Laid-Open No. 63-83762, by applying an electric charge to the dielectric belt, the transfer paper is Without applying a direct charge, the transfer paper is attracted to the dielectric belt by the polarized charges caused by electrostatic induction on the transfer paper and the electrostatic attraction of the charges on the dielectric belt, so that the toner image on the photoreceptor is The force for transferring is generated by the charge applied to the dielectric belt.

Therefore, according to this image forming apparatus, the separation of the transfer paper from the photoreceptor, the transfer of the toner image onto the transfer paper, and the fixing device can be performed without being affected by the type of transfer paper or differences in environmental conditions. Transfer paper can be stably and quickly transported to the printer without deteriorating the photoreceptor or causing paper jams.

(Problems to be Solved by the Invention) By the way, in a conventional image forming apparatus using a dielectric belt as a transfer means, as described in the above-mentioned Japanese Patent Laid-Open No. 63-83762, the drive roller and If the dielectric belt is simply stretched by a driven roller or the like, meandering or skewing will occur in the dielectric belt due to rotational driving of the dielectric belt.
The dielectric belt or transfer paper may be damaged, or the transferred image may be distorted.

Therefore, in this type of image forming apparatus, it is necessary to use some method to prevent the dielectric belt from meandering or shifting as described above.

The present invention has been made in view of the above-mentioned points, and an object of the present invention is to provide an opening in an accommodating member that accommodates the dielectric belt and its driving means, provided at both ends of the dielectric belt. Either protrusions are engaged, or members having an elastic modulus higher than that of the dielectric belt are disposed at both ends of the dielectric belt, or members at both ends of the dielectric belt are engaged with each other. It is an object of the present invention to provide an image forming apparatus that can prevent meandering or deviation of a dielectric belt by forming the dielectric belt to be thicker than other parts.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides an image information carrier that holds an image on a recording medium that is conveyed toward one image information carrier. In a transfer device for transferring information, the transfer device includes a dielectric belt, a drive means for driving the dielectric belt, and an opening on the transfer surface side of the recording medium that accommodates the dielectric belt and the drive means. accommodating means formed therein, and protrusions provided at both ends of the dielectric belt are engaged with openings of the accommodating means.

In order to solve the above-mentioned problems, the present invention also provides that elastic members having an elastic modulus higher than that of the dielectric belt are adhered or welded to both ends of the dielectric belt, and the dielectric belt is The length of the roller that stretches the belt in the width direction is shorter than the length of the portion of the dielectric belt where the elastic member is not provided.

Furthermore, in order to solve the above-mentioned problems, the present invention forms both side ends of the dielectric belt thicker than other parts of the dielectric belt, and also provides a roller for stretching the dielectric belt. The length in the width direction is made shorter than the length in the width direction of the portion of the dielectric belt that is not formed thickly.

(Function) According to the present invention, the protrusions provided at both ends of the dielectric belt are engaged with the openings of the accommodating member that accommodates the dielectric belt and its driving means, or the dielectric Either a member having an elastic modulus higher than that of the dielectric belt is provided at both ends of the body belt, or the thickness of both ends of the dielectric belt is made thicker than other parts. Since the dielectric belt is formed thickly, when the dielectric belt is stretched, both ends of the dielectric belt are held by the opening of the housing member, or by the ends of a bias roller, a drive roller, etc. Ru.

(Example) Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

However, in order to avoid complicating the explanation, illustrations and disclosures thereof will be omitted to avoid complicating the explanation, as well as the configuration and operation within the range that can be clearly recalled from the description of this specification, as well as the above-mentioned and other objects and novel features of the present invention. , or simplify it.

The transfer device of the image forming apparatus according to the present invention is entirely unitized by a transfer conveyance unit 4 as shown in FIG.

In FIG. 1, the transfer conveyance unit 4 is supported by a unit support member 15 of the main body of an image forming apparatus (for example, a copying machine), which is not shown, so as to be detachable from the main body of the apparatus.

The transfer surface side of this transfer conveyance unit 4 (upper side in Fig. 1)
An opening 4a is formed therein.

At the transfer position of this opening 4a (upper right in FIG. 1), a photoreceptor 12 which is configured to be rotatable as is well known is arranged.

Further, on the upstream side (right side in FIG. 1) of the transfer conveyance unit 4, a registration roller 1 for feeding the transfer paper P toward the transfer position of the opening 4a is arranged.

On the other hand, on the downstream side (left side in FIG. 1) of the transfer feeding unit 4, a toner image transferred from the photoconductor 12 is fixed to the transfer paper P discharged from the paper discharge position of the opening 4a. The fixing bag [16] is placed.

As is well known, the transfer paper P is moved by the registration roller 1 at a predetermined timing in synchronization with the rotation of the photoreceptor 12.
The photoconductor 12 is fed to a transfer position between the photoreceptor 12 and the transfer conveyance unit 4 .

The toner image formed on the photoreceptor 12 is transferred to the transfer paper P fed to this transfer position by a well-known image forming process.

The transfer paper P on which the toner image has been transferred is transferred to a transfer conveyance unit 4 by a transfer belt 11 made of a dielectric belt, which will be described later.
The paper is ejected from the paper ejection position downstream of the opening 4a, and the toner image transferred from the photoreceptor 12 is fixed by the fixing device 16.

On the other hand, as shown in FIG.
Belt drive roller 9, tension roller 10, pre-transfer roller 17, transfer charger 6, ) (tuck-up roller 7)
, cleaning blade 8, waste toner collection bottle 5, and the like are each formed into a unit and integrally supported.

As shown in FIG. 1, the transfer belt 11 is biased with appropriate tension by the belt drive roller 9, tension roller 10, pre-transfer roller 17, and backup roller 7 in the direction of the arrow (reverse in FIG. 1). It is suspended so that it can rotate freely (clockwise).

The belt drive roller 9 is grounded and disposed on the paper discharge position side of the transfer paper P, and both ends of its support shaft 9a, which protrudes through both sides of the transfer conveyance unit 4, are connected to the main body of the apparatus. Each is supported by a unit support member 15.

As a result, the entire transfer conveyance unit 4 is configured to rotate about the support shaft 9a of the belt drive roller 9 so as to be able to move toward and away from the photoreceptor 12 (see FIG. 2).

Here, in the embodiment shown in FIG. 1, a pair of pre-transfer guide plates are provided for guiding the transfer paper P fed by the registration roller 1 to the transfer position after being fed by a paper feeding means (not shown). The lower guide plate 18a of the 18
It is configured integrally with the transfer conveyance unit 4.

Further, in this embodiment, the fixing guide plate 19, which is disposed at the paper discharge position of the transfer conveyance unit 4 and guides the transfer paper P on which the toner image has been transferred, to the fixing entrance position of the fixing device 16 is also provided. It is configured integrally with the transport unit 4.

On the other hand, the cleaning blade 8 is integrated into the frame of the transfer conveyance unit 4 so as to come into contact with the surface of the transfer belt 11 on the downstream side of the active roller 9, that is, the lower surface of the transfer belt 11 in FIG. Waste toner that adheres to the surface of the transfer belt 11 (toner that adheres to the transfer belt 11 without being transferred onto the transfer paper P during transfer), paper dust generated when the transfer paper P is transported, etc. It works to scrape off.

The waste toner and paper powder scraped off by the cleaning blade 8 are stored in a waste toner collection bowl 1 and a hell 5 that are integrally provided within the transfer conveyance unit 4 .

As described above, the transfer conveyance unit 4 configured in this manner is centered around the support shaft 9a of the belt active roller 9.
The entire structure is configured to freely rotate towards and away from the photoreceptor 12.

The movement of the transfer conveyance unit 4 toward and away from the photoreceptor 12 is performed by a unit push-up lever 2.

As shown in FIG. 1, the unit push-up lever 2 is swingably disposed around a support shaft 2a horizontally suspended below the transfer conveyance unit 4. As shown in FIG.

This swinging of the unit push-up lever 2 is performed by turning on and off a push-up lever solenoid 3 disposed to engage with the base end of the unit push-up lever 2.

That is, in FIG. 1, when the push-up lever solenoid 3 is off, the unit push-up lever 2 swings clockwise due to the weight of the transfer conveyance unit 4, and the transfer conveyance unit 4 moves clockwise around the support shaft 9a. The transfer belt 11 of the transfer conveyance unit 4 rotates, and the transfer belt 11 of the transfer conveyance unit 4
separated from 2.

On the other hand, in FIG. 1, when the push-up lever solenoid 3 is on, the unit push-up lever 2 swings counterclockwise against the weight of the transfer conveyance unit 4, and the transfer conveyance unit 4 is rotated about the support shaft 9a. As a result, the transfer belt 11 of the transfer conveyance unit 4 comes into contact with the photoreceptor 12.

The positional accuracy of the transfer belt 11 when the transfer belt 11 and the photoreceptor 12 come into contact is determined by the protrusions formed on both sides near the transfer position due to the rotation of the transfer conveyance unit 4 in the counterclockwise direction. 20 are secured by abutting and engaging flanges 12a formed at both ends (non-image area portions) of the photoreceptor 12.

Further, as described above, the transfer conveyance unit 4 is supported by the unit support member 15 of the apparatus main body so as to be detachable from the apparatus main body.

That is, in this transfer unit 4, when the push-up lever solenoid 3 is turned off and the transfer belt 11 is separated from the photoreceptor 12, the bottoms of the paper feed side and the paper ejection side are aligned in the axial direction of the photoreceptor 12. The device is configured to be placed on a pair of guide rails 14 formed on the device main body side so as to be substantially parallel to the device body.

Thereby, the transfer conveyance unit 4 can be pulled out from the main body of the apparatus along the guide rail 14 in the direction of the arrow in FIG. 3 with the transfer belt 11 separated from the photoreceptor 12.

Therefore, in this image forming apparatus, by pulling out the transfer conveyance unit 4 from the main body of the apparatus as described above, it is extremely easy to remove the transfer paper when a jam occurs and to replace and maintain the transfer conveyance unit itself. I can do it.

Note that flanges 12a formed at both ends of the photoreceptor 12
The outer diameter of the photoreceptor 12 is formed to be slightly smaller than the outer diameter of the image forming area of the photoreceptor 12 .

Therefore, as shown in FIG. 1, when the push-up lever solenoid 3 is turned on and the transfer belt 11 is in contact with the photoreceptor 12, the transfer conveyance unit 4
The protrusions 20 formed on both sides of the photoreceptor 12 are engaged with both ends of the photoreceptor 12 by contacting the flange 12a, thereby preventing the transfer conveyance unit 4 from separating from the photoreceptor 12. be done.

On the other hand, the fixing logite plate 19 disposed at the paper discharge position of the transfer conveyance unit 4 is disposed extremely close to the transfer belt 11.

In this way, the fixing entrance guide plate 19 and the transfer belt 11
By making the gap between

Transfer paper P when the transfer paper P is separated from the transfer belt 11
is prevented from being caught in the transfer belt 11, and
The cleaning blade 8 prevents waste toner scraped off from the angel and the belt 11 from scattering to the upper surface side of the transfer belt 11.

On the other hand, the casing 6a of the transfer charger 6 is grounded, and by being integrated with the transfer conveyance unit 4, it also serves as a reinforcing stay for the transfer conveyance unit 4.

Further, the charge wire 6b of the transfer charger 6 is detachably connected to a terminal of a power source (not shown) provided in the main body of the apparatus on the back side of the transfer belt 11, so that the charge wire 6b is connected to the charge wire 6b from this power source. Predetermined power is supplied.

Next, another embodiment of the present invention will be described based on FIG.

The image forming apparatus shown in FIG. 4 is characterized by being provided with a first density detection sensor 21 and a second density detection sensor 22 for detecting the density on the surface of the transfer belt 11 of the transfer conveyance unit 4. There is.

Here, the first density detection sensor 21 is disposed upstream of the cleaning blade 8 and is configured to detect the surface density of the transfer belt 11 before being cleaned.

On the other hand, the second density detection sensor 22 is disposed downstream of the cleaning plate 8 and is configured to detect the surface density of the transfer belt 11 after being cleaned.

Therefore, according to this embodiment, the surface density of the transfer belt 11 before and after cleaning the cleaning plate 8 can be compared based on the outputs of the first density sensor 21 and the second density sensor 22. According to
It is possible to detect the state of deterioration of the cleaning blade 8, and it is possible to determine when to perform maintenance or replace the transfer conveyance unit 4.

Note that here, the first concentration detection sensor 21 is omitted and the second concentration detection sensor 21 is omitted.
Only the density detection sensor 22 is arranged, and when the output value of this second density detection sensor 22 reaches the output value corresponding to the preset usage limit surface density of the transfer belt 11, the surface dirt of the transfer belt 11 is detected. The configuration may be such that the limit is notified and the timing of maintenance or replacement of the transfer conveyance unit 4 is detected.

Next, based on FIG. 5, still another embodiment of the present invention will be described.

The image forming apparatus shown in FIG. 5 is equipped with a first density detection sensor 21 and a third density detection sensor 23 for detecting the density of the toner pattern formed on the photoreceptor 12 by a predetermined process. It is a feature.

Here, the third degree detection sensor 23 is arranged at a position before the transfer position near the photoreceptor 12 and is configured to detect the density of the toner pattern before being transferred to the transfer belt 11. has been done.

On the other hand, the first density detection sensor 21 is disposed downstream of the transfer position and is configured to detect the density of the toner pattern transferred to the transfer belt 11.

Therefore, according to this embodiment, these first and second concentration sensors 21 . And based on the output of the third concentration sensor 23,
The transfer rate of the toner pattern to the transfer belt 11 can be calculated by comparing the density before and after the transfer of the toner pattern.
It is possible to judge the lifespan of the toner 1 and adjust the toner density by changing the transfer conditions.

Next, based on FIG. 6, still another embodiment of the present invention will be described.

The image forming apparatus shown in FIG. 6 is characterized in that a surface potential detection sensor 24 for detecting the surface potential of the transfer belt 11 is provided.

Here, the surface potential detection sensor 24 is disposed downstream of the transfer position of the transfer belt 11 and is configured to detect the surface potential of the transfer belt 11.

Therefore, according to this embodiment, the surface potential detection sensor 24
Based on the surface potential of the transfer belt 11 detected by the transfer belt 11, the life of the transfer belt 11 can be determined and its transfer current can be controlled.

Next, still another embodiment of the present invention will be described based on FIGS. 7 and 8.

This embodiment is characterized in that the driving force is transmitted to the driving roller 9 that drives the transfer belt 11 via a torque limiter 25, as shown in FIG.

That is, in this embodiment, the power of the liver power source (motor) 35 is first transmitted to the input gear 25a of the torque limiter 25 via the drive gear 36.

Next, the power transmitted to the input gear 25a of the torque limiter 25 is as shown in FIG.

It is transmitted to the output shaft 25b of the torque limiter 25 using magnetism.

The output shaft 25b of this torque limiter 25 is.

It is integrally attached to the support shaft 9a of the drive roller 9 that drives the transfer belt 11.

Accordingly, the power transmitted to the output shaft 25b is transmitted to the drive roller 9 of the transfer belt 11.

Here, the transmission torque (magnetic force) of the torque limiter 25 may be affected by deterioration of the cleaning blade 8 or transfer belt 1.
1, the load torque on the drive roller 9 increases and the transfer belt 11 cannot operate normally, when the input gear 25a of the torque limiter 25 It is set in advance so that slippage occurs between the output shaft 25b and the output shaft 25b.

That is, according to this embodiment, the deterioration of the cleaning blade 8 and the deterioration of the bearings such as the drive roller 9 that drives the transfer belt 11 become severe, and the load torque of the active roller 9 increases, causing the transfer belt 11 to deteriorate. The rotation of the drive roller 9 is stopped when it can no longer operate normally.

Accordingly, it is possible to detect an abnormality in the transfer conveyance unit 4, and it is possible to determine when to perform maintenance or replace it.

Here, as the driving means for the transfer belt 11, the pre-transfer roller 17 on the transfer position side may be configured as a driving roller for the transfer belt 11.

On the other hand, in addition to the above-mentioned embodiments, for example, as shown in FIG. Even if the waste toner full detection sensor 26 is provided, it is possible to determine when the transfer and conveyance unit 4 should be maintained or replaced.

That is, here, the time required until the waste toner stored in the waste toner collection bottle 5 becomes full.

In other words, if the capacity of the waste toner collection bottle 5 is set in advance so that the capacity life of the waste toner collection bottle 5 and the life of the transfer belt 11 are the same, the waste toner full detection sensor 2 Due to the operation of the transfer conveyance unit 4
You can know when to replace it.

Furthermore, according to this detection method, the transfer belt 11 reaches the end of its service life at the same time that the waste toner stored in the waste toner collection bottle 5 becomes full, so that the transfer belt 11 reaches the end of its service life when the waste toner is full. This eliminates the need for troublesome work such as disposing of waste toner during use of the device.

By the way, like this transfer conveyance unit 4.

When the relatively wide endless transfer belt 11 is configured to be rotationally driven, as the transfer belt 11 rotates, the transfer belt 11 may gradually shift to one end side or meander. I often do this.

Therefore, in the embodiment of the present invention, as shown in FIG.
The width of the transfer belt 11 is formed to be larger than the width of each roller, and the transfer belt 11 is formed on the outer side of both ends of each roller.
It is configured so that both ends of the

As a result, due to its own elasticity, the transfer belt 11
Tension that tends to extend outward on both sides acts to prevent the transfer belt 11 from meandering.

Here, it is sufficient that at least one roller is formed to have a width smaller than the width of the transfer belt 11, and it is not necessary to form the width of all the rollers to be smaller than the width of the transfer belt 11.

Furthermore, the transfer belt 11 used in this embodiment is as follows:
As shown in FIG. 10, a belt-shaped elastic body 11a made of a material with high elasticity is attached to both ends of the elastic body 11a to improve the effect of preventing the transfer belt 11 from shifting when it is stretched. It may be something that has been done.

Furthermore, as shown in the cross section of FIG. 11, the transfer belt 11 used in this embodiment is formed so that the thickness of both ends of the transfer belt 11 is thicker than the thickness of other parts. The structure may be such that the meandering prevention effect of the transfer belt 11 is improved by increasing the rigidity of the end portions.

Further, the shapes of the drive roller 9, pre-transfer roller 17, etc. that stretch the transfer belt 11 are as follows:
: As shown, it is preferable to use a drum-shaped roller in which the outer diameter of the roller gradually increases toward the center.

Further, as another means for preventing the transfer belt 11 from shifting or meandering, as shown in FIG. 13.

In addition to forming ribs llb on both side ends of the transfer belt 11, as shown in FIG.
By engaging the ribs llb at both ends of the transfer belt 11,
It may be configured to prevent the transfer belt 11 from shifting and meandering.

Next, another embodiment of the present invention will be described.

This embodiment is characterized in that a bias roller for transfer is used instead of the transfer charger 6 as the transfer means disposed in the transfer conveyance unit 4.

That is, in this embodiment, as shown in FIG. 15, the transfer belt 11 is stretched between a transfer bias roller 27 and a drive roller 9, which are arranged in the transfer conveyance unit 4.

Further, the cleaning blade 8 and the waste toner collection bottle 5 are also integrally supported within the transfer conveyance unit 4.

Here, the transfer bias roller 27 is configured to be detachable from the apparatus main body, and is configured to receive power by being coupled to a power supply terminal on the apparatus main body side.

Further, the transfer belt 11 is formed of an elastic belt, and its width is configured to be larger than the width of the transfer bias roller 27, as shown in FIG.

Both ends of the transfer belt 11 are stretched around both ends of the transfer bias roller 27 to prevent the transfer belt 11 from meandering.

Furthermore, the width of the photoconductor 12 is determined by the transfer bias roller 27.
The width of the photoreceptor 1 is shorter than the width of the photoreceptor 1.
The entire surface of the image forming area 12A of No. 2.

It is configured to be in contact with the transfer belt 11.

Also, at both ends of the transfer bias roller 27.

In order to prevent leakage to the photoreceptor 12, the insulator portion 2
7a is provided.

Here, as another method for preventing meandering of the transfer belt 11, for example, as shown in FIG.
Ribs llc may be provided at both ends of the inner peripheral side of the transfer bias roller 27, and these ribs llc may be engaged with both ends of the transfer bias roller 27, or the method shown in FIGS. 9 to 12 described above may be used. Then, the transfer belt 11 and the transfer bias roller 27
may be engaged with.

FIG. 18 shows still another embodiment of the transfer conveyance unit according to the present invention.

In this embodiment, among the various means other than the transfer means arranged around the photoreceptor 12, a pre-transfer static elimination lamp 29, a separating claw 30 for separating the transfer paper from the photoreceptor 12 after transfer, and a photoreceptor A feature is that the waste toner storage section 31a of the cleaning device 31 is integrated with the transfer conveyance unit 4.

FIG. 19 shows still another embodiment of the transfer conveyance unit according to the present invention.

In this embodiment, the aforementioned transfer bias roller 27 is used as a driving means for the transfer belt 11, and
This transfer bias roller 27 and the transfer conveyance unit 4
A belt sliding member 3 formed into a semi-cylindrical shape by being integrated with the
2 is characterized in that the transfer belt 11 is stretched.

Here, the transfer bias roller 27 has a resistance value of 101 to improve its function as a drive roller.
It is preferable to use a rubber roller with a resistance of 3Ω.

Furthermore, in order to reduce the coefficient of friction between the belt sliding member 32 and the transfer belt 11, the surface of the belt sliding member 32 that slides against the transfer belt 11 is subjected to processing such as fluorine coating.

FIG. 20 shows still another embodiment of the transfer conveyance unit according to the present invention.

In this embodiment, a transfer charger 6 is used as the transfer means, and a semi-cylindrical belt sliding part 33 similar to the belt sliding member 32 described above is integrally formed on the casing 6a of the transfer charger 6. This belt sliding part 3
3 and a drive roller 9, the transfer belt 11 is stretched in tension.

Further, this allows the casing 6a of the transfer charger 6 to have a backup function for causing the photoreceptor 12 to press the transfer belt 11.

The backup function of the transfer charger is described in detail in Japanese Utility Model Application Publication No. 54-168845, so the explanation thereof will be omitted here.

By the way, as shown in FIG. 15, a transfer bias roller made of an elastic body is used as the transfer means disposed in the transfer conveyance unit 4, and the transfer bias roller 27 and the separation roller 9, When the transfer belt 11 is stretched, the transfer bias roller 27 and the photoreceptor 12 are pressed against each other, as shown in FIG. The width B becomes larger.

Therefore, if the separation position A of the transfer paper from the photoreceptor 12 is located at the nip between the photoreceptor 12 and the transfer belt 11, the recess of the transfer bias roller 27 that is generated at this nip As a result, the direction in which the transfer belt 11 is stretched and the direction in which the transfer paper is conveyed are different from each other, so that the transfer paper is separated by the curvature of this nip portion, making it impossible to convey the transfer paper smoothly.

Therefore, in this type of transfer means according to the present invention, as shown in FIG. A is set.

As a result, the stretching direction of the transfer belt 11 and the conveyance direction of the transfer paper can be made to match each other, and separation of the transfer paper due to the curvature of the nip portion is prevented, and smooth conveyance of the transfer paper is realized. Ru.

FIG. 22 shows still another embodiment of the image forming apparatus according to the present invention.

In this embodiment, a registration roller 1, a transfer conveyance unit 4
, the fixing device 16, the pre-transfer guide plate 18°, and the fixing entrance guide plate 19 are integrally supported by the housing member 34.

That is, as shown in FIG. 22, the housing member 34 includes the registration roller 1, the transfer conveyance unit 4, the fixing device 16,
It is formed to be large enough to accommodate the pre-transfer guide plate 18, the guide plate 19, and the fixing entrance guide plate 19.

Here, in the illustrated embodiment, an example is shown in which the transfer conveyance unit 4 and the housing member 34 that houses the entire unit are formed independently and are integrally fixed. The housing member may be formed into one container.

In this way, the registration roller 1, the transfer conveyance unit 22,
Fixing device 16, pre-transfer guide plate 18. By integrally supporting the fixing Rokaido plate 19 with the housing member 34, the registration roller 1 and the transfer conveyance unit 4 can be attached and removed from the main body of the apparatus.
, and a fixing device! 16 can be maintained and replaced extremely easily.

Further, as described above, the registration roller 1, the transfer conveyance unit 4, the fixing device 16. By integrally supporting the pre-transfer guide plate 18, the fixing plate 19, and the housing member 34, the registration rollers 1, pre-transfer guide plate 18, and transfer belt 11 can be moved against the photoreceptor 12 at the transfer section. Since the positional accuracy becomes accurate, it is possible to prevent the transfer paper from jamming or folding at the transfer section, and the transfer section of the image. Since the positional accuracy of the belt 11 at the separating section becomes accurate, it is possible to prevent jamming and folding of the transfer paper at this transfer section, as well as blurring and rubbing of the image.

Next, the differences in the principle process of the embodiment of the present invention configured as described above will be explained while comparing it with the basic process in a conventional image forming apparatus.

Here, in order to avoid complication, descriptions of well-known processes that are common to conventional basic processes, such as charging, exposure, erasing, development (monochrome or color), and pre-transfer static elimination, will be provided. Omitted.

FIG. 23 shows the principle process of an embodiment of the present invention, FIG. 24 shows the transfer paper conveyance process in the same embodiment, and FIG. 25 shows the basic process of a conventional image forming apparatus.

In FIGS. 23 and 24, the registration roller 1
The transfer paper P, which has been fed until then and has been on standby, is supplied toward the transfer section in synchronization with the rotation of the photoreceptor 12 in time with the rotation of the photoreceptor 12.

When the leading edge of the transfer paper P is supplied to the vicinity of the contact area between the photoreceptor 12 and the transfer belt 11, at the same time; the unit push-up solenoid 3 causes the unit push-up lever 2 to move the cleaning blade 8, transfer charger 6, ,
The transfer conveyance unit 4 including the hack up roller 7 and the waste toner collection bottle 5 is pushed up.

As a result, the transfer belt 11 comes into contact with the photoreceptor 12 with a predetermined nip width due to the action of the backup roller 7.

At this time, for the transfer charger 6 at the same time.

A predetermined voltage is applied, and a negative charge is applied to the transfer belt 11.

Here, the transfer charger 6 is composed of a corona discharger constructed by stretching a thin tungsten wire, and is connected to the photoreceptor 1.
The grounded conductor portion inside 2 serves as a counter electrode.

Further, the transfer belt 11 has an electrical resistance value.

It is composed of a semiconductor belt (already known from Japanese Patent Laid-Open No. 53-96838 by the same applicant as the present application) with a gloss of 101 to 1013 Ω.

Therefore, in the vicinity of the photoreceptor 12 of this transfer belt 11,
A negative charge is charged, the transfer paper P is polarized by this negative charge, and an electrostatic attraction is generated by the true charge on the transfer belt 11 and the polarized charge of the transfer paper P, and the transfer paper P is moved toward the transfer belt 1.
It is adsorbed onto 1.

On the other hand, the positively charged toner particles on the photoreceptor 12 are
As shown in the figure, by considering the transfer belt 11, the transfer paper P, and the gap G as dielectric bodies with different permittivity, the electrostatic attraction caused by the negative charge applied by the transfer charger 6 causes the transfer paper to transferred onto P.

At this time, the surface potential of the photoreceptor 12 is normally set to around 800V, so if the surface potential of the transfer belt 11 is set in advance to 2kV to 3kV by application of the transfer charger 6, it can be stabilized. It is possible to achieve a high-quality transfer.

In this embodiment, in order to make this transfer more reliable, the backup roller 7 brings the transfer belt 11 and the photoreceptor 12 into contact with each other with a sufficient nip width, thereby increasing the transfer efficiency. ing.

(Transfer paper sheet on which toner particles have been transferred as described above)
is conveyed toward the fixing section while being attracted onto the transfer belt 11 by electrostatic attraction.

Therefore, in the principle process of the present invention, the process of separating the transfer paper P using a separation charger or a separation claw in the conventional basic process shown in FIG. 2S is not necessary.

In other words, in the conventional basic process, in the transfer step,
A separate charger (AC
), the transfer paper P is separated by removing the static electricity and eliminating the adhesion force between the photoreceptor 12 and the transfer paper P.

Furthermore, in the conventional basic process, a separation claw is required to ensure separation of the transfer paper P.

In addition, in the principle process of the present invention, the transfer belt 11 has the function of conveying the transfer paper P, so the transfer paper conveyance belt used in the transfer paper conveyance section (not shown) in the conventional basic process, There is no need for a suction fan for sucking the transfer paper onto the transfer paper conveyance belt.

By the way, the transfer paper P transferred and conveyed by the principle process of the present invention passes through the transfer belt 11 from the ground roller (drive roller 9 in the illustrated example) during the conveyance.
The amount of charge is gradually relaxed.

Then, the transfer paper P whose electrostatic attraction has been weakened as described above has a small diameter (for example, φ20) at the entrance of the fixing section.
Due to the curvature separation due to the stiffness of the grounding roller 9 and the transfer paper P, it is separated from the transfer belt 11 and sent to the fixing section.

On the other hand, the rear end of the transfer paper P is connected to the photoreceptor 12 and the transfer belt 11.
At the same time as the transfer unit 4 exits the nip portion, the unit push-up solenoid 3 is turned off, and the transfer conveyance unit 4 separates from the photoreceptor 12.

This prevents deterioration of the photoreceptor 12 due to friction caused by contact between the photoreceptor 12 and the transfer belt 11.

In addition, in the transfer process, residual toner that is not transferred onto the transfer paper P but is scattered and directly attached to the transfer belt 11 during conveyance is reduced in the amount of charge by the grounding roller 9 and then removed by the cleaning blade 8. The waste toner is scraped off from the top of the transfer belt 11 and collected into the waste toner collection bottle 5.

Here, in order to improve the cleaning performance of the transfer belt 11, it is necessary to form the transfer belt 11 from a material with good release properties, or to coat the outer peripheral surface of the transfer belt 11 with a substance that improves release properties. There is.

Therefore, in this embodiment, a transfer belt 1 is coated with fluorine on the surface of a belt made of urethane rubber.
1 is used.

Further, in this embodiment, as described above, the transfer belt 11
Semiconductors are used as materials.

This is because if a conductive belt is used as the transfer belt 11, the charge from the transfer charger 6 will escape and the toner will no longer be transferred to the transfer paper P. Conversely, if an insulating belt is used as the transfer belt 11, the charge will escape from the transfer charger 6 and the toner will not be transferred to the transfer paper P. It becomes impossible to gradually relieve the charge on this belt by the roller 9,
A static eliminating device such as a static eliminating charger is required.

(Effects of the Invention) According to the present invention, when the dielectric belt is stretched, both ends of the dielectric belt are connected to the opening of the private member,
Alternatively, it is held at both ends of the drive roller, etc.
Meandering and deviation of the dielectric belt can be prevented.

[Brief explanation of the drawing]

1 is a schematic cross-sectional view of a transfer conveyance unit in an embodiment of the present invention, FIG. 2 is a schematic cross-sectional view showing the operation mode of the transfer conveyance unit, FIG. 3 is a schematic perspective view of the transfer conveyance unit, and FIG. The figure is a schematic cross-sectional view of another transfer conveyance unit in an embodiment of the present invention, FIG. 5 is a schematic cross-sectional view of still another transfer conveyance unit in an embodiment of the present invention, and FIG. A schematic cross-sectional view of another transfer conveyance unit, FIG. 7 is a plan view showing a method of tensioning the transfer belt in the transfer conveyance unit, and FIG. 8 is a schematic cross-sectional view of a torque limiter arranged in the drive means for the transfer belt. , FIG. 9 is a plan view showing another method of tensioning the transfer belt in the transfer conveyance unit, FIG. 10 is a partial sectional view of an example of the transfer belt, and FIG. 11 is a portion of another example of the transfer belt. 12 is a schematic side view of a roller that stretches the transfer belt, FIG. 13 is a partial sectional view of still another example of the transfer belt, and FIG. 14 is a schematic side view of a roller that stretches the transfer belt. FIG. 15 is a schematic sectional view showing another stretching method, FIG. 15 is a schematic sectional view of still another transfer conveyance unit in an embodiment of the present invention, and FIG.
Schematic perspective view of the transfer section of the transfer unit shown in FIG. 5, No. 17
FIG. 18 is a side view of only the transfer section showing another method of tensioning the transfer belt in the transfer unit shown in FIG. 15, FIG. 20 is a schematic sectional view of still another transfer conveyance unit in the embodiment of the present invention, FIG. 21 is a schematic sectional view of still another transfer conveyance unit in the embodiment of the present invention, and FIG. 22 is a schematic sectional view of still another transfer conveyance unit in the embodiment of the present invention, FIG. 23 is an explanatory diagram of the principle process in the embodiment of the present invention, and FIG. Explanatory diagram of the transfer paper conveyance process in the embodiment of the invention, 2nd
FIG. 5 is an explanatory diagram of the basic process in a conventional image forming apparatus, and FIG. 26 is an explanatory diagram of the transfer step of the principle process in an embodiment of the present invention. 1... Registration roller, 4... Transfer conveyance unit,
5...Waste toner collection bottle, 6° transfer charger,
7... Backup roller, 8... Cleaning plate, 9... Drive roller, 11... Transfer belt,
12... Photoreceptor, 17... Pre-transfer roller, 27...
- Transfer bias roller, 34...accommodating member. (1 other person) Beg 45 Kuni Tsui 5 I 61! 1 Tsuta 1? q and /7 Tsutsushi I35 Father begging? 'f D

Claims (1)

[Claims] 1. On the recording medium conveyed toward the image information carrier,
In the transfer device for transferring image information held on the image information carrier, the transfer device includes a dielectric belt;
The dielectric belt is composed of a driving means for driving the dielectric belt, and a housing means that houses the dielectric belt and the driving means and has an opening formed on the transfer surface side of the recording medium, and the dielectric belt A transfer device characterized in that projections provided at both ends of the transfer device are engaged with openings of the storage means. 2. The transfer device according to claim 1, wherein the housing means houses cleaning means for removing toner adhering to the surface of the dielectric belt. 3. The transfer device according to claim 2, wherein the storage means is provided with waste toner storage means for storing waste toner collected by the cleaning means. 4. Glue or weld elastic members having an elastic modulus higher than that of the dielectric belt to both ends of the dielectric belt, and set the length in the width direction of the roller on which the dielectric belt is stretched. 2. The transfer device according to claim 1, wherein the length of the dielectric belt is shorter than the widthwise length of a portion of the dielectric belt where the elastic member is not provided. 5. Both ends of the dielectric belt are formed to be thicker than other parts of the dielectric belt, and the length in the width direction of the roller that stretches the dielectric belt is set to be thicker than the other parts of the dielectric belt. 2. The transfer device according to claim 1, wherein the length in the width direction of the unformed portion is shorter.