JPH03102308A - Image forming device - Google Patents

Abstract

PURPOSE:To easily correct the deviation of irradiating position by scanning light when a main body frame is twisted by movably providing a beam transmitting member for correcting the deviation of position between a light beam deflecting means and a substance to be scanned. CONSTITUTION:The light beam transmitting member 20 whose cross section is wedge-shaped and which is a transparent body made of glass or plastic is arranged between the light beam deflecting means 3 for deflecting the luminous flux of a light source 2 and a photosensitive drum 4. Then, the member 20 is movably provided along a guiding groove 20c with a pin 20b as center. In the case that the main body frame 1, etc., is twisted with such constitution, the member 20 is adjusted to be turned by loosening a screw 20e once and it is fixed by screwing the screw 20e after confirming that the difference of the height of the scanning light L1 and L2 is eliminated. Therefore, the tilt of the scanning light is easily adjusted.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an image forming apparatus such as a laser beam printer that can correct the irradiation position of scanning light emitted from a scanning optical system. Conventional technology> In image forming devices such as laser beam printers,
A scanning optical system including a light source, deflection means, light beam imaging means, etc. is arranged within the main body frame. The scanning optical system is equipped with an irradiation position adjusting means for adjusting the irradiation position of the scanning light, and the irradiation position ff
The HIl adjusting means adjusts the light beam so that it is irradiated onto a predetermined position on the photoreceptor drum. <Problems to be Solved by the Invention> However, if the main body frame equipped with the scanning optical system and the photoreceptor drum is twisted, or if the reflector that guides the scanning light to the photoreceptor drum is not installed accurately, the irradiation of the scanning light may become difficult. If the position is parallel to the desired position or
There were some drawbacks. Here, the parallel deviation of the irradiation position can be corrected, for example, by electrically controlling the rotation of registration rollers that control the timing of feeding the recording sheet to the photoreceptor drum and changing the feeding timing. However, it is difficult to correct the tilt of the scanning light. In recent years, horizontal image forming apparatuses have also been proposed in which the photoreceptor drum, light source, deflection means, imaging lens, etc. are each assembled into units and all are attached to the main body frame.
In such image forming apparatuses that are not equipped with a reflective mirror that guides the scanning light, it is not possible to use the reflective ξ mirror as a means of adjusting the irradiation position, and the twisting of the main body frame may cause the irradiation to continue. There was a drawback that appeared as a positional shift. The present invention has been made to solve the above-mentioned problems of the prior art, and its purpose is to provide an image that can correct deviations in the irradiation position such as the inclination of the scanning light even if the main body frame is twisted. The purpose is to provide a form or device. <Means for Solving the Problems> Means for solving the above problems and applied to the embodiments described below include a light source that emits a light beam, a deflection means that deflects the light beam, and a device that is scanned by the deflection means. and a light beam transmitting member that is movably disposed between the deflection means and the scanned object and corrects a deviation in the irradiation position of the scanning light. It is characterized by

<Operation> According to the above means, when the light beam emitted from the light source is deflected by the deflection means and the light beam is scanned on the object to be scanned, the light beam is transmitted through the light beam transmission member. By performing a movement operation, it is possible to correct the deviation in the irradiation position of the scanning light.

Also, those with a structure that is not equipped with a reflective ξ mirror that guides the scanning light,
In other words, even if the structure is such that the irradiation position cannot be adjusted using a reflector, the shift in the irradiation position of the scanning light can be corrected by the light beam transmitting member.
There is no situation where twisting of the main body frame appears as a shift in the irradiation position. <Embodiment> An embodiment of the image forming apparatus according to the above means will be described below. [First Embodiment] FIG. 1 is a perspective view of a scanning optical system portion of a laser beam printer, and FIG. 2 is a sectional view of a laser beam printer equipped with the scanning optical system. First, an outline of a laser printer will be explained with reference to FIGS. 1 and 2. Reference numeral A in the figure is the device main body, and the main body frame 1 includes a scanning optical system, that is, a semiconductor laser that emits a modulated beam according to an image signal, and a modulated beam (light beam) emitted from this semiconductor laser that converts the modulated beam (light beam) into almost parallel light. A light source 2 having a collimator lens etc., a rotating polygonal boundary 3a for scanning the light beam emitted from the source 2, and this rotating polygon mirror 3a.
A deflection means 3 consisting of a drive motor etc. that rotationally drives the 1000-stage deflector 3 forms an image of the light beam as scanning light on the surface of the photoreceptor drum 40, and directs the scanning light at a constant speed on the surface of the photoreceptor drum 4. Imaging lens group 5a having scanning fθ characteristics
, 5b, etc. Further, the main body frame 1 is equipped with a photosensitive drum 4 as a scanned body on which a latent image is formed by being irradiated with scanning light scanned by the deflecting means 3. Furthermore, the main body frame 1
is equipped with a light beam transmitting member 20 for correcting a tilt between the scanning light and the photoreceptor drum 4 due to twisting of the main body frame 1, etc., as will be described later. Further, the paper feeding portion of the apparatus main body A (the right side portion in FIG. 2) is equipped with a stacking tray 6 for stacking a plurality of transfer materials S, and the base end of this stacking tray 6 is equipped with a stacking tray 6 for stacking the transfer materials S. A separation pad 7 and paper feed roller 8 are arranged to separate and feed the sheets one by one. Here, an auxiliary roller 9 is attached to the shaft of the feeding roller 8.
is fitted so that the auxiliary roller 9 comes into contact with the separation pad 7 when the feeding roller 8 is not feeding paper. Further, on the downstream side of the separation pad 7 in the direction in which the transfer material is conveyed, a conveyance roller 10 that comes into pressure contact with the auxiliary roller 9 is arranged. This conveyance roller 10 is driven by a motor M (first
(see figure) via a gear system (not shown), and is driven by the motor M. The peripheral portion of the photoconductor drum 4, that is, the downstream side of the conveyance roller 10 in the direction in which the transfer material is conveyed, is An image forming section 12 is arranged to visualize the latent image formed on the surface of the body drum 4. The image forming section 12 includes a charging roller 13 that charges the surface of the photoreceptor drum 4, a developing device l4 that has toner and develops a latent image formed on the surface of the photoreceptor drum 4, and a developer l4 that has toner and develops a latent image formed on the surface of the photoreceptor drum 4. A transfer roller 15 and the like are provided to transfer the toner image pressed against the surface and developed by the developing device 14 onto the transfer material S.

Further, a fixing device l6 is disposed downstream of the image forming section 12 in the transfer material conveyance direction, and a transfer material S is supported and discharged by a discharge guide l7 on the downstream side of the fixing device l6 in the transfer material conveyance direction. A discharge roller 18 made of sponge is disposed, and the transfer material S to which the toner image has been transferred by the image forming section 12 is fixed to the fixing device 16, and then passes through the discharge guide 17 and the discharge port. - The paper is discharged onto a discharge tray 19 placed above the stacking tray 6 with the image side facing upward by the roller 18. Next, the light beam transmitting member 20 installed in the scanning optical system will be explained in detail with reference to FIG. The light beam transmitting member 20 is formed of a transparent body such as a glass plate or a brass plate with a wedge-shaped cross section that is thinner on the lower side and thicker on the upper side. It is located between the photoreceptor drum 4, is parallel to the photoreceptor drum 4, and is equipped with a ring that is rotatable with respect to the main body frame l.

That is, a holding piece 20a and a bin 20b for rotatably attaching the holding piece 20a to the main body frame l are provided at one end in the length direction of the light beam transmitting member 20, and the light beam is transmitted around the bin 20b. The transparent member 20 is rotatable. Further, at the other end in the length direction of the light beam transmitting member 20, there is a holding piece 20d having a guide groove 20c for allowing rotation of the light beam transmitting member 20, and this holding piece 20d.
A screw 20e for fixing the bottle 20b to the main body frame L is provided, and the bin 20b? After rotating around the center, the other longitudinal end of the light beam transmitting member 20 is fixed to the main body frame 1 by the screw 20e. Next, the function of the light beam transmitting member 20 will be explained with reference to FIGS. 3(a) and 3(b).

The image writing side of the scanning light immediately after passing through the imaging lenses 5a and 5b is L. , the end of the writing is L. , the writing side of the image of the scanning light that has passed through the light beam transmitting member 20 is L, and the writing end side is L■.

For example, if the main body frame 1 is twisted, the scanning light LI
M is the scanning light L. If the scanning light is incident on the photosensitive drum 4 as it is, it will appear as a tilt corresponding to this difference in height. Therefore, when the light beam transmitting member 20 is inserted between the deflecting means 3 and the photoreceptor drum 4, the scanning light is refracted by the cough light beam transmitting member 20.
The difference in height between the scanning light L and the scanning light L2 after passing through 0 is the height difference between the scanning light L Ill+ Lit and the scanning light L2. Light L+, Lx
Let θ be the angle (declination) between
), δLXCOSθ, which is smaller than δ1.

The other end of the light beam transmitting member 20 in the length direction (the side through which the scanning light I.
If you lift it so that it is higher than the side where a passes,
As shown in FIG. 3(a), the scanning light L. The refraction point of ass
Scanning light L. The refraction point of the scanning beams L, . Since the scanning light Llm is refracted earlier than the scanning light Llm, the scanning light Llm after passing through the light beam transmission member 20 is refracted earlier than the scanning light Llm. is the scanning light L. As a result, the difference in height between the two becomes even smaller than in the above case (δLXCOSθ). Therefore, after assembling the apparatus main body A, for example, the photosensitive drum 4
A CCD line sensor etc. is arranged on the surface, and scanning light L. If you make it possible to detect the irradiation position of the scanning light ■5■,
Once the screw 20e is loosened and the light beam transmitting member 20 is rotated, the scanning light L is transmitted from the output signal of the CCD line sensor, etc.
When it is confirmed that the difference in height between 1 and scanning light L2 has almost disappeared, the inclination of the scanning light can be easily adjusted by tightening and fixing the screw 20e again. Regarding the parallel deviation of the irradiation position on the photoreceptor drum 4, it is possible to control the registration roller (1!I not shown) that determines the timing for feeding the transfer material S to the image forming section l2, or
Alternatively, as shown in FIG. 2, if a sensor l1 is provided upstream of the image forming section l2 to detect the passage of the transfer material S, and the timing of image writing is controlled by adding it to the image signal, parallel misalignment can be avoided. It can be solved. In addition, when the light beam transmitting member 20 is made of a transparent plastic plate, the bottle 20b can be integrally formed on one end in the length direction, and the guide groove 20c can be integrally formed on the other end. It is possible to simplify the structure by omitting the pieces 20a and 20d. [Second Embodiment] FIG. 4 shows a second embodiment of the light beam transmitting member 20. When the light beam transmitting member 20 is moved upward in its entirety, the irradiation position of the scanning light on the photoreceptor drum 4 can be moved upward, and when it is moved downward, the irradiation position of the scanning light can be moved downward. You can. Therefore, in this second embodiment, the light beam transmitting member 20 is not only rotated as in the first embodiment, but also movable in the vertical direction. That is, a holding piece 20g having a vertically elongated hole 20f is provided in place of the holding piece 20a at one end in the length direction of the light beam transmitting member 20, and the holding piece 20g is provided at the other end in the length direction.
Relief hole 2 that can be moved and rotated in the vertical direction instead of 0d
A holding piece 20i having a diameter of 0h is provided, and each holding piece 20g, 20i is fixed to the main body frame 1 with a fixing screw 20J. Therefore, the illumination position of the scanning light can be adjusted upward or downward by once loosening the screws 20j of each holding piece 20g, 20i and moving the entire light beam transmitting member 20 upward or downward. The parallel deviation of the irradiation position can be adjusted. Further, by rotating the other longitudinal end of the light beam transmitting member 20 as shown by the arrow in FIG. 4, the inclination of the scanning light can be corrected. By performing this vertical movement and rotation, you can adjust parallel deviation and tilt at the same time. Note that the means for vertically movably and rotatably fixing the light beam transmitting member 20 is not limited to the above-mentioned means; for example, the holding pieces 20g and 201 may each have an independent mechanism for vertically moving and rotating. It is also possible to set it up as follows. [Third Embodiment] FIGS. 5(a) to (C) show a third embodiment of the light beam transmitting member 20. In the first embodiment, the light beam transmitting member 20 is rotated about the bin 20b as shown in FIG. 1, but in the third embodiment, in addition to this, the light beam transmitting member 20 is rotated as shown in FIG. The light beam transmitting member 20 is further rotated using the pin 21a as a fulcrum. That is, Fig. 5 (b
). As shown in (C), a mounting member 21 is provided which has mounting portions 2lb at both ends, which are mounted to the main body frame l via a bin 21a so as to be rotatable in a plane perpendicular to the light beam transmitting member 20. , the holding piece 20a on the mounting portion 2lb facing the photosensitive drum 4;
A light beam transmitting member 20 is attached via a screw 20d, a bottle 20b, and a screw 20e. Here, an arc-shaped guide groove 21c is formed at the lower end of the attachment part 2lb, and the attachment part 2lb can rotate relative to the main body frame 1 along the guide groove 21c about the pin 21a. The mounting portion 2lb is fixed to the main body frame 1 by a screw 21d inserted into the guide groove 21c. Therefore, the inclination of the scanning light can be corrected by loosening the screw 20e and rotating the light beam transmitting member 20 about the pin 20b. Furthermore, by loosening the screw 21d and rotating the light beam transmitting member 20 about the bin 21a, the scanning light can be moved as shown in FIG. 5(a). That is, the light beam transmitting member 2
0 (when the light beam transmitting member 20 is located at the position shown by the solid line in the figure), the scanning light incident on the light beam transmitting member 20 is L3M, the scanning light emitted is L3M, and the light beam After rotating the transmitting member 20 (when the light beam transmitting member 20 is located at the position indicated by the two-dot chain line in the same figure), the scanning light incident on the light beam transmitting member 20 is set to L. , when the emitted scanning light is L4, the refraction point a4 of the scanning light L is located closer to the photosensitive drum 4 than the refraction point a3 of the scanning light L, and the scanning light L4 moves upward than the scanning light L3. do. By operating the light beam transmitting member 20 in this manner, the irradiation position of the scanning light on the photoreceptor drum 4 can be arbitrarily set and corrected. [Other Embodiments] Since the scanning optical system, especially the rotating polygon mirror 3a of the deflecting means 3, rotates at high speed, dust tends to adhere thereto, and when dust adheres thereto, the amount of light beam becomes insufficient, making the recorded image unclear. Make it. Therefore, as shown in FIG.
The imaging lenses 5a and 5b may be sealed.
In this case, the side plates 23 and 24 are shaped so that no gap occurs even when the light beam transmitting member 20 is rotated up and down. Further, the light beam transmitting member 20 may be a transparent body having at least two or more optical planes, and one optical plane may not be parallel to the other optical plane. It is not limited to Further, although the case where a semiconductor laser is used as the light source 2 is shown, a gas laser or the like may also be used. Effects of the Invention> As explained above, according to the present invention, since the light beam transmitting member for correcting the deviation in the irradiation position of the scanning light is movably disposed between the deflecting means and the object to be scanned, Even if the main body frame is twisted, etc., it is possible to correct irradiation position deviations such as the tilt of the scanning light.

[Brief explanation of drawings]

Claims (2)

[Claims] (1) A light source that emits a light beam, a deflection means that deflects the light beam, a scanned object that is irradiated with the scanning light scanned by the deflection means, and between the deflection means and the scanned object. An image forming apparatus comprising: a light beam transmitting member that is movably disposed on the substrate and corrects a shift in the irradiation position of the scanning light. (2) The image forming apparatus according to claim 1, wherein the light beam transmitting member is a glass plate or a plastic plate having a wedge-shaped cross section.