JPH0219869A - Image recorder - Google Patents

Abstract

PURPOSE:To eliminate the need of readjustment at the time of exchanging an optical scanning unit by correcting errors caused by the optical scanning unit by means of the optical scanning unit side and errors caused by a device main body by means of the main body side. CONSTITUTION:A laser unit 9 is disposed with plural internal screw parts 58 which is screwed up to rotating normally and reversely with external screw members 59 constituted hollowly. By turning the plural external screw members 59 as necessary, adjustment can be done in all directions and setting is performed as designed value. Consequently, errors caused by the laser unit 9 are corrected inside of the laser unit 9. After that, by turning and adjusting plural external screw members 55 as necessary, scanning on a normal scanning line L on a drum 15 is maintained and errors caused by the device body except for the laser unit 9 are corrected by the main body side. Thus, the optical scanning unit can be exchanged without adjusting.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to an image recording apparatus, particularly an electrophotographic image recording apparatus.

``Prior Art'' As one of the structural forms of this type, a photoreceptor drum serving as an image carrier is scanned with light corresponding to an image information signal using a laser scanning optical system or the like, and a latent image formed is transferred to a photoreceptor drum using a known electronic method. There is a device that creates images using a photographic process, transfers the images to a transfer material such as paper, and outputs the images.

By the way, recording using laser light requires very high precision, and due to variations in precision of the optical scanning unit, the unit mounting part, and even the surface to be scanned, there may be a difference between the surface to be scanned and the optical scanning unit. The relative positional relationship of
This deviation causes a problem in that the recorded image is distorted.

For example, as shown in FIG. 4, a circumferential positional shift of the scanning line L on the surface of the photosensitive drum 4 results in a shift in the leading edge writing position of the output image. In FIG. 4, scanning light from an optical scanning unit 8 made of a rotating polygon mirror or the like scans a scanning line L on the surface of the photosensitive drum 4, which rotates in the direction of the arrow. If the position of this scanning line L deviates and the position L+ or L2 is scanned, the leading edge writing position of the image on the transfer material P will also deviate from the predetermined position L° for each number.
This results in a position of L'l or t, +2.

Further, for example, as shown in FIG.
When scanning the position, the leading edge position of the image on the transfer material P is tilted from the predetermined position, and the position is L″3 or L
It ends up in position 4. That is, the parallelism with the leading edge of the transfer material or the perpendicularity with the right-angled edge of the leading edge of the transfer material is disturbed.

In order to solve the above problem, the present applicant has already published Japanese Patent Application Laid-Open No. 62-1
Publication No. 1240 makes one proposal. That is, in a laser recording device having an image carrier and an optical scanning unit for scanning the image carrier with a laser beam, the optical scanning unit has a plurality of positioning parts,
This positioning part includes a first positioning member having a hollow hole that determines the height of the optical scanning unit, and a second positioning member that is loaded into the hollow hole of the first positioning member and fixes the optical unit to the substrate to which the optical unit is attached. The present invention proposes a laser recording device having a positioning member, in which the relative positional relationship between the optical unit and the image carrier can be adjusted.

"Problems to be Solved by the Invention" However, the above-mentioned devices still have problems with serviceability or maintainability in the market. In other words, when assembling the device, it is good to be able to correct deviations in the relative positional relationship between the optical scanning unit and the scanned surface by adjustment;
When an inconvenience or the like occurs in the device in the market and it becomes necessary to replace the optical scanning unit or the like, it is necessary to readjust the deviation in the relative positional relationship in conjunction with the replacement.

``Object of the Invention'' The present invention has been made in view of the above-mentioned problems, and even when the optical scanning unit is replaced, there is no need to readjust the deviation in the relative positional relationship that accompanies the replacement. The present invention provides an image recording device with excellent serviceability and maintainability.

"Means for Solving the Problems" The present invention provides an image recording apparatus having an image carrier and an optical scanning unit, in which errors caused by the optical scanning unit are corrected on the optical scanning unit side when correcting mutual positional errors between the image carrier and the optical scanning unit. The image recording apparatus is characterized in that it has means for correcting, and means for correcting errors caused by the apparatus main body on the main body side.

``Embodiment'' An embodiment of the present invention will be described below by taking as an example an electrophotographic image recording apparatus that records by scanning a photoreceptor with a laser beam. FIGS. 2 and 3 show the overall configuration of the device.

A and B are the lower casing and the upper casing of the device, and the upper casing B
is connected to the lower casing so as to be openable and closable about the hinge portion 1, and is always urged in the opening direction by a biasing spring (not shown). When the open upper housing B is fully closed against the lower housing A against the biasing spring, the locking member engages and the upper housing B is held in the closed state with respect to the lower housing. Ru. FIG. 2 shows this confinement state.

When the lock member is released, the upper casing B opens with respect to the lower casing A around the hinge part 1, opens and rotates with the biasing force of the biasing spring, and is placed in a predetermined diagonally upward open position, with the predetermined position being approximately vertical. be held in the raised position. Figure S shows this open state.

In this open state, the inside of the apparatus is open, and internal inspection, insertion and removal of process cartridges, etc. can be easily performed.

On the entrance side of the lower housing, there are a paper cassette 2, a paper feed section 5 consisting of a paper feed slot roller 6, a registration roller 4, etc., and an image transfer discharger 6.
, a paper conveying section 7, an image fixing device 8, a laser unit 9 as an optical scanning unit, etc. are provided. On the upper housing B side, a process cartridge 10 and a laser reflection mirror 11 are installed.
, pre-exposure lamp 12, paper transport section 13, paper ejection tray 14
etc. are arranged.

In this example, the process cartridge 10 has four devices, a drum-type electrophotographic photoreceptor (hereinafter referred to as drum) 15, a charger 16, a developing device 17, and a cleaning device 18, and the upper part as shown in FIG. When the casing B is open, it is inserted into and removed from the upper casing B at a predetermined position along the guide rail 20 provided on the upper casing B side.

Image recording is performed in the state shown in FIG. 2, in which the process cartridge 10 is mounted on the upper housing B side and the upper housing B is closed and locked in the lower housing A.

That is, the drum 15 is driven to rotate in the direction of the arrow at a predetermined circumferential speed about the shaft 15a in response to the one-time recording start signal.

As the drum 15 rotates, the pre-exposure lamp 1 is
2, the entire surface is pre-exposed 11, and is then charged positively or negatively by a charger 16.

Next, by receiving laser beam scanning exposure LB by the laser beam scanning section unit 9 in the exposure section 19, an electrostatic latent image of the target image is formed on that surface.

The laser unit 9 consists of a semiconductor laser (not shown), a rotating polygon mirror (polygon mirror, mirror), an f-theta lens, etc. The modulated laser beam is output and passes through the reflecting mirror 11 to the exposure section 19 of the drum 15.
Then, the surface of the drum 15 is exposed in the main scanning direction of the laser beam in the drum generatrix direction.

The electrostatic latent image formed on the surface of the drum 15 is developed with toner by a developing device 17, and reaches the position of the image transfer discharge device 6. The toner developing device is synchronized with the rotation of the drum 15 and is successively transferred from the paper feeding section 5 onto the surface of the transfer paper P fed between the drum 15 and the transfer discharger 6.

The transfer paper P on which the toner image has been transferred is separated from the surface of the drum 15 by a separating member (not shown), introduced into the image fixing device 8 via the paper conveyance section 7, where the image is fixed, and then transferred to the paper conveyance section 16.
The image is then discharged to the paper discharge tray 14 as an image-formed product.

The surface of the drum 15 from which the transfer paper was separated is cleaned by the cleaning section 1.
The surface is cleaned in step 8 and subjected to repeated image formation.

The paper feed roller 3 is intermittently rotated in the paper feed direction at a predetermined number of rotations in the paper feed direction at each predetermined paper feed timing.
The sheets P in the cassette 2 are sent out toward the registration rollers 4 one by one during each intermittent rotation.

The paper P fed one sheet from the cassette 2 by the paper feed roller 3 has its leading edge caught by the nip of the registration roller 4, which is stopped at that point, and then is transferred to the drum 1.
The registration roller 4 is driven to rotate at a predetermined timing synchronized with the rotation of the image forming apparatus 5, and is fed toward the transfer unit 6.

FIG. 1 is an exploded perspective view of a scanning light irradiation position adjustment portion, which is a main part of the apparatus of the present invention. The block structure 30 is provided with a positioning pin 45, and a plate 50 having a hole 51 that tightly fits with the positioning pin 45 is provided. A plurality of female threads 53 are disposed on the plate 50, and a hollow male thread member 55 is screwed into the female threads 53 to such an extent that it can rotate forward and backward. The plate 50 is fixed by a machine screw 56 passing through the male thread member 55 and being screwed into the block structure 60. Further, a plurality of pedestals 52 are arranged on the plate 50. These pedestals 52 constitute one plane.

The laser unit 9 is fixedly supported on the pedestal 52 by machine screws 57.

The laser unit 9 is provided with a plurality of female threaded parts 58, and a hollow male threaded member 59 is screwed into the female threaded part 58 to such an extent that it can rotate forward and backward. In the laser unit 9, the machine screw 57 is connected to the male thread member 5.
9 and is screwed into the base 52 of the plate 50 to be fixed.

Next, the effect will be described. First, the plate 50 will be described. In FIG. 1, the side closer to the laser beam emission port 9a is F, the far side is F, the left and right sides are R, and the screw members 55 are designated as R, and the front side is 55FL, 55FR, the rear side is 55RI, 51SRR. Then, as shown in FIG.
If the male screw members 55FL and FR or 55RL and RR are rotated by the same amount with respect to the axis I parallel to the rotation axis of the drum 15,
The male screw members 55FL and 5 are rotatable toward the normal scanning line L above, and are connected to the central axis ■ of the scanning optical system.
If 5RL or 55FR and 55RR are rotated by the same amount, they can be rotated toward the regular scanning line L, and these rotations can be made independently of each other, so Play 1
-60 can be adjusted in all directions.

On the other hand, before the laser unit 9 is assembled into the main body of the apparatus, when the mounting surface on which it is assembled is in an ideal position, that is, when the plane formed by the pedestal 52 of the plate 50 forms a plane according to the design value, the laser unit 9 is placed in the ideal position. That is, adjustments are made using a jig or the like so that the scanning line is scanned according to the designed value. That is, as in the case of the plate 50 described above, by rotating the plurality of screw members 69 as necessary,
Adjustments can be made in all directions, and settings can be made according to ideal, ie, designed values. Therefore, the error caused by the laser unit 9 is corrected within the laser unit 9, and after adjustment, there is no difference between the individual laser units 9 and they are equivalent.

Thus, the adjusted laser unit 9 is attached to the plate 50.
After fixing it to the pedestal 52 part, as described above, by adjusting the rotation of the plurality of male thread members 55 as necessary,
Scanning on the regular scanning line L on the drum 15 is ensured. That is, errors caused by the main body of the apparatus other than the laser unit 9 are corrected on the main body side.

It goes without saying that the number of adjustment points n may be set to n = 5 if the structure such as the plate 50 is a rigid body.

Furthermore, although the above embodiments have shown an apparatus using a laser scanning optical system, the idea of the present invention is not limited to this. Needless to say, the present invention can also be applied to other devices.

Furthermore, the photoreceptor is not limited to a drum shape, but may of course be belt-shaped.

"Effects of the Invention" As described above, according to the apparatus according to the present invention, the error caused by the optical scanning unit is corrected when the mutual position error between the photoreceptor as an image carrier and the optical scanning unit is corrected. Correction is made on the optical scanning unit side, and errors caused by the device itself are corrected on the main body side, making it possible to create an image recording device that is not only easy to assemble during manufacturing, but also easy to service and maintain in the market. can be provided. In other words, since the optical scanning unit and the main body of the device into which it is installed each maintain their predetermined positions, complete compatibility is maintained between the individual optical scanning units, and replacement without adjustment is possible. It is extremely large.

[Brief explanation of the drawing]

The drawings show one embodiment, and Fig. 1 is an exploded perspective view showing the scanning light irradiation position adjustment part, Fig. 2 is a vertical cross-sectional view of the upper case in a closed state, and Fig. 6 is an exploded perspective view showing the scanning light irradiation position adjustment part. 4 and 5 are perspective views for explaining the problems of the conventional device, and FIG. 6 is a perspective view showing the gist of the present invention. 9. Laser unit 15. Fist drum type electrophotographic photoreceptor 5o.. Plate 51.. Hole 52.. Pedestal 5 &
Number: Female thread 55...Male thread member 56...Small screw 5
8...Female thread 57...Small screw 59...Threaded member. Patent applicant Canon Co., Ltd.

Claims (1)

[Claims] (1) In an image recording device having an image carrier and an optical scanning unit, when correcting the mutual position error between them, the optical scanning unit has a means for correcting the error caused by the optical scanning unit, and the apparatus main body An image recording device characterized by having means for correcting errors caused by the error on the main body side.