JPS5811982A - Image recording device - Google Patents

Abstract

PURPOSE:To reduce space occupied by a photosensitive element in the titled device and to reduce the size of the device by arranging an incident position of an exposing means on a plane area close to a changing point at which the photosensitive element starts to contact with a driving roller and a plane changes to a curved surface. CONSTITUTION:For an exposing position of a photosensitive element 1, a plane area (a) just prior to a point where the photosensitive element 1 starts to contact with a driving roller 2 is selected as a plane area reducing the variation of the photosensitive element and also the variation of speed. A developing device is arranged a curved area (b) where the variation of developing gap and speed is the smallest and the photosensitive element 1 contacts with the driving roller 2. A charger is arranged on an projected side in the plane area where the variation of the photosensitive element is small. Thus, the space occupied by the photosensitive element and the size of the device can be reduced by selecting the arrangement of the exposing position and each device.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image recording apparatus having an endless belt-like photoreceptor.

As an electrophotographic image recording device, a charger, an incident position of a slit-shaped exposure means, and a developing device are arranged in sequence along the circumference of a drum-shaped photoreceptor, and the image recording device is arranged in order according to the light intensity of the scanning beam from the exposure means. Many devices are used to record images.

However, in the above-mentioned type of recording apparatus in which all the image forming means are arranged around a drum-shaped photoreceptor, the internal space of the photoreceptor is wasted, resulting in an increase in the size of the entire apparatus. If the diameter of the drum is reduced to overcome this drawback, (a) the space and arrangement of each unit will be restricted;

(b) In the case of a slit-shaped exposure means, the imaging surface is a curved surface with a small radius of curvature, which not only deteriorates the imaging performance, but also increases the degree of non-parallelism if the scanning line of the scanning beam is not parallel to the drum axis. The scanning beam diameter also changes depending on the position.

(c) When the charger is of the scorotron type, the arrangement of the grid wires must be matched to the curvature surface of the photoreceptor, which complicates the process.

This results in disadvantages such as:

Therefore, we used an endless belt-like photoreceptor as the photoreceptor.
This is supported by one driving roller and one or more driven rollers, and by configuring these rollers with rollers whose circumference is smaller than the entire circumference of the endless belt-like photoreceptor, the photoreceptor inside the device is By reducing the space occupied by the body, the device can be downsized as a result. However, in a recording device using such an endless belt-like photoreceptor, the radius of curvature of the outer circumferential surface of the photoreceptor is small at the portion where the photoreceptor belt contacts the roller, and the radius of curvature of the outer circumferential surface of the photoreceptor is small depending on the location between the rollers. Phenomena such as sagging and wave pegs occur, so it is necessary to take sufficient consideration in setting the exposure position and the installation position of the charger and developer.

In other words, the exposure position should be at a position where the velocity fluctuation of the photosensitive surface is small and the radius of curvature is large, the developing device should be installed at a position where there is little variation in the developing cap, and the charger should be installed at a position whose shape is complex. It is necessary to set the position at a position where the position of the photoreceptor surface is less likely to fluctuate.

SUMMARY OF THE INVENTION An object of the present invention is to provide an image recording device having an exposure position, a charging device, and a developing device installation position that meet the above-mentioned requirements when an endless belt-like photoconductor is used as the photoconductor of the image recording device. shall be.

Hereinafter, the present invention will be explained in detail based on drawings showing embodiments thereof.

FIG. 1 schematically shows how an endless belt-like photoreceptor used in the image recording apparatus of the present invention is supported.

(For simplicity, an example supported by one driving roller and one driven roller is shown.) Endless belt-shaped photoreceptor 1
is a flexible film in which an inorganic or organic photoconductor is provided on a base film. When such a photoreceptor 1 is driven in the direction of the arrow with the driving roller 2 and the driven roller 3 placed on a rack as shown in the figure, the photoreceptor 1 is divided into four regions depending on flatness, speed characteristics, etc. . Of these four areas, the areas where the photosensitive surface has little positional variation with respect to other constituent units are the flat side area on the tension side and the curved area on the drive side. Further, the region where the photoreceptor feeding speed is stable is the curved surface region on the drive side and the flat surface region on the tension side near the drive side curved surface region. In the flat area (2) on the loose side, fluctuations in position and feed speed are likely to occur due to phenomena such as waviness of the photosensitive surface, and in the curved surface area (@) on the driven side, fluctuations in feed speed are likely to occur.

Considering the characteristics of each region of the endless belt-like photoreceptor 1 described above, the steps of charging, exposure, and development that are important for image formation are as follows:
It can be seen that it is desirable to perform this while moving to the drive side curved area.

More specifically, as the exposure position, a flat area immediately before the photoreceptor 1 contacts the drive roller 2 is selected as a flat area where there are few fluctuations in the photosensitive surface and little speed fluctuation.
The developing device is placed in a curved area where the photoconductor l and drive roller 2 are in contact, where fluctuations in the development gap and speed are minimal, and the charger is placed in a flat area of the photoconductor, so that fluctuations in the photoconductor surface are minimized. Providing it on the side with less tension is suitable for the above-mentioned purpose.

In FIG. 2, an original 4 is moved, and an image of this original is formed by an imaging optical system 7 using an in-mirror lens 5 and a mirror 6 on the surface of an endless belt-shaped photoreceptor l driven by a drive roller 2. An embodiment will be described in which an incident position 8, a charger 9, and a developer 10 are arranged in a copying apparatus of the type described above. The charger 9 is located in the flat area on the stretch side of the endless belt-like photoreceptor l, the developer lO is located in the curved area on the drive side,
The exposure position 8 is provided in a flat area immediately before the surface changes from a flat surface to a curved surface.

The other embodiment shown in FIG. 3 is the same as the embodiment shown in FIG. 2 except that a convergent light transmitting array 5' is used as the imaging means for exposure, and similar effects can be expected. .

In yet another embodiment shown in FIG. 4, a gas laser such as He-Ne or a semiconductor laser is used as a light source as a photoreceptor exposure means, and the light source beam is modulated and deflected to form a minute beam spot on the photoreceptor. Light beam scanning means 11 that performs exposure by scanning while changing the light intensity
This embodiment is the same as the embodiment shown in FIGS. 2 and 3 except that .

In each of the above embodiments, the endless belt-like photoreceptor l is 1
Although we have described an example in which a rack is provided between two driving rows 22 and one driven roller 3, as shown in FIG. By applying the above-mentioned arrangement relationship of the present invention even when tilted from the horizontal, it is possible to
The same effects as the embodiment shown in the figure (-1) can be obtained.

As described above, according to the present invention, even when the photoreceptor is shaped like an endless belt to downsize and simplify the device, it is easy to precisely adjust the parallelism of the scanning beam to the width direction of the photoreceptor, and the photoreceptor The gap between the body and the developing section can be maintained, the shape of the charger can be simplified, and the quality of copies can be improved.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram for explaining the supporting state of an endless belt-like photoreceptor and the properties of each part thereof, Fig. 2 is a sectional view showing an embodiment of the present invention, and Fig. 3 is another embodiment of the present invention. FIG. 4 is a cross-sectional view showing still another embodiment of the present invention, and FIG. 5 is a cross-sectional view showing still another embodiment. l...Endless belt-shaped photoreceptor 2...Drive roller 3...Followed roller 8...Incidence position 9...Charger 10...Developer 11...Light beam scanning means

Claims (1)

[Scope of Claims] (1) An image recording device having an endless belt-like photoreceptor supported by one driving roller and one or more driven rollers, charging means, slit-like exposing means, and developing means. A recording apparatus characterized in that the incident position of the exposure means is provided in a flat area near a point where the photoreceptor begins to come into contact with the drive roller and changes from a flat surface to a curved surface. (c) The recording device according to claim 1, wherein the charging means is provided in a flat area on the tension side of the photoreceptor belt where the drive roller and the photoreceptor are not in contact. (3) The recording device according to claim 1 or 2, characterized in that the developing means is provided in a curved area where the drive roller and the photoreceptor are in contact. (4) The slit-like exposure described above 4. The recording apparatus according to claim 1, wherein a light beam scanning means such as a laser beam is used as the means.