JP5504084B2 - Pin tractor and image forming apparatus - Google Patents

Description

  The present invention relates to a pin tractor that conveys continuous paper into an image forming apparatus.

  Conventionally, continuous copying paper used in an image forming apparatus has a plurality of sprocket holes provided along both sides in the conveyance direction, and is conveyed by a pin tractor having a plurality of pins fitted into the sprocket holes. ing. On the other hand, a feed roller provided in the image forming apparatus is suitable for conveying cut sheets. If the continuous copy paper is transported by the feed roller, the continuous copy paper is heavy and slips, which may cause a transport deviation in the copy paper. For this reason, a heavy continuous copying paper is conveyed by a pin tractor having a large conveying force.

  FIG. 9 is an external view of a conventional tractor belt used in a pin tractor. FIG. 2A is a side view of the tractor belt 50, and FIG. 2B is a plan view of the tractor belt 50 and a plan view of the continuous copy paper 3. The tractor belt 50 is formed in an annular shape, and a plurality of pins 61 are formed around it. The pins 61 are formed at equal intervals, and the intervals are equal to the intervals between the sprocket holes 30 formed in the continuous copy paper 3. And the diameter of the sprocket hole 30 is 4 mm normally, and the diameter of the lower part of the pin 61 fitted to this is 3.6 mm. The tractor belt 50 is rotated by driving means (not shown), and the pin 61 is fitted into the sprocket hole 30 so that the continuous copy paper 3 is conveyed.

  FIG. 10 is an explanatory view showing the relationship between the conventional pin 61 and the sprocket hole 30. The continuous copy paper 3 is composed of a plurality of media in multiple layers. The pin 61 has a substantially conical shape so that it can be easily inserted into the sprocket hole 30 of the continuous copying paper 3. Further, the lower portion of the pin 61 is fitted into the sprocket hole 30 so that a conveying force is easily generated. As described above, the diameter of the sprocket hole 30 is 4 mm, and the diameter of the lower portion of the pin 61 fitted to the sprocket hole 30 is 3.6 mm, so that a gap is generally generated between the sprocket hole 30 and the pin 61. ing. In the figure, as a result of this gap, an interlayer deviation B1 described later is generated between the print head side medium 31 which is the lowermost medium of the continuous copying paper 3 and the platen side medium 32 which is the uppermost layer. Is shown.

  FIG. 11 is an explanatory diagram showing interlayer misalignment caused by a conventional tractor belt. The continuous copy paper 3 is conveyed in the direction of the platen 6 by the pin tractor 1. The continuous copy paper 3 that has reached the printing unit 7 of the platen 6 is printed by the print head 4. The print head 4 is a wire dot impact type print head 4 and impacts the continuous copy paper 3 by wire dots. As a result, the same content is printed on the continuous copy paper 3 and can be copied onto a plurality of media.

  JP-A-7-266640 discloses a technique related to a pulling tractor for pulling a continuous form and a pushing tractor for pushing the continuous form.

JP-A-7-266640

  However, as described above, there is a dimensional difference between the diameter of the sprocket hole 30 (4 mm) and the diameter of the lower portion of the pin 61 (3.6 mm). There is a possibility that an interlayer shift B1 occurs in the pin tractor 1. As a factor causing the interlayer displacement B, a difference in distance corresponding to the thickness of the medium is generated by winding the continuous copy paper 3 around the platen 6 as shown in FIG. If there is a continuous copy paper 3 placed straight, no interlayer displacement B occurs there. If the straight continuous copying paper 3 in which no interlayer shift B is generated passes through the pin tractor 1 and is curved along the platen 6 as shown in FIG. And B3 are generated.

  On the pin tractor 1 side, which is the rear end of the continuous copying paper 3 in the conveyance direction, an interlayer shift B1 occurs between the print head side medium 31 and the platen side medium 32 as shown in FIG. On the other hand, when passing through the printing unit 7 which is the front end of the continuous copying paper 3 in the conveyance direction, the interlayer displacement B3 between the print head side medium 31 and the platen side medium 32 is further enlarged (B1 <B3). This interlayer deviation B3 also occurs in the printing unit 7 of the platen 6, and as a result, appears as a printing deviation between the print head side medium 31 and the platen side medium 32 of the continuous copy paper 3. .

  The problem to be solved by the present invention is that when the continuous copying paper 3 is transported by a pin tractor, the occurrence of the interlayer displacement B of the continuous copying paper 3 is reduced, so that the continuous copying paper 3 in the printing unit 7 of the platen 6 is reduced. An object of the present invention is to provide a pin tractor in which a printing deviation between the print head side medium 31 and the platen side medium 32 is reduced.

In order to solve the above-described problem, a pin tractor according to the present invention is disposed upstream of a platen with respect to a conveying direction of continuous copying paper composed of a plurality of media and is wound around the platen. In the pin tractor that conveys a plurality of pins, the plurality of pins are fitted into a plurality of sprocket holes provided at equal intervals on the continuous copy paper, and the plurality of pins includes a first pin having a predetermined size, A second pin having a size larger than that of the first pin and having a diameter larger than that of the sprocket hole and being press-fitted into the sprocket hole when fitted into the sprocket hole is provided. Is.

  According to the present invention having the above-described configuration, when a continuous copy paper is conveyed by a pin tractor, the possibility of causing an interlayer shift is reduced, and printing between the print head side medium 31 and the platen side medium 32 in the printing unit 7 of the platen 6 is performed. It becomes possible to provide a pin tractor with reduced displacement.

It is an external view of the tractor belt regarding 1st Embodiment. It is explanatory drawing which shows the state which set the continuous copy paper to the printer regarding 1st Embodiment. It is explanatory drawing which shows the conveyance route of the continuous copy paper inside a printer regarding 1st Embodiment. It is a top view which shows the conveyance state of the pin tractor regarding 1st Embodiment. It is a side view which shows the inside of the pin tractor regarding 1st Embodiment. It is a side view of the large diameter pin of the tractor belt regarding a 1st embodiment. It is explanatory drawing which shows the interlayer shift | offset | difference by the pin tractor regarding 1st Embodiment. It is an external view of the tractor belt regarding 2nd Embodiment. It is an external view of the conventional tractor belt currently used for the pin tractor. It is explanatory drawing which shows the relationship between the conventional pin and a sprocket hole. It is explanatory drawing which shows the interlayer shift | offset | difference by the conventional tractor belt.

<First Embodiment>
Hereinafter, a first embodiment of the present invention will be described. FIG. 2 is an explanatory diagram showing a state in which the continuous copy paper 3 is set in the printer 100 according to the first embodiment. The general-purpose printer 100 as an image forming apparatus feeds the continuous copy paper 3 from the continuous paper feed unit 21 provided behind the general-purpose printer 100 when printing on the continuous copy paper 3. The general-purpose printer 100 transports the continuous copy paper 3 by a transport route described later, and performs printing by the platen 6 and the print head 4. Thereafter, the continuous copy paper 3 is discharged backward from the continuous paper discharge unit 26 provided above the general-purpose printer 100.

  The continuous copy paper 3 is composed of a bundle of both the pre-printing continuous paper 35 and the printed continuous paper 36. The pre-printing continuous paper 35 and the printed continuous paper 36 are usually installed below the general-purpose printer 100. Therefore, a heavy load is applied to the conveyance of the continuous copy paper 3 as described above.

  FIG. 3 is an explanatory diagram showing a conveyance route of the continuous copy paper 3 inside the printer 100 according to the first embodiment. The continuous copy paper 3 is fed from the continuous paper feed unit 21 of the general-purpose printer 100 in the transport direction indicated by arrow A in the figure. The continuous copying paper 3 fed from the continuous paper feeding unit 21 is conveyed by the pin tractor 1 toward the lower side of the cylindrical platen 6. A conveying roller 22 is provided below the platen 6, and the continuous copy paper 3 is sandwiched between the platen 6 and the conveying roller 22 and conveyed toward the printing unit 7 of the platen 6. The continuous copy paper 3 that has reached the printing unit 7 of the platen 6 is printed by the print head 4. The print head 4 is a wire dot impact type print head 4 and impacts the continuous copy paper 3 by wire dots. The print head 4 moves along the cylinder of the cylindrical platen 6 to perform printing. The continuous copy paper 3 is composed of a plurality of media in multiple layers, and is composed of carbon paper provided between the layers or a non-carbon medium. As a result, the same content is printed on the continuous copy paper 3 and can be copied onto a plurality of media. The printed continuous copy paper 3 is pulled and conveyed by a pair of conveying rollers 23 and 24 provided in the vicinity of the continuous paper discharge unit 26 and is discharged from the continuous paper discharge unit 26.

  FIG. 4 is a plan view showing a conveyance state of the pin tractor 1 according to the first embodiment. The continuous copying paper 3 is provided with a plurality of sprocket holes 30 along the left and right medium side end portions 33 with respect to the conveying direction indicated by the arrow A in the drawing of the continuous copying paper 3. In the vicinity of the left and right medium-side end portions 33, perforations 34 are provided along the medium-side end portion 33 so that the portion of the sprocket hole 30 that becomes unnecessary after printing can be cut. The pin tractor 1 is made symmetrically and arranged symmetrically with respect to the conveyance direction of the continuous copy paper 3. The pin tractor 1 is disposed at the positions of the left and right sprocket holes 30 of the continuous copying paper 3 so that the continuous copying paper 3 can be conveyed with equal force on the left and right. The left and right pin tractors 1 are movable along the width direction of the continuous copy paper 3 in order to match the width of the continuous copy paper 3.

  FIG. 5 is a side view showing the inside of the pin tractor 1 according to the first embodiment. The figure shows one of the left and right pin tractors 1 made symmetrically. The pin tractor 1 is rotated by a left and right frame 13, a tractor belt 10 rotatably provided between the left and right frames 13, a belt support 14 that supports the rotation of the tractor belt 10, and a drive shaft (not shown). A drive wheel 15 that rotates the tractor belt 10 and a guide cover 16 are also included.

  The belt support portion 14 is formed integrally with one of the left and right frames 13. The periphery of the belt support portion 14 is formed smoothly, and the tractor belt 10 rotates around the belt support portion 14. Further, the belt support portion 14 has a support shaft hole 17 through which a support shaft (not shown) passes so that the pin tractor 1 can be moved in the width direction in accordance with the width of the continuous copy paper 3.

  The drive wheel 15 has a drive shaft hole 18 through which a drive shaft (not shown) passes, and has a plurality of teeth that mesh with the internal teeth of the tractor belt 10. The guide cover 16 is provided so that it can be opened and closed. After the sprocket holes 30 of the continuous copying paper 3 are fitted to pins 11 and 12 (to be described later) of the tractor belt 10, the continuous copying paper 3 can be set on the pin tractor 1 by closing the guide cover 16. Thus, the sprocket hole 30 is prevented from being detached from the pins 11 and 12, and the continuous copy paper 3 can be stably conveyed in the arrow A direction.

  Of the plurality of pins 11 and 12 of the tractor belt 10, the number of pins that are always fitted to the sprocket hole 30 is three. That is, in the state shown in the figure, the pins 11-1, 12-2 and 11-3 are fitted with the sprocket holes 30.

  FIG. 1 is an external view of a tractor belt 10 according to the first embodiment. 1A is a side view of the tractor belt 10, and FIG. 1B is a plan view of the tractor belt 10 and a plan view of the continuous copy paper 3. The tractor belt 10 is formed in an annular shape, and a plurality of pins 11 and 12 are formed around it. The plurality of pins includes a pin 11 as a first pin having a predetermined size and a large-diameter pin 12 as a second pin having a larger size than the pin 11.

  The main body of the tractor belt 10, the pin 11 and the large-diameter pin 12 are integrally formed and are made of a flexible resin. The centers of the pins 11 and the large-diameter pins 12 are formed at equal intervals, and the intervals are equal to the intervals between the centers of the sprocket holes 30 formed in the continuous copy paper 3. The diameter of the sprocket hole 30 is usually 4 mm, the diameter of the lower portion of the pin 11 fitted therein is 3.6 mm, and the diameter of the lower portion of the large diameter pin 12 is 4.4 mm. That is, the diameter of the pin 11 is smaller than the sprocket hole 30, but the diameter of the large-diameter pin 12 is larger than the sprocket hole 30. Therefore, the large diameter pin 12 is press-fitted into the sprocket hole 30.

  Since the continuous copying paper 3 is always conveyed while being fitted to the three pins 11-1, 12-2 and 11-3 on the tractor belt 10, a large-diameter pin 12 having a large diameter is arranged for every three pins. Structure. Thereby, one of the three pins is always press-fitted into the sprocket hole 30.

  FIG. 6 is a side view of the large-diameter pin 12 of the tractor belt 3 according to the first embodiment. The large-diameter pin 12 has the same height as the pin 11 but has a larger diameter than the pin 11. Like the pin 11, the large-diameter pin 12 has a substantially conical shape, and is easily inserted into the sprocket hole 30 of the continuous copying paper 3, and the lower part is firmly fitted into the sprocket hole 30 so that a conveying force is easily generated. is there. In particular, since the diameter of the lower portion of the large-diameter pin 12 is larger than the sprocket hole 30, when the large-diameter pin 12 is press-fitted into the sprocket hole 30, the edge of the sprocket hole 30 is deformed as shown in FIG. Will increase. Then, the interlayer displacement B1 does not occur in the pin tractor 1 (B1 = 0).

  As described above, the continuous copying paper 3 is always fitted to the three pins 11-1, 12-2 and 11-3 on the tractor belt 10, and the tractor belt 10 has a large-diameter pin 12 arranged for every three pins. To do. Accordingly, since the large-diameter pin 12 press-fitted into the sprocket hole 30 is always fitted to the continuous copy paper 3 (B1 = 0), the pin tractor 1 is transported without causing an interlayer shift B1. It will be.

  FIG. 7 is an explanatory diagram illustrating interlayer misalignment by the pin tractor 1 according to the first embodiment. The continuous copy paper 3 is conveyed in the direction of the platen 6 by the pin tractor 1. The continuous copy paper 3 that has reached the printing unit 7 of the platen 6 is printed by the print head 4. The print head 4 is a wire dot impact type print head 4 and impacts the continuous copy paper 3 by wire dots. As a result, the same content is printed on the continuous copy paper 3 and can be copied onto a plurality of media.

  As described above, the pin tractor 1 can be transported without causing the interlayer displacement B1 (B1 = 0). This interlayer shift B is corrected to the interlayer shift B1 (= 0) shown in FIG. 7 with respect to the interlayer shift B1 shown in FIG. This correction is performed even after the continuous copy paper 3 exits the pin tractor 1 and the platen 6 is wound and conveyed to the printing unit 7.

  As shown in FIG. 7, the interlayer displacement B occurs as the interlayer displacement B2 after passing through the printing unit 7 as a difference in distance due to the thickness of the medium when the continuous copy paper 3 winds the platen 6. However, the interlayer shift B2 is smaller than the interlayer shift B3 described with reference to FIG. 11 (B2 <B3). The interlayer displacement B2 also occurs in the printing unit 7 of the platen 6. As a result, the printing displacement that appears between the print head side medium 31 and the platen side medium 32 in the printing unit 7 can be reduced.

  In the present embodiment, the continuous copy paper 3 is conveyed with the large-diameter pin 12 being press-fitted into the sprocket hole 30, but when the continuous copy paper 3 leaves the pin tractor 1, the large-diameter pin 12 is A force for pulling out from the sprocket hole 30 is required. This becomes a load of the conveyance force, but it can be smoothly conveyed by increasing the driving force.

<Second Embodiment>
Hereinafter, a second embodiment of the present invention will be described. FIG. 8 is an external view of the tractor belt 40 according to the second embodiment. FIG. 2A is a side view of the tractor belt 40, and FIG. 2B is a plan view of the tractor belt 40 and a plan view of the continuous copying paper 3. The tractor belt 40 according to the second embodiment is different from the tractor belt 10 according to the first embodiment in that the tractor belt 40 has an elliptic pin 42 having an elliptical cross section.

  The tractor belt 40 is formed in an annular shape, and an ellipse pin 42 is formed around the pin 11 and a pin larger in size than the other pins 11. The main body of the tractor belt 40, the pin 11 and the elliptical pin 42 are integrally formed and are made of a flexible resin. The centers of the pins 11 and the elliptical pins 42 are formed at equal intervals, and the intervals are equal to the intervals between the centers of the sprocket holes 30 formed in the continuous copy paper 3. The elliptical pin 42 is provided with the elliptical long axis aligned with the conveying direction of the continuous copy paper 3.

  And the diameter of the sprocket hole 30 is 4 mm normally, and the diameter of the lower part of the pin 11 fitted to this is 3.6 mm. On the other hand, the major axis of the ellipse below the ellipse pin 42 is 4.4 mm, and the minor axis of the ellipse is 3.6 mm. That is, the diameter of the pin 11 is smaller than the sprocket hole 30, but the major diameter of the elliptical pin 42 is larger than the sprocket hole 30. Accordingly, since the continuous copy paper 3 is always conveyed by the three pins 11-1, 42-2 and 11-3 on the tractor belt 10, an elliptical pin 42 having a large diameter is arranged for every three pins. . Thereby, one of the three pins is always press-fitted into the sprocket hole 30.

  In particular, since the major diameter of the lower portion of the elliptic pin 42 is larger than the sprocket hole 30, when the elliptic pin 42 is press-fitted into the sprocket hole 30, the edge of the sprocket hole 30 is deformed and fitted as in the case shown in FIG. The power to do will increase. Then, the interlayer displacement B1 in the pin tractor 1 does not occur (B1 = 0), and as a result, the printing displacement that appears between the print head side medium 31 and the platen side medium 32 of the continuous copy paper 3 in the printing unit 7. Can be reduced.

  In the description of the above embodiment, since the continuous copying paper 3 is always fitted to three pins on the tractor belt 10, an example in which a large-diameter pin having a large diameter is arranged for every three pins has been described. However, it is not limited to this. That is, the present invention can also be applied to a structure in which the continuous copying paper 3 is always fitted to four pins on the tractor belt 10 and a large-diameter pin having a large diameter is arranged for every four pins. If the number of pins of the tractor belt 10 that is always fitted to the continuous copy paper 3 is large, stable conveyance is possible.

  In the description of the embodiment, the case where a plurality of pins are provided on the tractor belt has been described. However, the present invention can be applied even when a plurality of pins are provided on the tractor wheel. Even in this case, when the number of pins that are always fitted in the sprocket holes 30 of the continuous copy paper 3 is 3, a large-diameter pin having a large diameter is arranged for every 3 pins in the tractor wheel. What is necessary is just to make it the structure to do.

1 Pin tractor 3 Continuous copy paper 4 Print head 6 Platen 7 Print section 10 Tractor belt 11 Pin 12 Large diameter pin 42 Elliptic pin A Conveying direction B Interlayer displacement

Claims (7)

In a pin tractor that conveys the continuous copy paper that is disposed upstream of the platen with respect to the conveyance direction of the continuous copy paper constituted by a plurality of media and is wound around the platen,
A plurality of pins which fit into a plurality of sprockets holes provided at equal intervals on the continuous copy paper,
The plurality of pins includes a first pin having a predetermined size, a size larger than the first pin , and a diameter larger than the diameter of the sprocket hole. A pin tractor comprising a second pin having a size to be press-fitted .   2. The pin tractor according to claim 1, wherein the larger size means that a diameter of the second pin is larger than a diameter of the first pin.   The cross section of the second pin is elliptical, and is provided with the major axis of the elliptical in the conveying direction, and the large size means that the second pin has a larger diameter than the diameter of the first pin. The pin tractor according to claim 1, wherein the major axis of the ellipse is large.   4. The pin tractor according to claim 2, wherein the second pin is provided for each N pin, where N is the number of pins that are always fitted in the sprocket holes during conveyance of the paper. 5.   The pin tractor according to claim 4, wherein the plurality of pins are provided on a tractor belt.   The pin tractor according to claim 4, wherein the plurality of pins are provided on a tractor wheel. A pin tractor according to any one of claims 1 to 6;
An image forming apparatus comprising: an image forming unit that forms an image on a sheet conveyed by the pin tractor.

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