JPH0475952A - Paper feeder - Google Patents

Abstract

PURPOSE:To assemble a sprocket pin without using a jig by forming housing holes in a sprocket mainframe to house the sprocket pin retractably therein, and providing a cam portion and a cutout portion on a frame. CONSTITUTION:A frame 21 is provided with a sprocket mounting portion 24 as well as a cam groove 26 and a cutout portion 27 ranging overthere. A sprocket maniframe 32 has several housing holes 46 and cutout portions 47 formed in the outer periphery. In assembling, an engaging protrusion 36 on a roller 33 which is integrally assembled into the sprocket mainframe 32 is put into an axial hole 25 in the frame 21 through the sprocket mounting portion 24 and engaged with the side face on the opposite side. By Turning the mainframe 32 from the frame 21 as necessary, the cutout portion 47 is laid on top of the cutout portion 27. Then, the boss 51 of the sprocket pin 34 is inserted from the direction of an arrow mark (a), and the pin 34 is inserted into the housing hole 46 in the mainframe 32. This involves the boss 51 put into the cam groove 26. Such action is repeated as many times as the number of the pins 34. In this way, the pin 34 is easily assembled into the mainframe 32 without using a jig.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a paper feeding device used in a printer, and particularly to a fanfold paper feeding device.

(Prior Art) For example, printing paper used in printers, which are peripheral devices for personal computers, include cut paper, roll paper, and fanfold paper.

As shown in Figure 6, the fanfold paper feeding device uses a sprocket 2 that has sprocket pins 1 on its outer periphery that fit into perforation holes on both sides of the fanfold paper, and is connected to a platen shaft. This rotation of the sprocket 2 ensures that the fanfold paper is fed.

By the way, in this type of paper feeding device, the sprocket pin 1 is made to be freely retractable from the sprocket body 3 so that the sprocket pin 1 does not interfere with the print head.
The movement of this sprocket pin 1 is controlled by a cam,
The sprocket pin 1 is recessed near the print head and protrudes only at the position necessary for feeding the fanfold paper. That is, an annular cam groove is formed in the frame 4 in which the sprocket body 3 is rotatably incorporated, and the boss 5 formed protruding from the sprocket pin 1 is slidably inserted into the cam groove as a cam receiving part. However, for this reason, mutual assembly of the sprocket body 3, sprocket pin 1, and frame 4 is not easy.

In FIG. 6, reference numeral 6 denotes protrusions with claws formed on the sprocket main body 4. These protrusions 6 with claws are fitted into the shaft holes 7 formed in the frame 4, so that the sprocket main body 3 is attached to the frame 4. It is designed to be rotatably locked. Reference numeral 8 denotes a cover formed on the frame 4, and a fanfold paper feeding section is formed between the cover 8 and the outer peripheral surface of the sprocket 2. Further, the cover 8 is formed with a slot 9 through which the protruding sprocket pin 1 passes.

Conventionally, when assembling the sprocket body 3, sprocket pin 1, and frame 4, the boss 5 of the sprocket pin 1 smoothly enters the cam groove of the frame 4. Structures and methods as described have been adopted.

That is, in the paper feeding device described in this publication, guide grooves 10 are formed in the sprocket body 3 at the end surface facing the frame 4 and each sprocket pin (tractor pin) is housed therein. A punch hole is formed on the opposite end face. In addition, a jig 11 is used to assemble the sprocket 2 into the frame 4, and this jig 11 has a plurality of pin-shaped punches inserted into the punch holes of the sprocket body 3, respectively, into the frame 4. It is arranged in the same shape as the cam groove of No. 4 and is formed protrudingly.

To assemble the sprocket 2 into the frame 4, first set the sprocket body 3 on the jig 11, insert each punch of the jig 11 into each punch hole of the sprocket body 3, and Each sprocket pin 1 is inserted into the guide groove 10 and temporarily set.

After that, push the frame 4 into the sprocket body 3,
This sprocket body 3 has a protrusion with a claw (elastic hook) 6
into the shaft hole 7 of the frame 4.

At this time, each sprocket pin 1 is pressed radially outward of the sprocket body 3 by each punch of the jig 11,
The bosses 5 of each sprocket pin 1 enter the cam groove of the frame 4 while being aligned in a shape along the cam groove.

Also, disassemble the frame 4 and sprocket 2 again,
The jig 11 is also required when reassembling.

(Problems to be Solved by the Invention) However, the conventional structure and method described in the above publication
There was a problem in that the sprocket pin 1, sprocket body 3, and frame 4 could not be assembled to each other unless a special jig 11 was used.

Moreover, at this assembly stage, the sprocket body 3 is set on the jig 11, each sprocket pin 1 is temporarily set on this sprocket body 3, and then the sprocket 2 is integrated with the frame 4. However, there was a problem in that it took time to assemble, and as a result, the cost increased.

The present invention aims to solve these problems, and aims to provide a paper feeding device in which a sprocket pin can be smoothly and easily incorporated without using a jig. .

[Structure of the invention]

(Means for Solving the Problems) The present invention includes a frame and a sprocket in which a sprocket pin is provided on the outer periphery of a sprocket body rotatably incorporated in the frame, and the sprocket body is provided with a sprocket pin on the outer circumference of the sprocket body. A housing hole extending in the radial direction of the sprocket body and opening on the outer peripheral surface of the sprocket body is formed, and the sprocket pin is housed in the housing hole so as to be freely retractable, and the rotation axis of the sprocket body is attached to the frame. In order to achieve the above object, in a paper feeding device in which a surrounding annular cam part is formed and a cam receiving part provided on the sprocket pin is slidably engaged with the cam part, the sprocket body A sprocket-side notch is formed that opens from the outer circumferential surface of the sprocket main body to an end surface facing the frame, is continuous with the storage hole, and into which the cam receiving portion of the sprocket pin can be inserted; A frame-side notch is formed extending from the outer surface of the frame to the cam portion and overlapping the sprocket-side notch into which the cam receiving portion of the sprocket pin can be inserted.

(Function) When assembling the paper feeding device of the present invention, the sprocket body is first assembled into the frame. After that, rotate the sprocket body appropriately relative to the frame, and after overlapping the sprocket side notch of the sprocket body with the frame side notch of the frame, insert the sprocket pin into these notches from the outer surface of the frame and the outer peripheral surface of the sprocket body. At the same time as inserting the cam receiving part, insert this sprocket pin into the storage hole of the sprocket body. Accordingly, the cam receiving part of the sprocket pin is guided by the frame side notch and finally reaches the cam part of the frame. In use, the cam receiving part of the sprocket pin is slidably engaged with the annular cam part of the frame, so that the sprocket pin moves in and out of the outer peripheral surface of the sprocket body as appropriate as the sprocket rotates.

(Embodiment) Hereinafter, the structure of an embodiment of the paper feeding device of the present invention will be explained based on FIGS. 1 to 5.

This paper feeding device is used in a printer, which is a peripheral device of a personal computer, and is used to feed fanfold paper (not shown).

In Figures 1 and 2, 21 is the main body frame;
A cover 22 is integrally formed at the lower part of one side of the frame 21 to protrude. Further, a guide 23 is integrally formed on the rear portion of one side of the frame 21 (left side in the figure) to protrude and face the cover 22 from above with a small gap therebetween. Furthermore, a disc-shaped sprocket mounting portion 24 is integrally formed on the front portion of the frame 21 and projects from above, facing the cover 22 with a small gap therebetween. A circular shaft hole 25 is formed passing through the shaft in the axial direction. Although not shown, the print head of the printer is located in front of the frame 21.

A cam groove 26 is formed in the sprocket mounting portion 24 as an annular cam portion surrounding the center thereof. This concave cam groove 26 is connected to the sprocket mounting portion 24.
The distance from the center becomes larger on the rear side and smaller on the front side.

The sprocket mounting portion 24 also has a cam groove 2 extending from the outer upper surface of the sprocket mounting portion 24 to the lower side thereof.
A frame side notch 27 in the shape of a concave groove reaching 6 is formed. The connection part to the cam groove 26 in this notch part 27 is
It is located slightly forward of the top of the cam groove 26 and forms a slightly acute angle with respect to the cam groove 26 on the rear side (left side in the figure). At the same time, in the middle part of the cutout part 27, there is a step 2 that is slightly curved downward and rearward.
8 is formed.

In FIGS. 1, 4, and 5, 31 is a cylindrical sprocket, and this sprocket 31 is a sprocket body 3 that is rotatably incorporated into the frame 21.
A roller 33 is coaxially and integrally incorporated into the sprocket body 32, and a plurality of sprocket pins 34 are provided at a constant pitch on the outer periphery of the sprocket body 32. These sprocket pins 34 fit into feeding perforation holes formed at a constant pitch on both sides of the fanfold paper. The sprocket mounting portion 24 of the frame 21 and the sprocket 31 have approximately the same diameter and are located coaxially.

A plurality of, for example, four locking projections 36 are integrally formed at the center of one end surface of the roller 33, and these locking projections 36 can be elastically bent in the radial direction of the sprocket 31. The distal end of each of the locking protrusions 36 is provided with approximately 3.
Square-shaped claw portions 37 are respectively formed.

At the center of the sprocket body 32, a shaft portion 4j having a cylindrical outer circumferential surface is integrally formed on one end surface and protrudes, and a square shaft hole is formed through the center of the shaft portion 41. 42 is formed. A corresponding square shaft hole is formed in the center of the roller 33, and these square shaft holes 42 are for fixedly connecting a platen shaft (not shown) of the roller 33. . Furthermore, recesses 43 are formed on each of the four sides of the shaft hole 42, and the locking protrusions 36 of the roller 33 are formed in these recesses 43.
are penetrated through each.

The frame 21 of the sprocket body 32
The claw portions 37 of each of the locking protrusions 36 are rotatably fitted into the shaft hole 25 of the frame 21, and the claw portions 37 of the respective locking protrusions 36, which pass through the shaft hole 25, are slidably engaged with the other side surface of the frame 21. As a result, the sprocket body 3 is attached to the frame 21 together with the roller 33.
2 is rotatably locked.

Further, the sprocket body 32 has a plurality of radially formed storage holes 46 extending in the radial direction and opening on the outer peripheral surface of the sprocket body 32. A sprocket side notch 47 is formed. These notches 47 are
It is continuous with the storage hole 46 over its entire length, and opens from the outer peripheral surface of the sprocket body 32 to the end surface facing the frame 21, so as to overlap the frame-side notch 27 thereof. Note that the widths of the frame-side notch 27 and the sprocket-side notch 47 are approximately equal, but the diameter of the storage hole 46 is larger than this width.

The sprocket pin 34 is attached to the sprocket body 3
2, each of which is slidably housed in each of the storage holes 46,
It is movable only in the radial direction of the sprocket body 32, and the tapered tip is attached to the sprocket body 32.
Appropriately appears and disappears from the outer peripheral surface of. As particularly shown in FIG. 3, a boss 51 serving as a cam receiving portion that is slidably engaged with the cam groove 26 of the frame 21 is integrally formed at the base of the outer peripheral surface of the sprocket pin 34. ing.

This boss 51 protrudes from the sprocket pin 34 at right angles.
has a diameter slightly smaller than the width of the notches 27.47, and can be inserted into these notches 27.47. On the other hand, the diameter of the sprocket pin 34 is larger than the width of the notch 27.47.

The frame 21 and the sprockets 31 are arranged in pairs on the left and right, and a platen is coaxially connected between the pair of sprockets 31 facing each other.

Next, the operation of the above embodiment will be explained.

During assembly, first the sprocket body 32 is assembled together with the roller 33 into the frame 2I. To do this, the locking protrusion 36 of the roller 33 integrated into the sprocket body 32 is inserted into the shaft hole 25 of the frame 21 from the sprocket mounting portion 24 side. Accordingly, the locking projections 36 are once elastically deformed inward in the radial direction of the sprocket body 32, and the claw portions 37 of each locking projection 36 are engaged with the side surface of the frame 21 opposite to the sprocket mounting portion 24. . As a result, the sprocket body 32 is attached to the frame 2.
In contrast to No. 1, extraction is stopped and rotation is free.

Next, the sprocket body 32 is appropriately rotated with respect to the frame 2I, so that the sprocket side notch 47 of the sprocket body 32 overlaps the frame side notch 27 of the frame 2I. Next, the boss 51 of the sprocket pin 34 is inserted into these notches 27° 47 from the outer upper surface of the frame 21 and the outer peripheral surface of the sprocket body 32 (from the direction indicated by arrow a in FIG. 2), and this sprocket pin 34 into the housing hole 46 of the sprocket body 32. Along with this, the boss 51 of the sprocket pin 34
is guided by the frame side notch 27 and finally enters the cam groove 26 of the frame 21. In addition, since there is a step 28 in the middle of the frame side notch 27, the boss 51
While inserting the sprocket, the sprocket body 32 rotates slightly.

This is repeated for the number of sprocket pins 34 to be incorporated into the sprocket body 32, and each sprocket pin 34 is
are assembled one by one into the sprocket body 32 and the frame 21 (.

When it becomes necessary to disassemble the sprocket, the sprocket 31 can be removed from the frame 21 by forcibly elastically deforming the locking protrusion 36 inward in the radial direction of the sprocket body 32 and pulling it out from the shaft hole 25 of the frame 21. good. In this state, the sprocket pin 34 can be removed from the sprocket body 32 very easily.

According to the above configuration, the sprocket pin 34 can be smoothly and easily assembled into the sprocket body 32 while inserting the boss 51 of the sprocket pin 34 into the cam groove 26 of the frame 21 without using a jig. No need for installation know-how. Moreover, disassembly and subsequent reassembly can be similarly smoothly and easily performed. Therefore, cost reduction can also be achieved.

Note that during use, that is, when the printer prints, the fanfold paper passes between the top surface of the cover 22 of the frame 21, the bottom surface of the guide 23, and the outer peripheral surface of the sprocket 31. In this position, the sprocket pin 34 fits into the perforation hole of the fanfold paper, and the rotation of the sprocket 31 ensures that the fanfold paper is fed. Sprocket 31 rotates counterclockwise in FIG.

When the sprocket body 32 rotates, the sprocket pin 34 also rotates at the same time, but at this time, the position of the sprocket pin 34 in the radial direction of the sprocket body 32 is determined by the cam groove 26.

That is, as the sprocket body 32 rotates, the boss 51 of the sprocket pin 34 rotates as the sprocket body 320 rotates.
Since the sprocket pin 34 moves while being regulated by the annular cam groove 26 surrounding the rotating shaft, the sprocket pin 34
The sprocket body 32 is moved in the radial direction relative to the sprocket body 32, and protrudes and retracts from the outer circumferential surface of the sprocket body 32 as appropriate.

Specifically, on the front side of the sprocket 31, that is, at the position where the print head runs, the sprocket pins 34 are entirely inserted into the sprocket body 32, and these sprocket pins 34 are prevented from interfering with the print head.

Further, at the rear and lower sides of the sprocket 31, that is, at least at the position where paper is fed, the sprocket body 32
A sprocket pin 34 protrudes from there.

By the way, since the step 28 is formed in the notch 27, it is possible to prevent the sprocket pin 34 from coming off from the sprocket body 32 not only during use but also during assembly.

Of course, a separate member that can close the notch 27 may be provided.

〔Effect of the invention〕

According to the present invention, in order to control the amount of protrusion of the sprocket pin from the sprocket body rotatably incorporated in the frame, the cam receiving portion of the sprocket pin is engaged with the annular cam portion of the frame. In the feeding device, a sprocket-side notch is formed in the sprocket body, which opens from the outer peripheral surface of the sprocket body to the end face facing the frame, and is continuous with the sprocket pin storage hole through which the cam receiver can be inserted. , a frame-side notch is formed that extends from the outer surface to the cam part and overlaps the sprocket-side notch, through which the cam receiver can be inserted, so the sprocket pin can be inserted smoothly and easily into the sprocket body and frame without using a jig. can be integrated into the system, and no special integration know-how is required.
Assemblability is improved, and costs can therefore be reduced.

[Brief explanation of the drawing]

Figures 1 to 5 show an embodiment of the paper feeding device of the present invention, where Figure 1 is a plan view, Figure 2 is a side view of the frame, Figure 3 is a plan view of the sprocket pin, and Figure 3 is a plan view of the sprocket pin. FIG. 4 is a plan view of a sprocket without a sprocket pin, and FIG. 5 is a side view of a sprocket with a sprocket pin installed. Further, FIG. 6 is a plan view showing an example of a conventional paper feeding device. 21... Frame, 26... Cam groove as a cam part, 2
7... Frame side notch, 31... Sprocket, 32
... Sprocket body, 34 ... Sprocket pin, 4
6. Storage hole, 47. Sprocket side notch, 51.
・Boss as a cam receiving part. ] Tatami 3 [1

Claims (1)

[Claims] (1) A sprocket comprising a frame and a sprocket pin provided on the outer periphery of a sprocket body which is rotatably incorporated into the frame, and a sprocket pin extending in the radial direction of the sprocket body and extending around the outer periphery of the sprocket body. forming a storage hole opening in the surface, and storing the sprocket pin in the storage hole so as to be freely retractable;
An annular cam portion surrounding the rotation axis of the sprocket body is formed on the frame, and a cam receiving portion provided on the sprocket pin is slidably engaged with the cam portion; A sprocket side notch is formed that opens from the outer circumferential surface of the sprocket body to an end surface facing the frame, is continuous with the storage hole, and into which the cam receiving part of the sprocket pin can be inserted; A paper feeding device characterized in that a frame-side notch is formed that extends to the cam portion and overlaps the sprocket-side notch, into which a cam receiving portion of the sprocket pin can be inserted.