JPH06148758A - Image forming device - Google Patents

Abstract

PURPOSE:To restrain the vibration in the up-and-down direction of an original platen so as to improve copying accuracy and to improve image quality. CONSTITUTION:An original platen driving device 31 is provided with an annular endless gear 3 coupled with the original platen 2 so as to integrally linearly move, a sun gear 5 which is positionally fixed inside the endless gear 3 and in which the driving force of a motor 32 is inputted, a planet gear 6 rotatably provided between the gears 5 and 6 in a state where it meshes with both gears, and a coupling plate 11 turnably coupled with the rotary shaft of the gear 5 and supporting the gear shaft of the gear 6. Then, a pressing material 44 is pushed to the outside sliding member 41b of an Accuride(R) 41 for attaching the original platen 2 to a copying machine main body 1 in a wedge state by a leaf spring 45 having pressing force in a direction H.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus, and more particularly, to a copying machine or the like which reciprocally moves a document table during a copying operation.

[0002]

2. Description of the Related Art Conventionally, in a copying machine as an image forming apparatus for forming an image by moving a document table, when the document on the document table is scanned by an optical system, the document table first returns from a standby position. The scanning direction is moved to the scanning start position, then to the scanning end position in the feed direction to scan the document, and then moved from the scanning end position to the original standby position in the return direction.

A document table driving device 51 for moving the document table as described above is provided below the document table 52 as shown in FIG. 6 and has a structure as shown in FIG. When the document table 52 is moved in the feed (F) direction from the scanning start position, the feed solenoid 53 is turned on.
As a result, the latch 54 engages with the clutch brake 56 of the feed spring clutch 55, and the feed spring clutch 55 is brought into the engaged state. Therefore, the driving force input to the input gear 57 is the output gear 5
8 and then to the platen drive gear 59. As shown in FIG. 8, a rack 72 that meshes with the original table drive gear 59 is provided on the back surface of the original table 52. When a driving force is transmitted from the original table drive gear 59 to the rack 72, the original document is driven. The table 52 moves in the feed direction.

After that, when the document table 52 reaches the scanning end position, this state is detected by the detection switch 60 shown in FIG. 6, the feed solenoid 53 is turned off, and the return solenoid 61 is turned on. As a result, the latch 62 engages with the clutch brake 63 of the return spring clutch 67, and the return spring clutch 6
7 becomes a combined state. Therefore, the driving force input to the input gear 57 is applied to the gear 64, the input gear 65, and the output gear 6.
6 and the output gear 58 are transmitted to the document table drive gear 59 to move the document table 52 to the standby position in the return (R) direction.

However, in the above copying machine, in order to reciprocate the document table 52, devices such as a feed spring clutch 55, a return spring clutch 67, a feed solenoid 53, and a return solenoid 61 are required. In general, in a small-sized and low-priced copying machine of a manuscript table moving type, there is a problem that the cost ratio of each of the above-mentioned devices becomes high and the cost of the device increases.

Further, as shown in FIG.
Table glass 73 and metal table glass mount 7
Therefore, the height position of the original table 52 from the upper surface of the main body of the copying machine is high because the positional relationship among the table glass 73, the optical system, and the photoconductor affects the copying accuracy. Things are required. That is, for example, the SELFOC lens as an optical system that is normally used is
When the I (Operability index) distance is about 30 to 40 mm, the allowable value of the depth of focus is generally ± 0.25 mm. For this reason, if the document table driving device 51 and the document table 52 are formed separately, an error occurs in the attachment portion, and thus it is not possible to improve the copying accuracy.

In order to cope with such a problem, the applicant of the present application has previously proposed, in Japanese Patent Application No. 4-32257, a copying machine which adopts a document table driving device having an endless gear that moves integrally with the document table. Proposed.

Referring to FIG. 9 and FIG. 3 which is an explanatory view of the present invention, the endless gear 3 constituting the document table driving device 31 includes upper and lower rack portions 3a and 3b and left and right semicircles. It is composed of internal gears 3c and 3d and is attached to a main support 4 provided above the side surface of the copying machine main body 1. A sun gear 5 to which a driving force is transmitted and a planetary gear 6 that meshes with the sun gear 5 and the endless gear 3 are provided inside the endless gear 3. The planetary gear 6 and the sun gear 5 are connected to each other. Are rotatably connected to an input shaft 7 which is a rotation shaft of the sun gear 5, and are connected by a connecting plate 11 which supports a rotation shaft 9 of the planetary gear 6.

The upper surface of the main support 4 to which such a document table driving device 31 is attached is extended to the main body 1 side of the copying machine and is formed as a document table 2. It is fixed to an accuride 41 'provided on the upper surface of the copying machine main body 1 and is horizontally slidably supported by the accuride 41'. Accuride 41 '
Is composed of an outer member 41a ', an inner member 41b', and a ball 41c 'rotatably supported by these both members 41a', 41b '. The inner member 41b' is fixed to the copying machine main body 1. Then, the document table 2 is attached to the outer member 41a '.
Are attached with screws 42.

When the driving force is transmitted to the input shaft 7, the sun gear 5 rotates in the direction of arrow A, and along with this, the upper rack portion 5 is rotated.
The planetary gear 6 meshing with the gear rotates with the arrow B direction, and the endless gear 3 moves in the return (R) direction. After that, when the right semicircular internal gear 3d of the endless gear 3 reaches the planetary gear 6, the endless gear 3 stops horizontal movement,
The planetary gear 6 revolves around the sun gear 5 along the right semicircle internal gear 3d and moves downward. Thereafter, the planetary gear 6 meshes with the lower rack portion 3b, so that the document table 2 moves in the feed (F) direction.

Thus, as the endless gear 3 reciprocates in the horizontal direction, the main support integrally provided with the endless gear 3 reciprocates along the side surface of the copying machine main body 1, The document table 2 formed on the upper surface of the main support 4 is adapted to reciprocate along the upper surface of the copying machine main body 1.

This eliminates the need for a clutch or the like,
The number of parts can be reduced, and the cost can be reduced. Further, since the document table 2 is formed integrally with the endless gear 3, the document table 2 is less likely to move up and down. Therefore, the copying accuracy is improved, and the image blurring, the image blurring, and the like of the copied image generated by vibrating the document table 2 in the vertical direction are suppressed, and the image quality can be improved.

[0013]

However, although the above-mentioned structure is a structure capable of suppressing the deterioration of the image due to the attachment of the document table 2 and the document table driving device 31,
Since the vertical vibration of the endless gear 3 itself is not dealt with, the image quality is deteriorated due to the vibration of the endless gear 3, and a sufficient effect is not always obtained.

That is, the endless gear 3 has a structure
In the figure, there is a large amount of backlash in the vertical direction, and when a vertical force is received from the planetary gear 6 when the driving force is transmitted from the planetary gear 6, the vertical vibration easily occurs. Therefore, when the endless gear 3 vibrates, the main support 4 to which the endless gear 3 is attached and the document table 2 also easily vibrate in the vertical direction.

The Acculide 41 ', which mounts the original table 2 on the copying machine main body 1 as described above, is a ball 41c'.
Between the inner member 41b 'and the outer member 41a',
The ball 41c 'has a structure in which there is a gap for allowing the ball to move freely, and it is easy to generate backlash.
Since 1b 'holds the ball from the left and right, the backlash in the up and down direction is more likely to occur than the backlash in the left and right direction.

Therefore, such Acculide 4
In the configuration in which the document table 2 is fixed to the copying machine main body 1 at 1 ',
Since the fixing force is weak, when the main support 4 vibrates in the vertical direction due to the vibration of the endless gear 3, the document table 2 also vibrates in the vertical direction, causing the above-mentioned problems.

[0017]

In order to solve the above problems, the image forming apparatus of the present invention is mounted via a sliding member so as to be slidable along the upper surface of the main body of the image forming apparatus. And a pair of semi-circular internal gears for connecting the respective end portions of these rack portions and two rack portions provided in parallel with their tooth surfaces facing each other. And an annular endless gear that is linearly movable integrally with the platen and a fixed position at an intermediate portion between both rack portions of the endless gear, and receives the driving force of the motor. A sun gear, and a planetary gear that is rotatably provided between the sun gear and the endless gear by meshing with the sun gear and the endless gear, and is rotatably connected to the rotation shaft of the sun gear and the planetary gear. The gear shaft of An image forming apparatus provided with a document table driving device having a connecting plate which moves along a holding endless gear, wherein a pressing force applied to the sliding member in a direction orthogonal to a sliding direction. It is characterized in that means are provided.

[0018]

According to the above structure, since the sliding member is provided with the pressing means which is pressed in the direction orthogonal to the sliding direction of the document table, the sliding member is moved in the direction orthogonal to the sliding direction. Power will always be applied to. When such a force is applied, for example, when aclide is used for the sliding member, the gap between the ball that the aclide has and both members that support the aclide decreases and becomes small, and the sliding member ( Accurate) has less play. Therefore, even in the case of using the document table driving device including the endless gear that has a large vertical play and easily vibrates in the vertical direction, the vibration of the document table in the vertical direction is suppressed.

Moreover, since the force applied to the sliding member acts to prevent the movement of the original table moving through the sliding member, the conventional slidingly supported member is completely free. The speed at the time of movement is regulated rather than the configuration, and the occurrence of speed unevenness is suppressed.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The following will describe one embodiment of the present invention with reference to FIGS.

The copying machine which is the image forming apparatus of this embodiment is
As shown in FIG. 2, a manuscript table 2 having a substantially rectangular plate shape movably attached is installed on an upper portion of a copying machine main body 1 having a substantially rectangular parallelepiped shape. The center of the document table 2 has a transparent member such as a glass plate, and the document table 2 is driven by a document table driving device 31 described later. The copying machine main body 1 has an optical system including an irradiation lamp 15 and a rod lens array 24 on the upper part.
A photoconductor 13 is provided below the optical system, and a charger 1 for charging the photoconductor 13 is provided around the photoconductor 13.
4, a developing device 20 for developing the electrostatic latent image formed on the photoconductor 13 by the exposure operation of the optical system with toner, a transfer device 12 for transferring the toner image formed by the developing operation onto a transfer paper, and the photoconductor A cleaning device 17 for collecting the residual toner on the surface of 13 is provided.

On the side of the transfer paper supply to the photoconductor 13,
Conveying roller 22 that conveys the transfer paper from the manual paper feeding unit 21
While the registration roller 16 and the registration roller 16 are provided, a fixing device 19 for fixing the transfer paper on which the toner image is transferred by the transfer device 12 is provided on the output side of the transfer paper with respect to the photoconductor 13.
Is provided.

In the copying operation, the original table 2 is returned from the position where the end portion on the feed direction (F) side substantially coincides with the end portion of the copying machine main body 1, that is, from the standby position P ₁ first. The scanning start position P ₂ in the direction (R), and then
In order to scan the document by the optical system, the document is moved to the scanning end position P ₃ in the feed direction (F), and then the original standby position P
It is designed to move to ₁ .

As described above, in order to drive the document table 2, this copying machine is provided with the document table driving device 31 shown in FIGS. 1 and 3 to 5. This document table driving device 31
As shown in FIG. 3, it has the main support body 4 in which the endless gear 3 is provided. The main support 4 has a vertical wall shape, is connected to the document table 2 in a hanging manner, and moves together with the document table 2 along the side surface of the copying machine main body 1.
An oval recess is formed in the center of the main support 4, and the annular endless gear 3 having internal teeth is formed in the recess.
Is provided.

The endless gear 3 has an upper rack portion 3a and a lower rack portion 3 which are provided in parallel with their tooth surfaces facing each other.
b, and a left semi-circular internal gear 3c and a right semi-circular internal gear 3d having two semi-circular internal teeth connecting the respective ends of the racks 3a and 3b. There is. The outer peripheral surface of the endless gear 3 has a connecting plate 11 to be described later.
Is a sliding contact surface with which the bent portion 11a of FIG.

Inside the endless gear 3, a sun gear 5 is provided with its position fixed at an intermediate position between the upper and lower rack portions 3a and 3b. Between the sun gear 5 and the endless gear 3, these are mounted. A planetary gear 6 that meshes with both is provided.

The main support 4 also has an endless gear 3
A groove 8 through which the input shaft 7, which is the rotation shaft of the sun gear 5 passes, is formed in parallel with the upper and lower rack portions 3a and 3b. The driving force from the motor 32 is transmitted to the input shaft 7.

The gear shaft 9 as the gear shaft of the planetary gear 6 is rotatably connected near the center of the connecting plate 11.

The connecting plate 11 is, as shown in FIG.
The cross-section is formed into a substantially rectangular frame shape, the input shaft 7 of the sun gear 5 is rotatably connected near one end side, and the bent portion 11a formed on the other end side is an endless gear 3 The outer peripheral surface of is in sliding contact.

On the other hand, the main support 4 integrally provided with the endless gear 3 has the upper surface formed as the original table 2. That is, the upper surface portion of the main support 4 extends toward the copying machine main body 1 side, and is attached to the outer member 41a of the aclide 41, which is a sliding member provided on the upper surface of the copying machine main body 1, with screws 42. The main support 4 is supported by this accuride 41 and can be slid horizontally.

The Acculide 41, as shown in FIG.
The outer member 41a and the inner member 41b, which have a shape extending from the front side to the back side of the paper, and these both members 41a.4.
It is composed of a ball 41c rotatably supported at both ends in a direction orthogonal to the longitudinal direction of 1b. At the end of the outer member 41a on the main support 4 side, a pressing member 44 conforming to the shape of the outer member 41a is provided.
Along with the screw 43, the leaf spring 4 fixed to the copying machine main body 1
It is pressed in a wedge state in the H direction by the urging force of 5.
That is, the pressing member 44 and the plate spring 45 constitute the pressing means of the present invention.

Further, as shown in FIG. 1, the upper surface of the main support 4 further extends, and the glass mounting portion 3 is provided at the tip thereof.
5 are provided. The glass mounting portion 35 includes a glass placing portion 37 on which the table glass 36 is placed, an abutting portion 38 with which the tip of the table glass 36 abuts, and a protrusion 39 for fitting the table glass 36. And these are formed to have a U-shaped cross section. The projection 39 is fitted with the table glass 36,
The table glass 36 is firmly attached and plays a role of correcting the bending deformation of the table glass 36 or the glass mounting portion 37 in the arrow FG direction. When the table glass 36 is attached, the table glass 36 is obliquely attached, as indicated by the alternate long and short dash line in FIG.
To the glass mounting portion 35, gradually decreasing the inclination angle (direction of arrow E), and the table glass 3
The tip of 6 is inserted so as to abut the abutting portion 38. The table glass 36 is slidably supported also on sliders 40 provided on the upper surface of the copying machine body 1.

On the other hand, in the drive path from the motor 32 to the input shaft 7 of the sun gear 5, a driven gear 23 to which the driving force from the motor 32 is transmitted is provided in the copying machine main body 1. The driven gear 23 is meshed with a connecting / disconnecting gear 24 capable of connecting / disconnecting the drive path, and the connecting / disconnecting gear 24 is meshed with an input gear 26 fixed to the input shaft 7 of the sun gear 5.

The shaft 27, which is the gear shaft of the connecting / disconnecting gear 24, extends in the copying machine main body 1 on the side opposite to the main support 4, and a knob (Knob) 28 is provided at the tip thereof.
By pressing the knob 28, the connecting / disconnecting gear 24 can be moved in the direction of arrow D. By the movement of the connecting / disconnecting gear 24 in the direction of arrow D, the connecting / disconnecting gear 24 is moved. The meshing between the driven gear 23 and the driven gear 23 is disengaged, and the driving force from the motor 32 is cut off.

On the other hand, on the copying machine body 1 side of the knob 28, a spring 29 is provided between the knob 28 and the inner side wall 34 supporting the shaft 27, and when the pressing on the knob 28 is released, By the biasing force of the spring 29, the connecting / disconnecting gear 24 is returned in the direction of the arrow C so that the connecting / disconnecting gear 24 meshes with the driven gear 23 as before.

Then, the driven gear 23 and the disconnecting gear 2
4, shaft 27, knob 28, spring 29 and input gear 2
The driving force connecting / disconnecting mechanism 30 is constituted by 6.

The knob 28 is rotatable, and by rotating the knob 28, the shaft 2 can be rotated.
The connecting / disconnecting gear 24 can be rotated via 7. The knob 28, the shaft 27, the connecting / disconnecting gear 24, and the input gear 26 constitute a rotational force imparting mechanism 33.

In the above structure, the copying operation of the copying machine will be described first.

In the copying operation, as shown in FIG. 2, first, the original 25 is scanned by the optical system. That is, the document 25 placed on the transparent member of the document table 2
Is irradiated by the irradiation lamp 15, and the reflected light is
The photosensitive member 13 rotatably arranged is exposed through the rod lens array 24. Then, the photoconductor 13
The surface of the photosensitive drum 13 is uniformly charged by the charger 14 that faces the photoconductor 13 and is disposed in close proximity thereto, and the reflected light from the document 25 is exposed to the electrostatic latent image on the photoconductor 13. Are formed.

This electrostatic latent image is developed by the toner supplied from the developing device 20 and a toner image corresponding to the original 25 is formed on the photoconductor 13. Then, the transfer paper is supplied from the manual paper feed unit 21 to the photoconductor 13 via the conveying roller 22 and the registration roller 16, and the toner image is transferred by the transfer device 12 which is arranged in the vicinity of the photoconductor 13 so as to face the photoconductor 13. The transfer paper is transferred to paper, and the transfer paper is conveyed to the fixing device 19.

The residual toner adhered on the transfer device 12 after the transfer of the toner image onto the transfer paper is moved onto the photoconductor 13 by applying a voltage having a polarity opposite to that of the toner to the transfer device 12. The toner transferred from the transfer unit 12 is the photosensitive member 1
The toner remaining on the toner 3 is removed by the cleaning device 17 and collected in the toner storage unit 18. further,
After the transfer, the surface of the photoconductor 13 is uniformly discharged by the direct light of the irradiation lamp 15 to be in a standby state. On the other hand, when the transfer sheet is conveyed to the fixing device 19, the toner image on the transfer sheet is fixed on the transfer sheet by being heated and pressed by the fixing device 19, and then the transfer sheet is carried out.

Next, the operation of the platen drive device 31 will be described.

First, as shown in FIG. 1, when the driving force of the motor 32 is transmitted to the driven gear 23, the driven gear 23
The connecting / disconnecting gear 24 meshing with the gear rotates, and this rotation is transmitted to the input gear 26. This causes the sun gear 5 to rotate in the A direction and the planetary gear 6 to rotate in the B direction, as shown in FIG. As a result, the main support 4, that is, the document table 2 horizontally moves in the return (R) direction.

After that, as shown in FIG. 5, when the right semicircular internal gear 3d of the endless gear 3 reaches the planetary gear 6, the endless gear 3 stops horizontal movement, and the planetary gear 6 becomes a right semicircular internal tooth. It revolves around the sun gear 5 along the gear 3d and moves downward. After that, the planetary gear 6 meshes with the lower rack portion 3b, whereby the platen 2 moves in the feed (F) direction and copying is started.

As described above, as long as the sun gear 5 is rotating, the document table 2 alternately repeats the movements in the return direction and the feed direction. Therefore, the lengths of the upper and lower rack portions 3a and 3b in the endless gear 3 and the sun gear 5 are
Is set appropriately between the scanning end position P3 and the standby position P1 so that the document table 2 is moved to the scanning start position P2.
Can be moved to. Further, in this copying machine, since the operation of the document table 2 is controlled only by turning ON / OFF the motor 32, in one copying operation, the document image is not displayed until the document table 2 returns to the standby position P1. The copied transfer paper passes through the fixing device 19 and is discharged from the copying machine main body 1.

The operation when the document table 2 is stopped at a position other than the home position, that is, the standby position P1 due to a paper jam or a failure will be described.

For example, as shown in FIG. 5, when the planetary gear 6 is stopped at the position of the half-circumferential portion XX 'of the endless gear 3, the planetary gear 6 can be moved horizontally even if the document table 2 is moved horizontally.
The endless gear 3 does not rotate along the left semicircular internal gear 3c or the right semicircular internal gear 3d. Further, for example, even when the planetary gear 6 stops at the position of the horizontal portion Y · Y ′ of the endless gear 3, a gear having a large reduction ratio is used in the drive path from the motor 32 to the input shaft 7 of the sun gear 5. If it is, it is difficult to move the endless gear 3 horizontally.

However, in this embodiment, the motor 3
In the drive path from 2 to the input shaft 7 of the sun gear 5, a drive force connection / disconnection mechanism 30 for connecting / disconnecting this drive path, and the sun gear 5
And a rotational force applying mechanism 33 that applies a rotational force to the input shaft 7.

For this reason, the planetary gear 6 becomes the endless gear 3
When the knob 28 of the driving force connecting / disconnecting mechanism 30 is pushed in the direction of arrow D, as shown in FIG. 1, first, a stop provided at the other end of the shaft 27 is stopped. The contact gear 24 also moves in the direction of arrow D. At this time, the connecting / disconnecting gear 24 is engaged with the driven gear 2 while meshing with the input gear 26.
The mesh with 3 is released. Therefore, by rotating the knob 28 while pushing the knob 28, the input gear 26 is rotated, and the planetary gear 6 is placed in the right half circle of the endless gear 3 via the input shaft 7 and the sun gear 5. The tooth gear 3d is rotated. When the planetary gear 6 reaches the lower rack portion 3b of the endless gear 3, the document table 2 can be returned to the standby position P1 by, for example, manually moving the document table 2 horizontally manually. Even when a gear having a large reduction ratio is used in the drive path from the motor 32 to the input shaft 7, the original table 2 can be returned to the standby position P1 by continuing the rotating operation of the knob 28. it can.

Then, when the original 28 is returned to the standby position P1 and the pushing operation of the knob 28 is released, the spring 2 is released.
The urging force of 9 causes the knob 28 to move in the direction of arrow C, and the disconnecting gear 24 to move in the direction of arrow C as well, whereby the disconnecting gear 24 meshes with the driven gear 23 and the motor 32.
Drive path from the sun gear 5 to the input shaft 7 is connected.

As described above, in the copying machine of this embodiment, the outside member 41a is attached to the outside member 41a of the accuride 41 which slidably mounts the original table 2 on the copying machine main body 1.
The pressing member 44 conforming to the shape is pressed in a wedge state by a leaf spring 45 having a biasing force in the H direction orthogonal to the moving direction of the document table 2.

As a result, the gap for rotating the ball 41c formed between the outer member 41a and the inner member 41b and the ball 41c is narrowed, and the backlash of the accuride 41 itself is reduced. Therefore, due to the structure, the endless gear 3 having a large vertical play receives the vertical force from the planetary gear 6 when the driving force is transmitted from the planetary gear 6, and vibrates in the vertical direction. Even if the main support 4 vibrates in the vertical direction, since the backlash of the accuride 41 is small, the vibration of the document table 2 in the vertical direction is suppressed. As a result, the copying accuracy is improved and the image blurring and the image blurring of the copied image due to the vibration of the endless gear 3 itself in the vertical direction are suppressed, so that the image quality is improved.

Further, the force applied to the accuride 41 in the direction orthogonal to the sliding direction acts to hinder the movement of the platen 2 when the platen 2 moves through the aclide 41, so that the platen is completely free. Since the moving speed is regulated to some extent as compared with the conventional one in which 2 is moved, the unevenness of the moving speed of the document table 2 is reduced, which also improves the image quality.

[0054]

As described above, the document table mounting mechanism of the present invention is provided with the document table mounted via the sliding member so as to be slidable along the upper surface of the image forming apparatus main body. Two rack parts that are provided in parallel with their tooth surfaces facing each other and each end part of these two rack parts are connected to each other 2
A ring-shaped endless gear that is composed of individual semicircular internal gears and that is connected to the platen and is linearly movable integrally with the platen. A sun gear fixedly provided, to which the driving force of the motor is input, and a planetary gear that is rotatably provided between the sun gear and the endless gear by meshing with these gears, and the rotation shaft of the sun gear. An image forming apparatus provided with a platen drive device that is rotatably connected to a platen and that includes a connecting plate that supports a gear shaft of the planetary gear and that moves along an endless gear. The member is provided with a pressing means that is pressed in a direction orthogonal to the sliding direction.

As a result, the amount of backlash of the sliding member itself is reduced, so that vertical vibration of the document table is suppressed even when a document table driving device equipped with an endless gear with large vertical play is used. It As a result, the occurrence of image blurring, image blurring, etc. of the copied image due to the vertical vibration of the endless gear itself is suppressed, and the image quality can be improved.

Moreover, the force applied to the sliding member regulates the moving speed of the original table moving through the sliding member,
Since the occurrence of speed unevenness is suppressed, it is possible to further improve the image quality.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of essential parts showing a structure near a document table of a copying machine according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of the copying machine.

FIG. 3 is a perspective view of an essential part showing a document table driving device of the copying machine.

FIG. 4 is a cross-sectional view of the vicinity of accuride provided in the copying machine.

FIG. 5 is an explanatory diagram showing a positional relationship between an endless gear and a planetary gear in the platen drive device.

FIG. 6 is a front view showing a structure near a document table of a copying machine equipped with a conventional document table driving device.

FIG. 7 is a front view of the main parts showing the structure of a document table driving device in the copying machine shown in FIG.

8 is a schematic diagram showing a structure near a document table of a copying machine provided with the document table driving device shown in FIG.

FIG. 9 is a cross-sectional view of essential parts showing a structure near a document table of a conventional copying machine provided with a document table driving device of an endless gear system.

[Explanation of symbols]

 2 Manuscript table 3 Endless gear 3a Upper rack part (rack part) 3b Lower rack part (rack part) 3c Left semicircle internal gear (semicircle internal gear) 3d Right semicircle internal gear (semicircle internal gear) 4 Main Support 5 Sun Gear 6 Planetary Gear 7 Input Shaft (Rotary Shaft) 9 Gear Shaft (Gear Shaft) 11 Connecting Plate 23 Driven Gear 24 Disconnection Gear 26 Input Gear 31 Platen Drive 41 Acculide (Sliding Member) 41a Outer member 41b Inner member 41c Ball 42 Screw 43 Screw 44 Pressing material (pressing means) 45 Leaf spring (pressing means)

Claims (1)

[Claims] 1. A document table mounted via a sliding member so as to be slidable along the upper surface of an image forming apparatus main body, and two parallelly arranged tooth surfaces facing each other. An annular endless gear, which is composed of a rack portion and two semicircular internal gears that connect the ends of both rack portions, is connected to the document table, and is linearly movable integrally with the document table. And a sun gear that is fixedly provided at an intermediate portion between both rack portions of the endless gear and receives the driving force of the motor, and the sun gear and the endless gear mesh with these both gears. A platen having a planetary gear rotatably provided and a connecting plate that is rotatably connected to the rotation shaft of the sun gear and that supports the gear shaft of the planetary gear and moves along the endless gear. Drive An image forming apparatus provided, wherein the sliding member is provided with pressing means pressed in a direction orthogonal to the sliding direction.