JP2002130387A - Power transmission device and recording apparatus provided with power transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate adjustment of engagement status, that is, adjustment of backlash, in case where two gears mounted on two roller shafts as drive objects are directly engaged with a pinion gear fitted to a driving motor. SOLUTION: A power transmission device 50 comprises a transportation drive roller gear 51 as drive object, an eject drive roller gear 52 and a pinion gear 53 attached on a rotating shaft 33a of a drive motor 53. The pinion gear 53 displaces as a base 33b of the rotating shaft 33a of the drive motor 33 slides within a slot 59. The inner peripheral surfaces 59a, 59b of the slot 59 is formed by arcs having the center identical with the revolving center B of the eject drive roller gear 52, thereby the backlash between the pinion gear 53 and the eject drive roller gear 52 is kept constant consistently even when the pinion gear 53 displaces and the backlash between the pinion gear 53 and the transportation drive roller gear 51 can be adjusted with ease.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to various types of rotary shafts provided in recording devices such as printers and facsimile machines,
In particular, the present invention relates to a power transmission device that transmits power from a drive motor to a roller shaft related to an operation of paper feeding. The invention also relates to a recording device provided with the power transmission device.

[0002]

2. Description of the Related Art In a recording apparatus typified by a printer, a facsimile or the like, various rotating shafts, particularly, a roller shaft related to a sheet feeding / conveying operation are provided. As an example, there is a rotating shaft of a transport drive roller that transports print paper at a constant pitch according to recording information, for example, to a recording unit that performs recording on print paper as a recording material, and further from the transport drive roller. There is a rotating shaft of a paper discharge roller disposed on the downstream side in the transport direction for discharging the printed printing paper.
These two roller shafts may use one drive motor as a common drive source from the viewpoint of cost reduction.

In such a case, the transmission of rotational power from one drive motor to the two roller shafts is performed through a power transmission device. That is, a pinion gear is attached to the rotation shaft of the drive motor, and one end of the two roller shafts is
Gears to which power is transmitted from the pinion gears are respectively mounted. The pinion gear and two gears attached to one ends of the two roller shafts mesh with each other via a transmission gear, so that the rotational power of the drive motor is transmitted after being adjusted to a predetermined reduction ratio. .

[0004]

However, there is a problem of so-called backlash in the meshing of the gears. That is, there are three gears: a gear attached to the two roller shafts, a transmission gear of a power transmission device that transmits the rotational power of the drive motor to the gear, and a pinion gear attached to the drive motor. The backlash deteriorates the response performance of the two roller shafts to the rotation / stop operation of the drive motor, and consequently lowers the paper feeding accuracy.

On the other hand, it is preferable to omit the transmission gear as much as possible in order to reduce the phenomenon. For example, a pinion gear attached to a rotation shaft of a drive motor and a roller attached to the two roller shafts are provided for that purpose. When two gears are directly meshed with each other, the adjustment of the backlash becomes complicated. That is, since two gears are directly meshed with one pinion gear, if one is adjusted to an optimal meshing state and the other is in an inappropriate meshing state, an attempt is made to adjust the gears. There is a problem that one meshing state adjusted to a proper state is broken.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object the problem of directly engaging two pinion gears attached to a drive motor with two gears attached to two roller shafts to be driven. Another object is to facilitate the adjustment of the meshing state, that is, the adjustment of the backlash.

[0007]

According to another aspect of the present invention, there is provided a recording apparatus, comprising: a first rotating shaft and a second rotating shaft to which power is to be transmitted; A first gear attached to the first rotating shaft; a second gear attached to the second rotating shaft; and a drive serving as a common drive source for the first rotating shaft and the second rotating shaft. A power transmission device comprising: a motor; a driving motor mounting member for mounting the driving motor; and a pinion gear mounted on a rotation shaft of the driving motor and transmitting rotational power to the first gear and the second gear. The pinion gear meshes with the first gear and the second gear, and can be displaced along an arc centered on one of the rotation centers of the first gear and the second gear. So that the drive motor is attached to the drive motor mounting member. Characterized in that attached.

According to the first aspect of the present invention, in order to reduce the deterioration of responsiveness of power transmission due to backlash,
Even when two gears to be driven are meshed with one pinion gear, one meshing state is changed, that is, the other meshing state is adjusted without changing the backlash, that is, the backlash is adjusted. Can be. Hereinafter, a configuration for achieving the effect will be described.

[0009] The power transmission device is composed of two driving motors.
Rotating power is transmitted to the two rotating shafts. A pinion gear is mounted on the drive motor, and gears for rotating each of the two rotation shafts to be driven are mounted. The power transmission device directly meshes a pinion gear with two gears to be driven in order to reduce deterioration in responsiveness of power transmission due to backlash between gears of the power transmission device. By doing so, the backlash (accumulation of the backlash) is reduced to the maximum, and the deterioration of the responsiveness of the power transmission can be suppressed.

However, in this case, since two gears mesh directly with one pinion gear, the adjustment of the backlash becomes complicated. That is, if the drive motor is in a free state to adjust one of the backlashes, the other backlash also changes at the same time, making it difficult to adjust both backlashes to the optimum state at the same time.

However, in the present invention, even when the drive motor is in a free state, the pinion gear is displaced along an arc centered on the rotation center of one of the two gears to be driven. In this way, since the pinion gear is attached to the drive motor attachment member, the relative distance between the pinion gear and one of the gears to be driven is maintained,
That is, backlash is maintained. Therefore, this
It becomes possible to adjust the other backlash without changing the backlash between the pinion gear and one gear,
This makes it easy to adjust the backlash of the entire power transmission device.

According to a second aspect of the present invention, there is provided a recording apparatus comprising: a transport drive roller shaft serving as a rotation axis of a transport drive roller for transporting a recording material to a recording head unit for performing recording on the recording material; A discharge drive roller shaft that is disposed further downstream in the transport direction and serves as a rotation axis of a discharge drive roller that discharges the recording material on which recording has been performed, and a transport drive roller attached to one end of the transport drive roller shaft A gear, a paper ejection drive roller gear attached to one end of the paper ejection drive roller shaft,
A drive motor serving as a common drive source for the transport drive roller shaft and the paper discharge drive roller shaft, a frame member for attaching the drive motor, and a transport drive roller gear attached to a rotation shaft of the drive motor; A pinion gear for transmitting rotational power to the discharge drive roller gear, wherein the pinion gear meshes with the transport drive roller gear and the discharge drive roller gear, and the transport drive The drive motor is attached to the frame member so that the drive motor can be displaced along an arc centered on one of the rotation centers of the roller gear and the discharge roller gear.

According to the second aspect of the present invention, the rotation axis of the transport driving roller for transporting the recording material to the recording head portion for performing recording on the recording material, and the downstream of the transport driving roller axis in the transport direction. A power transmission device, which is disposed on the side and drives a rotation shaft of a paper discharge drive roller for discharging a recording material on which recording has been performed by one drive motor, is similar to the above-described invention of claim 1 of the present application. Since the configuration is adopted, the same operation and effect as the above-described invention of claim 1 of the present application can be obtained.

That is, the pinion gear attached to the rotating shaft of the drive motor is attached to one end of the transport driving roller gear attached to one end of the rotating shaft of the transport driving roller or one end of the rotating shaft of the paper discharge driving roller. The drive motor is mounted on a frame serving as a base of the recording apparatus so that the drive motor can be displaced along an arc centered on one of the rotation centers of the discharge drive roller gear. The backlash of one of the two gears can be adjusted without changing the backlash of the other.

According to a third aspect of the present invention, in the power transmission device according to the second aspect, the frame member has a circular arc centered on a rotation center of one of the transport driving roller gear and the paper discharge driving roller gear. Is formed at the base of the rotation shaft of the drive motor, and a convex portion is formed at the base of the guide groove, the convex portion being guided by the guide groove, A pinion gear is displaced along an arc centered on one of the rotation centers of the transport drive roller gear and the paper discharge drive roller gear.

According to the third aspect of the present invention, the same operation and effect as the above-described second aspect of the present invention can be obtained by simplifying the structure. That is, a projection is formed at the base (root) of the rotation shaft of the drive motor, and the projection is formed along an arc centered on the rotation center of one of the two gears. Since the guide member is guided by the arcuate keyway formed in the member, there is no need to provide any components other than the drive motor and the frame member. Similar effects can be obtained.

The recording apparatus according to the fourth aspect of the present invention provides the recording apparatus according to the first aspect.
A power transmission device according to any one of the above items 3 to 3 is provided. According to the invention as set forth in claim 4 of the present application, it is possible to obtain the same operation and effects as those of the above-described invention as set forth in any one of claims 1 to 3 in the recording apparatus.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. First, referring to FIG. 1, a recording apparatus (hereinafter, referred to as a “printer”) 100 according to the present invention will be described.
The outline of is outlined. Here, FIG. 1 is a side sectional view of a printer 100 according to an embodiment of the present invention. FIG.
The printer 100 includes a printer main body 3, a paper feed unit 5 provided at an upper rear portion of the printer main body 3, and a paper discharge unit 7 formed at the front of the printer main body 3. A hopper 11 is provided in the paper supply unit 5, and a plurality of sheets P can be stacked on the hopper 11, and a lower end surface of the paper P is pressed against a later-described paper supply roller 13 by a spring (not shown). It has become. The hopper 11
A paper feed roller 13 is provided immediately downstream of the paper feed roller. The paper feed roller 13 nips the paper P located at the uppermost position of the paper feed tray 11 with an opposing separation pad (not shown), separates the paper P from the next paper, and sends out the paper P one by one. Works.

The paper P sent out by the paper feed roller 13 reaches a portion of a transport roller 19 composed of a transport drive roller 15 located below and a transport driven roller 17 located above, where a power to be described later is applied. The paper is fed to the print head 21 located on the downstream side of the transport roller 19 in the paper transport direction while receiving the precise paper feed operation in the printing process by the transmission device.

The print head 21 is supported by a carriage 23, and the carriage 23 can reciprocate in a direction (main scanning direction) orthogonal to the paper feeding direction. A platen 25 is provided at a position facing the print head 21. The platen 25 functions to support the sheet P from below when printing is performed on the sheet P by the print head 21. The distance between the print head 21 and the platen 25 is
The thickness of the sheet P can be appropriately adjusted, so that the sheet P can smoothly perform high quality printing and printing while passing over the platen 25 smoothly. The paper P printed by the print head 21 is sequentially discharged by a discharge roller 27 provided in the discharge unit 7.

The discharge roller 27 includes a discharge drive roller 29 located on the lower side and a discharge driven roller 3 located on the upper side.
The sheet P is pulled out and discharged by the rotation of the discharge drive roller 29. The drive rollers 15 and 29 in the transport roller 19 and the paper discharge roller 27 are connected to the power transmission device 5 according to the present embodiment.
By 0, it is driven by one drive motor 33 (see FIG. 2). Here, FIG. 2 is a side view showing a state in which a main body cover of the printer 100 is removed, and FIG. 3 is a view showing details of a mounting structure of a drive motor 33.
0 is a front view. Hereinafter, the power transmission device 50 will be described in detail with reference to FIGS. 2 and 3.

Conveyance drive roller 15 and paper discharge drive roller 2
Numeral 9 includes a transport drive roller shaft 15a and a paper discharge drive roller shaft 29a, and is rotated by the rotation of the transport drive roller shaft 15a and the paper discharge drive roller shaft 29a. Conveyance drive roller shaft 15a and discharge drive roller shaft 29
a is the side frames 35, 3 serving as the base of the printer 100;
5 (FIG. 2 shows a side frame 35 located on the left side of the main body of the printer 100).

One end of the transport drive roller shaft 15a and one end of the discharge drive roller shaft 29a are respectively provided with a transport drive roller gear 51.
And a paper discharge drive roller gear 52 are mounted as shown in FIG.
3 directly meshes with a pinion gear 53 attached to the rotation shaft. Therefore, the rotational power of the drive motor 33 is directly transmitted to the transport drive roller shaft 15a and the discharge drive roller shaft 29a by the pinion gear 53, whereby the transport drive roller gear 51 and the discharge drive roller Backlash (accumulation of backlash) can be reduced as compared with a case where a transmission gear is interposed between the gear 52 and the pinion gear 53, and the paper feeding accuracy can be improved.

Here, the relationship of the reduction ratio (gear ratio) between the pinion gear 53 and the transport drive roller gear 51 and the discharge drive roller gear 52, that is, the drive speed of the transport drive roller 15 and the discharge drive roller 29 The relationship will be described with reference to FIG. In FIG. 1, by adjusting the speed reduction ratio, the rotation speed of the discharge drive roller 29 becomes
5 is set to be higher than the rotation speed by a fixed rate. Further, since the sheet pressing force by the conveying roller 19 is set to be larger than the pressing force by the sheet discharging roller 27, the sheet conveying when the conveying roller 19 and the sheet discharging roller 27 are both sandwiching the sheet. The speed is determined by the paper feed speed of the transport roller 19 irrespective of the paper discharge speed of the paper discharge roller 27. Therefore, the paper is always in a state in which a constant tension is applied between the transport roller 19 and the paper discharge roller 27, so that the paper does not bend between the transport roller 19 and the paper discharge roller 27. Thus, the distance (paper gap: PG) between the platen 25 and the print head 21 is kept constant, so that stable print quality can be obtained.

Next, referring to FIG.
A detailed configuration of the drive motor 33, particularly, a mounting structure of the drive motor 33 will be described. In FIG. 3, the drive motor 33 is
It is attached to a side frame 35 serving as a base of the printer 100 as a “drive motor attachment member” and a “frame member”. More specifically, the drive motor 33 is attached to the adapter plate 54 by two mounting screws 55, and the adapter plate 54 is fixed to the side frame 35 by three fixing screws 56, so that the drive motor 33 is It is attached to the frame 35. Therefore,
By loosening the three fixing screws 56, the drive motor 33 can move relative to the side frame 35, that is, can move relative to the transport drive roller gear 51 and the paper discharge drive roller gear 52.

In FIG. 3, the positional relationship between the drive motor 33, the adapter plate 54, and the side frame 35 is such that the side frame 35, the adapter plate 54,
The drive motor 33 is provided. Accordingly, in FIG. 3, the adapter plate 5 located on the other side of the side frame 35 is
4 and the outline of the drive motor 33 are drawn by hidden lines. Also,
In FIG. 3, the transport drive roller gear 51 and the paper discharge drive roller gear 52 that should be positioned on the front side of the drawing are indicated by phantom lines. Further, the rotation centers of the transport drive roller gear 51 and the discharge drive roller gear 52 are denoted by reference numerals A and B, respectively.
Thus, the center of rotation of the pinion gear 53 is indicated by the symbol C.

A slot 59 is formed in the side frame 35 as a "guide groove". The slot 59 is used to insert the drive shaft 33a of the drive motor 33 and the base (bearing portion) 33b of the drive shaft 33a as a “convex portion” from the back side to the near side of the paper of the side frame 35 in FIG. And the base portion 33b of the drive motor 33 does not rattle in the slot 59, that is, such that no clearance is generated, and
It is formed precisely in accordance with the outer diameter of the base 33b so that it can easily slide on the inner peripheral surfaces 59a and 59b of the slot 59.

In the slot 59, the inner peripheral surface 5
9a and 59b are the rotation center B of the discharge drive roller gear 52.
Are formed by circular arcs having the same center, so that when the base 33b slides along the inner peripheral surfaces 59a, 59b, that is, when the inside of the slot 59 is displaced, the pinion gear attached to the motor rotation shaft 33a is formed. Similarly, 53 is also displaced along a circular arc having the same center as the rotation center B of the discharge drive roller gear 52. The symbol m in FIG.
The arc, that is, the arc drawn by the rotation center C of the pinion gear 53 is shown.

The operation and effect of the slot 59 will be described below. When the three fixing screws 56 are loosened and the drive motor 33 is in a free state, that is, in a state in which the drive motor 33 can move relative to the side frame 35, the drive motor 33 In this state, the base 33b can be displaced in the slot 59. And at this time,
As described above, the rotation center C of the pinion gear 53 attached to the rotation shaft 33a of the drive motor 33 moves along an arc m having the same center as the rotation center of the paper discharge drive roller gear 52. Therefore, the relative distance between the discharge drive roller gear 52 and the pinion gear 53 is always kept constant. In other words, the paper ejection drive roller gear 52 and the pinion gear 53
The backlash at the time of meshing with is always kept constant.

Thus, even when the drive motor 33 is in a free state, the paper discharge drive roller gear 52 and the pinion gear 5
3, the backlash between the transport drive roller gear 51 and the pinion gear 53 can be adjusted without regard to the change in the backlash between the discharge drive roller gear 52 and the pinion gear 53. Becomes possible. In other words, even when two gears (the transport drive roller gear 51 and the discharge drive roller gear 52) are directly meshed with one gear (the pinion gear 53), the backlash in one meshed state is maintained in an appropriate state. , The backlash in the other meshing state can be adjusted,
Thus, the backlash adjustment of the power transmission device 50 having such a configuration becomes easy.

The slots denoted by reference numerals 57a to 57c are:
When the drive motor 33 moves relative to the side frame 33,
It is a slot for enabling the three fixing screws 56 to move,
Slots indicated by reference numerals 58a and 58b allow the screw threads to escape so that the mounting screws 55 and 55 (pan head small screws in this embodiment) for attaching the adapter plate 54 to the drive motor 33 do not interfere with the back surface of the side frame 35. It is a slot for

By the way, in this embodiment, the slot 5
9, the inner peripheral surfaces 59a and 59b are formed by an arc m having the same center as the rotation center B of the sheet discharging drive roller gear 52. The arc m is set such that the rotation center A of the transport driving roller gear 51 is the same center. It may be a circular arc. Further, the function and effect of the present invention can be obtained even if the pinion gear 53 to be displaced is not attached to the drive motor 33 as a power source, but functions as a mere transmission gear. Can be.

[0033]

As described above, according to the present invention, even when two gears attached to two roller shafts to be driven are directly meshed with a pinion gear attached to a drive motor, the pinion gear can be used. The drive motor is mounted so that the center of rotation of the roller is displaced along an arc that is the same as the center of rotation of the gear attached to one of the roller shafts. It is possible to adjust the backlash with the other gear while keeping the backlash constant, thereby facilitating the backlash adjustment in the power transmission device.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a recording apparatus according to the present invention.

FIG. 2 is a side view showing a state where a main body cover of the recording apparatus according to the present invention is removed.

FIG. 3 is a front view of the power transmission device according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ink-jet printer 13 Feed roller 15 Transport drive roller 15a Transport drive roller shaft 17 Transport driven roller 19 Transport roller 21 Print head 25 Platen 27 Discharge roller 29 Discharge drive roller 29a Discharge drive roller shaft 31 Discharge driven roller 33 Drive Motor 35 Side frame 50 Power transmission device 51 Conveyance drive roller gear 52 Discharge drive roller gear 53 Pinion gear 54 Adapter plate 55 Mounting screw 56 Fixing screw 59 Slot hole

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) H04N 1/31 H04N 1/31 5C074 // F16H 55/18 F16H 55/18 F term (reference) 2C058 AB15 AD03 AE02 AF29 2C059 BB05 BB11 BB13 3F049 AA02 DA12 EA00 EA21 LA05 LA07 LB03 3J009 DA08 EA04 EA11 EA35 EA43 EB24 ED11 ED14 FA17 FA18 3J030 AB01 BA01 BD02 CA10 5C074 AA13 CC26 GG15

Claims (4)

[Claims] 1. A first rotation shaft and a second rotation shaft to which power is to be transmitted, a first gear attached to the first rotation shaft, and an attachment to the second rotation shaft. A second gear, a drive motor serving as a common drive source for the first rotation shaft and the second rotation shaft, a drive motor mounting member for mounting the drive motor, and a rotation shaft of the drive motor. A pinion gear attached to the first gear and the second gear for transmitting rotational power to the first gear and the second gear, wherein the pinion gear meshes with the first gear and the second gear, and The drive motor is attached to the drive motor attachment member such that the drive motor can be displaced along an arc centered on one of the rotation centers of the first gear and the second gear. Power transmission device. 2. A transport drive roller shaft serving as a rotation axis of a transport drive roller that transports a recording material to a recording head unit that performs recording on a recording material, and is disposed downstream of the transport drive roller in the transport direction. A discharge drive roller shaft serving as a rotation axis of a discharge drive roller for discharging a recording material on which recording has been performed; a transport drive roller gear attached to one end of the transport drive roller shaft; and the discharge drive roller A discharge drive roller gear attached to one end of the shaft; a drive motor serving as a common drive source for the transport drive roller shaft and the discharge drive roller shaft; a frame member for mounting the drive motor; A pinion gear attached to a driving shaft and transmitting rotational power to the transport drive roller gear and the sheet discharge drive roller gear, wherein the pinion gear is The transfer drive roller gear and the discharge drive roller gear mesh with each other, and can be displaced along an arc around the center of rotation of one of the transfer drive roller gear and the discharge roller gear. And the drive motor is mounted on the frame member. 3. The guide member according to claim 2, wherein an arc-shaped guide groove is formed in the frame member along an arc centered on a rotation center of one of the transport drive roller gear and the sheet discharge drive roller gear. A protrusion that engages with the guide groove is formed at the base of the rotation shaft of the drive motor. The protrusion is guided by the guide groove, so that the pinion gear is driven by the transport drive roller gear or A power transmission device, wherein the paper discharge drive roller gear is displaced along an arc centered on one of the rotation centers. 4. A recording device comprising the power transmission device according to claim 1. Description: