JPS63136068A - Toner image transfer type image forming machine - Google Patents

Abstract

PURPOSE:To reduce the interval between an electrostatic discharger and a rotary drum by arranging a transfer area and a separation area in areas of specific different angles from the lowermost position of the rotary drum. CONSTITUTION:The transfer area 12 which is displaced in the opposite direction from the rotating direction of the rotary drum 4 is arranged in a specific angle range alpha1 of -90-0 deg. from the lowermost position 34 of the rotary drum 4 when viewed in the rotating direction of the rotary drum 4, preferably, in an area alpha2 of -45-0 deg.. The separation area 14 is also arranged in a specific angle area beta1 of -45-10 deg. from the lowermost position 34 of the rotary drum 4 when viewed in the rotating direction of the rotary drum 4, preferably, in an area beta2 of -20-0 deg.. Consequently, the space l1 between the peripheral surface of the rotary drum in the separation area and the upper end of an electrostatic discharger 32 is reduced greatly and a transfer material is securely separated from the peripheral surface of the rotary drum and conveyed.

Description

[Detailed Description of the Invention] Technical Field> The present invention relates to a toner image transfer type image generating machine, more specifically,
An electrostatic latent image is formed on a photoreceptor disposed on the circumferential surface of a rotating drum, this electrostatic latent image is then developed into a toner image, and the toner image is then transferred to a transfer material such as ordinary paper. This invention relates to a type of image generator.

<Prior Art> Recently, as an image generating machine such as an electrostatic copying machine, a small and inexpensive toner image transfer type image generating machine, which is particularly suitable for individuals or small businesses, has been widely put into practical use.

In such an image generating machine, a small-diameter rotating drum having a diameter of about 35 mm or less is used as the rotating drum having a photoreceptor disposed on its peripheral surface. In addition, as disclosed in Japanese Patent Application Laid-Open No. 59-126571,
Since the rotating drum has a small diameter, separation of the transfer material from the rotating drum after transfer is facilitated by the so-called stiffness and weight of the transfer material itself (so-called curvature separation effect). As a stripping means for separating the particles, a small and inexpensive static eliminator is used instead of a stripping corona discharger or the like.

FIG. 3 schematically illustrates a typical example of a conventional image generator as described above. The illustrated image generator includes a rotating drum 4 that is rotationally driven in the direction indicated by an arrow 2.

A suitable photoreceptor 6 is disposed on the circumferential surface of a small-diameter rotary drum 4 having a diameter of about 30 mm. Along the circumferential surface of the rotating drum 4, an electrostatic latent image forming area 8. Development area 10. Transfer area 12° Peeling area 14. The cleaning areas 16 are arranged sequentially in the rotational direction of the rotary drum 4. In the electrostatic latent image forming area 8, the photoreceptor 6 is first uniformly charged to a specific polarity by the action of the charging corona discharger 18, and then, as shown by the arrow 20, a suitable optical system is used to generate a latent image. The photoreceptor 6 is exposed corresponding to the image, thus the photoreceptor 6
An electrostatic latent image is formed thereon. Next, in the development area 10, the electrostatic latent image on the photoreceptor 6 is developed into a toner image by a development device 22 which may have an appropriate form. In the transfer area 12, a transfer material 28, which may be an ordinary paper, is conveyed between the guide members 24 and 26 and is brought into close contact with the photoreceptor 6, and a transfer corona discharger 30 is placed on the back surface of the transfer material 28 to apply a corona. Electric discharge is applied, and the toner image on the photoreceptor 6 is thus transferred to the transfer material 28.

In the peeling region I4, a static eliminator 32 is disposed at a distance from the static eliminator 32 facing the circumferential surface of the rotating drum 4. This static eliminator 32 includes a needle-like member having a large number of needle-like bodies on its upper edge, which is grounded with or without an appropriate bias power source (not shown), and whose upper edge has a sawtooth shape. It can be constructed from any suitable electrically conductive member such as a serrated member. If necessary, please refer to the above Japanese Patent Application Laid-open No. 59-1265.
Transfer corona discharger 30 as disclosed in No. 71
An insulating member (not shown) may also be provided between the static eliminator 32 and the static eliminator 32. In such a peeling area 14,
The transfer material 28 is separated from the circumferential surface of the rotating drum 4 (separation of the transfer material 28 will be described in more detail later).

The separated transfer material 28 is transferred to the lowermost portion 34 of the rotating drum 4.
is conveyed through a ti feed path 36 that extends substantially at the same height or below (in the illustrated case, extends downwardly to the left and then extends substantially horizontally to the left);
After the toner image is fixed by a suitable fixing device (not shown), it is discharged. On the other hand, the rotating drum 4 continues to rotate further, and in the cleaning area 16, first,
The photoreceptor 6 is removed by a toner removing means 38 which may be of any suitable form.
The residual toner is removed from the surface of the photoreceptor 6, and then, as shown by arrow 40, the photoreceptor 6 is irradiated with neutralizing light to eliminate the residual charge on the photoreceptor 6.

<Problems with the Prior Art> Therefore, the conventional image generating machine as described above has the following solution regarding the separation of the transfer material 28 from the circumferential surface of the rotating drum 4 performed in the separation area 14. There are issues that need to be addressed.

Continuing the explanation with reference to FIG. 3, the transfer material 2 used
If the transfer material 8 is relatively stiff, as shown by the solid line in FIG. In addition, the static electricity is sufficiently eliminated by the action of the static eliminator 32, and therefore, it is reliably separated from the circumferential surface of the rotating drum 4 and transported as required. However, if the transfer material 28 used is weak or has a curling characteristic of curving upward toward the front end, the transfer material 28 will not move around the rotating drum 4 as shown by the two-dot chain line in FIG. There is a tendency for the particles to move forward while being electrostatically attached to the circumferential surface of the rotating drum 4 without separating downward from the circumferential surface of the rotating drum 4 . In this case, there is a considerably large gap between the back surface of the transfer material 28 and the upper end of the static eliminator 32, and therefore the action of static eliminator 32 to remove static electricity from the transfer material 28 becomes insufficient, resulting in The material 28 is not sufficiently neutralized, and as a result, a situation occurs in which the transfer material 28 is not separated from the circumferential surface of the rotary drum 4 but ends up being wrapped around the rotary drum 4.

In order to solve the above problem, as shown in Figure 4,
It is conceivable to move the static eliminator 32 upward so that its upper end approaches the circumferential surface of the rotating drum 4. In this way, the upper end of the static eliminator 32 comes close to the back surface of the transfer material 28 that advances while adhering to the circumferential surface of the rotating drum 4, and therefore,
The transfer material 28 is sufficiently neutralized by the action of the static eliminator 32, thereby making it possible to separate the transfer material 28 from the circumferential surface of the rotating drum 4. However, when the static eliminator 32 is moved upward as shown in FIG. 4, the static eliminator 32 extends upward, interrupting the intended conveyance path 36 of the transfer material 28. Therefore, the transfer material 28, which is relatively stiff and moves downwardly from the circumferential surface of the rotating drum 4 as indicated by the solid line in FIG. 32, and its progress is obstructed.

<Problems to be solved by the invention> The above-mentioned problems in conventional image generating machines are caused by the transfer material 28
This is due to the existence of a considerably large distance β1 between the upper end of the static eliminator 32, which must be located below the intended conveyance path 36, and the circumferential surface of the rotating drum 4.

Therefore, the present invention eliminates the need to unnecessarily change the intended conveyance path of the transfer material (for example, by making it extend upwardly from the lowest portion of the rotating drum toward the downstream). The technology is capable of making it possible to sufficiently reduce the distance between the upper end of the static eliminator, which must be located below the initial conveyance path, and the circumferential surface of the rotating drum (for example, 5 fl or less). This will be a major issue.

<Solution Means of the Invention> According to the present invention, based on a geometrical analysis focusing on the fact that the circumferential surface of the rotating drum is circular, (a) the transfer area is viewed from the rotating direction of the rotating drum. It is arranged in an area within a predetermined angle α, -90 degrees ≦ α ≦ 0 degrees from the lowest part (in the past, the above angle α was usually about 130 degrees ≦ α ≦ 20 degrees), and (b) The peeling area is set at a predetermined angle β, − from the lowest part of the rotating drum when viewed in the rotating direction of the rotating drum.
The above technical problem is achieved by arranging the angle β in the range of 45 degrees≦β≦10 degrees (in the past, the angle β was usually 30 degrees <β).

That is, according to the present invention, there is provided a rotating drum having a photoreceptor disposed on the circumferential surface, and a plurality of electrostatic latent images are sequentially formed on the photoreceptor when viewed in the rotational direction of the rotating drum. an electrostatic latent image forming area; a developing area for developing the electrostatic latent image into a toner image;
A transfer area for transferring the toner image onto a transfer material and a peeling area for peeling the transfer material from the photoreceptor are arranged along the circumferential surface of the rotating drum, and the peeling area includes a A static eliminator is disposed opposite to the circumferential surface of the rotating drum, and the transfer material peeled off from the circumferential surface of the rotating drum in the peeling area is substantially the same as the lowest part of the rotating drum. In an image generator that is conveyed through a conveyance path that extends from a height to a level lower than that, the transfer area is at a predetermined angle α, -90 degrees ≦ from the lowest part of the rotary drum when viewed in the rotation direction of the rotary drum. The peeling area is arranged at a predetermined angle β from the lowest part of the rotary drum when viewed in the rotation direction of the rotary drum.
An image generator is provided, characterized in that the image generator is disposed in an area within −45 degrees≦β≦10 degrees.

Preferably, the predetermined angle α is 145 degrees≦α≦0 degrees, and the predetermined angle β is 120 degrees≦β≦0 degrees.

Hereinafter, a specific example of an image generator configured according to the present invention will be described in more detail with reference to the drawings.

The image generator shown in FIG. 1 is improved as compared to the conventional image generator shown in FIG. 3 as follows. First, the transfer area 12 where the transfer corona discharger 30 is located facing the circumferential surface of the rotating drum 4 at a distance is
Compared to the conventional case, it is displaced in the opposite direction to the rotational direction of the rotary drum 4. Such transcription area 12 is
An area within a predetermined angular range of 190 degrees to 0 degrees from the lowest portion 34 of the rotating drum 4 when viewed in the rotational direction of the rotating drum 4 (area indicated by symbol α1 in FIG. 1), preferably 145 degrees to 0 degrees. An area within a predetermined angle range that is 0 degrees (indicated by α in Figure 1)
2) is important.

Second, in addition to the above-mentioned displacement of the transfer area 12, the separation area 14, where the static eliminator 32 is located at a distance from the circumferential surface of the rotating drum 4, is also larger than the conventional case. It is displaced in the opposite direction to the rotation direction of 4. The peeling region 14 is an area within a predetermined angular range of 145 degrees to 10 degrees from the lowest portion 34 of the rotating drum 4 when viewed in the rotational direction of the rotating drum 4 (an area indicated by the symbol β1 in FIG. 1); It is important that it is located within a predetermined angular range, preferably from 120 degrees to 0 degrees (region indicated by reference numeral β2 in FIG. 1).

Regarding the above angular ranges α1 and α2 and β1 and β2, the following geometrical analysis should be noted.

That is, since the circumferential surface of the rotating drum 4 is circular, in the angle range of 190 degrees to 0 degrees from the lowest part 34 of the rotating drum 4 when viewed from the rotation direction of the rotating drum 4, the rotation direction of the rotating drum 4 is The circumferential surface of the rotating drum 4 descends as the rotation progresses. Then, the rate of decline relative to the progress in the rotation direction is determined according to the progress in the rotation direction (therefore, the angle is 0
degree)). On the other hand, from 0 degrees to 90 degrees from the lowest portion 34 of the rotating drum 4 when viewed in the rotational direction of the rotating drum 4.
In the angular range of degrees, the circumferential surface of the rotary drum 4 rises as the rotation direction of the rotary drum 4 advances. The rate of increase with respect to progress in the rotational direction increases as the rotational direction progresses (therefore, as the angle increases). Therefore, if the transfer area 12 and the peeling area 14 are arranged within the above angle range, the transfer material 28 directed downstream from the circumferential surface of the rotary drum 4 at the circumferential center of the transfer area 12 can be Even if the downward inclination of the required conveyance path 36 is set to be substantially the same as in the conventional case, the distance l between the circumferential surface of the rotating drum 4 in the peeling area 14 and the upper end of the static eliminator 32
I can be significantly reduced compared to the conventional case. Thus, the transfer material 28 moving downstream from the transfer zone 12
without unnecessarily changing the desired conveyance path 36, and so as to allow the static eliminator 32 to block the conveyance path 36 and protrude upward, so that the distance l, can be made as small as desired. It is desirable that the distance A is generally 7 fi or less, particularly 5 fi or less.

In the image generating machine shown in FIG. 1 to which the above-mentioned improvements have been added, if the transfer material 28 used is relatively stiff, the peripheral surface of the rotating drum 4 in the transfer area 12 is As shown by the solid line in FIG. 1, the transfer material 28 that has been brought into close contact with the rotary drum 4 moves downwardly from the circumferential surface of the rotating drum 4 due to its own stiffness and weight as it moves downstream, and in addition, the transfer material 28 separates from the circumferential surface of the rotating drum 4 as shown by the solid line in FIG. By this action, the static electricity is sufficiently eliminated, and therefore, it is reliably separated from the circumferential surface of the rotating drum 4 and conveyed along the conveyance path 36. If the transfer material 28 to be used is weak or has a curling characteristic of curving upward toward the front end, the transfer material 28 will not curl in the peeling area 14 as shown by the two-dot chain line in FIG. There is also a tendency for the particles to electrostatically adhere to the circumferential surface of the rotating drum 40 and prevent them from progressing. However, since the upper end of the static eliminator 32 is located close to the back surface of the transfer material 28 in the peeling area 14, the transfer material 28 is sufficiently and reliably neutralized by the action of the static eliminator 32, and therefore, the transfer material 28 is removed from the rotating drum. 4 and is transported along the transport path 36.

Since the image generator shown in FIG. 1 is substantially the same as the conventional image generator shown in FIG. 3 except for the above-mentioned configuration and operation, a description thereof will be omitted.

As already mentioned with respect to the conventional image generator illustrated in FIG. 3, if desired, an insulating member 42 of suitable form may be provided between the transfer corona discharger 30 and the static eliminator 32, as illustrated in FIG. Furthermore, instead of directly grounding the static eliminator 32, it can also be grounded via a suitable bias power supply 44. Furthermore, a corona discharger 30 for transfer
The transfer material 28 enters into the shield case of
In order to reliably prevent the conveyance of the transfer corona discharger 30 from being obstructed, a well-known guide line (not shown) extending obliquely in the conveyance direction is provided at the opening of the shield case of the transfer corona discharger 30. It can also be placed.

<Effects of the Invention> As described in detail above, according to the present invention, in an image generation machine that uses a small and inexpensive static eliminator as a peeling means, it is possible to prevent unnecessary changes in the desired transport path of the transfer material. Without any inconvenience, even if the transfer material is weak or has a curling characteristic that curves upward toward the front end, the transfer material that is brought into close contact with the circumferential surface of the rotating drum in the transfer area can be transferred to the rotating drum. can be reliably separated from the circumferential surface and transported as required.

[Brief explanation of the drawing]

FIG. 1 is a simplified cross-sectional view showing one specific example of an image generator improved according to the present invention. FIG. 2 is a sectional view of a tube passage section showing a partial modification of the image generator shown in FIG. 1. FIG. 3 is a cross-sectional view of a tube showing an example of a conventional image generator. FIG. 4 is a simplified partial sectional view showing a modification of a part of the image generator of FIG. 1. 4... Rotating drum 6... Photoreceptor 8... Electrostatic latent image forming area 10... Development area 12... Transfer area 14... Peeling area 16... Cleaning area 28... Transfer material 30...Transfer corona discharger 32...Static eliminator 34...Lowermost part of rotating drum Fig. 1 Fig. 3 Fig. 2 Fig. 4

Claims (1)

[Claims] 1. A rotating drum having a photoreceptor disposed on its peripheral surface;
Viewed in the rotational direction of the rotary drum, an electrostatic latent image forming area for forming an electrostatic latent image on the photoreceptor, a developing area for developing the electrostatic latent image into a toner image, and a developing area for developing the electrostatic latent image into a toner image. A transfer area for transferring a toner image onto a transfer material and a peeling area for peeling off the transfer material from the photoreceptor are arranged along the circumferential surface of the rotating drum, and the peeling area includes a A static eliminator is disposed facing the circumferential surface of the rotating drum, and the transfer material peeled off from the circumferential surface of the rotating drum in the peeling area is substantially at a circular height with the lowest part of the rotating drum. In an image generator that is conveyed through a conveyance path that extends downward from the transfer area, the transfer area is at a predetermined angle α, -90 degrees≦α from the lowest part of the rotary drum when viewed in the rotation direction of the rotary drum. ≦0 degrees, and the peeling area is located at a predetermined angle β,
An image generator characterized in that the image generator is disposed in an area within -45 degrees≦β≦10 degrees. 2. The image generator according to claim 1, wherein the predetermined angle α is −45 degrees≦α≦0 degrees. 3. The image generator according to claim 1 or 2, wherein the predetermined angle β is -20 degrees≦β≦0 degrees.