IMAGE FORMING UNIT AND MOVING UNIT

Abstract

An image forming apparatus includes a cover frame that holds a held shaft of an optical writing unit to allow a free movement thereof and urges the optical writing unit in a predetermined direction by using an urging coil spring to bring the held portion shaft of the optical writing unit separated from the writing operation position into contact with a contact target portion thereof.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic side view of a printer according to an embodiment of the present invention;

FIG. 2 is an enlarged view of a K process unit in the printer;

FIG. 3 is a perspective view of an example of an image forming apparatus that performs internal maintenance in a front-cover opening/closing mode;

FIG. 4 is a perspective view of an example of the image forming apparatus that carries out internal maintenance in a left-cover opening/closing mode;

FIG. 5 is a perspective view of an example of the image forming apparatus that performs internal maintenance in an upper-cover opening/closing mode;

FIG. 6 is an enlarged view of an upper cover and its peripheral structure in the printer;

FIG. 7 is a schematic side view for explaining an opening/closing operation of the upper cover;

FIG. 8 is a perspective view of a right end of a housing of the printer;

FIG. 9 is an exploded perspective view of the right end of the printer;

FIG. 10 is a schematic view of a state of contact between a first front-held shaft of an optical writing unit and a front positioning portion in the housing of the K process unit;

FIG. 11 is an enlarged front view of a front plate of a cover frame having two first urging coil springs provided thereon;

FIG. 12 is a perspective view of the first front-held shaft urged by the first urging coil springs and its peripheral structure;

FIG. 13 is an enlarged front view of the front positioning portion and a front plate of the cover frame when the upper cover is closed;

FIG. 14 is an enlarged front view of the front positioning portion and the front plate of the cover frame when the upper cover starts opening;

FIG. 15 is an enlarged front view of a through opening of the cover frame;

FIG. 16 is a lateral cross-sectional view of the cover frame and the optical writing unit;

FIG. 17 is a lateral cross-sectional view of the cover frame and the optical writing unit in a comparative example in which a center of the optical writing unit in a front-and-back direction is urged;

FIG. 18 is an enlarged view of a Y process unit and its peripheral structure of the printer as seen from a front side of the printer;

FIG. 19 is a front view of optical writing units, the cover frame, and four process units of the printer;

FIG. 20 is an enlarged view of the cover frame and a process-unit urging spring;

FIG. 21 is a front view of a front plate of a cover frame in an apparatus according to a first modification;

FIG. 22 is an enlarged front view of a cover frame and a front positioning portion in an apparatus according to a second modification; and

FIG. 23 is an enlarged front view of the front positioning section and the front plate of the cover frame when an upper cover starts opening.

Claims

1. An image forming apparatus comprising: a latent image carrier that carries a latent image on an endlessly moving surface;a latent-image writing unit that writes the latent image on the surface;a holder that moves between a first position and a second position while holding the latent-image writing unit to move the latent-image writing unit held by itself between a writing operation position and a retracted position; anda developing unit that develops the latent image carried by the latent image carrier,wherein the holder holds a held portion provided in the latent-image writing unit to allow a free movement thereof and urges the latent-image writing unit in a predetermined direction by an urging unit, thereby bringing the held portion in the latent-image writing unit into contact with a contact target portion of the holder when separated from the writing operation position.

2. The image forming apparatus according to claim 1, wherein the held portion is provided at a positioning reference position of the latent-image writing unit to be determined as a positioning reference region, a positioning portion that is used to position the positioning reference region of the latent-image writing unit placed at the writing operation position is provided in the image forming apparatus, and the positioning reference region of the latent-image writing unit urged by the urging unit at the writing operation position comes into contact with the positioning portion.

3. The image forming apparatus according to claim 2 wherein the positioning portion rather than the contact target portion is placed near the urging unit of the holder present at the first position in an urging direction.

4. The image forming apparatus according to claim 2, wherein the positioning portion in the image forming apparatus is arranged on an extension of the urging unit in an urging direction in the holder placed at the first position.

5. The image forming apparatus according to claim 1, wherein the contact target portion is formed of a material that is compressed and deformed with contact of the held portion.

6. The image forming apparatus according to claim 1, wherein the carrier that carries the latent image carrier includes a guiding unit that guides the latent image carrier from an operating position of the latent image carrier toward the write operating position of the latent-image writing unit, the latent image carrier is slid in the guiding unit to be attached/detached with respect to the holder, andthe holder has a second urging unit that urges the latent image carrier or a casing including the latent image carrier toward the operating position of the latent image carrier at the first position.

7. The image forming apparatus according to claim 1, wherein a plurality of contact surfaces extending in different directions are provided on the contact target portion, and the held portion urged by the urging unit comes into contact with the contact surfaces at the same time.

8. The image forming apparatus according to claim 7, wherein the urging unit urges the held portion of the latent-image writing unit.

9. The image forming apparatus according to claim 8, wherein the holder holds the held portion to allow a free movement thereof in a range of a clearance between the held portion inserted into a through opening formed therein and an inner peripheral surface of the through opening, the contact surfaces of the contact target portion are at least two of a plurality of surfaces constituting the inner peripheral surface, and at least another surface of the surfaces is an urging unit fixing surface on which the urging unit is fixed.

10. The image forming apparatus according to claim 1, wherein the latent-image writing unit writes the latent image on the latent image carrier based on optical scanning,the held portion is provided at each of one end and the other end of the latent-image writing unit in an optical scanning direction, andthe contact target portion is provided at each of one end and the other end of the holder in the optical scanning direction.

11. A moving unit for use in an image forming apparatus, the moving unit comprising: a latent image carrier that carries a latent image on an endlessly moving surface;a latent-image writing unit that writes the latent image on the surface; anda holder that moves between a first position and a second position while holding the latent-image writing unit to move the latent-image writing unit held by itself between a writing operation position and a retracted position, whereinthe holder holds a held portion provided in the latent-image writing unit to allow a free movement thereof and urges the latent-image writing unit in a predetermined direction by an urging unit, thereby ringing the held portion in the latent-image writing unit into contact with a contact target portion of the holder when separated from the writing operation position.