JPS5948366B2 - Document glass position adjustment device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a document table for an electrophotographic copying machine, etc., and more particularly to a device for finely adjusting the position of a document table glass.

Conventionally, when performing pit adjustment on a reflective original, the pits are often obtained by adjusting the position of the original platen glass.

In other words, this adjustment on the document table is performed by placing a test partial glass made to have the same thickness as the document glass on the holding frame to which the document glass is to be attached, and moving the partial glass while observing the pit condition. This is done by inserting spacers in the necessary locations and completing the adjustment, and then replacing the partial glass with the document table glass. However, in this adjustment method, since the spacer thickness is discontinuous, not only can only approximate pit adjustment be performed, but even if perfect pit adjustment is achieved, the difference between the partial glass and the document actually used The pit adjustment is rough due to the deviation in the thickness of the base glass. Particularly, in color copying machines that are being developed recently, there is a problem in that if there is a partial out-of-focus, color bleeding occurs and the copied image becomes unusable. In order to solve the above-mentioned adjustment problems of the conventional platen glass, the present invention provides a structure in which the platen glass is rotatably supported around an axis on the inner surface of the platen window into which the platen glass is dropped. A plurality of levers are positioned at the same position and support the document table glass at one end, and the levers are screwed into the device fixing part so as to abut the other end of the levers, and the amount of screwing of the levers is adjusted. The present invention proposes a position adjusting device for a document table glass, which includes a plurality of adjustment screws for rotating a lever. Hereinafter, details of one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is an overall cross-sectional view of a color image forming apparatus to which a document table glass position adjustment device of the present invention is applied.

In FIG. 1, a document table having a document table glass 2 on which an original is placed is provided on the upper surface of the machine housing 1, and a photoreceptor screen 3 extending in the horizontal direction is provided below the document table glass 2. Fixed position.

A charger 4 and a transfer electrode 5 that are movable along the photoreceptor screen 3 are provided above and below the photoreceptor screen 3.
The charger 4 charges the surface of the photoreceptor screen 3 prior to exposure. The transfer electrode 5 transfers an electrostatic latent image on the surface of the photoreceptor screen 3 to the transfer paper A when the photoreceptor screen 3 is exposed and a transfer paper A, which will be described later, is opposed to the surface thereof. The color image forming apparatus includes a full-surface exposure optical system and a slit exposure optical system Y that optically scans the document on the document table glass 2 and forms a color separated image on the photoreceptor screen 3.

The full-surface exposure optical system X includes an optical lamp 8, a condenser lens 9, a zoom lens 10, a mirror 11, and a color separation filter (not shown), and displays an enlarged image of the slide film attached to the slide holder 7. , an image is formed on a photoreceptor screen 3 through an original table glass 2. The slit exposure optical system Y includes an optical system box 13 that can be moved along a horizontal guide rod 12 above the photoreceptor screen 3, and the image of the document incident through the slit opening 5 to which an illumination lamp 14 is attached is mirrored. -16, enters the in-prism lens 17, passes through the mirror 18 and the light control device 19, and forms an image on the photoreceptor screen 3. The color image forming apparatus includes an image carrier or suction box 21 which is movable along a guide rod 20 which is mounted at approximately the same height as the photoreceptor screen 3. This suction box 21 receives the transfer paper A cut by the cutter 23 from the transfer paper roll 22, and attracts the transfer paper A to the bottom surface by the vacuum pressure applied inside the suction box 21. Further, a conveyor belt 24 made of a perforated belt is positioned directly below the suction box 21. The conveyor belt 24 has a built-in drying device that blows out drying air, so that when the transfer paper A under the box 21, which has undergone each development process described below, is transported to the position shown in the figure, it is not developed. Color separated images are fixed each time. At the bottom of the fuselage housing 1, there is a trolley 2 that is moved step by step along a rail 25.
On this cart 26, four developing devices 27, 28, 29, and 30 containing yellow, magenta, cyan, and black colored toners are located.

A lift device 31 is incorporated in the bottom of the body housing 1 to raise one of the corresponding developing devices 27, 28, 29, and 30 so that the developing device faces the running path of the transfer paper A. Therefore, when the transfer paper A, on which the color separated image has been made into a latent image by being opposed to the photoreceptor screen 3, passes through the elevated developing device, toner development of the corresponding color is performed, and this toner The image is dried and fixed, and such steps are performed four times on the same transfer sheet to form a complete color image.
In the color image forming apparatus as described above, a color image cannot be formed unless the image of the original on the original table glass 2 is completely formed on the photoreceptor screen 3.

In other words, color image forming apparatuses that form images through multiple exposure and development steps require stricter focus adjustment than ordinary monochrome copying machines. Therefore, the document table glass position adjusting device of the present invention as shown in FIGS. 2 to 4 is used.

FIG. 2 is an overall view of the document table described above, and the document table glass 2 is made in a size that can be dropped into the document table window 32. and,
The four sides of the original table glass 2 and the original table window 32 are covered with a decorative frame 33. Further, a pair of fixing metal fittings 34 and 35 made of angles having an L1-shaped cross section are fixed to the front and back sides of the document table window 32, and these fixing metal fittings 34,
Both ends of 35 are provided with position adjustment devices of the present invention, details of which are shown in FIGS. 3 and 4. In FIGS. 3 and 4, a shaft or pin 37 is inserted into a hole 36 drilled in the side surface of the fixing fittings 34 and 35, and the intermediate portion of the lever 38 is rotatably supported by this pin 37. Ru.

The lever 38 has an upwardly protruding protrusion 38a at one end, and this protrusion 38a is engaged with the bottom surface of a support bracket 39 fixed to the lower surface of the original light table glass 2, and bears the weight of the document table glass 2. do. A horizontally folded flap 38b is bent at the other end of the lever 38.
It is located in the internal space of the fixing fittings 34, 35 through.

Further, a screw hole 41 is formed on the upper surface of the fixing fittings 34, 35, and the tip of the screw hole 41 is connected to the flap 38.
The adjustment screw 42 abutted against b is screwed in. Furthermore, in order to prevent the fixing metal fittings 3 from loosening after adjusting the focus,
Screw holes 43 are formed in the side surfaces of the screw holes 4 and 35, and oval holes elongated in the vertical direction are formed at positions of the retainer fitting 39 corresponding to these screw holes 43. At the focused position, as shown in FIG. 3, the support and the fixture 34 can be fixed by tightening them with a fixing screw 44. Since the device of the embodiment has the above configuration, the lever 38
By dropping the document glass 2 into the document glass window 32 so that it is supported by the protrusion 38a of the document glass 2, and adjusting the screwing amount of the adjustment screw 42 while observing the focus state of the document on the document glass 2. Perfect focus adjustment is possible.

Of course, subsequent out-of-focus can be prevented by tightening the fixing screw 44 after all the position adjustment devices have been adjusted. As is clear from the above description, according to the present invention, stepless adjustment can be performed compared to the conventional method using spacers, so a precise adjustment state can be obtained, and the platen glass used can be adjusted. Since the adjustment is made using
The focusing state is no longer adversely affected by individual differences in the document platen glass or by thickness deviations between the glass and the partial glass used for testing.

[Brief explanation of drawings]

FIG. 1 is an overall sectional view of a color image forming apparatus to which the present invention is applied, FIG. 2 is an exploded perspective view of a document table to which the present invention is applied, and FIG. 3 is the position of the document table glass according to the present invention. FIG. 4 is an exploded perspective view of the adjustment device, and FIG. 4 is an enlarged sectional view of the same position adjustment device. 2...Original table glass, 37...Pin,
38...Lever, 42...Adjustment screw,
44...Fixing screw.

Claims (1)

[Claims] 1. A plurality of levers that are rotatably supported around an intermediate portion and positioned on the inner surface of the document table window into which the document table glass is dropped, and that support the document table glass at one end, and the other ends of these levers. A position adjusting device for a document table glass, comprising a plurality of adjusting screws screwed into a device fixing portion so as to abut each other, and rotating a corresponding lever by adjusting the screwing amount of the adjusting screws.