JPH10142859A - Automatic senser positioning mechanism for image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device provided with automatic senser positioning mechanism which can secure high reliability and maintenance without needing the adjustment of sensor positioning. SOLUTION: This mechanism is constituted by attaching an image detection sensor 20 to a swinguable support plate 17 (sensor support member) which turns in conjunction with the opening/closing of an upper unit, by providing a torsion coil spring (energizing means) 19 for energizing the swinguable support plate 17 frontward and a retraction means for retracting the image detection sensor 20 when the upper unit is opened, by providing the image detection sensor 20 with a positioning pin 20b so that it juts out, and by forming on the swinguable plate 17 a positioning rib 4c which abuts on the positioning pin 20b. Thus, because in conjunction with the closing of the unit, the image detection sensor 20 is automatically positioned in the directions of the height and front and back of the sensor 20, the need to adjust the positioning of the image detection sensor 20 is obviated, and high reliability and maintenance are secured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic positioning mechanism of a sensor provided in an image forming apparatus such as a copying machine or a laser beam printer employing an electrophotographic system.

[0002]

2. Description of the Related Art In an image forming apparatus such as a copying machine or a laser beam printer, for example, an image detection sensor for detecting a toner image on a transfer drum, which is an object to be detected, is located at a position separated from the transfer drum by a predetermined distance. FIG. 9 shows a conventional example of a positioning mechanism of the image detection sensor.
Shown in

FIG. 9 is a partial side view of an image detecting sensor installation portion (transfer drum portion) of an image forming apparatus. In FIG. 9, reference numeral 130 denotes a transfer drum which is an object to be detected. Has an image portion 130a and non-image portions (flanges) 130b formed at both ends in the axial direction. The non-image portion 130b is formed to have a slightly smaller diameter than the image portion 130a.

[0004] Further, a fixing plate 1 attached to the apparatus body side.
A swinging plate 132 is pivotally attached to the upper and lower sides of the swinging plate 132 in a vertical direction (in the direction of arrow a in the figure) about a shaft 133, and a positioning roller rotatably supported at both ends of the swinging plate 132. 134 is in contact with the non-image portion 130b of the transfer drum 130. Further, a leaf spring 135 is provided on the swing plate 132.
An image detection sensor 120 is fixed to the slide plate 136, and the image detection sensor 120 is moved up and down with respect to the swing plate 132 together with the slide plate 136 (arrows in the drawing). b direction)
And is pressed toward the center of the transfer drum 130 by the leaf spring 135.

[0005]

However, the lens 120a of the image detection sensor 120 and the transfer drum 130
In order to accurately determine the distance S ₀ from the surface of the image portion 130a, the distance S ₀ between the sensor adjustment protrusion 120c formed on the image detection sensor 120 and the tip of the positioning roller 134 is determined.
_It was necessary to adjust ₁ to a desired size using a jig or the like and fix the image detection sensor 120 to the slide plate 136. For this reason, the image detection sensor 12 at the time of unit assembly
However, there is a problem in that the positioning adjustment of 0 is troublesome, and high maintainability and reliability cannot be secured.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object the object of the present invention is to eliminate the need for adjusting the positioning of a sensor and to assure a highly reliable and maintainable sensor automatic positioning mechanism for an image forming apparatus. Is to provide.

[0007]

To achieve the above object, according to the first aspect of the present invention, a detection object support member is provided on a unit which opens and closes by rotating with respect to an image forming apparatus main body. Attach the sensor to the sensor support member that rotates in conjunction with the opening and closing operation of the
A biasing means for biasing the sensor support member in the swinging direction and the front-back direction and a retracting means for retracting the sensor when the unit is opened are provided, and a positioning projection is provided on the sensor, and the positioning projection is provided on the sensor. A positioning portion to be abutted or fitted is formed on the sensor support member to constitute a sensor automatic positioning mechanism of the image forming apparatus.

According to a second aspect of the present invention, in the first aspect of the present invention, the top of the positioning projection is formed into an anti-spherical shape, and the positioning portion is formed of a positioning rib. A sliding tapered surface is formed on the portion.

According to a third aspect of the present invention, in the first aspect of the present invention, the positioning projection is constituted by a plurality of columnar pins, and the top is formed into an anti-spherical shape, and the plurality of positioning sections are formed. And at least one positioning projection has a fitting circular hole into which the pin is to be fitted, and another positioning projection has a fitting elongated hole into which the pin is to be fitted. A sliding tapered surface is formed on the periphery of each opening of the mating hole and the fitting long hole.

Therefore, according to the present invention, in response to the closing operation of the unit, the detected object support member comes into contact with the positioning projection of the sensor in the retracted state, and the positioning projection contacts the detected object support member. Positioning of the sensor in the height direction is automatically performed by the sensor, and at the same time, the positioning portion formed on the detected object support member abuts on the positioning protrusion attached to the sensor support member biased in one of the front and rear directions or By the fitting, positioning of the sensor in the front-rear direction or in the front-rear direction and the left-right direction is automatically performed, so that positioning adjustment of the sensor becomes unnecessary, and high reliability and maintainability are secured.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

<First Embodiment> FIG. 1 is a side sectional view showing an automatic sensor positioning mechanism according to a first embodiment of the present invention.
2 is a view in the direction of arrow A in FIG. 1, FIG. 3 is a longitudinal sectional view showing the opening and closing operation of a laser beam printer having an automatic sensor positioning mechanism according to Embodiment 1 of the present invention, and FIG. 5 is a partial sectional view showing a state when the process unit is detached, FIG. 5 is a vertical sectional view of the laser beam printer, and FIG. 6 is a partial sectional view showing a state when the laser beam printer is loaded with the process unit.

As shown in FIG. 5, the laser beam printer according to this embodiment includes an apparatus main body 1 and an upper unit 2 which is opened and closed by rotating the apparatus main body 1 about an opening / closing support shaft 2a. The upper unit 2 is provided with a laser scanner 3, a process unit 4, and a transfer belt unit 5. Process unit 4
Is detachably mounted on the upper unit 2,
It has a rotatable photosensitive drum 4a, which is an object to be detected. As shown in detail in FIG. 6, the transfer belt unit 5 includes a driving roller 5a and driven rollers 5b and 5c.
And an endless transfer belt 5e wound between the transfer roller 5d and the transfer roller 5d.
Part of “a” is covered by the upper cover 5f.

On the other hand, on the apparatus main body 1 side, a developing device turret 6 having four developing toner cartridges 6a, a belt cleaner 7, a paper feeding roller 8 and a conveying roller 9 and a registration roller 10, which constitute a paper feeding system, and a transfer roller A roller 11, a transport belt 12, a fixing device 13, a paper discharge roller 14, and the like are provided. A plurality of recording papers 15 are stacked and stored on the bottom of the apparatus main body 1.

The laser beam corresponding to the image signal is output from the laser scanner 3 and the process unit 4
Is irradiated on the photosensitive drum 4a, a latent image corresponding to an image is formed on the photosensitive drum 4a, and the latent image is stored in a plurality of developing toner cartridges 6a provided in the developing device turret 6. The developed toner is developed using toner of each color (for example, yellow, cyan, magenta, and black) and is visualized as a color toner image.

The color toner image on the photosensitive drum 4a is transferred onto the transfer belt 6e of the transfer belt unit 5 which is driven to rotate in the direction of the arrow in the figure by the action of a transfer roller 5d.

On the other hand, the recording paper 15 stored in the bottom of the apparatus main body 1 is separated and fed one by one by a paper feed roller 8,
It is conveyed to the registration roller 10 via the conveyance roller 9,
The toner is supplied to the transfer nip between the transfer belt 5 e and the transfer roller 11 at an appropriate timing by the registration roller 10.

The recording paper 15 receives the transfer of the color toner image carried on the transfer belt 15 e by passing through the transfer nip portion, and is then sent to the fixing device 13 by the transport belt 12. After receiving the fixation of the color toner image, the sheet is finally discharged out of the apparatus by the discharge roller 14.

In such a laser beam printer, for example, when the upper unit is rotated upward about the opening / closing support shaft 2a as shown in FIG. 3 when the process unit 4 is attached and detached, the upper unit is opened, as shown in FIG. Then, the upper unit stay 16 attached to the upper unit 2 also rotates in the same direction about the opening / closing support shaft 2a (see FIG. 3).

Here, one end of a swing support plate 17 is pivotally attached to the upper unit stay 16 by a pin 18, and an image detection sensor 20 is attached to the other end of the swing support plate 17. The image detection sensor 2
Numeral 0 is positioned at a predetermined position with respect to the photosensitive drum 4a, which is an object to be detected.

As shown in detail in FIG. 1, brackets 16a, 17a are respectively provided on one end of the upper unit stay 16 and the swing support plate 17, and one of the brackets 16a is long in the front-rear direction. A long hole 16b is formed, and the swing support plate 17 is supported movably in the front-rear direction with respect to the upper unit stay 16 within a range in which the pin 18 can move along the long hole 16b. A torsion coil spring 19 is wound around the pin 18, and one end of the torsion coil spring 19 is locked in a hole 16 c formed in the upper unit stay 16, and the other end is connected to a bracket 17 a of the swing support plate 17. It is locked by the formed spring hook 17b. Accordingly, the swing support plate 17 and the image detection sensor 20 attached thereto are urged upward and forward (to the left in FIG. 1) by the torsion coil spring 19.

On the other hand, as shown in FIG. 1, a positioning rib 4c having a width L1 (see FIG. 2) is integrally formed on the side of the bottom plate 4b of the process unit 4 near the image detection sensor 20 so as to protrude downward. A sliding tapered surface 4d is formed at the tip of the positioning rib 4c.

A lens 20a is mounted on the front surface of the image detection sensor 20, and two cylindrical positioning pins 20b are provided on the upper surface in the width direction (perpendicular to the paper surface of FIG. 1) of the positioning rib 4c. They are integrally provided to project upward at a predetermined interval L0 (<L1) shorter than the dimension L1. The top of each positioning pin 20b is formed in a hemispherical shape.

Further, as shown in FIG. 4, a pivoting hook 21 is rotatably supported on the pivoting support plate 17 about a support shaft 22. An engagement groove 21a with which the hook 5g attached to the upper cover 5f of the belt unit 5 is to be engaged is formed.
The rotation hook 21 is urged in one direction by a hook spring 23.

When the upper unit 2 is rotated by a predetermined angle about the opening / closing support shaft 2a and opened as described above, as shown in FIG. 3, the upper unit stay 16 is moved to the opening / closing support shaft 2a. , The swing support plate 17, the image detection sensor 20, and the rotation hook 21.
Also rotates in the same direction about the opening / closing support shaft 2a. Then, as shown in FIG.
When the hook 5g is engaged, the rotation hook 21 and the image detection sensor 20 remain at that position, and the process unit 4 becomes detachable in the direction of the arrow in FIG. After that, when the upper unit 2 is further rotated upward and opened, the rotation hook 21, the image detection sensor 20, and the transfer belt unit 5 are rotated upward together with the upper unit 2 around the opening and closing support shaft 2a. I do.

Next, from the state shown in FIG.
Is rotated in the opposite direction (downward) about the opening / closing support shaft 2a, and is closed. As shown in FIG. 1, a positioning rib 4c protruding from the process unit 4 side protrudes from the image detection sensor 20. Approaching the positioning pin 20b. Here, since the swing support plate 17 and the image detection sensor 20 attached thereto are urged forward (to the left in FIG. 1) by the torsion coil spring 19 as described above, the swing support plate 17 projects from the image detection sensor 20. The positioning pin 20b thus positioned is located ahead of a predetermined position (the position shown in FIG. 6).

Therefore, when the upper unit 2 is further closed, the sliding tapered surface 4d of the positioning rib 4c on the process unit 4 first contacts the anti-spherical top of the positioning pin 20b on the image detection sensor 20, As shown in FIG. 6, the top of the positioning pin 20b is brought into contact with the bottom plate 4b of the process unit 4 while sliding on the sliding tapered surface 4d, thereby positioning the image detecting sensor 20 in the height direction with respect to the photosensitive drum 4a. Is completed.

At the same time, the circumferential portion of the positioning pin 20b on the image detecting sensor 20 abuts on the ridge line between the sliding tapered surface 4d and the side surface 4e of the positioning rib 4c, so that the image detecting sensor 20 can move with respect to the photosensitive drum 4a. The positioning in the front-rear direction is completed.

As described above, in the present embodiment,
Since the positioning of the image detection sensor 20 in the height direction and the front-back direction with respect to the photosensitive drum 4a is automatically performed in conjunction with the operation of closing the upper unit 2, the positioning adjustment of the image detection sensor 20 becomes unnecessary, and the apparatus has high reliability. And maintainability are ensured.

Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 7 is a side sectional view showing an automatic sensor positioning mechanism according to Embodiment 2 of the present invention, and FIG. 8 is a view in the direction of arrow B in FIG. 7, in which FIGS. The same elements as those shown are denoted by the same reference numerals.

In the present embodiment, as shown in FIG. 8, the bottom plate 4b of the process unit 4
f and the elongated columnar projection 4g are the same distance L2 (= L) as the distance L0 between the two positioning pins 20b on the image detection sensor 20 side.
0), the projections are integrally formed downward, and one cylindrical projection 4f is formed with a fitting circular hole 4h, and the other long cylindrical projection 4g is formed with a fitting long hole 4i. . Then, on the periphery of each opening of the fitting circular hole 4h and the fitting long hole 4i,
Sliding tapered surfaces 4j and 4k extending downward are formed, respectively.

In the same manner as in the first embodiment, the projections 4f and 4g projecting from the bottom plate 4b of the process unit are attached to the image detection sensor 20 as shown in FIG. When approaching the protruding positioning pin 20b, the swing support plate 17 and the image detection sensor 20 attached thereto are urged forward (to the left in FIG. 7) by the torsion coil spring 19, so that the image detection sensor The positioning pin 20b protruding from the reference numeral 20 is located forward of a predetermined position.

Therefore, when the upper unit is further closed, the sliding tapered surfaces 4j and 4k formed on the respective projections 4f and 4g on the process unit first become the anti-spherical surfaces of the positioning pins 20b on the image detection sensor 20 side. The positioning pin 20b contacts the bottom of the process unit while sliding on the sliding tapered surfaces 4j and 4k, whereby the positioning of the image detection sensor 20 in the height direction is completed. .

At the same time, the positioning pins 20b on the image detecting sensor 20 are connected to the projections 4f and 4g on the process unit.
Are fitted in the fitting circular hole 4h and the fitting long hole 4i, respectively, but one of the positioning pins 20b is fitted in the fitting circular hole 20h.
The positioning of the image detection sensor 20 in the front-back and left-right directions is completed.

Therefore, also in the present embodiment, since the positioning of the image detection sensor 20 is automatically and accurately performed in conjunction with the closing operation of the upper unit, the same effect as in the first embodiment can be obtained.

[0036]

As is apparent from the above description, according to the present invention, the object-to-be-supported member comes into contact with the positioning projection of the sensor in the retracted state in conjunction with the closing operation of the unit, and the positioning projection is moved. Positioning of the sensor in the height direction is automatically performed by contacting the detected object support member, and at the same time, the positioning portion formed on the detected object support member is moved to the sensor support member biased in one of the front and rear directions. Positioning the sensor in the front-rear direction or in the front-rear direction and left-right direction is automatically performed by abutting or fitting to the attached positioning protrusion, eliminating the need for sensor positioning adjustment, ensuring high reliability and maintainability. Is obtained.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a sensor automatic positioning mechanism according to Embodiment 1 of the present invention.

FIG. 2 is a view in the direction of arrow A in FIG. 1;

FIG. 3 is a longitudinal sectional view showing an opening / closing operation of the laser beam printer including the sensor automatic positioning mechanism according to the first embodiment of the present invention.

FIG. 4 is a partial cross-sectional view showing a state in which a process unit of the laser beam printer including the sensor automatic positioning mechanism according to Embodiment 1 of the present invention is detached and attached.

FIG. 5 is a longitudinal sectional view of the laser beam printer including the sensor automatic positioning mechanism according to the first embodiment of the present invention.

FIG. 6 is a partial cross-sectional view showing a state in which a laser beam printer having the sensor automatic positioning mechanism according to Embodiment 1 of the present invention is loaded with a process unit.

FIG. 7 is a side sectional view showing a sensor automatic positioning mechanism according to a second embodiment of the present invention.

8 is a view in the direction of arrow B in FIG. 7;

FIG. 9 is a partial side view of an image detection sensor installation unit (transfer drum unit) of an image forming apparatus showing a conventional image detection sensor positioning mechanism.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image forming apparatus main body 2 Upper unit (unit) 4 Process unit (detected object support member) 4a Photosensitive drum (detected object) 4b Bottom plate 4c Positioning rib (positioning part) 4d Sliding tapered surface 4f, 4g Positioning protrusion (positioning) Part) 4h fitting circular hole 4i fitting long hole 4j, 4k sliding taper surface 17 swing support plate (sensor support member) 19 torsion coil spring (biasing means) 20 image detection sensor (sensor) 20b positioning pin (positioning projection) 21) Rotating hook (evacuation means)

Claims (3)

[Claims] An object support member is provided in a unit that opens and closes by rotating with respect to an image forming apparatus main body, and a sensor is attached to a sensor support member that rotates in conjunction with opening and closing operations of the unit. An urging means for urging the sensor support member in at least one of the front and rear directions and a retracting means for retracting the sensor at the time of opening the unit are provided, and a positioning projection is provided on the sensor, and the positioning projection is provided on the positioning projection. A sensor positioning mechanism for an image forming apparatus, wherein a positioning portion that abuts or fits is formed on the sensor support member. 2. The positioning projection according to claim 1, wherein a top portion of said positioning projection is formed in an anti-spherical shape, said positioning portion is formed of a positioning rib, and a sliding tapered surface is formed at a tip of said positioning rib. An automatic sensor positioning mechanism for the image forming apparatus according to claim 1. 3. The positioning projection comprises a plurality of cylindrical pins, the top of which is formed in an anti-spherical shape, and the positioning section comprises a plurality of positioning projections, and at least one positioning projection includes the pin. Forms a fitting hole to be fitted, forms a fitting long hole into which the pin is fitted in another positioning protrusion, and slides around the periphery of each opening of the fitting circular hole and the fitting long hole. 2. The automatic sensor positioning mechanism according to claim 1, wherein a tapered surface is formed.