JPH0723812Y2 - Belt-shaped photoconductor facing parts Gear-up assurance device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of the Invention The present invention relates to a belt-shaped photoconductor that faces a belt-shaped photoconductor and maintains a constant gap between the image-formed component and the belt-shaped photoconductor. Gap assurance device.

2. Description of the Related Art In a general electrophotographic copying apparatus, a photosensitive drum is used as an electrostatic latent image holder, and a charging device, an image exposure device, a developing device, a transfer device, a cleaning device, etc. are arranged around the photosensitive drum. Is configured. However, in recent years, a copying machine in which a belt-shaped photosensitive member has been adopted as an electrostatic latent image holding member instead of the photosensitive drum has been put into practical use, and has been particularly successful in the field of high-speed copying machines.

The structure of a conventional electrophotographic copying machine using a belt-shaped photoreceptor is shown in FIG. 3, for example. In FIG. 3, an endless belt-shaped photosensitive member 10 is wound around a driving roll 12, a tension roll 14, and a driven roll 16, and is configured to give a constant tension by the tension roll 14. The belt-shaped photosensitive member 10 is driven by rotating the driving roll 12 in the direction of the arrow in the figure.
It is designed to rotate in the same direction as 12. First, the belt-shaped photoreceptor 10 is uniformly charged with a positive polarity or a negative polarity by the charging corotron 18, and then an electrostatic latent image corresponding to the original 22 is formed on the belt-shaped photoreceptor 10 by the image exposure device 20. Reference numeral 24 denotes an inter image lamp for removing unnecessary images between the electrostatic latent images formed on the belt-shaped photoreceptor 10 or a side for removing unnecessary images on both sides of the electrostatic latent image. It is an unnecessary image removing lamp such as an image lamp, and is provided so as to face the tension roll 14.

The electrostatic latent image formed on the belt-shaped photoconductor 10 is developed by the developing device 26.
Are developed and visualized. The developing device 26 is, for example, a magnetic brush developing device, and includes a transport roll 30 and a developing roll.
28, and develops an electrostatic latent image with a magnetic developer. The toner image on the belt-shaped photoreceptor 10 thus developed is then transferred onto the transfer paper 34 by the transfer corotron 32, and the toner image on the transfer paper is fixed by a fixing device (not shown) to obtain a hard copy. . On the other hand, the untransferred toner, that is, the residual toner on the belt-shaped photoreceptor 10 is cleaned by the cleaning device 36, and one copy cycle is completed.

In an image forming apparatus such as an electrophotographic copying machine that adopts such a belt-shaped photoreceptor 10, the position of the tension roll 14 is the circumferential length error of the belt-shaped photoreceptor 10, or the belt-shaped photoreceptor.
Due to the position and shape errors of the driving roll 12 and the driven roll 16 that support 10 and the like, they fluctuate in the direction of the arrow (tensioning direction).

Problems to be solved by the invention Therefore, if the unnecessary image removing lamp 24 is provided so as to face the tension roll 14, the unnecessary image removing lamp is provided.
The gap between 24 and the belt-shaped photoconductor 10 changes from the desired X to X '. Therefore, there is a problem that the amount of erasing the unnecessary image on the belt-shaped photoconductor 10 by the unnecessary image removing lamp 24 is changed. This problem is not limited to the unnecessary image removing lamp as the facing component, and affects the charging characteristic or the cleaning characteristic even in the case of a charging corotron, a cleaning device, or the like.

The present invention has been made in view of such a point, and an object thereof is to provide the opposing component and the belt-shaped photoconductor even if the position of the tension roll changes due to a circumferential length error of the belt-shaped photoconductor or the like. An object of the present invention is to provide a device for ensuring a gap between opposed parts of a belt-shaped photoconductor that can always keep the gap between them constant.

Means for Solving the Problems In order to solve the above-mentioned problems of the prior art, the present invention provides an image forming apparatus in which a belt-shaped photosensitive member is rotatably supported by a plurality of rolls. One of them is a tension roll movably biased by a biasing means so as to apply tension to the belt-shaped photoconductor,
An image forming component is provided on the main body side of the image forming apparatus via a supporting means so as to face the belt-shaped photoreceptor wound around the outer circumference of the tension roll, and a pair of gap holding circles having a diameter larger than that of the tension roll. Plates are provided concentrically with the tension rolls at both ends of the tension rolls, and the image forming component is pressed against the pair of gap maintaining discs by a biasing means, so that the gap between the image forming component and the belt-shaped photoreceptor is increased. The belt-shaped photosensitive member is characterized in that the gap is kept constant and the image forming component is movable in a direction of enlarging a distance between the image forming component and the tension roll against the urging force of the urging means. Provide a facing part gap assurance device.

Action When the tension roll moves due to a circumferential length error of the belt-shaped photosensitive member, the gap holding discs provided concentrically with the tension roll at both ends of the tension roll also move following the movement of the tension roll. Since the image forming component is pressed against the gap holding disc by the biasing means, the image forming component also follows the movement of the tension roll, and the gap between them can always be kept constant.

Further, since the image forming component can be moved in the direction of enlarging the interval between the image forming component and the tension roll against the urging force of the urging means, the belt-shaped photoreceptor can be easily replaced.

Embodiment Hereinafter, the present invention will be described in detail based on an embodiment shown in the drawings.

Referring to FIGS. 1 and 2, there are shown a partially cutaway plan view and a side view, respectively, of an embodiment of the present invention. Belt-shaped photoconductor frames 40 on both sides of the tension roll 14,
40 are provided. The structure shown in Fig. 1 is a tension roll.
Since the frame portions on both sides supporting 14 are symmetrical, only one side will be described below.

A bracket 42 is fixed to the belt-shaped photoconductor frame 40, and one end of a shaft 44 is slidably fitted to the bracket 42. The other end of the shaft 44 is inserted in the cylinder 46, and the coil spring 48 is inserted between the bracket 42 and the cylinder 46.
The coil spring 48 urges the cylinder 46 to the left in FIG. A tension roll housing 50 is fixed to the cylinder 46, and the tension roll housing 50 can move in the left and right directions in the elongated hole formed in the frame 40 in FIG. 1 so as to follow the movement of the cylinder 46. Has become. A disk-shaped butting member 52 is integrally provided on the tension roll housing 50.
It is rotatably attached to the 50 through a bearing.

In the present embodiment, the disc-shaped butting member 52 is provided integrally with the tension roll housing 50,
This may be configured separately from the tension roll housing 50 so that the shaft of the tension roll 14 is just rotatably fitted.

Reference numeral 54 is a copier frame.
56 is slidable or fixedly attached. A support plate 60 is further attached to the copier frame 54,
The unnecessary image removing lamp 24 is supported on the support plate 60, and the unnecessary image removing lamp 24 is constantly urged rightward in the drawing by the coil spring 58 and is pressed against the abutting member 52. The force relationship between the coil spring 48 and the coil spring 58 needs to be set so that the spring force of the coil spring 48 is larger than the spring force of the coil spring 58.

Since the present embodiment is configured in this way, the unnecessary image removing lamp 24 is always abutted against the abutting member 52 that follows the movement of the tension roll 14. Therefore, even if the position of the tension roll 14 changes, the gap between the belt-shaped photoreceptor 10 wound around the tension roll 14 and the unnecessary image removing lamp 24 can be always kept constant. Therefore, even if the position of the tension roll 14 changes due to the circumferential length error of the belt-shaped photosensitive member or the like, the erase amount of the unnecessary image is not affected by this.

In the embodiment described above, the unnecessary image removing lamp 24 is only mounted on the support plates 60, 60, but the support plate 60
It is more practical to attach a guide member on top and guide the movement of the unnecessary image removal lamp.
The 24 may be attached to one end of the shaft 56. In this case, the shaft 56 needs to be slidably attached to the copier frame 54.

Further, in the above-described embodiment, the disc-shaped abutting member
52 is provided integrally with the tension roll housing 50, and the gap is kept constant by constantly pressing the unnecessary image removing lamp 24 against the abutting member 52, but the present invention is limited to such a configuration. Instead, for example, a rotating member may be provided at both ends of the unnecessary image removing lamp 24, and the rotating member may be constantly brought into contact with the tension roll 14 to keep the gap constant.

In the above-described embodiment, the case where the unnecessary image removing lamp is provided as the image forming component facing the tension roll 14 has been described, but the present invention is not limited to this, and the opposing component may be, for example, a corotron or a cleaning device. It does not matter if it is a device or the like.

Effect of the Invention As described in detail above, according to the present invention, the image forming component is provided on the main body of the image forming apparatus so as to face the belt-shaped photoconductor wound around the outer circumference of the tension roll, and the gap is maintained to follow the movement of the tension roll. Since the image forming component is pressed against the disk for urging by the urging means, the gap between the belt-shaped photosensitive member and the image forming component facing the belt-shaped photosensitive member is always kept constant regardless of the fluctuation of the position of the tension roll. There is an effect that can be.

Further, since the image forming component can move in the direction of enlarging the distance between the image forming component and the tension roll against the urging force of the urging means, it also has an effect that the belt-shaped photoreceptor can be easily replaced. There is.

[Brief description of drawings]

FIG. 1 is a partially cutaway plan view of an embodiment of the present invention, FIG. 2 is a side view of FIG. 1, and FIG. 3 is a schematic configuration diagram of an electrophotographic copying machine employing a belt-shaped photoreceptor. 10 ... Belt-shaped photoreceptor, 12 ... Drive roll, 14 ... Tension roll, 16 ... Followed roll, 18 ... Charging corotron, 20 ... Image exposure device, 24 ... Unnecessary image removal lamp,
26 ... Developing device, 32 ... Transfer corotron, 36 ... Cleaning device, 40 ... Belt-shaped photoconductor frame, 50 ... Tension roll housing, 52 ... Abutting member, 54 ...
… Copier frame, 60 …… Support plate.

Claims (1)

[Scope of utility model registration request] 1. An image forming apparatus for rotatably supporting a belt-shaped photosensitive member by a plurality of rolls, wherein one of the plurality of rolls applies tension to the belt-shaped photosensitive member by a first urging means. Is a tension roll that is movably biased to the image forming apparatus main body side, through a supporting means, the image forming component is provided facing the belt-shaped photoreceptor wound around the outer periphery of the tension roll, A pair of gap holding discs having a diameter larger than that of the tension rolls are provided concentrically with the tension rolls at both ends of the tension rolls, and the second biasing means biases in a direction opposite to the biasing direction of the first biasing means. By pressing the image forming component against the pair of gap holding discs by a biasing means, the gap between the image forming component and the belt-shaped photoreceptor is kept constant, and Forming parts counterparts gap assurance device for a belt-shaped photosensitive member, characterized in that it is movable in a direction to increase the spacing between the tension roller against the urging force of the second biasing means.