JP2006001718A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus, restraining increase in number of parts and reducing the size of a member for pressing paper to a paper feed roller. <P>SOLUTION: A push-up member 9 includes: an insert hole 9b rotated around one bearing 8a of a platen roller bearing 8; an insert part 9a supported on a raised part 1f formed by cutting and raising the base 1c of a chassis 1; and a fulcrum 9f of rotation. The push-up member 9 takes the insert hole 9b of the push-up member 9 and the fulcrum 9f of rotation as the center of rotation at least in pressing the paper to the paper feed roller 2. Further, a line connecting between the insert hole 9b of the push-up member 9 and the insert part 9a is inclined at a predetermined angle to the normal of one side 1a of the chassis 1. Further, the raised part 1f of the base 1c of the chassis 1 is provided with an oblong hole 1g formed so that the insert part 9a of the push-up member 9 is inserted to be moved in the vertical direction. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus provided with a push-up member for pressing a sheet against a paper feed roller.

  2. Description of the Related Art Conventionally, an image forming apparatus including a push-up member for pressing a sheet against a sheet feeding roller is known (see, for example, Patent Document 1, Patent Document 2, and Patent Document 3).

  In Patent Document 1, the rotation support shaft portion of the push-up member is attached to both end portions of the feed roller supported by one side surface and the other side surface of the chassis, and the rotation support shaft portion of the push-up member is pushed up with the rotation support shaft as the rotation center. A sheet feeding device configured to press a sheet against a sheet feeding roller by rotating a member is disclosed.

  In Patent Document 2, a guide shaft (shaft member), two lift plates (push-up members) that are attached to the guide shaft and lift both ends of the paper, and a guide are provided to press the paper against the paper feed roller. A paper feed mechanism provided with a center guide (push-up member) that is attached to a shaft and lifts the center of the paper is disclosed.

  Further, in Patent Document 3, a rubber roller shaft (shaft member) and two push-up levers (which are attached to the rubber roller shaft and push the press plate disposed below the paper) are pressed to press the paper against the paper feed roller. A hopper for an automatic paper feeder of a printer provided with a push-up member is disclosed.

  Conventionally, a thermal transfer printer is known as an example of an image forming apparatus. FIG. 10 is a perspective view showing the overall structure of a conventional thermal transfer printer. FIG. 11 is a plan view of the conventional thermal transfer printer shown in FIG. FIG. 12 is a perspective view showing a detailed structure of the push-up member according to the conventional example shown in FIG. First, the structure of a conventional thermal transfer printer will be described with reference to FIGS.

  As shown in FIG. 10, a conventional thermal transfer printer includes a sheet metal chassis 101, a rubber paper feed roller 102 for feeding paper, a paper feed roller shaft 103 to which the paper feed roller 102 is attached, A paper feed roller gear 104 for rotating the paper feed roller shaft 103, a paper feed roller bearing 105 for rotatably supporting the paper feed roller shaft 103, a resin paper cassette 106 for storing paper, and at the time of printing A platen roller 107 that presses the paper, a platen roller bearing 108, a metal push-up member 109 that presses the paper against the paper feed roller 102, and a compression coil spring 110 that biases the push-up member 109 in a predetermined direction ( 11), a drive gear 111 against which the push-up member 109 abuts, and a drive for driving the drive gear 111 as shown in FIG. A motor 112 functioning as a power source, an intermediate gear 113 for transmitting a driving force from the motor 112 to the driving gear 111, a motor 114 functioning as a driving source for driving the paper feed roller 102, A plurality of intermediate gears 115 for transmitting a driving force to the sheet feeding roller gear 104 and a metal motor bracket 116 to which the motor 112 and the motor 114 are attached are provided.

Further, as shown in FIG. 10, the chassis 101 has one side surface 101a to which the motor bracket 116 is attached, the other side surface 101b, and a bottom surface 101c that connects the one side surface 101a and the other side surface 101b. In addition, an ink sheet insertion portion 101d for attaching an ink sheet (not shown) is provided on the other side surface 101b. A platen roller bearing 108 that rotatably supports both end portions of the platen roller 107 is attached to the one side surface 101a and the other side surface 101b. Further, as shown in FIG. 12, the push-up member 109 has two insertion holes 109a, a contact portion 109b, and a pressing portion 109c. As shown in FIG. 10, the two insertion holes 109a are rotatably supported by platen roller bearings 108 attached to one side surface 101a and the other side surface 101b of the chassis 101, respectively. Further, the abutting portion 109b is formed so as to abut on the drive gear 111 by the urging force of the compression coil spring 110 (see FIG. 11). As shown in FIG. 11, the compression coil spring 110 is disposed below the vicinity of the pressing portion 109c. Further, the pressing portion 109c is disposed below the pressing plate 106a of the paper cassette 106, as shown in FIG. Further, the pressing portion 109 c rotates the pressing plate 106 a of the paper cassette 106 upward as the push-up member 109 rotates in the arrow H direction by the urging force of the compression coil spring 110.

  The drive gear 111 is attached to one side surface 101 a of the chassis 101. On one side surface 101a side of the drive gear 111, a cam mechanism portion 111a with which the contact portion 109b of the push-up member 109 contacts is provided. The cam mechanism 111a has a circumferential portion 111b and a recess 111c. The drive gear 111 is engaged with the small diameter gear portion 113 a of the intermediate gear 113. As shown in FIG. 11, the intermediate gear 113 is attached to one side surface 101 a of the chassis 101. Further, the intermediate gear 113 has a small diameter gear portion 113 a that engages with the drive gear 111 and a large diameter gear portion 113 b that engages with the motor 112.

  A pressing plate 106 a is provided at a predetermined position of the paper cassette 106. The pressing plate 106a is formed to be rotatable around a fulcrum portion 106b. Further, the pressing plate 106 a is formed so as to contact the paper feed roller 102 by being pushed up by the pressing portion 109 c of the push-up member 109. The paper feed roller 102 is disposed above the pressing plate 106 a of the paper cassette 106. Further, the paper feed roller 102 is configured to convey the paper in the paper feed direction (arrow I direction) by rotating. The paper feed roller 102 is attached near the center of the paper feed roller shaft 103. The vicinity of both ends of the paper feed roller shaft 103 is rotatably supported by a paper feed roller bearing 105 attached to one side surface 101a and the other side surface 101b of the chassis 101. A paper feed roller gear 104 is attached to the end of the paper feed roller shaft 103 on the side surface 101a side so as not to idle. As shown in FIG. 11, an intermediate gear 115 is engaged with the paper feed roller gear 104. The plurality of intermediate gears 115 are arranged to engage with the motor 114.

Next, with reference to FIG. 10 and FIG. 11, the paper feeding operation of the conventional thermal transfer printer will be described. First, as shown in FIG. 10, when the intermediate gear 113 rotates in the arrow J direction by the driving force from the motor 112 (see FIG. 11), the driving gear 111 rotates in the arrow K direction. As a result, the contact portion 109b of the push-up member 109 changes from the state of contact with the circumferential portion 111b of the drive gear 111 to the state of contact with the recess 111c of the drive gear 111. As a result, the push-up member 109 rotates in the arrow H direction, so that the pressing portion 109 c of the push-up member 109 can press the press plate 106 a of the paper cassette 106 against the paper feed roller 102. Next, the driving force of the motor 114 (see FIG. 11) is transmitted to the paper feed roller gear 104 via a plurality of intermediate gears 115 (see FIG. 11). As a result, the paper feed roller shaft 103 and the paper feed roller 102 rotate, so that the paper is conveyed in the direction of arrow I.
JP 2003-20130 A JP-A-10-250854 Japanese Utility Model Publication No. 62-20029

  In the conventional thermal transfer printer shown in FIGS. 10 to 12, a platen roller in which insertion holes 109 a of a push-up member 109 are attached to one side surface 101 a and the other side surface 101 b of the chassis 101 in order to press the paper against the paper feed roller 102. Since it is attached to the bearing 108, the push-up member 109 needs to have the same size as the distance from the one side surface 101 a to the other side surface 101 b of the chassis 101. For this reason, there has been a problem that the push-up member 109 becomes large.

  Further, in the structure disclosed in Patent Document 1, in order to press the paper against the paper feed roller, the rotation support shaft portion of the push-up member is supported at both end portions of the feed roller supported on one side surface and the other side surface of the chassis. Therefore, the push-up member needs to be as large as the distance from one side surface of the chassis to the other side surface. For this reason, there exists a problem that a pushing-up member becomes large.

  In the structure disclosed in Patent Document 2, a shaft member, two push-up members that lift both ends of the paper, and a push-up member that lifts the center of the paper are provided to press the paper against the paper feed roller. Therefore, there is a problem that the number of parts of the member for pressing the paper against the paper feed roller increases.

  Further, in the structure disclosed in Patent Document 3, a shaft member and two push-up members that push up a pressing plate disposed below the paper are provided in order to press the paper against the paper feed roller. There is a problem in that the number of components for pressing the paper against the paper feed roller increases.

  The present invention has been made to solve the above-described problems, and one object of the present invention is to suppress an increase in the number of parts and to press a sheet against a sheet feeding roller. An object of the present invention is to provide an image forming apparatus capable of reducing the size of a member.

Means for Solving the Problems and Effects of the Invention

  An image forming apparatus according to a first aspect of the present invention includes a sheet metal chassis having one side surface, the other side surface, and a bottom surface connecting the one side surface and the other side surface, a platen roller on which a sheet is pressed during printing, A platen roller bearing mounted on one side surface of the chassis and rotatably supporting the platen roller, a paper feed roller for feeding paper, and a push-up member for pressing the paper against the paper feed roller In the image forming apparatus, the push-up member is provided on the first rotation support shaft portion that rotates about the first support portion including the platen roller bearing, and the second support portion formed by cutting and raising the bottom surface of the chassis. The push-up member includes a second turning support shaft portion and a third turning support shaft portion to be supported, and the push-up member is a first rotation support shaft portion of the push-up member at least when the paper is pressed against the paper feed roller. And a line connecting the first rotation support shaft portion and the second rotation support shaft portion of the push-up member with respect to the normal direction of the one side surface of the chassis. The second support portion on the bottom surface of the chassis is formed with a long hole into which the second rotation support shaft portion of the push-up member is inserted so as to be movable in the vertical direction.

In the image forming apparatus according to the first aspect, as described above, the push-up member is provided with the first rotation support shaft portion that rotates around the first support portion provided on one side surface of the chassis, and the bottom surface of the chassis. By providing the second rotation support shaft portion supported by the second support portion provided on the chassis, the distance from the first rotation support shaft portion of the push-up member to the second rotation support shaft portion is set to The distance from the one side surface to the other side surface can be made smaller. Thereby, a pushing-up member can be made small. Further, by using only one push-up member for pressing the paper against the paper feed roller, it is possible to suppress an increase in the number of parts of the member for pressing the paper against the paper feed roller. Further, by causing the platen roller bearing to function as the first support portion of the push-up member, the number of parts can be reduced as compared with a case where a member for attaching the first rotation support shaft portion of the push-up member is separately provided. it can. Further, the second support portion on the bottom surface of the sheet metal chassis is formed by cutting and raising the bottom surface of the chassis, so that a member for supporting the second rotation support shaft portion of the push-up member is separately provided. Thus, the number of parts can be further reduced. In addition, the push-up member is configured so that the first rotation support shaft portion and the third rotation support shaft portion of the push-up member are at the center of rotation at least when the paper is pressed against the paper feed roller. Since it is possible to suppress the reaction force generated when the paper feeding roller is pressed from being applied to the second rotating support shaft portion of the lifting member, the second rotating support shaft portion of the lifting member presses the paper against the paper feeding roller. It is possible to suppress deformation due to a reaction force that is sometimes generated. Further, by forming a long hole in the second support portion on the bottom surface of the chassis into which the second rotation support shaft portion of the push-up member is movably inserted in the vertical direction, the push-up member becomes the first rotation support shaft portion. When the second pivot shaft is pivoted about the third pivot shaft, the second pivot shaft of the push-up member moves upward along the elongated hole. Therefore, the second pivot shaft of the push-up member Can be prevented from coming into contact with the inner surface of the hole of the second support portion on the bottom surface of the chassis. Thereby, the push-up member can be easily rotated around the third rotation support shaft portion. Further, the second support portion on the bottom surface of the chassis is inclined by inclining a line connecting the first rotation support shaft portion and the second rotation support shaft portion of the push-up member with respect to the normal direction of one side surface of the chassis. Can be disposed at a position that does not interfere with the platen roller disposed in the normal direction of the first support portion on one side surface of the chassis.

  An image forming apparatus according to a second aspect of the present invention includes a chassis having a one side surface, the other side surface, and a bottom surface connecting the one side surface and the other side surface, a sheet feeding roller for feeding a sheet, and a sheet. A push-up member for pressing against the paper feed roller, the push-up member turning around a first support portion provided on one side surface of the chassis, and a bottom surface of the chassis And a second rotation support shaft portion supported by a second support portion provided at the top.

  In the image forming apparatus according to the second aspect, as described above, the push-up member is provided with the first rotation support shaft portion that rotates about the first support portion provided on one side surface of the chassis, and the bottom surface of the chassis. By providing the second rotation support shaft portion supported by the second support portion provided on the chassis, the distance from the first rotation support shaft portion of the push-up member to the second rotation support shaft portion is set to The distance from the one side surface to the other side surface can be made smaller. Thereby, a pushing-up member can be made small. Further, by using only one push-up member for pressing the paper against the paper feed roller, it is possible to suppress an increase in the number of parts of the member for pressing the paper against the paper feed roller.

  In the image forming apparatus according to the second aspect, it is preferable that the platen roller to which the sheet is pressed at the time of printing and the platen roller that is attached to one side surface of the chassis to rotatably support the first support portion of the push-up member. The chassis is made of sheet metal, and the second support portion on the bottom surface of the chassis is formed by cutting and raising the bottom surface of the chassis. If comprised in this way, a number of parts can be reduced compared with the case where the member for attaching the 1st rotation spindle part of a raising member is provided separately. Further, the second support portion on the bottom surface of the sheet metal chassis is formed by cutting and raising the bottom surface of the chassis, so that a member for supporting the second rotation support shaft portion of the push-up member is separately provided. Thus, the number of parts can be further reduced.

In the image forming apparatus according to the second aspect, it is preferable that the push-up member further includes a third rotation support shaft portion, and the push-up member performs the first rotation of the push-up member at least when the paper is pressed against the paper feed roller. The moving support shaft and the third rotation support shaft are used as the rotation center. With this configuration, it is possible to suppress at least a reaction force generated when the sheet is pressed against the paper feed roller from being applied to the second rotation support shaft portion of the push-up member. It is possible to suppress the shaft portion from being deformed due to a reaction force generated when the sheet is pressed against the sheet feeding roller.

  In the image forming apparatus according to the second aspect, it is preferable that the push-up member is pivoted about the first pivot support shaft portion and the third pivot support shaft portion of the push-up member at least when the sheet is pressed against the paper feed roller. In addition, the second support portion on the bottom surface of the chassis is formed with a long hole into which the second rotation support shaft portion of the push-up member is inserted so as to be movable in the vertical direction. If comprised in this way, when a push-up member rotates centering on a 1st rotation support shaft part and a 3rd rotation support shaft part, the 2nd rotation support shaft part of a push-up member follows an elongate hole. Since it moves upward, it can suppress that the 2nd rotation spindle part of a raising member contacts the inner surface of the hole of the 2nd support part of the bottom face of a chassis. Thereby, the push-up member can be easily rotated around the third rotation support shaft portion.

  In the image forming apparatus according to the second aspect, preferably, a line connecting the first rotation support shaft portion and the second rotation support shaft portion of the push-up member is predetermined with respect to the normal direction of one side surface of the chassis. The angle is inclined. With this configuration, even when another member is disposed in the normal direction of the first support portion on the one side surface of the chassis, the second support portion on the bottom surface of the chassis is replaced with the first support portion on the one side surface of the chassis. It can arrange | position in the position which does not interfere with the other member arrange | positioned in the normal line direction of a support part.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view showing the overall structure of a thermal transfer printer according to an embodiment of the present invention. FIG. 2 is a plan view of the thermal transfer printer according to the embodiment shown in FIG. 3 and 4 are views showing a detailed structure of the push-up member according to the embodiment shown in FIG. 5 to 8 are sectional views for explaining the detailed structure of the thermal transfer printer according to the embodiment shown in FIG. First, the structure of a thermal transfer printer according to an embodiment of the present invention will be described with reference to FIGS. In the present embodiment, a thermal transfer printer as an example of the image forming apparatus of the present invention will be described.

  As shown in FIGS. 1 and 2, the thermal transfer printer according to the embodiment of the present invention includes a sheet metal chassis 1, a rubber paper feed roller 2 for feeding paper, and a paper feed roller 2. A paper feed roller shaft 3, a paper feed roller gear 4 for rotating the paper feed roller shaft 3, a paper feed roller bearing 5 for rotatably supporting the paper feed roller shaft 3, and a resin-made product for storing paper. Paper cassette 6, platen roller 7 for pressing the paper during printing, platen roller bearing 8, metal push-up member 9 for pressing the paper against paper feed roller 2, and push-up member 9 in a predetermined direction A tension coil spring 10 that urges the actuator, a drive gear 11 against which the push-up member 9 abuts, a motor 12 (see FIG. 2) that functions as a drive source for driving the drive gear 11, and a drive force from the motor 12 An intermediate gear 13 for transmitting to the motor 11, a motor 14 (see FIG. 2) functioning as a drive source for driving the paper feed roller 2, and a drive force from the motor 14 for transmitting to the paper feed roller gear 4. A plurality of intermediate gears 15 (see FIG. 2) and a metal motor bracket 16 to which the motor 12 and the motor 14 are attached.

  Further, as shown in FIG. 1, the chassis 1 has one side surface 1a to which the motor bracket 16 is attached, the other side surface 1b, and a bottom surface 1c connecting the one side surface 1a and the other side surface 1b. The one side surface 1a is provided with a spring attachment hole 1d to which one end of the tension coil spring 10 is attached. In addition, an ink sheet insertion portion 1e for attaching an ink sheet (not shown) is provided on the other side surface 1b.

  Here, in the present embodiment, the bottom surface 1c of the chassis 1 is provided with a cut and raised portion 1f into which the insertion portion 9a of the push-up member 9 is inserted. The insertion portion 9a is an example of the “second rotating support shaft portion” in the present invention, and the cut-and-raised portion 1f is an example of the “second support portion” in the present invention. The cut-and-raised portion 1f is disposed in the vicinity of the center between the one side surface 1a and the other side surface 1b. Further, as shown in FIG. 2, the cut-and-raised portion 1 f is disposed on the paper feed roller 2 side at a predetermined interval from the platen roller 7. Thereby, the cut-and-raised portion 1 f can be easily formed in a predetermined size without being brought into contact with the platen roller 7. A platen roller bearing 8 including a first bearing 8a and a second bearing 8b that rotatably support both end portions of the platen roller 7 is attached to the first side surface 1a and the second side surface 1b. The one bearing 8a is an example of the “first support portion” in the present invention.

  In the present embodiment, as shown in FIG. 3, the push-up member 9 is provided with an insertion hole 9b, a spring mounting portion 9c, a contact portion 9d, a pressing portion 9e, and a rotation fulcrum 9f. Yes. The insertion hole 9b is an example of the “first rotation support shaft portion” in the present invention, and the rotation support point 9f is an example of the “third rotation support shaft portion” in the present invention. As shown in FIG. 1, the insertion hole 9 b is rotatably supported by one bearing 8 a of the platen roller bearing 8. Thereby, as shown in FIG. 4, the rotation center line (line B) connecting the center of the insertion hole 9b of the push-up member 9 and the center of the insertion portion 9a is the axial direction of the platen roller 7 (see FIG. 2) and It has an inclination angle (θ) with respect to the normal direction of the one side surface 1 a of the chassis 1. As shown in FIG. 5, the other end of the tension coil spring 10 that urges the spring mounting portion 9c in the direction of arrow C is attached to the spring mounting portion 9c. As a result, a force that rotates in the direction of arrow D is generated in the push-up member 9. Further, the abutting portion 9 d is formed so as to abut on the drive gear 11 by the urging force of the tension coil spring 10. The pressing portion 9e is disposed below the pressing plate 6a of the paper cassette 6. Further, the pressing portion 9 e pushes the pressing plate 6 a of the paper cassette 6 upward as the push-up member 9 rotates in the direction of arrow D by the urging force of the tension coil spring 10. Thereby, the pressing plate 6a of the paper cassette 6 rotates in the direction of arrow E. Moreover, the rotation fulcrum 9f is provided in the outer peripheral part of the pushing-up member as shown in FIG. Further, the rotation fulcrum 9f contacts the bottom surface 1c of the chassis 1 when the push-up member 9 rotates by a predetermined angle in the direction of arrow D in FIG. As a result, the push-up member 9 rotates around the center of the insertion hole 9b (see FIG. 3) and the rotation fulcrum 9f. In this case, as shown in FIG. 8, the cut-and-raised portion 1f of the bottom surface 1c of the chassis 1 is provided with a long hole 1g extending obliquely upward so that the insertion portion 9a of the push-up member 9 can move in the vertical direction. It is possible to suppress the insertion portion 9a of the push-up member 9 from coming into contact with the inner surface of the elongated hole 1g of the cut-and-raised portion 1f. Thereby, the push-up member 9 can rotate around the center of the insertion hole 9b (see FIG. 3) and the rotation fulcrum 9f.

  Further, the drive gear 11 is attached to one side surface 1a of the chassis 1 as shown in FIG. A cam mechanism portion 11 a with which the contact portion 9 d of the push-up member 9 contacts is provided on the one side surface 1 a side of the drive gear 11. The cam mechanism portion 11a is formed with a circumferential shape portion 11b and a recess portion 11c. The drive gear 11 is engaged with the small diameter gear portion 13 a of the intermediate gear 13. The intermediate gear 13 is attached to one side surface 1a of the chassis 1 as shown in FIG. The intermediate gear 13 has a small diameter gear portion 13 a that engages with the drive gear 11 and a large diameter gear portion 13 b that engages with the motor 12.

Further, as shown in FIG. 1, a pressing plate 6 a is provided at a predetermined position of the paper cassette 6. As shown in FIG. 7, the pressing plate 6a is formed to be rotatable in the direction of arrow E around the fulcrum portion 6b. Further, the pressing plate 6 a is formed so as to come into contact with the paper feeding roller 2 by being pushed up by the pressing portion 9 e of the lifting member 9. The paper feed roller 2 is disposed above the pressing plate 6 a of the paper cassette 6. The paper feed roller 2 is configured to convey the paper in the paper feed direction (the direction of arrow A in FIG. 1) by rotating. Further, as shown in FIG. 1, the paper feed roller 2 is attached near the center of the paper feed roller shaft 3. The vicinity of both ends of the paper feed roller shaft 3 is rotatably supported by a paper feed roller bearing 5 attached to one side surface 1a and the other side surface 1b of the chassis 1. A paper feed roller gear 4 is attached to the end of the paper feed roller shaft 3 on the one side surface 1a side of the chassis 1 so as not to idle. As shown in FIG. 2, an intermediate gear 15 is engaged with the paper feed roller gear 4. The plurality of intermediate gears 15 are arranged to engage with the motor 14.

  Next, the paper feeding operation of the thermal transfer printer according to the present embodiment will be described with reference to FIGS. First, as shown in FIG. 5, when the intermediate gear 13 rotates in the direction of arrow F by the driving force from the motor 12 (see FIG. 2), the drive gear 11 rotates in the direction of arrow G. Accordingly, the contact portion 9d of the push-up member 9 is driven from the state of contact with the circumferential portion 11b of the drive gear 11 as shown in FIGS. 5 and 6, as shown in FIGS. It will be in the state contact | abutted to the recessed part 11c of the gear 11. FIG. At this time, the push-up member 9 starts to rotate in the direction of arrow D in FIG. 5 with the center of the insertion hole 9b (see FIG. 3) and the insertion portion 9a as the center of rotation, and rotates by a predetermined angle. 9 f contacts the bottom surface 1 c of the chassis 1. Accordingly, as shown in FIG. 7, the push-up member 9 rotates in the direction of arrow D with the center of the insertion hole 9b (see FIG. 3) and the rotation fulcrum 9f as the rotation center. The pressing plate 6a of the paper cassette 6 is pressed against the paper feed roller 2 by the portion 9e. Next, the driving force of the motor 14 (see FIG. 2) is transmitted to the paper feed roller gear 4 via a plurality of intermediate gears 15 as shown in FIG. As a result, the paper feed roller shaft 3 and the paper feed roller 2 rotate, so that the paper is conveyed in the direction of arrow A in FIG.

  In the present embodiment, as described above, the push-up member 9 has the insertion hole 9b that rotates about the one bearing 8a of the platen roller bearing 8 attached to the one side surface 1a of the chassis 1, the one side surface 1a of the chassis 1, The distance from the insertion hole 9b of the push-up member 9 to the insertion portion 9a is determined by providing the insertion portion 9a that rotates about the cut-and-raised portion 1f provided on the bottom surface 1c near the center of the other side surface 1b. The distance from one side surface 1a of the chassis 1 to the other side surface 1b can be reduced to about half. As a result, the size of the push-up member 9 can be reduced to about half. Further, by using only one push-up member 9 for pressing the paper against the paper feed roller 2, it is possible to suppress an increase in the number of parts of the member for pressing the paper against the paper feed roller 2. .

  Further, in the present embodiment, by making the one bearing 8a of the platen roller bearing 8 function as the rotation center of the push-up member 9, a member for attaching the insertion hole 9b of the push-up member 9 is provided separately. The number of parts can be reduced. Further, when the cut-and-raised portion 1f of the bottom surface 1c of the chassis 1 made of sheet metal is formed by cutting and raising the bottom surface 1c of the chassis 1, a member for supporting the insertion portion 9a of the push-up member 9 is separately provided. In comparison, the number of parts can be further reduced.

  Further, in the present embodiment, the push-up member 9 is configured so that the center of the insertion hole 9b and the turning fulcrum 9f of the push-up member 9 are set as the rotation center at least when the paper is pressed against the paper feed roller 2. Since at least the reaction force generated when the paper is pressed against the paper feed roller 2 can be suppressed from being applied to the insertion portion 9a of the push-up member 9, the insertion portion 9a of the push-up member 9 is pressed against the paper feed roller 2. It is possible to suppress deformation due to a reaction force that is sometimes generated.

Further, in this embodiment, the elongated member 1g is formed in the cut-and-raised portion 1f of the bottom surface 1c of the chassis 1 so that the insertion portion 9a of the push-up member 9 is movably moved in the vertical direction. When rotating about the moving fulcrum 9f, the insertion portion 9a of the push-up member 9 moves upward along the elongated hole 1g, so that the insertion portion 9a of the push-up member 9 is cut and raised on the bottom surface 1c of the chassis 1 It can suppress contacting with the inner surface of the 1f hole. Thereby, the push-up member 9 can be easily rotated around the rotation fulcrum 9f.

  Further, in the present embodiment, the chassis is formed by inclining a rotation center line connecting the center of the insertion hole 9b of the push-up member 9 and the center of the insertion portion 9a with respect to the normal direction of the one side surface 1a of the chassis 1. The cut-and-raised portion 1 f of the bottom surface 1 c of 1 can be disposed at a position where it does not interfere with the platen roller 7 disposed in the normal direction of the one bearing 8 a on the one side surface 1 a of the chassis 1.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  For example, in the above embodiment, the thermal transfer printer is shown as an example of the image forming apparatus. However, the present invention is not limited to this, and the image forming apparatus includes a push-up member for pressing the paper against the paper feed roller. The present invention can also be applied to other image forming apparatuses such as inkjet printers and laser printers other than thermal transfer printers.

  Moreover, although the example which attached the 1st rotation support shaft part (insertion hole) of the raising member to the platen roller bearing was shown in the said embodiment, this invention is not limited to this, The 1st rotation support shaft of a raising member is shown. The shaft portion may be attached to another member. Note that the first rotation support shaft portion may have a shape other than the hole shape.

  Moreover, in the said embodiment, the line which connects the 1st rotation support shaft part (insertion hole) and the 2nd rotation support shaft part (insertion part) of a raising member inclines with respect to the normal line direction of the one side surface of a chassis. However, the present invention is not limited to this, and a line connecting the first rotation support shaft portion and the second rotation support shaft portion of the push-up member is defined with respect to the normal direction of one side surface of the chassis. You may comprise so that it may become parallel.

  Moreover, in the said embodiment, although the example which provided the rotation fulcrum (3rd rotation support shaft part) of the raising member in the outer peripheral part of the raising member was shown, this invention is not restricted to this, It showed in FIG. Like the push-up member 19 according to the modification of the present embodiment, the rotation fulcrum 19f may be formed in a convex shape that protrudes downward, and provided outside the outer peripheral portion of the push-up member 19. In this case, the rotation fulcrum 19f may be formed in contact with the bottom surface of the chassis in a state where the contact portion 19d is in contact with the circumferential portion of the drive gear by the urging force of the tension coil spring. The insertion portion 19a is formed so as to be inserted into the cut-and-raised portion of the bottom surface of the chassis, and the other end of the tension coil spring 10 is attached to the spring attachment portion 19c. The structure of the modified example other than the above is the same as that of the above-described embodiment.

1 is a perspective view showing the overall structure of a thermal transfer printer according to an embodiment of the present invention. It is a top view of the thermal transfer printer by one Embodiment shown in FIG. It is a perspective view for demonstrating the detailed structure of the raising member by one Embodiment shown in FIG. It is a top view for demonstrating the detailed structure of the raising member by one Embodiment shown in FIG. It is sectional drawing which showed the state which the contact part of the raising member by one Embodiment of this invention contact | abutted to the circumferential shape part of the drive gear. It is sectional drawing which showed the state which the contact part of the raising member by one Embodiment of this invention contact | abutted to the circumferential shape part of the drive gear. It is sectional drawing which showed the state which the contact part of the raising member by one Embodiment of this invention contact | abutted to the recessed part of the drive gear. It is sectional drawing which showed the state which the contact part of the raising member by one Embodiment of this invention contact | abutted to the recessed part of the drive gear. It is sectional drawing which showed the state which the contact part of the raising member by the modification of one Embodiment of this invention contact | abutted to the circumferential shape part of the drive gear. It is the perspective view which showed the whole structure of the thermal transfer printer by an example of the past. It is a top view of the thermal transfer printer by an example of the prior art shown in FIG. It is a perspective view for demonstrating the detailed structure of the raising member by an example of the prior art shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Chassis 1a One side 1b The other side 1c Bottom 1f Cut and raised part (2nd support part)
1 g Long hole 2 Paper feed roller 7 Platen roller 8 Platen roller bearing 8a One bearing (first support part)
9 Push-up member 9a Insertion part (second rotational support shaft part)
9b Insertion hole (first pivot support shaft)
9f Rotation fulcrum (third rotation fulcrum)

Claims (6)

A sheet metal chassis having one side surface, the other side surface, and a bottom surface connecting the one side surface and the other side surface, a platen roller to which paper is pressed during printing, and attached to the one side surface of the chassis, An image forming apparatus comprising: a platen roller bearing that rotatably supports a platen roller; a paper feed roller that feeds the paper; and a push-up member that presses the paper against the paper feed roller. ,
The push-up member is supported by a first rotation support shaft portion that rotates around a first support portion including the platen roller bearing, and a second support portion that is formed by raising the bottom surface of the chassis. A second rotation support shaft portion and a third rotation support shaft portion,
The push-up member has at least the first turning support shaft portion and the third turning support shaft portion of the push-up member as a rotation center at least when the paper is pressed against the paper feed roller,
A line connecting the first rotation support shaft portion and the second rotation support shaft portion of the push-up member is inclined at a predetermined angle with respect to the normal direction of the one side surface of the chassis,
The image forming apparatus, wherein the second support portion on the bottom surface of the chassis is formed with a long hole into which the second rotation support shaft portion of the push-up member is movably inserted in the vertical direction. A chassis having a side surface, the other side surface, and a bottom surface connecting the one side surface and the other side surface;
A paper feed roller for feeding paper,
One push-up member for pressing the paper against the paper feed roller,
The push-up member is supported by a first rotation support shaft portion that rotates around a first support portion provided on the one side surface of the chassis and a second support portion provided on the bottom surface of the chassis. An image forming apparatus having a second rotation support shaft portion. A platen roller against which the paper is pressed during printing;
A platen roller bearing attached to the one side surface of the chassis and rotatably supporting the platen roller, and functioning as the first support portion of the push-up member;
The chassis is made of sheet metal;
The image forming apparatus according to claim 2, wherein the second support portion on the bottom surface of the chassis is formed by cutting and raising the bottom surface of the chassis. The push-up member further has a third rotation support shaft portion,
4. The push-up member has the first pivot support shaft portion and the third pivot support shaft portion of the push-up member as rotation centers at least when the sheet is pressed against the paper feed roller. 5. The image forming apparatus described in 1.   5. The slot according to claim 4, wherein the second support portion on the bottom surface of the chassis is formed with a long hole into which the second rotation support shaft portion of the push-up member is movably inserted in the vertical direction. Image forming apparatus. The line connecting the first rotation support shaft portion and the second rotation support shaft portion of the push-up member is inclined at a predetermined angle with respect to the normal direction of the one side surface of the chassis. The image forming apparatus according to any one of 2 to 5.

Images