JPS6290636A - Exposing device - Google Patents

Abstract

PURPOSE:To eliminate a light leak in an opening part by providing plural shutter members opposite the slit of a light shield member and moving them in the same direction with the movement of a photosensitive body, and opening and closing the shutters independently in synchronism with the moving speed. CONSTITUTION:The shutters 1 and 2 are arranged on both top and reverse surface sides of a slit plate 3 to open or shield an exposure area from light through rotating shafts 5 and 6. The slit 4 is normally closed by the shutter 2 and open by the shutter 1. When the slit 4 is formed so as to form an image on the surface of the photosensitive body, the shutter 2 is rotated and opened. Then, the shutter 1 is closed in synchronism with the rotating speed of the photosensitive body at the end of the image formation. Thus, the shutters 1 and 2 are opened and closed to eliminate a light leak in the middle of opening and closing operation. Thus, the opening/closing periods of >=2 shutters are controlled, so the light leak in the opening parts of the shutters is eliminated and the photosensitive body is exposed.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Object of the Invention [Industrial Application Field] The present invention relates to an exposure device that performs exposure scanning of an original image on a moving photoreceptor.

[Conventional technology]

In a copying apparatus that uses this type of exposure device, the length of the copy material such as transfer paper (the length of the copy material in the direction of movement and the length in the direction of movement) is the same as the length of exposure on the photoreceptor (the length in the direction of movement of the photoreceptor and the length in the direction of movement). If the length is smaller than the length in the feeding direction, the toner will adhere to the exposed area (uncharged area) in the feeding direction on the photoreceptor that protrudes from the copying material. As a result, the toner in this area was wasted, and the toner adhering to this area was transferred to the cleaning process, causing problems such as the toner scattering inside the device and staining the device. .

Furthermore, even within the exposure area corresponding to the size of the copy material, if there is a solid black area around information such as text or pictures, there is a problem that the consumption of toner increases due to this solid black area. .

As a countermeasure to this problem, conventionally, a single shutter that rotates or moves back and forth to block the image exposure is used, and the exposure area is determined by determining the exposure start position and exposure end position, and the copying material is fed. It has been attempted to prevent image formation on the photoreceptor which occurs on images outside the length or on solid black areas within the copy material.

[Problem that the invention seeks to solve]

In order to cleanly cut the edges of the image at the start and end of exposure, the operating speed of the shutter must be synchronized with the moving speed of the photoreceptor.

However, in a configuration in which the start and end of exposure are determined by the rotation of a single shutter or the reciprocating movement of a shutter on a plane, the operating directions of the shutter at the start and end of exposure are reversed, and the start and end of exposure of the photoconductor is Furthermore, it is impossible to operate the shutter in the rotational direction of the photoreceptor in synchronization with the photoreceptor movement speed at the end of exposure.

As a countermeasure to this problem, a configuration can be considered in which the same shutter has an opening and a light shielding part, and the shutter is operated in the same direction at the start of 1gl light and the end of exposure, but in this configuration, multiple exposures are performed within the same copy material. When the start and end of the exposure are repeated, the shutter must be returned halfway, and at this time, the opening of the shutter crosses the optical path during exposure, causing light leakage when the shutter returns. For this reason, a mechanism for blocking the entire light is required, and the structure is complicated and expensive.

The object of the present invention is to obtain an exposure apparatus that does not have the above-mentioned drawbacks.

1. Configuration of the Invention [Means for Solving Problems] The present invention provides an exposure apparatus that scans an original image and performs slit exposure on a moving photoreceptor. a first shutter member disposed opposite to the slit and movable in the same direction as the moving direction of the photosensitive member and in synchronization with the moving speed of the photosensitive member, and used when starting the A light;

This exposure apparatus is characterized by separately having a second shutter member used at the end of exposure.

[For production]

By controlling the opening and closing timing of two or more shutters,
The start and end of exposure to the photoreceptor can be repeated multiple times without causing light leakage.

〔Example〕

FIG. 1 is a sectional view showing an embodiment of the present invention, and FIG. 2 is a perspective view thereof.

In Fig. 11-2, shutters 1 and 2 are arranged on both the front and back sides of the slit plate 3, and are attached to rotating shafts 5 and 6 respectively bearing on the edges of the slit 4, completely opening the image exposure area. , so that it can be shaded from light. Reference numerals 7 and 8 designate motors that drive the one-rotation shafts 5 and 6 via gear trains 9, 10, 11, and 12, respectively, and are configured to control the operating width and operating speed of the shutters 1 and 2. 1
2 and 13 are the motors 7 and 13 based on the output of the CPU 14.
This is a drive circuit that drives 8.

The operation will be explained below with reference to FIG. 3.

The shutter 2 is in a state where the slit 4 is closed.

Shutter 1 is in a state where the slit can be heard (Figure 3 a)
.

When opening the slit 4 to form an image on the photoreceptor surface, the edge of the exposure area formed on the photoreceptor changes depending on the rotational speed of the photoreceptor (not shown) and the rotation of the shutter 2. The shutter 2 is rotated so that the speeds are synchronized (FIG. 3b).

To finish forming an image on the surface of the photoreceptor, the shutter 1 is moved so that the rotational speed of the photoreceptor and the speed of change on the photoreceptor of the optical path closed by the shutter are synchronized (Fig. 3 c, d). ).

After the shutter 1 is closed, the shutter 2 is closed (FIG. 3e) and the shutter I is opened to return to the initial state (FIG. 3a).

'' By using two legs, the opening and closing of the shutter 2 can be repeated any number of times without light leaking during opening and closing.

In the above embodiment, the slit 4 was opened and closed by rotating the shutter 2, but the same effect can be obtained by using a plurality of planar shutters and alternately moving them in parallel. FIGS. 4a to 4e show an example using two parallel moving shutters, and shutters 15 and 16 correspond to shutter 2 in the above example.

Driving control of the shutter shaft mentioned above (If the optical path comes from directly above, to specifically describe when the shutter 2 is closed rather than open, the speed of the photoreceptor on the body surface is set to Vm/se.
c, the length of the shutter (in the non-longitudinal direction) is M++m, and the counterclockwise rotation of the shutter from the vertical state in FIG.

Further, control during other operations can also be obtained as described above.

In this example, two rotary shutters are attached to each of the front and back surfaces of the slit plate, but as shown in Fig. 5, two rotary shutters are attached to the same slit plate. It can also be placed on the surface. Also, the shutter is 2
It is also possible to use more than one sheet. Furthermore, although one illustrated example clearly shows only one side, the opposite direction can be similarly performed.

C. Effects of the Invention As described above, according to the present invention, by controlling the opening/closing timing of two or more shutters, the opening and closing of exposure to the photoconductor can be performed multiple times when the shutter is returned. This can be done continuously without any light leakage due to the shutter opening.

In addition, when a one-rotation shutter is used, compared to a movable shutter, the operating speed can be increased with a simpler configuration.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an exposure apparatus showing an embodiment of the present invention;
FIG. 2 is a perspective view thereof, FIG. 3 is an explanatory diagram of its operation, FIG. 4 is an explanatory diagram of another embodiment of the present invention, and FIG. 5 is a cross-sectional view showing still another embodiment of the present invention. It is. 1-2-13 No. 14 is a shutter, 3 is a slit plate, and 4 is a slit. Figure 1 Figure 2 Figure 5 Figure 3 Figure 4

Claims (1)

[Claims] (1) In an exposure device that performs slit exposure on a moving photoreceptor while scanning an original image, there is provided a light shielding member having a slit for regulating an exposure area, and a light shielding member disposed opposite to the slit in the same direction as the moving direction of the photoreceptor. An exposure apparatus characterized by separately having a first shutter member, which is used at the start of exposure, and a second shutter member, which is used at the end of exposure, and which is movable in synchronization with the moving speed of the photoreceptor.