JPH08226517A - Gear intermittent rotation transmission device, sheet feeding device, and image forming apparatus - Google Patents

Abstract

PURPOSE: To enable smooth meshing without biting and strinking of mutual tips in meshing of a driving gear and a driven gear with a partially toothless gear, and also to improve durability of the partially toothless gear. CONSTITUTION: The tooth depth on the drive transmitting side tooth flank A is so constituted as to be higher than that on the drive non-transmitting side tooth flank B, on the top of at least the second and the later teeth continuing from the cutout end parts of teeth of respective partially toothless gear parts 31a, 31b of a partially toothless gear 31 to which a driving gear 10 and a driven gear 19 are faced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding device for feeding sheets one by one from a sheet accommodating portion such as a sheet feeding cassette provided in an image forming apparatus such as a copying machine, a printer and a facsimile. The present invention relates to a gear intermittent rotation transmission device that intermittently transmits a rotational force to a feed roller or the like of a separation roller pair.

[0002]

2. Description of the Related Art A drive mechanism of a so-called retard separation type sheet feeding device, which is a conventional separation type using a reverse rotation roller, will be described with reference to FIGS. 4 is a perspective view of a drive mechanism of the retard separation type sheet feeding device, FIG.
FIG. 4 is an enlarged view of a main part of a conventional one-rotation missing tooth clutch gear portion. In FIG. 4, the rotation force of the one-rotation intermittent drive is transmitted to the half-monthly paper feed roller 1 and the feed roller 2a of the sheet separation roller pair 2 by the one-rotation intermittent clutch gear 29.

The toothless clutch gear 29 is designed to rotate integrally with a notched cam 30 provided with a notched portion 30a and a notched gear 31 having toothless portions 31a and 31b coaxially with each other. The notched portion 31a of the notched gear 31 faces the drive gear (idler gear) 10, and the notched portion 31b faces the driven gear (second gear) 19, respectively.
Armature (hook) of solenoid 6 locked to 30a
When the gear 6a is removed, the toothed portion 31c of the partly tooth-missing gear 31 has a spring 32 for biasing the idler gear 10 and the second gear 19 so as to mesh with each other.

As shown in FIG. 5, the first to third teeth, which are continuous in the rotational direction from the notched ends of the tooth-missing portions 31a and 31b of the tooth-missing gear 31, have smooth tooth engagement. As is performed, among the apex portions of the teeth, the meshing start side is cut to be low, and the idler gear 10 side of the drive gear and the second gear 19 side of the driven gear are also cut in the same direction.

Deformation slits 33a and 33b as shown in FIG. 5 are provided over a number of teeth continuing in the rotational direction from the notched ends of the tooth portions 31a and 31b.

[0006]

As described above, the tooth-missing gear 31 shown in the above-mentioned conventional example has the apex from the notch end of each tooth of the tooth-missing portions 31a and 31b to several teeth continuing in the rotational direction. Of these, the teeth are cut so that the meshing start side becomes lower. That is, the toothed portion 31 that continues in the rotational direction from the notched end portion of the tooth of the toothless portion 31a facing the idler gear 10 of the drive gear.
At c, the tooth top of the tooth is cut so that the tooth depth of the tooth surface A on the drive transmission side is higher than that of the tooth surface B on the non-drive transmission side. Tooth part 31
In the toothed portion 31c continuing from the notched end of the tooth of b in the rotation direction, the tooth depth of the tooth flank A of the drive transmission side is lower than that of the tooth flank B of the non-driving transmission side in the top of the tooth. Has been cut into.

With the above structure, the idler gear of the drive gear
10 and the tooth-missing portion 31a of the tooth-missing gear 31 mesh smoothly with the toothed portion 31c, but the second gear 19 of the driven gear and the tooth-cutting edge portion of the tooth-missing portion 31b. From the top of the teeth of the tooth-missing gear 31, the tooth engagement of the drive transmission side tooth surface A is lower than the tooth engagement of the non-drive transmission side tooth surface B of the toothless portion of the toothless gear 31. There is a problem in that not only the eyes but also the second tooth escapes and the tooth tips hit each other and bite into each other to stop the rotation of the gear.

Further, a slit for deformation having a conventional shape
In the case of 33a and 33b, the slits 33a and 33b were broken from the roots, and there was a problem in durability.

The present invention is to solve the above-mentioned problems.
The purpose is to drive gears for toothless gears,
An object of the present invention is to provide a gear intermittent rotation transmission device in which meshing of a driven gear can be smoothly carried out without the tooth tips abutting against each other and biting into each other, and further improving the durability of the tooth-missing gear.

[0010]

A typical configuration according to the present invention for achieving the above object has a toothless portion at a position where a drive gear and a driven gear face each other and a toothed portion at another position. A tooth-missing gear having a tooth-missing gear and a tooth-missing clutch gear in which a notch cam having a notch at one location on the outer periphery is arranged coaxially with the tooth-missing gear, and a hook for locking the notch at the notch In the gear intermittent rotation transmission device including a spring member that biases the toothed portion of the tooth-missing gear so as to mesh with each of the drive gear and the driven gear when disengaged, In order to make the tooth depth of the tooth flank on the drive transmission side higher than that of the tooth flank on the non-driving power transmission side within the apex of at least the first tooth and subsequent teeth continuing in the rotational direction from the notched end portion of the toothless portion. The gear intermittent rotation transmission device is characterized by being cut into That.

Further, the tooth-chipped gear is made of a material having elasticity. Deformation slits are provided for several teeth extending in the rotation direction from the notch ends of the teeth of each tooth-chipped portion, and It is characterized in that it has a hole at the end for distributing stress.

Further, the first tooth which continues in the rotational direction from the notched end of the tooth of the tooth missing gear is cut from the vicinity of the pitch circle so that it is lower than the tooth brush after the second tooth. It is characterized by having done.

A sheet feeding device according to the present invention has the gear intermittent rotation transmission device, and an image forming apparatus according to the present invention is provided with the sheet feeding device and the sheet feeding device. A recording unit that records the sheet on the fed sheet in accordance with the image information.

[0014]

According to the intermittent gear rotation transmission device of the present invention, at least the first tooth and the succeeding teeth continuing in the rotation direction from the notched end portions of the tooth-missing portions corresponding to the drive gear and the driven gear of the tooth-missing gear. Cut the tooth depth of the tooth flank on the drive transmission side to be higher than the tooth depth on the tooth flank on the non-driving power transmission side (that is, from the notch end of the tooth of the tooth loss portion on the drive gear side in the rotational direction). Driven by the toothed part that follows the toothed part and the toothed part that continues in the rotation direction from the notched end of the tooth on the toothless part on the driven gear side. The meshing of the teeth on both the gear side and the driven gear side becomes smooth, and there is no contact between the tooth tips.

Further, since a hole for dispersing stress concentration is provided at the end of the deformation slit continuing from the toothless portion in the rotation direction, it is possible to prevent the deformation slit from being broken at the root.

Further, the image forming apparatus provided with the sheet feeding device having the gear intermittent rotation transmitting device records the image on the smoothly fed sheet by the action of the gear intermittent rotation transmitting device. You can

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A laser beam printer having a retard separation type sheet feeding device will be described as an example of an image forming apparatus having a sheet feeding device having a gear intermittent rotation transmitting device according to the present invention with reference to the drawings. In the following description, a case where recording paper is used as the sheet will be described, but various sheets made of synthetic resin or the like can also be applied.

FIG. 1 is a sectional explanatory view of a laser beam printer equipped with a retard separation type sheet feeding device, FIG. 2 is a perspective view showing a drive mechanism of the retard separation type sheet feeding device, and FIG. 3 is a toothless clutch. It is a principal part enlarged view seen from the side surface of a gear part.

In FIG. 1, the recording papers P loaded in the cassette 50 are picked up by a half-moon paper feeding roller 1 which is a feeding rotary member, separated one by one by a sheet separating roller pair 2, and a conveying roller pair 3 By cashier pre-guide
It is conveyed to the registration roller pair 52 along the line 51.

After that, the recording paper P is conveyed by the registration roller pair 52 in accordance with the rotation of the photosensitive drum 53 as an electrophotographic photosensitive member arranged in the process cartridge 4 serving as recording means, and the recording paper P is transferred by the transfer roller 54. The toner image on the photosensitive drum 53 is transferred onto P.

After that, the recording paper P is guided by the separation guide 55, the conveyance guide 56, and the entrance guide 57 to be heated and pressed by the roller pair of the fixing roller 58 and the pressure roller 59, so that the toner image on the recording paper P is permanent. Fix as an image. At this time, since the recording paper P is wrapped around the fixing roller 58, the recording paper P is forcibly separated by the separation claw 60 and is conveyed by the fixing paper discharge rollers 61 and 62, and is conveyed along the conveyance guide rib 64.

Further, the recording paper P is transported by the transport roller pair 65 along the transport guides 66, 67 and discharged and stacked on the face-down tray T by the discharge device 68 which also serves as a curl remover.

Next, the gear intermittent rotation transmission device according to the present invention will be specifically described. As shown in FIG. 3, a tooth-missing portion 31a formed of a material having elasticity such as resin and facing the idler gear 10 serving as a drive gear of the tooth-missing gear 31, and a tooth-missing portion facing the second gear 19 serving as a driven gear. Of the tops of the first to third teeth continuing in the rotation direction from the notched ends of the respective teeth of the portion 31b, the toothbrush of the drive transmission side tooth surface A is the non-drive transmission side tooth surface B.
Each is cut so that it is higher than the toothpaste.

That is, a toothed portion 31c continuing from the notched end of the tooth of the toothless portion 31a on the idler gear 10 side in the rotational direction, and a second
As shown in FIG. 3, the cutting direction of the tooth top portion of the toothless portion 31b on the gear 19 side is opposite to that of the toothed portion 31c continuing from the tooth notch end portion in the rotational direction.

Further, a toothless portion facing the idler gear 10
31a and the first tooth of each toothed portion 31c continuing in the rotational direction from the notched end of each tooth of the toothless portion 31b facing the second gear 19 is cut from the vicinity of the pitch circle r1, and the second tooth The eye and the third tooth are formed by cutting from the tip circle r2.

Deformation slits 33 are provided for several teeth continuing in the rotational direction from the notched ends of the tooth missing portions 31a and 31b.
a and 33b are provided respectively, and holes 34a and 34b for preventing stress concentration are provided at the ends of the slits 33a and 33b, respectively.

In FIG. 2, the rotational force for intermittent rotation of one rotation is transmitted to the feed roller 2a of the half-monthly paper feed roller 1 and the pair of sheet separation rollers 2 by the one-rotation missing tooth clutch gear 29.

The toothless clutch gear 29 is designed to rotate integrally with the notched cam 30 provided with the notched portion 30a and the toothless gear 31 having toothless portions 31a and 31b coaxially with each other. And the toothless portion 31a of the toothless gear 31 is an idler gear.
When the armature 6a serving as the hook of the solenoid 6 locked to the cutout portion 30a of the cutout cam 30 is disengaged at a position facing the gear 10, and the cutout portion 31b faces the second gear 19, respectively. The toothed portion 31c is the idler gear 10 and the second gear.
The spring 19 is configured to have a biasing force to rotate so as to engage with each other.

The toothless clutch gear 29 is D with respect to the paper feed shaft 18.
Since the shaft is fixed by the cut portion 18a and the D-cut portion 18a positions the toothless clutch gear 29 and the half-moon paper feed roller 1, no adjustment is necessary.

The notch portion 30a of the notch cam 30 has the armature 6
The rotational force transmitted from the drive motor 8 to the motor shaft gear 9 and the idler gear 10 in the state of being locked to a is transmitted to the toothless gear 31 because the toothless gear 31 and the idler gear 10 do not mesh with each other. The half-month feeding roller 1 remains stopped.

Further, since the tooth-missing gear 31 and the second gear 19 are not meshed with each other, the drive system connected from the second gear 19 to the feed roller 2a is free to rotate. Therefore, the feed roller 2a moves in the direction of returning the sheet by the rotational force transmitted from the drive motor 8 through the motor shaft gear 9, the idler gear 11, the drive gear 12 of the retard roller 2b, the drive shaft 13, the joint 14, and the torque limiter 16. It rotates along with the rotating retard roller 2b and rotates in the direction of the broken line arrow a in FIG.

Further, the rotational force of the drive gear 12 is the idler gear.
Drive gear (shaft fixed gear) of the transport roller 3a via 24
Is transmitted to drive the transport roller drive shaft 26 to rotate the transport roller 3a in the sheet transport direction. The transport roller 3b rotates together with the transport roller 3a.

From the above state, the solenoid 6 is energized to pull the armature 6a. When the armature 6a is pulled and the engagement state of the cutout portion of the cutout cam 30 is released, the toothless clutch gear 29 is rotated in the clockwise direction (direction of arrow b in FIG. 2) by the spring 32, and first in the counterclockwise direction ( The idler gear 10 and the partly tooth-missing gear 31 rotating in the direction of arrow c in FIG.
The toothed portion 31c, which continues in the rotation direction from the notched end of the tooth of the toothless portion 31a, starts meshing, and the rotational force from the drive motor 8 is transmitted to the toothless gear 31.

As described above, the toothed portion which continues in the rotation direction from the notched end portion of the tooth of the toothless portion 31a facing the idler gear 10
The first tooth of 31c is cut from around the pitch circle r1 and
Since the tooth and the third tooth are formed by cutting from the tooth tip circle r2, the toothless gear 31 smoothly meshes with the idler gear 10 without the tooth tips hitting each other.

Even if the tooth tips contact each other, the tooth depth of the first tooth is low, so that the deformation slit 33a allows the tooth tips to easily escape and the second tooth to engage with each other to reliably transmit the driving force. Go.

When the partly tooth-missing gear 31 meshes with the idler gear 10 and rotates a little, the toothed part 31c continuing in the rotational direction from the notch ends of the teeth of the other partly toothless part 31b starts to mesh with the second gear 19. Then, similarly to the above, the toothed portion 31c continuing in the rotation direction from the notched end portion of the tooth of the toothless portion 31b smoothly meshes with the gear to transmit the rotational driving force.

However, in this case, the cutting direction of the tooth tops of the toothed portion 31c facing the second gear 19 is opposite to the cutting direction of the toothed portion 31c facing the idler gear 10. Cage, toothed part where idler gear 10 faces
Since the drive transmission side tooth surface A is arranged in the opposite direction to the disposition direction of the drive transmission side tooth surface A on the top of the tooth of 31c, the second gear 19
Also, the tooth flank A on the drive transmission side can be effectively meshed.

As described above, when the rotational force from the idler gear 10 is transmitted to the tooth-chipped gear 31 and rotation starts for a while, the tooth-chipped gear 31 meshes with the second gear 19 and transmits the rotational force. After that, the rotational force is transmitted to the second gear 19, the drive shaft 20, the third gear 21, and the drive gear 22 of the feed roller 2a, and the feed roller 2a starts rotating in the sheet conveying direction.

Here, the feed roller 2a is fixed to the feed roller shaft 23, and a rotating body restraint releasing means such as a one-way clutch is unnecessary. On the other hand, since the retard roller 2b is acted on by the torque of the torque limiter 16 or more, the retard roller 2b starts rotating with the feed roller 2a and rotates in the sheet conveying direction.

The toothless clutch gear 29 rotates once and the notched cam
When the notch 30a of 30 is hooked on the armature 6a of the solenoid 6 again, it returns to the initial state and does not rotate until the armature 6a of the solenoid 6 is pulled again.

Then, one rotation of the toothless clutch gear 29 rotates the half-month paper feed roller 1 once in the sheet conveying direction to convey the recording paper P to the sheet separating roller pair 2, and the sheet separating roller pair 2 makes the recording paper P. Is conveyed to the conveying roller pair 3.

Here, when the recording paper P picked up by the half-month paper feed roller 1 is double or more, the recording paper P
Since the frictional force between the recording papers P is smaller than the frictional force between the rollers and the recording paper P or between the rollers, the recording papers P slip and the retard roller 2b exerts only a torque less than a predetermined value of the torque limiter 16. 2b starts rotating in the same direction as the rotation direction of the drive gear 12 in the direction of returning the sheet (the direction of the arrow d in the broken line in FIG. 2), and returns the recording paper P on the retard roller 2b side (lower side) to the cassette 50 for recording. Paper P
And separate them one by one.

When the recording paper P is being conveyed by the conveying roller pair 3, the trailing edge of the recording sheet P is still sandwiched by the nip portion of the sheet separating roller pair 2 for a while. At this time, since the feed roller 2a is in the rotation free state, the recording paper P
And the retard roller 2b also rotates with the torque limiter 16
Since a torque larger than a predetermined value is applied, the recording paper P is rotated.

When the trailing edge of the recording paper P passes through the nip portion of the sheet separating roller pair 2, only a torque less than a predetermined value acts on the retard roller 2b, so that the sheet starts to rotate in the direction of returning the sheet and the feed roller 2a is in the rotation free state. It rotates with the retard roller 2b.

[0045]

The gear intermittent rotation transmission device according to the present invention is
Since it has the above-described configuration and operation, at least the first portion that continues in the rotational direction from the notched end portion of the tooth of the toothless portion of the toothless gear.
By cutting the tops of the teeth after the tooth so that the tooth flank on the drive transmission side is higher than the tooth flank on the non-drive transmission side, smooth meshing can be performed without the tooth tips of the gears contacting each other.

Further, the first tooth continuing from the notched end of the tooth of the tooth-missing gear in the direction of rotation is cut from the vicinity of the pitch circle to lower the tooth depth, and a slit for deformation is provided to make the operation smoother. Can be engaged with each other.

Further, by providing a hole for stress dispersion at the end of the deformation slit, the durability of the partly tooth-missing gear is improved, which is particularly advantageous in the partly-missing clutch gear of high speed rotation.

Further, in the image forming apparatus provided with the sheet feeding device having the gear intermittent rotation transmission device, the sheet fed smoothly by the sheet feeding device exhibits the action of the gear intermittent rotation transmission device. Images can be recorded on.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory diagram of a laser beam printer including a retard separation type sheet feeding device.

FIG. 2 is a perspective view showing a drive mechanism of a retard separation type sheet feeding device.

FIG. 3 is an enlarged view of a main part as seen from a side surface of a toothless clutch gear part.

FIG. 4 is a diagram illustrating a conventional example.

FIG. 5 is a diagram illustrating a conventional example.

[Explanation of symbols]

1 ... Half-moon feeding roller, 2 ... Sheet separating roller pair, 3 ... Conveying roller pair, 4 ... Process cartridge, 6 ... Solenoid, 6a ... Armature, 10 ... Idler gear, 19 ... Second
Gear, 29 ... Toothless clutch gear, 30 ... Notched cam, 30a ... Notched portion, 31 ... Toothed gear, 31a, 31b ... Toothless portion, 31c ... Toothed portion, 32 ... Spring, 33a, 33b ... Deformation slit , 34a, 34b ... Holes, 50 ... Cassette, 51 ... Pre-registration guide, 52 ... Registration roller pair, 53 ... Photosensitive drum, 54 ... Transfer roller, 55 ... Separation guide, 56 ... Conveying guide, 57 ... Entrance guide, 58 ... Fixing roller, 59 ... Pressure roller, 60 ... Separating claw, 61,62 ... Fixing paper ejection roller, 64 ... Conveying guide rib, 65
… Conveying roller pair, 66, 67… Conveying guide, 68… Ejecting device,
T ... face down tray, P ... recording paper, A ... drive transmission side tooth surface, B ... non-drive transmission side tooth surface, r1 ... pitch circle, r2
… Tooth circle

Claims (5)

[Claims] 1. A tooth-missing gear having toothless portions at positions where a drive gear and a driven gear face each other and toothed portions at other positions, and a notch at one outer periphery coaxial with the toothless gear. A toothless clutch gear in which a notched cam having a portion is arranged, and when a hook that engages with the notched portion of the notched cam is removed, the toothed portion of the toothless gear has a toothed portion of the drive gear and the driven gear. In a gear intermittent rotation transmission device provided with a spring member for biasing a rotation so as to mesh with each other, at least the first tooth and subsequent teeth continuing in the rotation direction from the notch end of the tooth of each tooth-missing gear of the tooth-missing gear. Within the top of the tooth,
A gear intermittent rotation transmission device, characterized in that the tooth depth of the tooth flank on the drive transmission side is cut to be higher than the tooth depth on the tooth flank on the non-drive power transmission side. 2. The tooth-missing gear is made of a material having elasticity, and the deforming slits are provided for several teeth continuing from the notched ends of the teeth of the respective tooth-missing portions in the rotation direction. The gear intermittent rotation transmission device according to claim 1, wherein the terminal has a hole for stress distribution. 3. A structure in which the first tooth continuing from the notched end portion of the tooth of the tooth missing gear in the rotational direction is cut from the vicinity of the pitch circle to be lower than the tooth brush of the second tooth and thereafter. The gear intermittent rotation transmission device according to claim 1, characterized in that. 4. A sheet feeding device comprising the gear intermittent rotation transmission device according to claim 1. Description: 5. An image forming apparatus, comprising: the sheet feeding device according to claim 4; and a recording unit that records the sheet fed by the sheet feeding device in correspondence with image information. apparatus.