JP4625312B2 - Image forming apparatus - Google Patents

Description

The present invention relates to an image forming apparatus using an electrophotographic method with a transfer device for transferring peeling the toner image on the photosensitive member to the paper.

  In a transfer device of a cut paper laser printer or a copying machine using an electrophotographic method, there is a method of using a transfer material made of a dielectric belt or an insulating drum for the purpose of conveying a transfer material such as paper and transferring and peeling. In this transfer belt system, charges are induced on the belt surface by corona discharge from the back surface of the dielectric belt, and the sheet is attracted and conveyed by this charge, and the image formed on the drum is applied to the sheet. Transcript. Thereafter, the charge at the leading edge of the sheet is removed so that the sheet in close contact with the photosensitive member is easily peeled off.

Compared to the corotron transfer method that transfers and separates by corona discharge, which is widely used in the past, a mechanism that presses the paper against the drum and then separates it becomes unnecessary, so the paper can be transported stably with a simple configuration. There is. Further, since the transfer is performed by bringing the paper into close contact with the photosensitive member by the belt, the image quality is superior to that of corotron transfer, and there is an advantage that printing can be performed uniformly from the leading edge to the trailing edge of the paper.
On the other hand, as the transfer belt is used, it is exposed to ozone generated by corona discharge, and the electrical resistance and elastic modulus fluctuate and deteriorate due to friction with the paper. When the electrical resistance fluctuates greatly, the efficiency of transferring the toner image onto the paper, that is, the transfer efficiency is lowered, so that the image quality deteriorates. Also, the transfer belt is supported by applying tension to both ends with rollers, and one of the rollers is driven. Therefore, if the elastic modulus changes, the moving speed changes, resulting in a speed difference from the photoreceptor. Becomes prominent. As a result, the print quality deteriorates, such as character blurring of the image transferred to the paper. Therefore, in the transfer belt system, it is necessary to replace the transfer belt when the transfer belt deteriorates.

In general, in the case of a configuration having at least a plurality of rolls such as a roll for driving the belt and a tension roll for stretching the belt, a roll moving mechanism for moving at least one rotation shaft from the rotational drive position to another roll direction is provided. It has been proposed to perform belt replacement work by providing and releasing the tension of the belt (see, for example, Patent Document 1).
In addition, there has been proposed a belt replacement work that can be performed while the unit is pulled out forward of the apparatus main body without moving the unit from the apparatus main body to another location (see, for example, Patent Document 2).
Further, in the configuration having three rollers in the belt, both ends of the first and second rollers are supported by a pair of blades, and both ends of the third roller are arranged outside the blades, There has been proposed a belt having a belt attaching / detaching function supported by a tension blade which is slidable (see, for example, Patent Document 3).
Further, the transfer device is composed of a transfer belt holding unit for holding the transfer belt and a storage unit for mounting the transfer belt holding unit, and the transfer device is transferred by a holding member having the same phase shape as the connecting shaft provided in the storage unit. The structure which hold | maintains a belt holding | maintenance unit is proposed (for example, refer patent document 4).

  Furthermore, a high voltage power supply method has been proposed in which a helical spring is pressure-bonded to a power supply plate to facilitate assembly of the high voltage power supply member and to reliably stabilize power supply and reception (for example, Patent Document 5). reference).

Japanese Patent Laid-Open No. 08-123294

Japanese Patent Laid-Open No. 05-213472

JP 05-018449 A

Japanese Patent Laid-Open No. 2003-076150

Japanese Patent Laid-Open No. 06-181071

As described above, in order to facilitate maintenance in printers and copiers, the transfer belt is configured as a unit, the unit is mounted in a retractable storage mechanism, and can be easily detached from the main unit, and the unit when the transfer belt is at the end of its life There is a method to exchange every time. In this case, since a storage mechanism for storing the slide rail and the unit is required, the number of parts increases and the cost increases. In addition to the above-described rollers, a corona transfer device and a support roller for pressing the transfer belt against the photosensitive member are incorporated in the transfer belt. Of these, only the transfer belt deteriorates mainly in function, but when replacing the unit, these built-in parts are also replaced. Therefore, in a printer that performs printing in large quantities, replacement for each unit is not possible. The cost for maintaining the apparatus, that is, the running cost will increase.
On the other hand, if only the transfer belt is to be replaced by the unit configuration method, the internal parts inside the transfer unit must be removed and reattached, which takes time. During maintenance such as replacement of normal parts, the apparatus is stopped and the work is performed. Therefore, the apparatus must be stopped for a long time when the transfer belt is replaced. If the maintenance takes a long time in this way, not only will there be any problems in the work during that time, but the maintenance cost will be enormous.

  The present invention relates to a toner image carrier, a transfer belt that sucks and conveys a transfer material, a transfer belt holding unit that holds the transfer belt, and a transfer that imparts a charge opposite in polarity to the toner to the back surface of the transfer material. In the transfer device of the image forming apparatus, the image forming apparatus includes: a transfer device; a high-voltage power supply unit that supplies a high-voltage power supply to the transfer device; and a charge-eliminating unit that neutralizes charges at the tip of the transfer material that is in close contact with the toner image carrier. A power supply unit is provided on the image forming apparatus side, and the high-voltage power supply unit is capable of following up and down operations of the transfer device.

  According to the present invention, since the transfer device and the transfer belt holding unit can be easily detached and the transfer belt can be replaced without complicating the configuration of the device, the cost of the device and maintenance can be reduced.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of an image forming apparatus of the present invention. In the case of an organic photoconductor (OPC) used in a copying machine, a printer, etc., the surface of the photoreceptor 1 is negatively charged by corona discharge of the charger 2. In the reversal development method often used in printers, a latent image is formed by an optical system 3 such as a semiconductor laser, and a negative polarity toner 5 having the same polarity as the potential of the surface of the photoreceptor 1 is developed on the photoreceptor 1 by the developing machine 4. Adhere to. The paper 6 conveyed by the paper travel member reaches the transfer belt 8 through the guide plate 7. The transfer belt 8 is supported at both ends by a driving roller 9 and a driven roller 10, and rotates in the arrow direction when the driving roller 9 rotates. Since a high voltage is applied from the high voltage power supply 13 to the transfer wire 12 of the transfer device 11 provided inside the transfer belt, a charge having a polarity opposite to that of the toner is generated on the surface of the transfer belt 8 by corona discharge. . The conveyed paper 6 transfers the toner image by this electric charge, and at the same time, adsorbs the paper 6 to the transfer belt 8 and conveys it. Thereafter, since a high voltage is applied to the peeling wire 14 of the transfer device 11 from the high voltage power supply 15, the leading edge of the sheet is neutralized by corona discharge, and the sheet 6 conveyed by the transfer belt 8 is transferred to the driving roller 9. Then, after being neutralized by the static eliminator 16, the toner is fixed by the fixing device 17, and the toner remaining on the photoreceptor 1 after the transfer is cleaned by the cleaner 20 through the precharge 18 and the erase lamp 19. .

  As described above, as the transfer belt 8 is used, the characteristic values such as electric resistance and elastic modulus change with time, so that the transfer belt 8 needs to be replaced periodically. In the present invention, in order to easily replace the transfer belt 8, the following configuration is adopted.

  As shown in FIG. 2, the transfer device 21 includes a transfer belt holding unit 22 and a storage unit 23 that are independent of each other. The transfer belt holding unit 22 includes a transfer belt 8, a driving roller 9, a driven roller 10, a transfer device 11, and the like. On the other hand, the storage unit 23 includes a metal plate frame, an electrical cable for controlling electrical components, and the like.

  A method of removing the transfer device 21 will be described with reference to FIGS. First, as shown in FIG. 3, first, the transfer device 21 is lowered from the position in the normal printing state to the position at the time of jam clear. At this time, as shown in FIG. 4, the high-voltage power supply unit 28 provided in the housing of the image forming apparatus rotates around the rotation center shaft 37 and moves in parallel through the long hole 35 provided in the high-voltage power supply unit 28. In addition, the electrode part 33 of the high-voltage power supply part 28 also has a structure that rotates around the rotation center shaft 38. As a result, the transfer device 11 fixed to the transfer device 21 can rotate around the drive roller 9.

  FIG. 5 shows a configuration diagram of the high-voltage power supply unit 28. The high voltage power supply unit 28 includes an electrode unit 33, a sheet metal holder 39, a resin holder 40, a torsion coil spring 41, and a high voltage power supply unit temporary fixing member 34.

  The sheet metal holder 39 is provided with three projecting members 36 for attaching the high voltage power supply unit 28 to the transfer device 21. The resin holder 40 includes a fixing member 42 that fixes the end 41 a of the torsion coil spring 41, a stopper 43 that stops the electrode portion 33 at a predetermined position as the electrode portion 33 rotates, and a high-voltage power feeding portion 28. A stopper 29 for stopping at a predetermined position is provided. The electrode part 33 and the sheet metal holder 39 are fixed by screws 44, and the high-voltage power supply part temporary fixing member 34 is fixed to the resin holder 40 by screws 47.

  Further, the resin holder 40, the sheet metal holder 39, and the torsion coil spring 41 are fixed by screws 45 and nuts 46. At this time, the torsion coil spring 41 is incorporated in the sheet metal holder as shown by the arrow in FIG.

  Next, the holder 24 fastened to the roller 9 for driving the transfer material, which is provided with the roller for preventing surface damage when the photosensitive member is pulled out as shown in FIG. 3, is removed. Thereafter, as shown in FIG. 6, the transfer device 21 is pulled out along the guide plates 25 and 26 provided in the housing of the image forming apparatus. At this time, the high voltage power supply unit 28 provided in the housing of the image forming apparatus is stopped at a predetermined position by the stopper 29 provided in the resin holder 40 and the high voltage power supply unit provided on the back side of the high voltage power supply unit 28. It is temporarily fixed by the temporary fixing member 34.

  Further, after the transfer device 21 is removed, the torsion coil spring 41 provided in the sheet metal holder 39 always applies a rotational force in the clockwise direction so that the electrode portion 33 of the high-voltage power feeding unit 28 does not rotate counterclockwise by an external force such as its own weight. The stopper 43 is in a fixed position. Accordingly, as shown in FIG. 7, the terminal portion 11 a of the transfer device 11 can be securely attached to the electrode portion 33 of the high-voltage power feeding portion 28 by being inserted along the guide plates 25 and 26 when the transfer device 21 is attached. If the positions of the transfer device 21 and the high-voltage power supply unit 28 do not match, the three protruding members 36 provided on the high-voltage power supply unit 28 abut against the storage unit 23 of the transfer device 21 and attach the transfer device 21. It has a structure that cannot be done. Accordingly, it is possible to prevent the transfer device 21 from being attached in a state where the terminal portion 11 a of the transfer device 11 is not aligned with the electrode portion 33 of the high-voltage power supply portion 28.

  Finally, a method for removing the transfer belt 8 will be described with reference to FIGS. FIG. 8 is an enlarged view of the transfer belt holding unit 22, and FIG. 9 is an enlarged view of the storage unit 23. As shown in FIG. 8, a parallel portion 31 in the arc-shaped portion of the holding member 27 is formed at the end of the driving roller 9 in the transfer belt holding unit 22. Further, as shown in FIG. 9, a parallel portion 32 of a notch hole is formed in the fixing portion of the transfer belt holding unit 22 of the storage unit 23.

  First, as shown in FIG. 10, the transfer belt holding unit 22 is rotated in the A direction around the roller 9 that drives the transfer material, and the parallel portion 31 and the storage unit 23 in the arc-shaped portion of the drive roller holding member 27 are rotated. The parallel part 32 of the notch hole of the fixing part of the transfer belt holding unit 22 is aligned. Next, when both are parallel, the transfer belt holding unit 22 can be removed from the storage unit 23 by pulling out the transfer belt holding unit 22 in the direction of arrow B. Then, the tension of the transfer belt 8 is released by removing the screw 30 of the holding member of the roller 9 that drives the transfer material and rotating the driving roller holding member 27 in the C direction as shown in FIG. The transfer belt 8 can be removed.

1 is a configuration diagram of an image forming apparatus of the present invention. It is a block diagram of a transfer apparatus. It is a figure showing the position of the transfer apparatus at the time of jam clear. It is a figure showing the position of the high voltage electric power feeding part provided in the housing | casing of an image forming apparatus. It is a block diagram of a high voltage electric power feeding part. FIG. 6 is a diagram illustrating a state in which the transfer device is pulled out by a guide plate provided in a housing of the image forming apparatus. It is a figure when a high voltage electric power feeding part is attached to the transfer apparatus. It is an enlarged view of a transfer belt holding unit. It is an enlarged view of a storage unit. It is a figure which shows the removal method of a transfer belt holding | maintenance unit. It is a figure which shows the removal method of a transfer belt.

Explanation of symbols

  1 is a photosensitive member, 2 is a charger, 3 is an optical system, 4 is a developing machine, 5 is toner, 6 is paper, 7 is a guide plate, 8 is a transfer belt, 9 is a driving roller, 10 is a driven roller, and 11 is Transfer device 11a is a transfer device feeding terminal portion, 12 is a transfer wire, 13 is a high voltage power source, 14 is a peeling wire, 15 is a high voltage power source, 16 is a static eliminator, 17 is a fixing device, 18 is a precharge, 19 is Erase lamp, 20 is a cleaner, 21 is a transfer device, 22 is a transfer belt holding unit, 23 is a storage unit, 24 is a holder, 25 is a guide plate, 26 is a guide plate, 27 is a drive roller holding member, and 28 is a high-voltage power supply unit. , 29 is a stopper, 31 is a parallel portion in the arc-shaped portion of the holding member 27, 32 is a parallel portion of a notch hole in the transfer belt holding unit fixing portion of the storage unit 23, 33 is an electrode portion, and 34 is a temporary high-voltage power feeding portion. Fixing member, 35 A long hole, 36 is a projecting member, 37 is a rotation center axis of the high-voltage power supply unit, 38 is a rotation center axis of the electrode unit, 39 is a sheet metal holder, 40 is a resin holder, 41 is a torsion coil spring, 41a is an end of the torsion coil spring , 42 is a fixing member, 43 is a stopper, 30, 44, 45 and 47 are screws, and 46 is a nut.

Claims (4)

A toner image carrier;
A transfer belt that sucks and conveys a transfer material;
A transfer belt holding unit for holding the transfer belt;
A transfer device for applying a charge having a polarity opposite to that of the toner to the back surface of the transfer material;
A high-pressure feeding unit for supplying high voltage power to the transfer device,
In the image forming apparatus having a charge eliminating unit for neutralizing the transfer material tip of charge in close contact with the toner image carrier,
The transfer belt, the transfer belt holding unit, the transfer device, and the charge eliminating portion constitute a transfer device,
The high voltage power supply unit is provided on the image forming apparatus side, the rotation center of the high voltage power supply unit rotating with respect to the housing of the image forming apparatus, and the transfer device rotating with respect to the housing of the image forming apparatus. The transfer device is arranged at a position different from the center of rotation, and the transfer device is rotated with respect to the housing of the image forming apparatus to lower the transfer device from the position of the normal printing state. It can be rotated with respect to the casing of the image forming apparatus following the up and down movement of the image forming apparatus ,
The high pressure feed unit is a structure in which an electrode portion and a resin holder, the electrode portion, said rotatable relative to the resin holder, and is stopped at more predetermined positions of the resin holder torsion coil spring and the stopper An image forming apparatus.   The high-voltage power supply unit is engaged with a storage unit that mounts the transfer belt holding unit, so that the high-voltage power supply unit is held at a predetermined position of the casing of the image forming apparatus even when the transfer unit is detached alone. The image forming apparatus according to claim 1.   The high-voltage power supply section is provided with a protruding member for attaching the transfer device, and when the high-voltage power supply portion is not disposed at a regular position with respect to the transfer belt holding unit, the transfer device is not attached. The image forming apparatus according to claim 1, wherein:   2. The high-voltage power supply unit is temporarily fixed to a housing of the image forming apparatus by a high-voltage power supply unit temporary fixing member provided in the high-voltage power supply unit when the transfer device is attached. Image forming apparatus.

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