JP3780558B2 - Driven pulley support mechanism of image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a driven pulley support mechanism of an image forming apparatus, and more particularly to a mechanism that supports a driven pulley for driving a recording head.
[0002]
[Prior art]
Conventionally, a driving pulley driven to rotate by a motor, a driven pulley rotatably supported, a belt laid between the driving pulley and the driven pulley, and fixed to the belt via a carriage, An image forming apparatus that includes a recording head that moves in the belt installation direction in accordance with the rotation of the drive pulley and forms an image on a sheet is considered. In this type of image forming apparatus, it is possible to transmit a driving force to the carriage via the driving pulley and the belt, and to move the recording head fixed to the carriage in the belt erection direction. Therefore, an image can be formed at a desired position on the paper.
[0003]
[Problems to be solved by the invention]
However, in this type of image forming apparatus, the driven pulley is rotatably supported by a holder, and the lower end of the holder is fixed to a frame disposed along the movement range of the carriage. For this reason, when belt tension is applied to the driven pulley, the tension generates a moment that causes the driven pulley to move from the frame. Accordingly, there is a possibility that the driven pulley swings with the application of the tension, and the position control of the recording head cannot be executed sufficiently accurately. Further, if the structure for fixing the holder is made strong, the above-mentioned swing can be suppressed, but in this case, the image forming apparatus is increased in size and its manufacturing cost is increased.
[0004]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a driven pulley support mechanism for an image forming apparatus that has a simple configuration and can satisfactorily prevent the driven pulley from swinging due to belt tension.
[0005]
[Means for Solving the Problems and Effects of the Invention]
In order to achieve the above object, the invention according to claim 1 is constructed such that a drive pulley that is driven to rotate by a motor, a driven pulley that is rotatably supported, and the drive pulley and the driven pulley. A belt, a biasing member that biases the driven pulley in a direction parallel to the belt, and a belt that is fixed to the belt via a carriage and moves in the direction in which the belt is laid in response to the rotation of the driving pulley and paper A driven pulley support mechanism of an image forming apparatus that is provided in an image forming apparatus that includes a recording head that forms an image on a frame and a frame that is disposed along a movement range of the carriage and that supports the driven pulley. And
A pair of bearings rotatably receiving both ends of the rotation shaft of the driven pulley ; a pair of engaging parts formed in a direction parallel to the belt and slidable at both edges of the cut part of the frame; and the driven A holder having a receiving part that receives a biasing force of the biasing member at the same height as the belt is provided on a straight line connecting the rotation shafts of the pulley and the drive pulley .
[0006]
In the present invention configured as described above, the holder includes a biasing member that biases the driven pulley in a direction parallel to the belt, and the holder that rotatably receives both ends of the rotation shaft of the driven pulley is provided between the driven pulley and the drive pulley. It has a receiving part which receives the urging force of the urging member on the straight line connecting the rotation axes and at the same height as the belt. For this reason, the tension applied from the belt to the driven pulley is arranged on the same straight line as the reaction force (hereinafter referred to as reaction force) applied from the urging member and cancels out positively. Therefore, the moment for swinging the driven pulley does not act, and the swing of the driven pulley can be satisfactorily prevented with a simple configuration.
[0007]
Therefore, in the present invention, or size of the image forming apparatus, without or to increase its production cost, Ru can allow for precise position control of the recording head.
[0008]
[0009]
[0010]
[0011]
[0012]
[0013]
[0014]
The holder of the present invention includes a pair of engaging portions that are formed in a direction parallel to the belt and are slidable at both edges of the cut portion of the frame.
[0015]
Therefore, in this invention, rocking | fluctuation with respect to the said straight line can also be prevented even if an engaging part engages with a flame | frame . For this reason, for some reason, even mode Mento acts on the holder, it is possible to prevent the swinging of the holder by the engagement of the engaging portion. Therefore, in the present invention, in addition to the above effects, the driven pulley can be prevented from swinging better, and the position control of the recording head can be performed more precisely.
[0016]
According to a second aspect of the invention, in addition to the configuration of claim 1 Symbol placement, the engaging portion is formed in a lateral U-shape, the frame surface opposite to the at least the belt with respect to the cut section end edges It is characterized in that it is slidable in contact with.
Furthermore, in the invention described in claim 3, in addition to the configuration described in claim 1 or 2, the rotating shaft and the urging member are arranged in a line on a straight line parallel to the belt at the center in the width direction of the belt. It is characterized by being.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing an internal structure of an ink jet printer (hereinafter simply referred to as a printer) 1 to which the present invention is applied. As shown in FIG. 1, the printer 1 includes a frame 3 provided in a cover 2, a rubber platen 10, a carriage driving mechanism 20 that drives a carriage 21, and ink stored in an ink cartridge 44 on a recording paper P. And an ink jet recording unit 40 for discharging the ink.
[0018]
The platen 10 is disposed along the left-right direction (the direction in the printer 1 is defined by arrows in FIG. 1), and the platen shaft 11 is rotatably supported by the side wall plates 3a, 3c of the frame 3 at both left and right ends. Yes. A platen gear 12 that rotates integrally with the platen 10 and the platen shaft 11 is fixed to the left end of the platen shaft 11, and a driving force from a motor (not shown) is transmitted to the platen gear 12. For this reason, the platen 10 is rotationally driven in a predetermined paper feeding direction.
[0019]
Next, the configuration of the carriage drive mechanism 20 will be described with reference to FIG. A carriage 21 is horizontally arranged on the front side of the platen 10, and the carriage 21 is supported by a guide shaft 22 supported on the side wall plates 3 a and 3 b of the frame 3 so as to be movable in the left-right direction. Further, the front end portion of the carriage 21 is also supported by a guide rail portion 3 d formed on the frame 3.
[0020]
On the other hand, a driven pulley 23 is rotatably provided at the left end of the movement range of the carriage 21, and a drive pulley 24 that is rotationally driven by a DC motor 25 is provided at the right end thereof. An endless timing belt 26 is installed between the driven pulley 23 and the driving pulley 24, and the lower end portion of the carriage 21 is fixed to the timing belt 26. Therefore, according to the rotation of the DC motor 25, driving force is transmitted through the pulleys 23 and 24 and the timing belt 26, and the carriage 21 reciprocates in the left-right direction along the guide shaft 22 and the guide rail portion 3d. . An encoder member 30 is disposed below the carriage 21. The encoder member 30 is a well-known member for detecting the amount of movement of the carriage 21 made of a film in which light transmitting portions and light shielding portions are alternately arranged.
[0021]
Next, the recording unit 40 will be described. A box-shaped head holder 41 having an open top and front is mounted on the carriage 21, and a plurality of nozzles that eject ink are provided on the rear end surface of the head holder (that is, the end surface facing the platen 10). A provided recording head 42 is provided. In addition, the ink cartridge 44 described above is replaceably mounted in the opening portion in front of the head holder 41. Therefore, the recording head 42 can form an image on the recording paper P disposed on the platen 10 by ejecting the ink supplied from the ink cartridge 44 from the recording head 42. Further, by moving the carriage 21 via the DC motor 25, the image can be formed at a desired position on the recording paper P.
[0022]
Next, a support mechanism for the driven pulley 23 in the printer 1 will be described with reference to FIGS. As shown in the exploded perspective view of FIG. 2, the driven pulley 23 is rotatably supported by a holder 50, and the holder 50 is slidable on a support portion 60 as a support member formed on the bottom surface 3 e of the frame 3. It is supported by.
[0023]
The support portion 60 is formed by cutting and raising the inside of the cut portion 31 formed at the left end of the bottom surface 3 e, and has a substantially rectangular plate-shaped shaft portion 61 protruding in the direction of the driven pulley 23. A rectangular cut 61a is formed on the end surface of the shaft 61 on the driven pulley 23 side, and a coil spring 63 as a biasing member is fitted into the cut 61a. The coil spring 63 may be replaced with another elastic member such as a rubber piece.
[0024]
Further, the holder 50 has a pair of upper and lower bearing portions 51 that rotatably receive the upper and lower ends of the rotating shaft 23a of the driven pulley 23, and a bottomed hole portion 53 that fits the shaft portion 61 and the coil spring 63 (FIG. 3 : receiving). Equivalent ). Then, by fitting the hole portion 53 of the holder 50 into the shaft portion 61, the driven pulley 23, the coil spring 63, and the shaft portion 61 are connected to the timing belt 26 as shown in FIGS. In the center in the width direction (vertical direction in the figure), the belts are arranged in a line on a straight line parallel to the belt (that is, on a straight line connecting the driven pulley 23 and the drive pulley 24). Furthermore, a pair of engaging portions 55 that are formed in a laterally U-shaped shape on both the left and right side lower portions of the holder 50 on the driven pulley 23 side and slidably engage the both end edges 31a of the cut portion 31 from above and below are provided. Is formed. 3A is a plan view showing the configuration of the support mechanism for the driven pulley 23, and FIG. 3B is a sectional view taken along the line AA. In FIG. 3B, the side wall plate 3b is omitted.
[0025]
In the support mechanism of the driven pulley 23 configured as described above, the holder 50 can slide in the direction parallel to the timing belt 26 along the hole portion 53 along the shaft portion 61 and the engaging portion 55 along both end edges 31a. The tension is applied to the timing belt 26 by the biasing force of the coil spring 63. In the present support mechanism, the support portion 60 supports the holder 50 from the linear drive pulley 24 side. For this reason, the tension applied to the driven pulley 23 from the timing belt 26 is arranged on the same straight line as the reaction force applied from the support portion 60 via the coil spring 63 and cancels out positively. Accordingly, the driven pulley 23 is swung, that is, the moment caused from the frame 3 does not act, and the swiveling of the driven pulley 23 can be satisfactorily prevented with a simple configuration. Further, in the present support mechanism, the holder 50 is prevented from swinging by the fitting of the hole portion 53 and the shaft portion 61, and the engagement portion 55 is closer to the driven pulley 23 side than the support portion 60 and the cut portion 31. Since both end edges 31a are sandwiched from above and below, it is possible to better prevent the driven pulley 23 from swinging in the direction of lifting from the frame 3. Therefore, the position control of the recording head 42 can be executed very precisely. In the present support mechanism, the engaging portion 55 only needs to be in contact with both end edges 31a from at least the side opposite to the timing belt 26, that is, the lower surface.
[0026]
Furthermore, in this support mechanism, since the support portion 60 is formed by cutting and raising the bottom surface 3e of the frame 3, the positional relationship between the support portion 60 and the frame 3 can be stabilized and the configuration can be further simplified. it can. Therefore, the position control can be performed more precisely without increasing the size of the printer 1 or increasing the manufacturing cost.
[0027]
In addition, this invention is not limited to the said embodiment at all, It can implement with a various form in the range which does not deviate from the summary of this invention. Hereinafter, a reference example of the present invention in which an urging member such as the coil spring 63 is omitted will be described . FIG. 4 is an exploded perspective view showing a reference example of the support mechanism of the driven pulley 23.
[0028]
In this support mechanism, the notch 131 is formed at the left end of the bottom surface 103e of the frame 103, and the inside thereof is cut and raised to form the support 160. However, the support mechanism 160 extends from the support pulley 23 in the direction of the driven pulley 23. The shaft portion 161 formed so as to protrude from the inner surface is not provided with a cut, and has a slightly longer rectangular plate shape. The holder 150 that receives the rotating shaft 23 a of the driven pulley 23 with the bearing portion 151 is formed with a hole portion 153 that fits the shaft portion 161, and has long holes in the left and right airfoil portions that face both end edges 131 a of the cut portion 131. 155 and protrusions 157 were formed. Further, a screw hole 175 and a long hole 177 are formed in each end edge 131a at positions facing the long hole 155 and the protrusion 157, respectively.
[0029]
Each of the long holes 155 and 177 has a substantially concentric oval shape formed long in a direction parallel to the shaft portion 161. For this reason, when the shaft portion 161 is fitted into the hole portion 153 and the protrusion 157 is fitted into the elongated hole 177, the holder 150 is disposed to be slidable in parallel with the shaft portion 161 on the bottom surface 103e. Then, after the tip of the shaft portion 161 is brought into contact with the bottom of the hole portion 153, the holder 150 is fixed to the frame 103 by screwing a screw 179 as a fixing member into the screw hole 175 through the elongated hole 155. be able to.
[0030]
Even in this support mechanism, the tension applied to the driven pulley 23 from the timing belt 26 and the reaction force applied to the holder 150 from the shaft portion 161 cancel each other positively, and the swing of the driven pulley 23 can be satisfactorily prevented. Further, since the projection 157 can slide in the long hole 177, the holder 150 can be moved to a desired position by changing the position where the shaft portion 161 abuts against the bottom of the hole portion 153 by cutting the shaft portion 161 or the like. It can be fixed with. Therefore, by adjusting the fixing position of the holder 150, the timing belt 26 can be installed with a desired tension without bending.
[0031]
FIG. 5 is an exploded perspective view showing still another reference example of the support mechanism of the driven pulley 23. In this support mechanism, the notch 231 is formed at the left end of the bottom surface 203e of the frame 203, and the inside thereof is cut and raised to form the support portion 260. The upper portion of the support portion 260 is substantially the same as the center in the width direction of the timing belt 26. It was bent horizontally at a position where it was placed at a height. A screw hole 267 and an elongated hole 269 are formed in the horizontal portion 261. The holder 250 that receives the rotating shaft 23a of the driven pulley 23 by the bearing portion 251 is formed with a protruding portion 253 protruding in a flat plate shape along the horizontal portion 261. The protruding portion 253 has a screw hole 267 and an elongated hole 269. A long hole 257 and a protrusion 259 are formed at positions opposite to each other. Further, similarly to the support mechanism exemplified first, a lateral H-shaped engagement portion 255 that engages with both end edges 231a of the cut portion 231 is formed at the lower portion of the holder 250.
[0032]
In this support mechanism, the holder 250 is slid along a straight line connecting the pulleys 23 and 24 in a state where the engaging portion 255 is engaged with both end edges 231a and the projection 259 is fitted in the elongated hole 269. Can do. Then, after the holder 250 is disposed at a position where the timing belt 26 is installed with a desired tension, a screw 270 as a fixing member is screwed into the screw hole 267 through the long hole 257, and the holder 250 is moved to the position. Can be fixed to. Further, the fixing portion by the screw 270 is disposed on the straight line. For this reason, the tension applied to the driven pulley 23 from the timing belt 26 and the reaction force applied to the holder 250 from the fixed portion cancel each other positively, and the swing of the driven pulley 23 can be satisfactorily prevented.
[0033]
Furthermore, the present invention can be applied to various image forming apparatuses other than the ink jet printer. However, since the ink jet recording unit 40 is larger and heavier than other types of recording units, the effects of the present invention appear more remarkably in the above embodiments.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an internal structure of an ink jet printer to which the present invention is applied.
FIG. 2 is an exploded perspective view illustrating a configuration of a support mechanism of the driven pulley.
FIGS. 3A and 3B are a plan view and a cross-sectional view showing a configuration of a support mechanism of the driven pulley.
FIG. 4 is an exploded perspective view illustrating a reference example of a support mechanism of a driven pulley.
FIG. 5 is an exploded perspective view showing still another reference example of the support mechanism of the driven pulley.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Inkjet printer 3,103,203 ... Frame 10 ... Platen 20 ... Carriage drive mechanism 21 ... Carriage 22 ... Guide shaft 23 ... Driven pulley 24 ... Drive pulley 26 ... Timing belt 40 ... Recording unit 42 ... Recording head 50, 150, 250 ... Holder 51, 151, 251 ... Bearing part 53, 153 ... Hole 55, 255 ... Engagement part 60, 160, 260 ... Support part 61, 161 ... Shaft part 63 ... Coil springs 155, 177, 257, 269 ... Long Holes 157, 259 ... Projections 175, 267 ... Screw holes 179, 270 ... Screws

Claims (3)

A driving pulley driven to rotate by a motor;
A driven pulley supported rotatably;
A belt constructed between the drive pulley and the driven pulley;
A biasing member that biases the driven pulley in a direction parallel to the belt;
Is fixed through the carriage to the belt, a recording head for forming an image on a sheet while moving in the erection direction of the belt in response to rotation of said drive pulley,
A frame disposed along a movement range of the carriage;
A driven pulley support mechanism of the image forming apparatus, which is provided in an image forming apparatus comprising:
A pair of bearings rotatably receiving both ends of the rotation shaft of the driven pulley ; a pair of engaging parts formed in a direction parallel to the belt and slidable at both edges of the cut part of the frame; and the driven A follower of an image forming apparatus, comprising: a holder having a receiving portion that receives a biasing force of the biasing member at the same height as the belt and that is on a straight line connecting the rotation shafts of the pulley and the drive pulley. Pulley support mechanism. 2. The engagement portion is formed in a laterally U-shape and is slidable by contacting at least a frame surface opposite to the belt with respect to both edges of the cut portion. A driven pulley support mechanism of the image forming apparatus. 3. The driven pulley support for an image forming apparatus according to claim 1 , wherein the rotating shaft and the urging member are arranged in a line on a straight line parallel to the belt at the center in the width direction of the belt. mechanism.

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