JPH0398063A - Image recorder - Google Patents

Abstract

PURPOSE:To improve the ability of assembling an irradiation device to a photosensitive drum and to eliminate an adjusting work by pressing a positioning member which is integrally formed with the irradiation device to the rotary shaft of the photosensitive drum or a rotary shaft supporting member through an elastic member so that the irradiation device may be positioned to the photosensitive drum. CONSTITUTION:The irradiation device 21 is held so that it can move in the optical axis direction of its emitted light with respect to the photosensitive drum 13 and the positioning member 21-b which is integrally formed with the irradiation device 21 is pressed to the rotary shaft 13a of the photosensitive drum 13 or the rotary shaft supporting member 26-a through the elastic member 22 so that the irradiation device 21 may be positioned to the photosensitive drum 13. A part of the irradiation device directly comes into contact with the photosensitive drum 13 and the positional relation between the irradiation device 21 and the photosensitive drum 13 is decided. Thus, the ability of assembling the irradiation device to the photosensitive drum is improved and the adjusting work is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an image recording device that uses laser light or LED light flux. (Prior Art) In an image recording device that records an image by irradiating a photoreceptor drum with laser light from an irradiation device, such as a laser printer, the irradiation device includes a method of deflecting and scanning laser light, an LED array, and a fluorescent tube. There are various methods, such as a light emitting element array such as an array, a method that combines a liquid crystal shutter array and a focusing light transmitter array. FIG. 6 shows the main structure of the laser printer.

In the figure, a laser beam emitted from a semiconductor laser 1 is made into a parallel beam by a collimating lens 2, and is deflected and scanned by an imaging lens 6 and a rotating polygon 917 via a slit 3, a first cylinder lens 4, and a mirror 5, and then is exposed to light. The image is formed on the body drum 13. The second cylinder lens 12 corrects the surface tilt of the rotating polygon R7.

Among the above-mentioned members, all except the photoreceptor drum l3 are housed in the housing as an irradiation device.

The light beam emitted from the irradiation device is imaged and scanned on the photoreceptor drum, but when the image formation condition is ideal, it will be as shown in Figure 7 (a), but if the positional accuracy deviates in the optical axis direction, the image will be scanned. Figure 7 (
b).

In general, the ideal state 71! (Fig. 7(a)), that is, the image is formed on the photoreceptor drum. However, in reality, as shown in Fig. 7(b), the image forming position may vary depending on the precision of the parts. For example, it deviates from the drum by a deviation amount ΔZ. When this amount of deviation is large, the tail of the energy distribution widens as shown in the figure, and the spot diameter ω is the same as the ideal spot diameter ω. This becomes a big problem as the resolution of the recorded image decreases and the thickness of the characters changes. Furthermore, if the irradiation device and the photosensitive drum 13 are not parallel, the actual scanning line L may be bent with respect to the ideal scanning line La as shown in FIG. 8, or the actual scanning line L may be bent as shown in FIG. Actual writing 4@W may deviate from ideal writing @Wa. Note that in FIGS. 8 and 9, the second cylinder lens 12 is shown as a part of the irradiation device.

Because of the above-mentioned problems, the positional accuracy between the irradiation device and the photoreceptor drum must be set with high precision, and in all conventional image recording devices, the positioning of the irradiation device on the frame base of the image recording device cannot be adjusted. Above, a fixing method is adopted. (Problems to be solved by the invention) The conventional fixing method had problems in that it was difficult to assemble the irradiation position and it took time to adjust. In addition, small desktop laser printers have a structure that opens up and down in a crocodile-like manner using a hinge for convenience such as removing jammed paper, replacing the image forming unit, and maintenance, and the irradiation device is attached to the upper structure. In addition, since the photoreceptor drum is disposed on the lower structure, the clearance of the hinge becomes a cause of error, and it is particularly difficult to achieve positional accuracy between the two. It is an object of the present invention to provide an image recording device that has improved assemblability and can omit adjustment work.

(Means for Solving the Problems) In order to achieve the above object, in the image recording apparatus of the present invention, an irradiation device is held movably in the optical axis direction of the emitted light with respect to the photoreceptor drum, and The irradiation device is positioned with respect to the photoreceptor drum by pressing a positioning member integrated with the irradiation device against the rotating shaft of the photoreceptor drum or the rotation shaft support member via an elastic member. (Function) A part of the irradiated part comes into direct contact with the photoreceptor drum,
The positional relationship between the irradiation device and the photoreceptor drum is determined.

(Embodiment) In FIG. 1, the reference numeral 2l indicates an optical housing as an irradiation device, which includes a semiconductor laser 1, a collimating lens 2, a slit 3, a first e-cylinder lens 4, as shown in FIG. A mirror 5, an imaging lens 6, a rotating polygon mirror 7, a second cylinder lens, etc. are arranged.

The optical housing 21 has three mounting parts 21-a and two positioning members 21-b on its outer edge, and is mass-produced with high precision due to its integral shape, with little variation between parts.

As shown in detail in FIGS. 2 and 3, each mounting portion 21-a is integrally connected to the upper structure 14 of the image recording device by a fixing screw 23 via an elastic member 22 made of an extensible coil spring. It is held in the upper frame 25. Note that the reference numeral 21-C in FIG. 3 indicates a laser beam exit window. In this holding state, the optical housing 2l opens the laser beam exit window 21-
It is movable in the optical axis direction of the light emitted from c, that is, in the axial direction of the fixing screw 23, depending on the degree of deflection of the elastic member 22. On the other hand, as shown in FIG. 1 and FIG.
a is formed, and a photosensitive drum l3 is placed in this recess.
The bearing portion 13-a is pivotally supported for positioning.

Now, focusing on the positioning member 21-b of the optical housing 2l, the tip of the positioning member 21-b is formed with a recess 21-d that can engage with the bearing portion 13-a of the photosensitive drum. ．． The setting position on the upper frame 25 of the optical housing 2l is determined when the upper structure 14 rotates in the direction of the arrow in FIG. 3 and reaches the normal closed position.
The recess 21-d is engaged with the recess 21-d, and the elastic member 22 is appropriately bent so that the optical housing 21 is pressed against the photoreceptor drum 13 only by the elastic force. Therefore, when the image recording apparatus is usable, the optical housing 2l is free with respect to the upper frame 25 and is positioned only with respect to the photosensitive drum 13.

Therefore, in the example shown in FIG. 3, the clearance of the hinge portion that pivots the upper structure 14 and the lower structure 15 at one end does not affect the positional accuracy between the optical housing and the photosensitive drum. If dimensional accuracy is ensured between the structural parts of the optical housing 2l, accuracy with respect to the photoreceptor drum will also be ensured in the optical axis direction and the scanning direction. Therefore, the position of the irradiation device is maintained relative to the photoreceptor drum, and it follows the swinging of the photoreceptor drum, making it resistant to vibrations, ensuring good images are always obtained, and it is easy to assemble and requires no adjustment. ．． Next, an example in which the irradiation device is configured with a light emitting element array will be described. As shown in FIG. 4, an irradiation device using a light emitting element array includes a light emitting element array substrate 31. It is composed of a convergent light transmission body 32, a heat sink 33, a holding housing 34, etc. arranged in an array. In the case of this example as well, the holding housing 34 is similar to the previous example, as shown in FIG.
The housing mounting portion 34-a, which is integral with the housing mounting portion 34-a, is held on the upper frame 25 by a fixing screw 36 via an elastic member 35.
Then, the positioning member 34-b, which is formed integrally with the holding housing 34, is elastically pressed into engagement with the recessed end of the positioning member 34-b and the bearing portion of the photosensitive drum for positioning. In this case as well, the same effect as in the previous example is obtained. (Effects of the Invention) According to the present invention, the ease of assembling the irradiation device to the photoreceptor drum is improved, and adjustment work is not required. Furthermore, the image is not affected by vibrations.

[Brief explanation of drawings]

Figures 1 and 5 are exploded perspective views illustrating embodiments of the image recording device according to the present invention, Figure 2 is a cross-sectional view illustrating details of the mounting section, and Figure 3 is a desktop small laser printer. 4 is an explanatory diagram of the irradiation device related to the light emitting element array, FIG. 6 is a diagram illustrating the configuration of the optical system of the image recording device, and FIG. 7 is a diagram illustrating the structure between the irradiation device and the photoreceptor drum. Figures 8 and 9 are diagrams that compare the beam shape, spot shape, and energy distribution between the case where the dimensional accuracy is ideal and the case where the relative position is shifted. It is. l3... Photosensitive drum, 21... Optical housing,
21-b, 34-b... positioning member, 22. 35
. . . Elastic member, 34 . . . Holding housing. Me I

Claims (1)

[Scope of Claims] In an image recording device that records an image by irradiating a photosensitive drum with a light beam from an irradiation device, the irradiation device is held movably in the optical axis direction of the emitted light with respect to the photosensitive drum. In addition, the irradiation device is positioned with respect to the photoreceptor drum by pressing a positioning member integrally formed with the irradiation device against the rotation shaft or rotation shaft support member of the photoreceptor drum via an elastic member. image recording device.