JPH0220820A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent the occurrence of errors in adjusting an image forming line by rocking an illuminator with respect to a frame and adjusting it so that the image forming line can be in parallel with the rotary axis of a photosensitive drum. CONSTITUTION:When the illuminator 3 is mounted on the frame 2, they are arranged to rock freely by using as the rocking central point a perpendicular (l) orienting the direction perpendicular to a plane including the locking plane of the frame 2 from the central position of the image forming line L in their main-scan direction in which an image is formed on the photosensitive body drum 1. The illuminator 3 is rocked on the frame 2 around the perpendicular (l) to adjust the position of the illuminator 3. Through this rocking operation, the image forming line L in the main-scan direction in which an image is formed on the photosensitive body drum 1 rocks around the central position, and the illuminator 3 is positioned to be parallel to the rotary axis 1b of the photosensitive drum 1. Thus, the image forming line L in the main-scan direction can be adjusted without errors; in the case of errors, they can be minimized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image forming apparatus that forms an image by scanning a photoreceptor drum with a laser beam.

[Prior Art] A conventional image forming HFf includes a photoreceptor drum and a locking surface that rotatably holds the photoreceptor drum, is spaced from the held photoreceptor drum, and is parallel to the rotation axis of the photoreceptor drum. A laser beam that is fixed on a locking surface and modulated by image information is irradiated in the main scanning direction to form an image on the outer circumferential surface of the photoreceptor drum, on a line parallel to the rotation axis. There are known devices equipped with an irradiation device that scans the imaging line while moving the image. The irradiation device irradiates the laser beam in the main scanning direction so that the image forming line in the main scanning direction formed on the outer peripheral surface of the photoreceptor drum is parallel to the rotation axis of the photoreceptor drum. Positioned and fixedly placed. This positioning is performed on the production line of the image forming apparatus and requires high accuracy. However, if the positioning accuracy is low, the image forming line will be tilted, and the image transferred and formed on paper or the like will also be tilted diagonally, degrading the image quality. To solve this problem, for example, Japanese Utility Model Application Publication No. 61-132853 discloses that the irradiation device and the photoreceptor drum are connected by moving the illumination fAis <optical box) by 1ffi with respect to the main body frame with the positioning bin as the center. An r4 height forming device is disclosed which allows the relative position to be changed by y4m.

[Problems to be Solved by the Invention] As in the image forming apparatus of the above publication, it is possible to accurately adjust the position of the imaging line in the main scanning direction; α by swinging the illumination device. But accurately shine! Even if the 8@ position is oscillated, a slight adjustment error will occur. When such an error occurs, it also affects the positional relationship with other parts,
It may be necessary to adjust the position of the photoreceptor drum, etc.

The present invention has been devised in view of the above problems, and its purpose is to improve g1t! of the image forming line in the main scanning direction formed on the photoreceptor drum by swinging the irradiation position VL. ! of,
It is an object of the present invention to provide an image forming apparatus that can perform adjustment without causing errors, and can reduce adjustment errors even if they occur.

[Means for Solving the Problems] The image forming apparatus of the present invention includes a photoreceptor drum, a frame that rotatably holds the photoreceptor drum, and a frame that is spaced apart from the held photoreceptor drum and that rotates the photoreceptor drum. A frame having a locking surface parallel to the axis, and a laser beam that is locked on the locking surface and modulated by image information is irradiated in the main scanning direction, and is placed above the outer peripheral surface of the photoreceptor drum and above the rotation axis. and an irradiation device that scans the image formation line while forming an image on a line parallel to the irradiation device, the irradiation device and the frame are configured to form an image on the photoreceptor drum by the laser beam. are able to swing relative to each other about a perpendicular line extending in a direction perpendicular to the surface including the locking surface from the center position of the main scanning direction imaging line;
The image forming line can be adjusted to be parallel to the rotation axis of the photosensitive drum by swinging the irradiation device with respect to the frame about the one line. .

[Function] When the image forming apparatus of the present invention is installed in a frame, the image forming apparatus of the present invention is arranged such that when the irradiation device is installed in a frame, the surface including the locking surface of the frame is Head in the direction that is perpendicular to! 1! They are arranged so that they can swing relative to each other with the line as the center of swing. Then, by swinging the irradiation device with respect to the frame around the I line, the position r1 of the irradiation vRj is adjusted.

Due to this swinging operation, the image forming line in the main scanning direction formed on the photoreceptor drum swings around its center position.
Align the irradiation device so that it is parallel to the rotation axis of the photoreceptor drum.

[Example] Hereinafter, a specific example of image formation [1] according to the present invention will be described based on the drawings. Here, FIG. 1 is a vertical sectional view in the side direction of the image forming apparatus section, FIG. 2 is a plan view of the frame, and FIG. 3 is a plan view showing the inside of the irradiation device.

The image forming apparatus of this embodiment includes a photosensitive drum 1, a frame 2, and an illumination device 3 as main components.

The photosensitive drum 1 has a cylindrical shape and has a photosensitive layer made of a Se compound on its outer peripheral surface 1a, and has both ends of a rotating shaft 1b rotatably held by a first frame 21, which will be described later.

The frame 2 includes a pair of first frames 21 that hold the photoreceptor drum 1, and a locking surface that is arranged substantially horizontally at a distance from the photoreceptor drum 1 and parallel to the rotation axis 1b of the photoreceptor drum 1. 22a. Second
In the frame 22, there is a tera A4 device which will be described later! From the central position WIC of the main scanning direction imaging line 1- formed on the photoreceptor drum 1 by the laser beam B irradiated from 3, it heads in a direction perpendicular to the locking surface 22a! l! A pivot shaft 23 whose axis is aligned with the line λ is provided to protrude from the locking surface 22a. And each engagement hole 306-30 mentioned later
At the position corresponding to 8 is a lock 112 of the second frame 22.
Engagement shafts 24 to 26 formed to protrude from 2a are shaped like m<. Thread grooves are formed at the tips of each of the engagement shafts 24 to 26, and nuts 27 to 29 are screwed into the thread grooves, so that the irradiation device M3, which will be described later, is connected to the second frame 2.
It is fixed at 2.

The irradiation unit 5AWt3 includes a housing 30, a laser device 31 that irradiates a laser beam B modulated by image information, a polygon scanner 32 that deflects and scans the irradiated rape beam B, and a lens system 33 that makes the laser beam B into a spot shape. , a reflection mirror 34 that reflects the laser beam 8 to the outer peripheral surface 1a of the photoreceptor drum 1, and an SO8 reflection 11 [3
The SO8 light receiving element 35 detects the start of irradiation of the laser beam B by detecting the reflected light from the laser beam B. In this irradiation device r3, a laser beam B irradiated from a laser device 31 forms an image on the outer circumferential surface 1a of the photoreceptor drum 1, and the image formation line L in the main scanning direction is parallel to the rotation axis 1b. Positioned. and the bottom 3 of the housing 30
01 has a shaft hole 302 that opens on the lower surface 301a side as described above! ! It is formed on a bowl, and the pivot shaft 23 is loosely fitted into this shaft hole 302. In addition, the housing 30 includes
Support portions 303 to 305 are provided at three locations, at both ends of the reflecting mirror 34 and near the laser device 31, with parts of the support portions 303 to 305 protruding from the lower surface 301a of the bottom portion 301 and in which the locking surface 22a of the second frame 22 and the distal end surface come into contact. is formed. Each of the support parts 303 to 305 is provided with engagement holes 30 (3 to 308) extending vertically through the distal end surface, and the engagement shafts 24 to 26 are inserted into each of the engagement holes 306 to 308. Each of the supporting parts 303 to 305 is fixed to the second frame 22 by nuts 27 to 29 which are screwed onto the engagement shafts 24 to 26.The respective engagement holes 306 to 308 are centered on the vertical si. The irradiation device 3 is formed into a long hole whose long diameter extends in the direction along the circular arc.Thereby, when the nuts 27 to 29 are loosened, the engagement shafts 24 to 26 move in the long diameter direction of the engagement holes 306 to 308. It is possible to swing around the shaft hole 302 (vertical IIA9.) to the extent possible.

The image forming apparatus of this embodiment is configured as described above and J3
Next, a method of adjusting this image forming apparatus will be explained.

The photosensitive drum 1 and the irradiation device 3 are attached to a predetermined position on the frame 2 on the production line. That is, the shaft hole 302 is fitted into the pivot I-shaft 23 of the second frame 22, and the engagement holes 306-308 are fitted into the engagement shafts 24-26. As a result, the irradiation device 3 is mounted in an ar-bag such that it can swing relative to the second frame 22 around the shaft hole 302 and the pivot shaft 23 (II or II). In this state, move the irradiation device around the pivot shaft 21, J: and shaft hole 302 (I line)! Perform a positional exam by shaking the 3. By this swinging operation, the laser beam B irradiated from the radar device 31 causes the outer circumferential surface 1a of the photoreceptor drum 1 to be
The image forming line L in the main scanning direction that is imaged above is located at the center of the IC.
oscillates around the center.

After positioning so that the main scanning direction condensation line L is parallel to the rotation axis 1b, nuts 27 to 29 are screwed onto each of the engagement shafts 24 to 26 to attach the irradiation device l'23 to the second frame 22. Fixed against.

However, as shown in FIG. 4, even if the main scanning direction imaging line L has an adjustment error of angle θ with respect to the regular main scanning imaging line Lo, the main scanning direction imaging line 1 -
Since the medium flame position C coincides with the regular main scanning imaging line Lo, the errors at both ends La and Lb are equal, and the mv! The error is small.

Incidentally, as shown in FIG. 4, the pivot shaft 21 and the shaft hole 302, which are the center of swing of the irradiation lff 13, are shifted from the perpendicular line in the direction of the rotation axis of the photoreceptor drum 1 (in the direction of arrow a).
11fP+, when a gl adjustment error of the same angle θ occurs, the center 4Q 1lff Cr of the main scanning direction imaging line L+ changes the angle θ with the position P+ as the center.
The position will be shifted. Therefore, one end tal l-Ia of the main scanning direction imaging line L1 has a larger error than the other end L1b.

-h, position 1 where the pivot shaft 21 and the shaft hole 302 deviate from the perpendicular intersection in the direction perpendicular to the rotation axis direction (in the direction of the arrow)]
z, the main scanning direction imaging line L
tG;tThe reference position D2 becomes a position shifted in the direction of rotation by an angle θ around position 1ffP2. Therefore, in the main scanning direction, one end 12a of the main scanning direction imaging line 1-2
protrudes and the other end 1-tb is retracted. Note that the larger the pivot shaft 21 and the shaft hole 302 (perpendicular lines) are deviated in the direction of the arrow a and the direction of the arrow, the larger the adjustment error becomes.

As described above, in the image forming apparatus of this embodiment, since the pivot shaft 21 and the shaft hole 302, which serve as the center of one-shot movement, are provided on the perpendicular line, an adjustment error of the image forming line L in the -scanning direction occurs. Even in this case, the error can be made small. Further, by swinging the irradiation device 3 fJJ, the position can be adjusted with an extremely simple operation. Furthermore, even if the mounting position of the photoreceptor drum 1 is misaligned or the main body frame is distorted,
! This can be dealt with by adjusting by swinging 3.

When mounting the photoreceptor in this way, the main scanning direction imaging line L is at an angle θ with respect to the regular main scanning imaging line Lo, due to misalignment of the position (angle) or distortion of the frame, etc.
If an error occurs and the center axis of the oscillation of the irradiation device 3 is at a different position from the center of the main scanning direction imaging line, when the irradiation wave 'f13 is oscillated by vJ to make the respective lines parallel In this case, the main scanning direction imaging line L shifts in the directions of arrows a and 2, causing problems such as image loss. On the other hand, in the present invention, since the central axis of the swing of the illumination O1 device 3 is configured to pass through the center of the main scanning direction imaging line L, the illumination device 3 is swung to perform the main scanning. When the direction imaging line 1- is adjusted to be parallel to the regular main scanning imaging line Lo, the main scanning direction imaging line 1.
can be made to coincide with the regular main scanning imaging line Lo without shifting, and the above-mentioned error will not occur.

Furthermore, the structure for position adjustment is extremely simple by arranging the pivot shaft 21 and the shaft hole 301 in a predetermined position (O'I!l), and the number of parts is small and costs can be reduced. .

a3, in this example, the shaft hole 30213 and the engagement hole 306
~308 irradiation! 4'F13 side, and the corresponding pivot shaft 23 and engagement shafts 22 to 24 are attached to the frame 2.
Although they are installed on the opposite sides, it is also possible to install them on the opposite sides. In addition, when the irradiation device 3 is rocked, it can be moved slightly. Adding IJ/WJ leveling means is even better.

[Yu light effect] In the image forming apparatus of the present invention, the irradiation device and the frame are as follows:
It heads in a direction perpendicular to the center of the main scanning direction imaging line formed on the photoreceptor drum by the laser beam, including the locking surface! l! They can be oscillated relative to each other with a as the oscillation center, and by oscillating the irradiation device relative to the frame about a perpendicular line, the imaging line can be adjusted to be parallel to the rotation axis of the photoreceptor drum. It becomes. Therefore, by swinging the irradiation device, the image forming line formed on the photoreceptor drum can be adjusted without causing any error, and even if an adjustment error occurs, it can be corrected. ! ! The gt difference can be made small.

[Brief explanation of the drawing]

1 to 4 relate to embodiments of the present invention, in which FIG. 1 is a vertical sectional view in the side direction of the main part of the image forming apparatus, FIG. 2 is a plan view of the frame, and FIG. 3 is the interior of the irradiation device. Plan view without showing, 4th
The figure is an explanatory diagram showing a state in which an adjustment f1 error occurs in the imaging line in the main scanning direction. 1... Photosensitive drum 1a... Outer peripheral surface 1b...
Rotating shaft 2... Frame 2a... Connection +1
Surface 3...Irradiation device B...Laser beam 1-...Main scanning direction imaging line C...Center position Text...Perpendicular line Patent applicant
Minolta Camera Co., Ltd. Representative Patent Attorney Hiroshi Okawa Figure 3

Claims (1)

[Claims] (1) a photoreceptor drum, a frame that rotatably holds the photoreceptor drum and has a locking surface spaced apart from the held photoreceptor drum and parallel to the rotation axis of the photoreceptor drum; A laser beam that is locked on a locking surface and modulated by image information is irradiated in the main scanning direction, and the image is formed on the outer peripheral surface of the photoreceptor drum and on a line parallel to the rotation axis. In the image forming apparatus, the irradiation device and the frame are arranged to move from the central position of the main scanning direction imaging line, which is imaged on the photoreceptor drum by the laser beam, to the They are mutually swingable about a perpendicular line perpendicular to a plane including the stop surface, and by swinging the irradiation device relative to the frame about the perpendicular line, the imaging line An image forming apparatus characterized in that the image forming apparatus can be adjusted so that the photoreceptor drum is parallel to the rotation axis.