JPH0738094B2 - Image forming device corona discharger - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to mutual position adjustment of a photoconductor and a corona discharger in an image forming apparatus including a belt-shaped photoconductor having a deviation adjusting roller.

2. Description of the Related Art In electrostatic copying machines, there are several known mechanisms for releasing the corona discharger from the photoconductor in order to remove the transfer paper from around the photoconductor when jammed, and when setting this corona discharger. In addition, some of them also have means for restricting the photoconductor and the corona discharger to a predetermined distance. However, in most of these cases, as in the case of the drum-shaped photoconductor, the photoconductor is not displaced. Therefore, the belt-shaped photoconductor is used, and it is possible to prevent the belt-shaped photoconductor from being biased by the deviation adjusting roller. In a copier that is adjustable, the position of the belt-shaped photoconductor is displaced by the adjustment of the deviation adjustment roller, and the gap between the belt-shaped photoconductor and the corona discharger is changed. However, the separation performance varies.

An object of the present invention is to provide a corona discharger in which even if the belt-shaped photoconductor is displaced by a deviation adjustment operation, the belt-shaped photoconductor is followed and the constant distance is always maintained. is there.

Structure The present invention is an image forming apparatus provided with a corona discharger that faces a belt-shaped photoconductor having a deviation adjusting roller and applies an electric charge to the belt-shaped photoconductor. The end block of the corona discharger comes into contact with the side plate for adjusting the deviation roller when the corona discharger is brought close to the photoconductor side, and the gap between the belt-shaped photoconductor and the corona discharger is always maintained. In order to keep the same, the rear surface of the corona discharger is pressed by the transfer separation / conveyance unit case at the three positions of the end of the corona discharger and the vertex of the center of the isosceles triangle. It will be described according to the embodiment shown in FIG.

FIG. 1 is a side view showing the overall structure of the image forming apparatus according to the present invention, FIG. 2 is a side view showing the relationship between the transfer separation charger and the belt-shaped photoreceptor in FIG. 1, and FIG. 3 is a deviation adjusting roller. FIG. 4 is a cross-sectional view showing the relationship with a corona discharger, FIG. 4 is a perspective view showing a deviation adjusting device, and FIGS. 5 and 6 are all the same as FIG. 3 showing a state in which the deviation adjusting roller is adjusted and displaced. FIG. 7 is a perspective view of a transfer separation / transport unit case, and FIG. 8 is a perspective view of a corona discharger.

In FIG. 1, the light source 2 is placed on the contact glass 1.
The original image illuminated by a and 2b is projected on the belt-shaped photoconductor 6 supported by the driving roller 18, the driven roller 19, and the deviation adjusting rollers 20 and 21 through the lens 3 and the mirrors 4 and 5. The toner image formed by the developing device 7 is transferred by the transfer charger 13 onto the transfer paper which is fed by the feed rollers 11a, 11b, 11c through the registration roller 12 at the same timing. Then, the transfer paper separated from the photoconductor by the separation charger 14 is discharged to the paper discharge tray 10 via the conveying device 28 and the fixing device 9. On the other hand, at the same time as the transfer, the photoconductor is destaticized by the destaticizing lamp 17, the residual toner after the transfer is cleaned by the cleaning device 8, and is recharged by the charging device 22. A transmissive optical sensor 24, conductive brushes 23a and 23b, an erase lamp 16, backup rollers 15a and 15b, and a light guide 25 are provided around the belt-shaped photoreceptor 6.

By the way, in the above process, the transfer paper cannot be completely avoided due to its nature of abnormal transfer (the transfer paper is not fed normally, and is torn, jammed, or stuck. Jam). , Transfer, transfer charger 13,
As shown in FIG. 2, the transfer device 28 and the transfer device 28 are configured as an integrated transfer / separation transfer unit 30 so that the jammed paper generated at these parts can be easily removed.

That is, as shown in FIG. 2, the transfer charger 13, the separation charger 14, and the transport device 28 are rotatable about the drive roller 29a of the rollers 29a and 29b supporting the transport belt of the transport device 28. The transfer / separation / conveyance unit 30 is attached in series to the case 30a of the transfer / separation / conveyance unit 30 as shown in FIG. On the other hand, a lever 33 provided with a support shaft 31a provided on a rotating plate 31 for transmitting rotation by engagement of a pin and a groove and a pin 34 for sliding a groove 35 provided on the machine frame at the other end. One end of is rotatably coupled, and a spring 32 is provided between the drive roller 29a portion and the pin 34. As shown in the drawing, since the support shaft 31a is displaced to the position 31b beyond the line connecting the shaft center of the drive roller 29a and the center of the pin 34, the transfer separation / conveyance unit 30 may move in either direction due to the dead point. It will be pushed by 32. Note that the clockwise rotation is restricted by the pin 36 in its rotation range. In the figure, reference numeral 26 is a transfer entrance guide, 27 is a separation guide, and 41 is a leaf spring.

FIG. 3 is a cross-sectional view showing the relational position between the belt-shaped photosensitive member 6 and the transfer (separation) charger. As shown in FIG. 4, the deviation adjusting rollers supporting the deviation adjusting rollers 20 and 21 on the left and right are supported. By adjusting and fixing the plates 39 and 40 to the machine frame 38 in the directions of the arrows A and B, the deviation adjustment of the photoconductor belt is performed. In the present invention, however, the end blocks 37a and 37b of the transfer (separation) charger are provided. Are respectively brought into contact with the side plates 39 and 40 for supporting the deviation adjusting rollers, so that the gap between the belt-shaped photosensitive member 6 and the corona discharge wire 42 is maintained in parallel and at a constant distance. Therefore, the leaf springs 41a and 41b are provided between the transfer / separation / conveyance unit 30 and the transfer (separation) charger so that the charger can be drivenly engaged with the deviation adjusting roller.

The present invention makes it possible to perform the secondary operation using the leaf spring provided between the transfer / separation / conveyance unit and the transfer / separation charger with higher accuracy.

That is, as shown in FIG. 4, as the deviation adjusting rollers, two rollers 20 and 21 arranged in parallel are used. Therefore, the deviation adjusting roller support plates 39 for supporting these rollers on the left and right,
Of the 40, if the supporting portions for the roller 20 are 39a, 40a and the supporting portions for the roller 21 are 39b, 40b, these supporting portions 39a, 40a, 39b, 40b and the end block 37a of the transfer (separation) charger block 37 will be described. , 37b will come into contact at four points.

As shown in FIG. 8, two end engaging portions 43a and 43b are formed on the end blocks 37a and 37b of the charger block 37 so that they engage with the supporting portions 39a, 40a, 39b and 40b. There is.

A case 30a of the transfer / separation / conveyance unit 30 is arranged on the back surface side of the charger block 37, and presses the charger block 37 against the edge of the roller support portion via a leaf spring. The arrangement state of the leaf springs with respect to the unit case 30a is as shown in FIG. That is, a total of three leaf springs 41a, 41a, 41b are attached inside the charger block 37 of the unit case 30a.
The pair of leaf springs 41a, 41a are arranged parallel to one axis of the corona discharge wire 42 mounted in the charger block 37, and the other leaf spring 41b is
The leaf springs 41a, 41a are attached at a position apart from this line at the center of the line connecting them.

For further explanation, as is apparent from FIG. 7, one leaf spring 41b is attached to the center of the side portion of the unit case 30a, and the other two leaf springs 41a and 41a are attached to the other side portions of the case, respectively. Although attached separately, the line connecting the three pressing points of the leaf spring forms an isosceles triangle, and the angles α are made equal in the figure. Then, it is desirable to increase the acting force of the leaf spring by taking the dimension D corresponding to the height of the isosceles triangle as large as possible. As for the spring force of the leaf spring, the spring force of 41b is set to about three times the spring force of 41a to balance the two.

It should be noted that even if the transfer (separation) charger (corona discharger) is displaced to some extent with respect to the transfer / separation / conveyance unit 30, the conveyance device 28 can operate normally, so that there is no influence.

Further, instead of using the contact between the corona discharger end block and the deviation adjusting roller support plate, the contact with the deviation adjusting roller support shaft may be used.

Effect As described above, according to the present invention, in the image forming apparatus having the belt-shaped photoconductor provided with the deviation adjusting device,
Even if the belt-shaped photoconductor is displaced by the deviation adjusting operation, the corona discharger is pressed and brought into contact with the side edge of the deviation adjusting roller support plate from the back surface by the leaf spring provided in the unit case 30a at the apex of the isosceles triangle. The corona discharger can be made to follow the belt-shaped photoconductor at a constant distance.
Therefore, even when the photosensitive body is displaced by adjusting the deviation, the corona discharger follows and keeps a predetermined distance at all times, so a constant corona discharge can be performed at any time, and the transfer and separation performance can be kept constant. You can

Further, since it is not necessary to make the charger itself a rigid body, it is possible to realize a low-cost charger with a simple structure.

[Brief description of drawings]

FIG. 1 is a side view showing the overall structure of the image forming apparatus according to the present invention, FIG. 2 is a side view showing the relationship between the transfer separation charger and the belt-shaped photoreceptor in FIG. 1, and FIG. 3 is a deviation adjusting roller. FIG. 4 is a cross-sectional view showing the relationship with a corona discharger, FIG. 4 is a perspective view showing a deviation adjusting device, and FIGS. 5 and 6 are all the same as FIG. 3 showing a state in which the deviation adjusting roller is adjusted and displaced. 7 and 8 are perspective views of the charger holding portion of the transfer / separation / conveyance unit case, and FIG. 8 is a perspective view of the transfer (separation) charger block. 6 ... Belt-shaped photoreceptor, 7 ... Developing device, 8 ... Cleaning device, 9 ... Fixing device, 13 ... Transfer charger, 14 ... Separation charger, 20, 21 ... Offset adjusting roller, 28 ... Conveying device,
30 ... Transfer / separation / conveyance unit, 30a ... Unit case, 37
… Charger blocks, 37a, 37b… End blocks, 3
9, 40 ... Adjusting roller support plates, 41a, 41b ... Leaf springs, 43a, 43
b ... End block engaging part.

Claims (1)

[Claims] 1. An image forming apparatus comprising a corona discharger which faces a belt-shaped photosensitive member having a deviation adjusting roller and applies an electric charge thereto, wherein a unit incorporating the corona discharger and a paper conveying roller is a belt. When the unit is brought closer to the photoconductor side, the end block of the corona discharger comes into contact with the side plate for adjusting the deviation roller of the photoconductor so that the belt-shaped photoconductor can be moved. In order to keep the gap between the body and the corona discharger constant, a pressing point was provided between the case of the unit and the corona discharger at the apex position forming an isosceles triangle at both ends of the corona discharger and the center. A corona discharger for an image forming apparatus, characterized in that a pressing means is interposed.