JP2008101644A - Driving device and image forming apparatus - Google Patents

Abstract

Provided are a space-saving, low-cost, resource-saving drive device, a developing device using the same, and an image forming apparatus equipped with the developing device, in which a projection area occupied by a transmission means is minimized.
One driving source, at least one first driven body that changes speed in accordance with a speed mode, and at least one second driven object that does not change speed or has a different rate of speed change. A drive body, drive transmission means 2 and 6 for transmitting drive from the drive source 1 to each driven body, and at least one of the drive transmission means 2 and 6, a transmission means 9 and switching means 15a and 16 are provided. In the driving apparatus having the above, the speed change means 9 is constituted by a combination of two sets of gears 8 and 18 having the same inter-shaft distance and different reduction ratios, and when one is engaged, the other is not engaged, and the switching is performed. The means 15a and 16 move the speed change means 9 in the axial direction and change the combination of gears engaged with each other.
[Selection] Figure 1

Description

  The present invention relates to a driving device that rotates a plurality of driven bodies with a single driving source, and an image forming apparatus equipped with the developing device.

In recent years, electrophotographic apparatuses such as copiers and printers can transfer and fix images on various transfer papers by changing the transfer paper conveyance speed and image forming speed (process linear speed) according to the paper thickness. There is a need to.
Therefore, conventionally, a method for changing the transfer paper conveyance speed and image forming speed (process linear speed), a method for changing the speed, a method for changing the speed of the drive source itself such as a motor, and the rotation direction of the drive source. There are proposed a method corresponding to the change, a method using a speed change unit, a switching unit, a technique in which a main motor connected to the developing sleeve controls the number of rotations according to a variation in the number of rotations of the image carrier (for example, a patent) References 1 to 4).
However, in any of Patent Documents 1 to 4, even if there are a plurality of the rotationally driven bodies connected to the respective driving sources, the rotational speed is increased or decreased in the same manner before and after switching.
Although not disclosed in the applicant's research, a plurality of driven bodies are operated by one driving source with a driving device having a plurality of speed modes. In order to operate a driven body whose speed is changed or not changed according to the speed mode, or to drive a driven body having a different rate of change, a technique has been developed in which transmission means and switching means are provided in at least one drive train. ing.
JP-A-5-265271 JP-A-2005-54661 JP 2002-72771 A JP-A-9-62089

However, some rotated drives must not be changed in speed. For example, in a developing paddle that stirs toner in a developing device, draws toner to the vicinity of the developing roller, and supplies the toner to the surface of the developing roller, the toner supply amount tends to depend on the rotational speed.
If the rotational speed is fast, bias in the developing device occurs when the toner is agitated, and if it is slow, the toner does not sufficiently adhere to the surface of the developing roller due to insufficient pumping amount when the toner is pumped to the developing roller, affecting the image. Therefore, it is necessary to keep the speed constant.
In the above-mentioned unpublished research by the present applicant, the gear train is switched by shifting the drive train provided on the Y-shaped swing lever by moving the swing lever. However, since the projection area becomes large, it is necessary that there is a margin in the projection area and that there is a margin in the depth.
In view of the above circumstances, an object of the present invention is to provide at least one drive means with a speed change means so that one drive source can handle a plurality of driven bodies, and two sets of the speed change means are provided. By using a combination of gears with different reduction ratios with the same inter-shaft distance, the projected area occupied by the speed change means can be reduced as much as possible, and a space-saving, low-cost, resource-saving drive device is used. An object of the present invention is to provide a developing device and an image forming apparatus equipped with the developing device.

In order to solve the above-mentioned problems, the invention according to claim 1 is directed to one drive source and at least one first driven that is driven by the drive source and changes the speed in accordance with the speed mode. At least one second driven body that does not change speed or has a different rate of speed change, drive transmission means for transmitting drive from the drive source to each driven body, and at least of the drive transmission means In a drive device having one speed change means and its switching means, the speed change means is composed of a combination of two sets of gears having different reduction ratios having the same distance between the shafts, and when one is engaged, the other is not engaged. The switching means is characterized by a drive device that moves the speed change means in the axial direction and changes the combination of meshing gears.
Further, the invention according to claim 2 is that the two sets of gears as the speed change means are moved in the axial direction by the switching means, and themselves rotate, and are separated from the gears of the speed change means on the shaft. The drive device according to claim 1, wherein the drive device is disposed on a second shaft on which a gear for transmitting driving is disposed on the downstream side of the first shaft and on a first shaft that does not move.
According to a third aspect of the present invention, there is provided the driving device according to the second aspect, wherein the two gears provided on the first shaft and the gear provided on the second shaft are each integrally manufactured. Features.

According to a fourth aspect of the present invention, the two gears provided on the second shaft are separate and can move independently in the axial direction with respect to the second shaft, and the minimum distance is the first gear. 3. The driving device according to claim 2, wherein the two gears provided on the shaft are arranged so that there are teeth at intervals wider than the axial length of each of the two gears, and each gear is biased in the direction of the minimum interval. It is characterized by.
According to a fifth aspect of the present invention, the second shaft and the gear disposed on the second shaft are attached to a support member movable in the axial direction, and the support member extends in the movement direction. And a rack integrally provided on the support member and a motor meshing with the rack, and the drive device according to claim 2 which is the drive switching means.
According to a sixth aspect of the invention, the guide member of the support member is different from the speed change means provided on the first shaft and the second shaft, and the gear meshes with the gear that transmits the drive to the downstream side. The drive device according to claim 5, which is a shaft of

The invention according to claim 7 is characterized in that the speed change means is a speed increasing mechanism, according to any one of claims 1 to 6.
The invention according to claim 8 is characterized in that the speed change means is a speed reduction mechanism, and the drive device according to any one of claims 1 to 6.
According to a ninth aspect of the present invention, the drive source corresponds to a speed mode of the second speed or higher, the speed is changed, the drive transmission means having the speed change means uses the speed change means, and the speed is changed. 9. The drive device according to claim 7, wherein the drive device transmits a constant speed to the driven body regardless of the mode.
According to a tenth aspect of the present invention, the drive source has a constant speed regardless of the speed mode of the second speed or higher, and the drive transmission means having the speed change means uses the speed change means. The drive device according to claim 7 or 8, wherein the drive device changes speed and transmits drive to the driven body.
According to an eleventh aspect of the present invention, there is provided an image forming apparatus equipped with the driving device according to the ninth or tenth aspect.
According to a twelfth aspect of the present invention, the driven member connected to the first driving mechanism is a developing roller of the developing device, and the driven member connected to the second driving mechanism is the toner of the developing device. 12. The image forming apparatus according to claim 11, wherein the image forming apparatus is a developing paddle for stirring and pumping.

  According to the present invention, in a drive device having a plurality of speed modes and including a drive transmission means in which a drive source and a plurality of driven bodies are connected, at least one drive means is provided with a speed change means. A plurality of driven bodies that change the speed corresponding to the speed mode, a thing that keeps the speed constant regardless of the speed mode, and a speed ratio that changes the speed corresponding to the speed mode. By making it possible to handle various types of gears (or different speed increase ratios) with a single drive source, by changing the gear combination of the two gear sets with different reduction ratios with the same distance between the axes. By dealing with this, it is possible to achieve space saving, low cost, and resource saving by minimizing the projected area occupied by the transmission means.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic perspective view showing an embodiment of a drive device using the present invention. FIG. 2 is a front view of the embodiment of the drive device of FIG. FIG. 3 is a plan view showing a case of deceleration of the embodiment of the drive device of FIG. FIG. 4 is a plan view showing the case of speed increase in the embodiment of the drive device of FIG. FIG. 5 is a plan view showing the vicinity of the speed change means of the embodiment of the drive device of FIG.
According to FIGS. 1 to 5, two systems of drive mechanisms are connected to the output shaft of the motor 1 as a drive source. The first drive mechanism 2 connects the rotational driving force of the motor 1 with the first gear 3 and the second gear 4, and rotates the first coupling shaft 5 that rotates coaxially with the second gear 4. Thereby, a driven body (not shown) which is the first driven body is rotated. The first drive mechanism 2 is a drive mechanism having no speed change means.

In the second drive mechanism 6, the rotational driving force of the motor 1 is transmitted to the third gear 7, the fourth gear 8, and the speed change means 9, and a driven body that is a second driven body by the second coupling shaft 10. Rotate a (not shown). The fourth gear 8 is a two-stage gear, and includes a small-diameter gear 8a and a large-diameter gear 8b, and rotates about the first shaft 11.
The speed change means 9 includes a second shaft 12, a fifth gear 13 and a sixth gear 14 that are provided on the second shaft 12 and rotate together with the second shaft 12, and a support member 15 that holds them. The motor 16 is for moving the support member 15.
That is, by moving the support member 15 with the motor 16 via the rack 15a provided on the support member 15, the combination of the small-diameter gear 8a and the sixth gear 14 at the position in FIG. 3 and the large position at the position in FIG. The transmission means 9 is configured by having two combinations of gears, that is, a combination of the radial gear 8 b and the fifth gear 13.
When the speed change means 9 is a speed increasing means, the normal time is shown in FIG. 3, and the speed increasing time is shown in FIG. On the contrary, when the speed change means 9 is a speed reduction means, the normal time is shown in FIG. 4 and the speed reduction time is shown in FIG.

Further, a seventh gear 17 for transmitting drive to the downstream side is disposed on the second shaft 12, and an eighth gear 18 that meshes with the seventh gear 17 is disposed on the third shaft 19. Further, the eighth gear 18 meshes with the ninth gear 20 and rotates integrally with the second coupling shaft 10 which is the shaft thereof, thereby rotating the driven body A (not shown).
The support member 15 is arranged in a state of being movable in the vertical direction in FIGS. 3 and 4 with the first shaft 11 and the third shaft 19 as guide rods. The fourth gear 8 disposed on the first shaft 11 and the eighth gear 18 disposed on the third shaft 19 mesh with the sixth and seventh gears 14 and 17 disposed on the second shaft 12, respectively. The accuracy of the center distance is ensured by the support member 15.

FIG. 5 shows how the gear is attached to the second shaft 12. The second shaft 12 is provided with a D-cut portion, into which a fifth gear 13 and a sixth gear 14 are inserted. And it is each urged | biased inside (arrow direction) by the spring 21 as an urging means, and has stopped at the D cut end.
Unless the dimension (illustrated) between the D cut ends is larger than the tooth width (illustrated) of the fourth gear 8, both the fifth gear 13 and the sixth gear 14 mesh with the fourth gear 8. In particular, attention is required.
In this way, the gears provided on the second shaft 12 are configured separately, and by energizing the respective gears, when the second shaft 12 is moved, the second shaft 12 can be moved without first meshing. Without breaking the moving mechanism, it is possible to take safety measures such that the meshing is normalized by the rotation of the gear provided on the first shaft 11.

In addition, by using the third shaft 19 that is the shaft of the eighth gear 18 that meshes with the guide member of the support member 15, the accuracy of the distance between the shafts can be ensured, and abnormal noise due to poor gear meshing can be prevented. .
The drive source 1 changes the speed according to the speed mode, and the drive transmission means (second drive mechanism) to the driven body that wants to keep the speed constant and the driven body that has a different reduction ratio (or speed increasing ratio). By using the speed change means 9 for 6, it is possible to deal with various driven bodies with one drive source 1, and to achieve low cost and resource saving. Further, since the rotation unevenness accuracy of the drive source 1 itself does not change by keeping the speed of the drive source 1 constant, the rotation unevenness accuracy is not lowered even during deceleration.

FIG. 6 is a table showing combinations of speed mode, speed change means, and drive source as a table. FIG. 6 is a table summarizing the speed mode, the state of the drive source at that time, and the necessity of the various driven bodies and the speed change means at that time.
First, it is assumed that the first driven body changes its speed in accordance with the speed mode. In this case, naturally, in the speed mode 1 (normal speed), no speed change means is required. Next, in the case of the speed mode 2 (for example, half speed), if the speed of the drive source 1 (FIG. 1) is also changed according to the speed mode at this time, the speed ratio with the drive source 1 Is the same as in the case of the speed mode 1, so that no speed change means is required. When the speed of the drive source 1 is kept constant at the same speed as the speed mode 1, it is necessary to change (decelerate) the speed of the first rotated body. Therefore, deceleration means is required.
Next, the second driven body is kept at a constant speed regardless of the speed mode. In the speed mode 1 (normal speed), no speed change is required as in the first driven body. Next, in the case of the speed mode 2 (for example, half speed), if the speed of the drive source 1 is changed in accordance with the speed mode at this time, the speed of the second driven body is changed ( Speed increasing), and speed increasing means is required. If the speed of the drive source 1 is kept constant at the same speed as the speed mode 1, no speed change means is required.

Next, it is assumed that the third driven body is changed in speed according to the speed mode, but the speed ratio is different. In this case, naturally, in the speed mode 1 (normal speed), no speed change means is required. Next, in the case of the speed mode 2 (for example, half speed), if the speed of the driving source 1 is changed in accordance with the speed mode, the speed ratio with the driving source 1 is different. A transmission means is required.
If it is necessary to further reduce the speed of the drive source 1, a speed reduction means is required. If it is not necessary to reduce the speed as much as the drive source 1, speed increasing means is required. Even when the speed of the driving source 1 is kept constant at the same speed as the speed mode 1, the speed ratio between the driving source 1 and the third driven body at that time is different from the speed mode 1. Requires a transmission means.
As described above, the plurality of driven bodies correspond to the speed mode, change the speed, keep the speed constant regardless of the speed mode, and change the speed corresponding to the speed mode. However, it is the gist of the present invention to provide a speed change means for operating with one drive source even in various situations such as those with different reduction ratios (or speed increase ratios).

FIG. 7 is a schematic view showing an image forming apparatus provided with a driving device using the present invention.
In the image forming apparatus A of FIG. 7, a latent image is formed on the photosensitive member 22 by charging 23 and writing 24, and the latent image is developed with toner by the developing device 25.
Transfer paper (not shown) is conveyed from the paper supply unit 26, timed by the registration unit 27, transferred to the previous toner image by the transfer unit 28, fixed by the fixing unit 29, and then discharged by the paper discharge unit 30. Released.
The speed mode of the image forming apparatus A has a normal speed and a half speed. The half speed is a thick paper mode, and when a transfer paper thicker than specified is used, the fixing property at the fixing unit 29 is lowered. Therefore, in order to ensure the fixability, the conveyance speed is reduced to about half the normal speed, and the passage time of the thick paper fixing unit 29 is increased.
In the embodiment of the image forming apparatus A shown in FIG. 7, in the case of the half-speed mode, the speed is reduced from the above-described latent image formation (charging and writing), and the speed is maintained until the paper discharge is completed. To do.

FIG. 8 is a schematic perspective view showing a developing device operated by a driving device using the present invention. FIG. 9 is a schematic view showing the relationship between the developing device of FIG. 8 and the photosensitive member. 8 and 9 show a developing device 25 that is operated by a driving device using the present invention.
In the developing device 25, the driven roller referred to in the driving device according to the present invention includes a developing roller 31. This is for adhering the toner 32 to the latent image formed on the photosensitive member 22, and is disposed in the immediate vicinity of the photosensitive member 22.
In order to adhere the toner 32 to the photosensitive member 22, the speed ratio between the photosensitive member 22 and the developing roller 31 is important. Therefore, when the photosensitive member 22 is decelerated in the half speed mode, the developing roller 31 needs to be decelerated while maintaining the same speed ratio.

The other driven body in the developing device 4 is a developing paddle 33. The toner 32 is present around the developing paddle 33. The toner 32 is agitated by rotating it, and the toner 32 is moved to the developing roller as shown in the figure. It also has a function of pumping up to the vicinity of La 31.
However, since the toner 32 is a substance having a very high fluidity, if it takes a long time to pump up, the toner 32 falls from the gap between the developing paddles 33, and the toner 32 cannot be pumped up as expected in the vicinity of the developing roller 31. As a result, the toner 32 on the developing roller 31 becomes insufficient, and the toner 32 does not adhere sufficiently on the photosensitive member 22 so that a normal image cannot be formed.
Therefore, in order to sufficiently secure the toner 32 in the vicinity of the developing roller 31, it is necessary to keep the developing paddle 33 at the same speed as the normal speed mode without reducing the speed of the developing paddle 33 even at the half speed. Accordingly, the developing roller 31 in FIG. 9 is a first driven body, and the developing paddle 33 is a second driven body.
The developing roller 31 is coupled to the coupling 34 provided on the shaft thereof via the first coupling shaft 5 of FIG. 1, and the developing paddle 33 is coupled to the coupling 35 provided on the shaft. Thus, the second coupling shaft 10 shown in FIG.
By making the same driving source 1 correspond to the developing roller 31 whose speed is changed in conjunction with the speed mode and the developing paddle 33 that is desired to maintain a constant speed without being linked to the speed mode, the cost can be reduced. An image forming apparatus including a resource-saving drive device can be provided.

It is a schematic perspective view which shows embodiment of the drive device using this invention. It is a front view of embodiment of the drive device of FIG. It is a top view which shows the case of the deceleration of embodiment of the drive device of FIG. It is a top view which shows the case of the speed increase of embodiment of the drive device of FIG. It is a top view which shows the transmission means vicinity of embodiment of the drive device of FIG. It is a figure which shows the combination of a speed mode, a transmission means, and a drive source as a table | surface. 1 is a schematic view illustrating an image forming apparatus including a driving device using the present invention. It is a schematic perspective view which shows the developing device operated with the drive device using this invention. It is the schematic which shows the relationship between the image development apparatus of FIG. 8, and a photoreceptor.

Explanation of symbols

A Image forming device 1 Drive source (motor)
2 Drive transmission means (first drive mechanism)
3 First gear 4 Second gear 5 First coupling shaft 6 Drive transmission means (second drive mechanism)
7 third gear 8 fourth gear 8a small diameter gear 8b large diameter gear 9 speed change means 10 second coupling shaft 11 first shaft (guide member)
12 Second shaft 13 5th gear 14 6th gear 15 Support member 15a Switching means (rack)
16 Switching means (motor)
17 7th gear 18 8th gear 19 3rd axis (guide member)
20 9th gear 21 Biasing means (spring)
25 Developing device 31 Developing roller (first driven body, rotationally driven body)
33 Development paddle (second driven body, rotationally driven body)

Claims (12)

  One drive source, at least one first driven body that is driven by this drive source and changes the speed in accordance with the speed mode, and at least one that does not change the speed or has a different rate of speed change In the driving device having a second driven body, drive transmission means for transmitting drive from the drive source to each driven body, and at least one of the drive transmission means, a transmission means and a switching means thereof, the transmission means Is composed of a combination of two sets of gears having the same distance between the shafts and different reduction ratios, and when one is engaged, the other is not engaged, and the switching means moves the transmission means in the axial direction, And the drive device characterized by changing the combination of meshing gears.   Two sets of gears as the speed change means are moved in the axial direction by the switching means, and themselves rotate, and a gear for transmitting the drive to the downstream side different from the gear of the speed change means is arranged on the shaft. The drive device according to claim 1, wherein the drive device is disposed on the second shaft and the first shaft that does not move.   3. The drive device according to claim 2, wherein the two gears provided on the first shaft and the gear provided on the second shaft are each integrally manufactured.   The two gears provided on the second shaft are separate and can move independently in the axial direction with respect to the second shaft, and the shafts of the two gears provided on the first shaft with a minimum interval. 3. The driving device according to claim 2, wherein the gears are arranged so that the teeth are present at intervals wider than the length of the direction, and each gear is urged in the direction of the minimum interval.   The second shaft and the gear disposed on the second shaft are attached to a support member that is movable in the axial direction, and the support member is provided integrally with the guide member that extends in the movement direction and the support member. 3. The drive device according to claim 2, wherein the drive switching means is moved in the axial direction by a rack and a motor meshing with the rack.   The guide member of the support member is a shaft of a gear that meshes with a gear that transmits drive to the downstream side, unlike the speed change means provided on the first shaft and the second shaft. 5. The drive device according to 5.   The drive device according to claim 1, wherein the speed change unit is a speed increasing mechanism.   The drive device according to claim 1, wherein the speed change unit is a speed reduction mechanism.   The drive source corresponds to a speed mode of 2nd speed or higher, changes the speed, and the drive transmission means having the speed change means uses the speed change means and receives a constant speed regardless of the speed mode. The drive device according to claim 7 or 8, wherein the drive device transmits the signal to a drive body.   The drive source has a constant speed regardless of the speed mode of the second speed or higher, the drive transmission means having the speed change means uses the speed change means, and changes the speed corresponding to the speed mode, 9. The driving apparatus according to claim 7, wherein driving is transmitted to a driven body.   An image forming apparatus comprising the driving device according to claim 9.   The rotation drive body connected to the first drive mechanism is a developing roller of the developing device, and the rotation drive body connected to the second drive mechanism is a developing paddle for toner agitation and pumping of the development device. The image forming apparatus according to claim 11, wherein

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