JPH0586945U - Paper edge detection structure - Google Patents

Abstract

(57) [Abstract] [Purpose] In the structure that detects the edge of the paper, the paper is pressed against the inclined plate by the holding roller and the paper is stretched to keep the distance between the sensor and the paper constant, and It is possible to detect the edge portion of the paper without being affected by waviness, curl, and the like. [Constitution] The motor 17 rotates and the timing belt 16
The cam 15 is rotated 90 degrees via and the frame 10 is pushed down. As a result, the holding roller 9 pivotally supported by the frame 10 presses the sheet 4 against the inclined plate 11, and the leading end of the sheet 4 is stretched while the sheet 4 follows the inclined plate 11 so that the distance between the sensor 12 and the sheet 4 is always constant. Since it is constant, the edge portion of the paper can be accurately detected.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a paper edge detection structure for a printer, a thermal transfer device, or the like in the field of electronic equipment, which detects the edge of the paper, conveys the paper to a predetermined position, and prints, prints, or copies. is there.

[0002]

[Prior Art]

 Conventionally, for example, as shown in FIG. 4, the sheet 4 is stocked on an auto sheet feeder 21, and the auto sheet feeder 21 is connected to a motor 18 via a timing belt 19. When the motor 18 starts rotating, the paper feed roller 20 carries the paper 4 and carries the paper 4 toward the pinch roller 5. The pinch roller 5 is connected to the stepping motor 7 by a timing belt 6, and the pinch roller 5 rotates in accordance with the rotation of the stepping motor 7. The pinch roller 5 grips the paper 4, and the controller (not shown) controls the rotation direction of the stepping motor 7 to convey the paper 4 back and forth. At this time, an upper and lower paper tray 8 is provided to regulate the vertical direction of the paper 4 so that the paper 4 can pass through the regular position even if the paper 4 is curled, and the paper 4 is conveyed between the upper and lower paper trays 8. It The upper and lower paper trays 8 can be provided with holes through which light from the sensor passes and a diffuse reflection plate 13, respectively. The sensor 12 emits light, and when the sheet 4 is present, the sheet 4 is recognized by sensing the light reflected by the sheet 4. If the sheet 4 does not exist, the diffuse reflection plates 13 arranged at the opposite positions of the upper and lower sheet trays 8 are exposed to light, and the diffused light does not return the reflected light. Therefore, it is determined that there is no sheet.

The paper 4 is guided by the upper and lower paper trays 8 while being fed by the pinch rollers 5, and reaches the sensor 12 for edge detection. The sheet edge is detected, the counting of the stepping motor 7 is started, and the sheet 4 passes over the sheet edge sensor 12. After feeding the required amount of the sheet 4, the stepping motor 7 rotates in the reverse direction, and the pinch roller 5 interlocks with the timing belt 6 to convey the sheet 4 in the reverse direction. The paper edge sensor 12 detects the edge portion of the paper 4 again when the edge portion of the paper 4 reaches the paper edge sensor 12, and conveys the paper 4 by the required pulse count number from this point to the print start portion. Then, the paper 4 and the ink sheet 3 are nipped between the thermal head 1 and the platen 2, and a voltage is applied to the thermal head 1 to melt the ink sheet 3 and start printing on the paper 4.

Further, as shown in FIG. 5, for example, when the leading edge of the paper 4 is curled, the distance from the paper edge sensor 12 is changed, which prevents erroneous detection and being out of the detection range of the paper edge sensor 12. Therefore, it is necessary to control the interval between the upper and lower paper trays 8 that regulate the vertical direction of the paper 4 to a predetermined dimension. Further, for example, as shown in FIG. 6, even if the space between the upper and lower paper trays 8 is managed, the paper 4 may make a wave within the space, and as a result, the distance between the paper edge sensor 12 and The detection accuracy depends on the state of the paper 4 such as the change of the.

[0005]

[Problems to be solved by the device]

 Since the conventional paper edge portion detection structure is configured as described above, the paper 4 will be corrugated or curled in this space unless the space between the upper and lower paper bases 8 is reduced as much as possible. However, the distance between the sensor 12 and the paper 4 is not constant, and there is a possibility that the detection distance range up to the detected object is deviated. Alternatively, due to the characteristics of the sensor 12, the emitted light spreads toward the end, and the detection position may change subtly when the paper position moves up and down, which may reduce the detection accuracy or, in some cases, cause the sensor 12 to come too close to detect it. Problems such as not occurring occur.

If the pinch roller 5 and the sensor 12 are not arranged as close to each other as possible, the end surface of the sheet 4 hangs down due to its own weight and approaches the sensor 12. Therefore, in order to prevent this, the interval between the upper and lower sheet trays 8 is set to 0. If the proper distance from the sensor 12 is maintained by keeping the distance from about 3 to 0.5 mm, the paper 4 with a thickness of about 0.1 mm and the leading edge curled or corrugated is placed on the upper and lower paper trays 8. It is difficult to convey through the gap, and in practice, at the above-mentioned gap distance, the print surface of the paper 4 comes into contact with the upper and lower paper trays 8 and a defect such as scratching the print surface occurs, or the paper 4 does not move. It becomes difficult to remove the paper 4 when a jam occurs. Further, there is a problem that the distance from the sensor 12 changes due to the difference in the thickness of the sheet 4 and the dry state of the sheet 4 due to the difference in stiffness.

The present invention has been made to solve the above-described problems, and manages the gap between the upper paper tray and the lower paper tray more than necessary and does not worry about the thickness of the paper. It is intended to provide a structure for stably detecting the edge portion of the paper.

[0008]

[Means for Solving the Problems]

 In the paper edge detecting structure according to the present invention, an inverted V-shaped inclined plate is provided, and the paper is pressed by the rollers inclined by the same amount as the inclination angle.

[0009]

[Action]

 With the above configuration, the edge of the paper can be stretched, and there is no change in the distance from the sensor due to waviness of the paper itself when the edge of the paper is detected, preventing damage to the printing surface and erroneous detection. You can do it.

[0010]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an assembly sectional view of the present invention, in which 4 is a sheet, and a motor 18 rotates from a state of being stocked in an automatic sheet feeder 21 and a feeder roller 20 is rotated clockwise through a timing belt 19. The sheet is rotated and conveyed, passes between the thermal head 1 and the platen 2 through the sheet conveying tube 23, and reaches the pinch roller 5. Although an ink sheet is not shown in this figure, it goes without saying that it is located between the thermal head 1 and the paper 4. A timing belt 6 is connected to the stepping motor 7 and drives the pinch roller 5. The pinch roller 5 conveys the sheet 4 toward the left side of the drawing. The flapping of the sheet 4 at this time is regulated by the sheet stands 8 above and below the passage of the sheet 4.

The role of the upper and lower paper trays 8 at this time is not to regulate the gap between the sensor 12 and the paper 4 for detecting the edge portion of the paper 4 as in the conventional case, but simply to move the paper 4 from the pinch roller 5 to the paper. Since it is a guide for conveying the sheet 4 to the inclined plate 11 and then pressing the sheet 4 against the inclined plate 11 by the holding roller 9, the gap between the upper and lower sheet trays 8 is about 1 to 2 mm, which is smaller than that of the conventional example. Management is eased. The paper 4 reaches the sensor 12 while being guided by the upper and lower paper trays 8 and detects the edge portion of the paper 4. From this point of time, the controller 4 (not shown) conveys the sheet 4 while counting the number of pulses of the stepping motor 17 to remove the meandering of the sheet 4. When the required amount of conveyance is counted, the motor 17 rotates, the cam 15 rotates 90 degrees via the timing belt 16, and the frame 10 is pushed down.

As a result, the holding roller 9 presses the sheet 4 against the inclined plate 11, the leading edge of the sheet 4 is stretched while the sheet 4 follows the inclined plate 11, and the edge portion of the sheet to be detected by the sensor 12 does not wavy. When it comes into pressure contact with the inclined plate 11, the stepping motor 7 is reversely rotated by a controller (not shown), and the pinch roller is interlocked with the timing belt 8 to start the reverse conveyance of the sheet 4. The inclined plate 11 has a window 22 through which the light of the sensor 12 passes. Reverse conveyance is continued until the edge of the sheet 4 reaches the sensor 12 again, and the count is cleared when the edge of the sheet 4 can be detected by the sensor 12. When the detection of the edge portion is completed, the motor 17 rotates, the cam 15 rotates 90 degrees via the timing belt 16, and the cam 15 is locked to two positions on both sides of the shaft 15a of the cam 15 and the upper surface of the frame 15. The frame 10 is lifted by the force of the spring 14. The distance from the sensor 12 calculated in advance to the specified position for starting printing is conveyed while counting the number of pulses of the pulse motor.

FIG. 2 is a detailed view of the sensor portion of the present invention, in which two holding rollers 9 having both ends of the shaft supported by the inclined plate 11 are pressed against a part of the frame 10. A diffuse reflector 13 scatters light emitted from the sensor 12 when the sheet 4 is not present. FIG. 3 is a perspective view of the inclined plate portion of the present invention, showing a state in which the sheet 4 is stretched when the edge portion of the sheet is detected.

The cam 15 for vertically moving the holding roller 9 axially supported by the frame 10 via the frame 10 has a structure in which it is operated by, for example, a motor 17 by a train wheel. Be done.

[0015]

[Effect of the device]

 The present invention prevents the corrugation and fluttering of the paper by placing the edge of the paper along the inclined plate and stretching the edge only when detecting the edge of the paper, and the distance from the sensor to the paper is always constant. , It is possible to enable stable detection within the detection distance range of the sensor. Also, you don't have to worry about paper thickness, elongation, stiffness, and dryness. Further, since it does not affect the printing surface, it can be easily manufactured without pushing the accuracy of the member, and the management of the member can be omitted, so that the cost can be reduced.

[Brief description of drawings]

FIG. 1 is an assembled sectional view of the present invention.

FIG. 2 is a detailed view of a sensor unit of the present invention.

FIG. 3 is a perspective view of an inclined plate portion of the present invention.

FIG. 4 is a sectional view of a conventional assembly.

FIG. 5 is a detailed view of a conventional sensor unit.

FIG. 6 is a detailed view of a conventional sensor unit.

[Explanation of symbols]

 1 Thermal Head 2 Platen 3 Ink Sheet 4 Paper 5 Pinch Roller 6 Timing Belt 7 Stepping Motor 8 Paper Stand 9 Holding Roller 10 Frame 11 Inclination Plate 12 Sensor 13 Diffuse Reflecting Plate 14 Spring 15, 19 Cam 16 Timing Belt 17, 18 Motor 20 Feeder Roller 21 Auto sheet feeder 22 Tilt plate window 23 Paper transport tube

Claims (2)

[Scope of utility model registration request] 1. A sheet edge detection sensor, a sheet table for guiding the sheet to a conveyance path, a pinch roller that conveys the sheet by sandwiching and rotating the sheet from above and below, and a timing belt that rotates the pinch roller. In a paper feed structure having a stepping motor for driving the timing belt, an inclined plate for bending the paper into an inverted V shape has a window through which light emitted from the paper edge detection sensor is passed and is located in the vicinity of the sensor. A holding roller for causing the paper to follow the inclined plate,
A frame for holding the holding roller rotatably, and a means for pressing the holding roller pivotally supported by the frame against the inclined plate or separating the holding roller from the holding roller. By pressing, the paper is made to follow the shape of the inclined plate, and the edge of the paper is stretched, the distance from the sensor is kept constant and the paper edge can always be detected stably. Paper edge detection structure characterized by transporting. 2. The paper edge detection structure according to claim 1, wherein a diffuse reflection plate is arranged at a position corresponding to the paper edge detection sensor of the frame.