JP3032426B2 - Paper cassette - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feed cassette provided with a pinch roller and a mechanism for pressing the pinch roller against a paper transport roller of a printing apparatus.

[0002]

2. Description of the Related Art A conventional example of this type of sheet cassette will be described with reference to FIGS. FIG. 6 is a longitudinal sectional side view showing the internal structure of the paper feed cassette by omitting the rear portion thereof and showing only the front end side. In the drawing, reference numeral 1 denotes a cassette case having an upper opening, and a large number of sheets (FIG. A paper storage unit 2 for storing paper (not shown) is formed. In this paper storage unit 2, a pressing plate 4 for pressing a paper against a paper feed roller 3 on a printing device (not shown) side is held so as to be able to move up and down. I have. Separating claws 5 are provided on both sides of the leading end of the sheet storage unit 2 to separate the overlapping sheets one by one when the sheet on the pressing plate 4 is pulled out by the sheet feeding roller 3. Further, a guide surface 7 for guiding the sheet pulled out from the cassette case 1 by the sheet feed roller 3 toward the sheet conveying roller 6 on the printing apparatus side is formed on the leading end side of the cassette case 1. On the back side, a paper feed passage 10 having a lower opening in which a vertical guide surface 8 and a plurality of ribs 9 face each other is formed.

A roller housing recess 1 for accommodating a pinch roller 100 which is in contact with the paper transport roller 6 is provided in a portion of the cassette case 1 ahead of the paper feed passage 10.
01 is formed. A coil spring 103 is inserted through a hollow hole 102 formed at the center of the pinch roller 100.

FIGS. 7 and 8 show the front end of the cassette case 1. As is apparent from these figures, the pinch roller 100 is provided on both sides of the roller housing recess 101. FIG.
The insertion path 104 having a lower opening for bending and inserting the coil spring 103 protruding from both sides of the coil spring 103 backward, a spring retainer 105 for pressing an intermediate portion of the coil spring 103 from above, and a tip of the coil spring 103 are locked. A spring hook 106 is formed.

[0005] Pinch roller 100 to cassette case 1
Is assembled as follows. First, the coil spring 103 is inserted into the hollow hole 102 of the pinch roller 100, a hand is inserted from the back side of the cassette case 1, the coil spring 103 is inserted into the insertion path 104, and locked on the spring hook 106. In this case, before the cassette case 1 is mounted on the printing apparatus, the pinch roller 100 is partially moved from the roller storage recess 101 to the paper storage unit 2 by the urging force of the coil spring 103 as shown by the imaginary line in FIG. When the cassette case 1 is mounted on the printing apparatus, as shown by a solid line in FIG.
Since 00 is pressed by the sheet conveying roller 6, the intermediate portion of the coil spring 103 is bent and retreats inward of the roller housing concave portion 101. Due to the bending of the coil spring 103 when the pinch roller 100 retreats, a pressure contact force of the pinch roller 100 against the sheet conveying roller 6 is generated. As a result, the paper pulled out by the paper feed roller 3 is guided by the guide surface 7 and is fed to the printing unit of the printing device by the paper transport roller 6 and the pinch roller 100.

[0006]

As described above, the coil spring 103 has two functions of rotatably supporting the pinch roller 100 and urging the pinch roller 100 toward the paper transport roller 6. However, at the time of assembly, the coil spring 103 must be bent and inserted into the insertion path 104 and locked on the spring hook 106 while maintaining the tension state of the coil spring 103, so that the winding path of the coil spring 103 becomes long. . Further, since many parts of the coil spring 103 are hidden behind the cassette case 1, it is necessary to work with the hands from the back side of the cassette case 1, so that the assembling work is difficult. As a result, the ends of the coil spring 103 may be separated during assembly.
In this case, the coil spring 103 and the pinch roller 100 jump out of the cassette case 1 due to the elasticity of the coil spring 103, and the work must be performed again.

[0007]

According to the first aspect of the present invention,
A cassette case in which a paper storage portion for storing a large number of papers in a stacked state is formed, a pinch roller having a hollow hole at the center thereof and contacting a paper conveyance roller of a printing apparatus, and a hook at both ends; The coil spring, which has a free length longer than the length of the pinch roller and is inserted into the hollow hole, is arranged at a position facing a substantially central portion of both end surfaces of the pinch roller with a predetermined interval therebetween, and A pair of spring hooks formed in a cassette case for supporting the hooks of the coil springs in tension, and the coil springs disposed between the spring hooks and both end faces of the pinch roller and from the spring hooks This is a paper feed cassette composed of a spring press that holds down the float of the paper.

According to a second aspect of the present invention, in the first aspect of the invention, one end of the coil spring is provided with a hook having an outer diameter smaller than the inner diameter of the hollow hole of the pinch roller and locked by one spring hook. And a hook formed at the other end of the coil spring and having an outer diameter larger than the inner diameter of the hollow hole and hooked to the other spring hook.

[0009]

According to the first aspect of the present invention, the hooks at both ends of the coil spring are supported by the spring hook while the coil spring passed through the pinch roller is pulled, and the hook of the coil spring is prevented from coming off from the spring hook by the spring press. However, since the spring hook is disposed substantially at the center of both end faces of the pinch roller and the spring press is disposed between the both end faces of the pinch roller and the spring hook, the coil spring is pulled straight. It can be supported by a simple short straight path as it is, and it is possible to expose most of the cassette case to the front side except for a small part facing the spring retainer of the coil spring protruding from both end faces of the pinch roller. As a result, the pinch roller and coil spring can be easily assembled from the front side of the cassette case. It can stand.

According to the second aspect of the present invention, the coil spring is inserted into the small hole of the pinch roller from one end on the small hook side, and the smaller hook is first engaged with the spring hook. Even if the user releases his / her hand from the hook during assembly in which the larger hook is engaged with the spring hook, it is possible to avoid the occurrence of a work error that the pinch roller comes off from the coil spring.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. 6 to 8 are denoted by the same reference numerals, and description thereof is omitted. A roller housing recess 12 for housing a pinch roller 11 that is in contact with the paper transport roller 6 is formed in a portion of the cassette case 1 that is ahead of the paper feed passage 10. A coil spring 14 is inserted through a hollow hole 13 formed at the center of the pinch roller 11. As shown in FIG. 2, the hollow hole 13 is formed in a hub 15 integrally formed at an intermediate portion inside the pinch roller 11. As a result, the overall length of the hollow hole 13 fitted into the coil spring 14 is reduced, so that the degree of freedom of the pinch roller 11 in the tilt direction with respect to the axial direction is promoted,
As a result, the pinch roller 1 is
1 has a structure that makes it easy to adhere to the entire circumference. A hook 14a having an outer diameter smaller than the inner diameter of the hollow hole 13 is formed at one end of the coil spring 14, and a hook 14b having an outer diameter larger than the inner diameter of the hollow hole 13 is formed at the other end. Is formed. Further, the coil spring 14 is formed by winding the wire in a state close to the close winding, but the free length of the coil portion not including the hooks 14a and 14b is set to a value longer than the axial length of the pinch roller 11. Have been.

An opening 16 having an upper surface opening is formed on both sides of the roller accommodating concave portion 12 having an upper surface opening and a pin-shaped spring hook 17 is provided on the bottom surface of the opening 16. 11 are provided so as to be opposed to the substantially central portions of both end surfaces at a predetermined interval. Between the spring hook 17 and the end of the pinch roller 11, a column 18 standing from the bottom of the roller accommodating recess 12 is integrally formed. A pressing piece 19 for pressing against the roller 6 is integrally formed, and a spring retainer 20 for covering the coil spring 14 from the surface side of the roller accommodating recess 12 is integrally formed on the upper end of the support column 18.

In such a configuration, when assembling the pinch roller 11 to the cassette case 1, the hooks 14 a and 14 b at both ends thereof are fitted to the spring hook 17 while the coil spring 14 passed through the pinch roller 11 is pulled. Then, the hook 14a of the coil spring 14 from the spring hook 17 is
14b can be retained. In this case, the spring hooks 17 are disposed so as to oppose substantially the center portions of both end surfaces of the pinch roller 11, and the spring retainer 20 is connected to the pinch roller 1.
1, the coil spring 14 can be supported by a simple short straight path while being pulled straight, and the coil spring 14 can be supported from both end faces of the pinch roller 11. Most of the projecting coil spring 14 can be exposed on the surface side of the cassette case 1 except for a small portion opposed to the spring retainer 20, and the spring retainer 20 is structured to be bent from the tip of the column 18. Therefore, it is easy to move the coil spring 14 in the stretched state from the upper side to the lower side of the spring retainer 20. Therefore, the pinch roller 11 and the coil spring 14 can be easily assembled from the front side of the cassette case 1. This is an effect corresponding to the first aspect of the present invention. Until the hooks 14 a and 14 b of the coil spring 14 are locked to the spring hook 17, the pinch roller 11 is
The pinch roller 11 is not dropped during the assembling operation because the pinch roller 11 can be supported by the bottom surface of the pinch roller.

When assembling the pinch roller 11 to the cassette case 1, as shown in FIG. 5, first, one end of the coil spring 14 on the small hook 14a side is inserted into the hollow hole 13 of the pinch roller 11, and Roller 1
1 is stored in the roller storage recess 12 and, as shown in FIG.
Place the smaller hook 14a first on one spring hook 1
7, and then the larger hook 14 b is locked to the other spring hook 17. By taking such a procedure, the larger hook 14b is put on the spring hook 1b.
Even if the user releases his / her hand from the hook 14b during the assembling operation, the hook 14b is prevented from dipping into the hollow hole 13, so that an operation error that the pinch roller 11 comes off from the coil spring 14 is prevented. It is possible to avoid. This is the effect of the second aspect of the present invention.

Further, since the spring hook 17 has a pin shape, the hooks 14a and 14b of the coil spring 14 can be easily fitted from the upper end thereof. The coil spring 14 stretched between the spring hooks 17 in this manner can be pressed from the front side of the cassette case 1 by the spring presser 20, so that the coil spring 14 can be prevented from being detached from the spring hook 17.

In the state before the cassette case 1 is mounted on the printing apparatus, the pinch roller 11 is partially stored in the roller storage recess 12 by the urging force of the coil spring 14 as shown by a virtual line in FIG. Although it protrudes to the unit 2, when the cassette case 1 is attached to the printing device,
As shown by the solid line in FIG. 1, the pinch roller 11 is pressed by the sheet transport roller 6, so that the pinch roller 11 bends the intermediate portion of the coil spring 14 and retreats into the roller accommodating recess 12. Due to the bending of the coil spring 14 when the pinch roller 11 retreats, a pressing force of the pinch roller 11 against the paper transport roller 6 is generated. As shown in FIG. 3, the coil spring 14 is pressed toward the sheet conveying roller 6 by pressing projections 19 at portions protruding from both end surfaces of the pinch roller 11. Side, the pinch roller 11 with respect to the sheet transport roller 6 due to the bending of the coil spring 14.
Therefore, it is not always necessary to form the pressing projection 19 on the support column 18 for pressing the coil spring 14 toward the paper conveying roller 6 because the pressing force of the coil spring 14 can be increased.

[0017]

According to the first aspect of the present invention, a pair of spring hooks for latching both ends of the coil spring inserted through the hollow hole of the pinch roller are fixed with respect to substantially the center portions of both ends of the pinch roller. A spring press is provided between the spring hook and both end faces of the pinch roller for holding the coil spring floating from the spring hook, so that the coil spring passed through the pinch roller While pulling, the hooks at both ends are supported by spring hooks, and the spring retainers prevent the coil spring hooks from coming off from the spring hooks. The spring retainer is located between both end faces of the pinch roller and the spring hook, The ring can be supported by a simple short straight path while being pulled straight, and most of the surface of the cassette case other than the small part facing the spring retainer of the coil spring protruding from both end faces of the pinch roller The pinch roller and the coil spring can be easily assembled from the front side of the cassette case.

According to the present invention, a hook having an outer diameter smaller than the inner diameter of the hollow hole of the pinch roller is formed at one end of the coil spring, and a hook larger than the inner diameter of the hollow hole is formed at the other end of the coil spring. Since the hook defined to the outer diameter was formed, by inserting from the small hook side end of the coil spring into the hollow hole of the pinch roller and taking the procedure of locking the smaller hook first to the spring hook, Even if the hand is released from the hook during the assembly in which the larger hook is engaged with the spring hook, it is possible to avoid the occurrence of an operation error that the pinch roller comes off the coil spring.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional side view showing one embodiment of the present invention.

FIG. 2 is a plan view showing a central portion on the distal end side of the cassette case.

FIG. 3 is a vertical sectional side view showing a relationship between a coil spring and a spring retainer.

FIG. 4 is a perspective view showing a central portion of the cassette case at a front end side with a part cut away.

FIG. 5 is an exploded perspective view showing a support structure of a pinch roller with respect to a central portion on a front end side of the cassette case with a part cut away.

FIG. 6 is a longitudinal sectional side view showing a conventional example.

FIG. 7 is a perspective view showing a central portion of a front end side of the cassette case with a part cut away.

FIG. 8 is an exploded perspective view showing a support structure of a pinch roller with respect to a center portion on a front end side of the cassette case with a part cut away.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cassette case 2 Paper storage part 6 Paper conveyance roller 11 Pinch roller 13 Hollow hole 14 Coil spring 14a, 14b Hook 17 Spring hook 20 Spring holding

Claims (2)

(57) [Claims] 1. A cassette case in which a paper storage portion for storing a large number of papers in a stacked state is formed, a pinch roller having a hollow hole at the center and contacting a paper conveyance roller of a printing apparatus, and A coil spring having a hook and having a free length longer than the length of the pinch roller and being inserted into the hollow hole, facing a substantially central portion of both end surfaces of the pinch roller at a predetermined interval; A pair of spring hooks formed in the cassette case and supported on the hooks of the coil springs in a tension state, and the spring hooks disposed between these spring hooks and both end faces of the pinch roller. A paper feed cassette comprising: a spring presser for holding the coil spring from floating from above. 2. An end of the coil spring is formed with a hook having an outer diameter smaller than the inner diameter of the hollow hole of the pinch roller and hooked to one of the spring hooks. 2. The paper feed cassette according to claim 1, wherein a hook defined to have an outer diameter larger than the inner diameter and locked by the other spring hook is formed.