JP2843085B2 - Image forming device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus, and more particularly to, for example, a method of arranging an exposure light source inside a photosensitive drum and developing toner simultaneously or immediately after exposure from the inside of the photosensitive drum. To an image forming apparatus.

(Prior art)

An example of this type of image forming apparatus is described in, for example,
This is disclosed in Japanese Patent Application Laid-Open No. 58-153957, which was published on March 13, 2013. In this image forming apparatus, the photoconductor layer is exposed from the transparent substrate side of the photoconductor including the transparent substrate and the transparent electrode layer and the photoconductor layer formed thereon,
The toner charged by the exposure is selectively adhered to the surface of the photoconductor layer at the same time as or immediately after the exposure by a developing device arranged on the photoconductor layer side to form a toner image.

In this image forming apparatus, the above-mentioned JP-A-58-1539 is used.
Although it is not clear in No. 57, a drive roller is used to drive the photosensitive drum, and the drive roller is provided at a position for absorbing the diameter tolerance of the photosensitive drum, that is, at a position directly opposite to the exposure point. In this conventional technique, for example, when the drive roller is disposed outside the photoconductor drum, when the diameter of the photoconductor drum is smaller than the reference, a gap is generated between the drive roller and the photoconductor drum, and the driving force is lost. When the driving roller is larger than the standard, there is a drawback that a load is applied to the driving roller or the roller diameter changes to cause an error in the peripheral speed of the photosensitive drum.

In view of this, the present applicant proposes, for example, in Japanese Patent Application No. 2638159, an image forming apparatus in which the drive roller of the photosensitive drum is disposed symmetrically with respect to the support roller of the photosensitive drum with respect to the rotation center of the photosensitive drum. did.

[Problems to be solved by the invention]

According to the technology of Japanese Patent Application No. 2638159, although the above-mentioned disadvantages can be solved with respect to the stability of driving the photosensitive drum,
A new problem has arisen when feeding paper. That is, when the paper is fed in a state substantially parallel to the exposure optical axis or when the paper is fed from the developing device side, the driving roller hinders. At this time, if the sheet is fed while avoiding the driving roller, the image forming apparatus itself becomes large. In addition, if the diameter of the photosensitive drum becomes small, the peripheral side surface of the photosensitive drum becomes small, and it becomes impossible to arrange a driving roller.

Therefore, a main object of the present invention is to dispose the driving roller at a position where it does not hinder the sheet feeding, and to apply the driving force to the photosensitive drum reliably and to cause no fluctuation in the peripheral speed of the photosensitive drum. An object of the present invention is to provide an image forming apparatus.

[Means for solving the problem]

Briefly, the present invention provides a photosensitive drum including a transparent substrate and a transparent conductive layer and a photoconductive layer formed thereon and being rotated in a predetermined direction, and contacting the transparent substrate side of the photosensitive drum. A plurality of support rollers for supporting the rotation in a predetermined direction, and an exposure light source arranged on the transparent substrate side of the photosensitive drum and exposing the photoconductor layer through the transparent substrate and the transparent conductive layer; and Developing means disposed on or near an exposure position of an exposure light source on the photoconductor layer side of the photoconductor drum, and selectively attaching toner to the photoconductor surface simultaneously with or immediately after the exposure to form a toner image An image forming apparatus comprising: a driving roller that contacts the photoconductor layer surface of the photoconductor drum to apply rotation to the photoconductor drum and that can change its position; An image forming apparatus, wherein at least one of them is configured as a movable support roller whose position can be displaced, and the mounting shafts of the movable support roller and the drive roller are arranged so as to face each other across the photosensitive drum. .

[Action]

A rotational force is applied to the photosensitive drum by a driving roller, and the photosensitive drum is rotated in a predetermined direction.
The rotation of the photosensitive drum is supported by a plurality of support rollers. When the diameter of the photosensitive drum is smaller than the reference, both the movable support roller and the drive roller are displaced toward the center of the photosensitive drum. When the diameter of the photosensitive drum is larger than the reference, the movable supporting roller and the driving roller are displaced in the outer peripheral direction of the photosensitive drum. Therefore,
In any case, the driving roller surely comes into contact with the surface of the photosensitive drum with a stable contact pressure to apply a rotational force.

If the drive roller and the movable support roller are simultaneously displaced while being pulled together by, for example, a coil spring, as in the embodiment, the drive roller and the movable support roller are always engaged in the direction in which they approach each other. A more stable contact pressure can be secured to the outer peripheral surface of the drum.

〔The invention's effect〕

According to the present invention, the photosensitive drum can be always rotated stably without being relatively affected by the diameter tolerance of the photosensitive drum due to the displacement of the driving roller and the movable support roller.

Further, since the drive roller is disposed at a position facing the movable support roller with the photosensitive drum interposed therebetween, the drive roller does not hinder sheet feeding. Therefore, paper can be fed substantially parallel to the optical axis of the exposure light or from above the developing device side, and the size of the device can be reduced.

The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

〔Example〕

FIG. 2 is an illustrative sectional view showing an optical printer as one embodiment of the present invention. Hereinafter, the present invention will be described as being applied to an optical printer, but it should be pointed out in advance that the present invention can be applied to other image forming apparatuses, such as a copying machine and a facsimile.

Referring to FIG. 2, the optical printer 10 includes a main body 12, and a photosensitive drum 14 is rotatably supported inside the main body 12.
As shown in FIG. 3, this photosensitive drum 14 is laminated on a transparent substrate 14a made of, for example, glass and the like, as in JP-A-58-153957 cited above. It includes a transparent conductive layer 14b and a photoconductor layer 14c.

A drive roller 16 is provided so as to come into contact with the outer surface of the photoconductor drum 14 (the surface of the photoconductor layer 14c).
16 rotates the photosensitive drum 14 by the driving force from the driving source of the motor 17. Since the photosensitive drum 14 is rotatably supported by two fixed support rollers 18 and 20 and one movable support roller 22 which are in contact with the inner surface thereof, that is, the surface of the transparent base 14a, the drive roller 16 , The photosensitive drum 14 is also rotated in the direction of arrow B.

As is apparent from FIG. 1, the drive roller 16 is disposed at an end (preferably both ends) of the photosensitive drum 14 in the width direction, and on the other hand, at an end of the photosensitive drum 14 which contacts the drive roller 16. The surface is formed slightly rough, so that the photosensitive drum 14 is accurately rotated by the friction between the two.

As described above, the photosensitive drum 14 is supported at three points by the fixed support rollers 18 and 20 and the movable support roller 22 on the inner side.
The photosensitive drum 14 is disposed at both ends in the width direction. The movable support roller 22 is disposed on a line connecting the drive roller 16 and the center of the photosensitive drum 14. That is, the movable support roller 22 is provided at a position facing the drive roller 16 with the photosensitive drum 14 interposed therebetween. The fixed support roller 18 is disposed on an extension of an exposure position of the photosensitive drum 14 described later.

As shown in FIG. 1, the mounting shaft 16a of the drive roller 16 is supported by side plates 28 disposed at both ends of the photosensitive drum 14 so as to be displaceable in the radial direction of the photosensitive drum 14. In addition, the mounting shaft 24 of the fixed support rollers 18 and 20 and
26 are directly fixed to the side plates 28 respectively. On the other hand, the mounting shaft 30 of the movable support roller 22 is not directly fixed to the side plate 28. That is, the mounting shaft 30 of the movable support roller 22 is moved by the coil spring 32 so that the movable support roller 22 is
Side plates on both sides so that pressing force can be applied inside
Attached to 28. Therefore, the movable support roller 22
Can follow the fluctuation in the radial direction of the inner circumference of the photosensitive drum 14 and can be brought into close contact with the photosensitive drum 14 in a state where the pressing force is constantly applied. Therefore, the contact positions of the fixed support rollers 18 and 20 with the inner periphery of the photoconductor drum are constant even if the inner periphery of the photoconductor drum 14 is eccentric, but the contact positions of the movable support rollers 22 are inside the photoconductor drum 14. It changes following the eccentricity of the circumference. Therefore, even when the diameter or roundness of the photosensitive drum 14 varies, such a dimensional variation can be absorbed by the displacement of the movable support roller 22.

Further, the mounting shaft 16a of the drive roller 16 and the movable support roller 2
A coil spring 33 is hung around the second mounting shaft 30, so that the drive roller 16 and the movable support roller 22 are pulled against each other. In this state, the coil spring 32 acts to simultaneously drive the two rollers 16 and 22 to the photosensitive drum.
Since the roller 14 is pressed in the circumferential direction, the change in the contact pressure of the drive roller 16 with respect to the photosensitive drum 14 is absorbed by the displacement of the drive roller 16 and the movable support roller 22, and the contact pressure is maintained constant.

Note that the mounting shaft 30 of the movable support roller 22 is
However, the mounting shafts 24 and 26 of the fixed support rollers 18 and 20 are shortened and individually mounted on the side plates 28 at both ends. The fixed support roller 18
An interval for exposing the photosensitive drum 14 to be described later is formed between them.

2 and 4, an LED head 34 is further disposed inside the photosensitive drum 14. On one main surface of the LED head 34, an LE in which a large number of LED elements are arranged on a straight line extending in the width direction of the photosensitive drum 14.
A D array 34a is formed, and light from this LED array 34a
A rod lens array or convergent light transmitter 36 fixed to the LED head 34 by the arm 36a irradiates the photoconductor layer 14c between the fixed support rollers 18 through the transparent base 14a and the transparent conductive layer 14b of the photosensitive drum 14. Is done.

By arranging the fixed support roller 18 on the optical axis of the exposure light in this way, the focus of the exposure light is reliably brought on the photoconductor layer 14c of the photosensitive drum 14. That is, at the position where the exposure light is irradiated, the photosensitive drum 14 is always maintained at a fixed position by the fixed support roller 18, and therefore, the position of the photoconductor layer 14c to which the exposure light is irradiated does not change.

The photosensitive drum 14, the LED head 34, and the like are fixed to a support member 38 by a mounting shaft, as is clearly understood from FIGS.
A part of.

Further, a developing device 40 is provided on the right side of the photosensitive drum 14. The developing device 40 includes a support shaft 38a (the fourth
(See FIG. 1), and is mounted so as to be always engaged with the photosensitive drum 14 by a coil spring (not shown). The developing device 40 has a magnet roller 42 and a spike regulating plate 44, and the toner is
It is formed as a magnetic brush on the circumference of 42. Then, the height of the magnetic brush, that is, the height of the spike is adjusted by the spike restricting plate 44, and is transferred to a portion facing the photosensitive drum 14 in accordance with the rotation of the magnet roller 42. That is,
The toner is sent between the magnet roller 42 and the photoconductor layer 14c of the photosensitive drum 14.

In order to perform good toner development, it is necessary not only to accurately set the interval between the above-mentioned portions where the magnet roller 42 and the photosensitive drum 14 face each other, but also to make the portions relative to the optical axis of the exposure light. The magnet roller 42 and the photosensitive drum 14 need to be positioned so as to be orthogonal to each other exactly. Therefore, in this embodiment, the above-described positioning of this portion is performed by the photosensitive drum 14 as shown in FIGS.
The developing device 40 is integrally fixed to the supporting member 38 as a latent image carrier unit 39. On the other hand, the above-mentioned interval can be defined by rotatably providing gap rollers 46 at both ends of the magnet roller 42 as shown in FIG. 1 and bringing the gap rollers 46 into contact with the surface of the photosensitive drum 14.

However, the portions of the photoconductor drum 14 facing the magnet roller 42 are not always exactly perpendicular to the optical axis of the exposure light simply by being fixed to the support members 38 as described above. In that case, the side plate 28 to which the LED head 34 is fixed may be slightly rotated. In this way, when finely adjusting the relative positional relationship between the developing position by the magnet roller 42 and the irradiation position of the exposure light, the LED head provided in the photosensitive drum 14 can be obtained simply by rotating the side plate 28. 34, that is, the position of the converging light transmitting body 36 can be easily adjusted.

The latent image carrier unit 39 thus integrally formed by the support member 38 is detachably attached to the main body 12 along a positioning member (not shown) in the state shown in FIGS. 1 and 4. . That is, the latent image carrier unit 39 is configured to be slidable in the length (width) direction of the photosensitive drum 14, and by inserting and removing in the direction, the main body is
Attached to 12.

In the optical printer 10, a voltage is applied between the magnet roller 42 of the developing device 40 and the transparent conductive layer 14b of the photoconductor drum 14, and the LED head 34 disposed inside the photoconductor drum 14 and the converging light transmission The image information is irradiated by the body 36 and is developed by the developing device 40 to form a toner image on the surface of the photosensitive drum 14.

On the other hand, the recording paper 48 sent by the feed roller 47 is sent to the transfer position after the timing is adjusted by the register roller pair 50. Then, the photosensitive drum 14 and the pressure transfer roller 52
Thus, the recording paper 48 is pressed to transfer the toner image onto the recording paper 48. The recording paper 48 after the transfer is separated from the photosensitive drum 14 by a claw 54.
And is conveyed to a fixing device including a heating roller 56 and a heating roller 58. Therefore, when the recording paper 48 passes between the heating roller 56 and the pressure roller 58, the toner image is heated and pressed, and the fixing process is completed. And
The recording paper 48 is separated by the separation claw 60 and discharged out of the main body 12.

[Brief description of the drawings]

FIG. 1 is a diagram showing a light beam according to an embodiment of the present invention. FIG. 2 is a perspective view showing a latent image carrier unit in which a photosensitive drum and a developing device in the printer are integrated. FIG. 2 is an illustrative sectional view showing the entire optical printer of this embodiment. FIG. 3 is an enlarged partial sectional view showing an example of a layer structure of a photosensitive drum that can be used in this embodiment. FIG. 4 is a side view showing the latent image carrier unit shown in FIG. In the figure, 10 is an optical printer, 12 is a main body, 14 is a photosensitive drum, 16 is a drive roller, 18 and 20 are fixed support rollers, 22 is a movable support roller, 28 is a side plate, 34 is an LED head, and 36 is a focusing property. Light transmitting body, 38 is a supporting member, 38a is a supporting shaft, 39 is a latent image carrier unit, 40 is a developing device, 42 is a magnet roller,
46 denotes a gap roller.

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masaru Ozawa 1-6, Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (56) References JP-A-58-98746 (JP, A) (58) Surveyed field (Int. Cl. ⁶ , DB name) G03G 15/08 G03G 15/00 115 G03G 21/00 350

Claims (3)

(57) [Claims] A photosensitive drum including a transparent substrate and a transparent conductive layer and a photoconductive layer formed thereon and rotated in a predetermined direction; A plurality of support rollers for supporting rotation in the direction, a light source for exposure arranged on the transparent substrate side of the photoconductor drum and exposing the photoconductor layer through the transparent substrate and the transparent conductive layer, and a photoconductor drum And a developing means for selectively adhering toner to the surface of the photoconductor at the same time as or immediately after the exposure and forming a toner image at or near the exposure position of the exposure light source on the side of the photoconductor layer In the forming apparatus, a driving roller that contacts the photoconductor layer surface of the photoconductor drum to apply rotation to the photoconductor drum and can change the position thereof, wherein a small number of the plurality of support rollers Wherein one of the movable supporting rollers is configured as a movable supporting roller whose position can be changed, and the movable supporting roller and the driving roller are arranged so that mounting shafts thereof are opposed to each other across the photosensitive drum. apparatus. 2. The image forming apparatus according to claim 1, wherein said movable supporting roller and said driving roller are simultaneously displaceable. 3. The remaining of the plurality of support rollers is configured as a fixed support roller whose position cannot be changed.
The image forming apparatus according to claim 1.