JPH07206220A - Inclination detector for record paper sheet - Google Patents

Abstract

PURPOSE:To detect inclination of a paper sheet even in printing by a paper sheet end shift detector mechanism with simple mechanical constitution. A CONSTITUTION:An inclination detector is provided with a sensor lever 2 which drives responsive to slanting of a paper sheet end in conveying a record paper sheet 1, a slit setting means 3 which drives simultaneously with the sensor lever 2 and measures a semicircular or a fan-shaped paper sheet end slanting quantity, a count means 5 which measures a slit provided at the slit setting means 3, and a means for detecting whether or not the slit measurement quantity measured by the count means 5 is larger than the standard value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording paper skew detection device, and more particularly, to detect the skew of the recording paper by measuring the amount of paper edge deviation of the recording paper with a mechanically simple structure. The present invention relates to a skew detection device capable of

[0002]

2. Description of the Related Art Generally, a plotter or printer, which is a kind of image forming apparatus, has a print head for forming an image on a recording sheet being conveyed on a platen and a recording sheet conveying direction for holding the print head. A carriage that is scanned in a direction perpendicular to the (longitudinal direction of the recording paper) (width direction of the recording paper), and a recording paper detection sensor that is provided on the carriage and detects whether or not the recording paper exists on the platen. , And a control unit for controlling the entire apparatus including a print control means for outputting a print signal to the print head. Then, while the recording paper is being conveyed, a print signal is output from the print control means under the control of the control unit and ink is ejected from the print head to form an image on the recording paper.

In the case where an image is formed using a large-sized recording paper among such plotters and printers, if the recording paper is not conveyed well and the recording paper is skewed and there is a paper edge misalignment, it exceeds a predetermined amount. There is a possibility that the accuracy of image formation may deteriorate and wrinkles may occur on the recording paper. Therefore, conventionally, the skew of the recording paper is detected by using the recording paper detection sensor provided on the carriage. In other words, the carriage is scanned once to detect the position of the paper edge of the recording paper by the recording paper detection sensor, then the recording paper is conveyed by a certain amount, and the carriage is scanned again to the recording paper detection sensor again. Detects the position of the paper edge. Then, the presence / absence of skew of the recording paper is detected from the conveyance amount of the recording paper and the difference between the first detected paper edge and the second detected paper edge. If the detected skew feeding amount exceeds the allowable amount, the skew feeding correcting mechanism is operated to correct the skew feeding amount.

[0004]

However, in the conventional skew feeding detecting device for a recording sheet of this type, the carriage is scanned twice to detect the position of the edge of the recording sheet to detect the skew feeding. Therefore, there is a problem that the control becomes complicated and it takes time to detect the skew. Further, since the position of the paper edge is detected by using the recording paper detection sensor provided on the carriage, skew feeding cannot be detected during image formation (printing), and skew feeding that occurs during printing will not occur. It had the drawback that it could not be detected.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a recording paper skew detection device that can detect even during printing by a paper edge deviation detection mechanism having a simple mechanical structure. It is in.

[0006]

In order to achieve the above object, the present invention has a structure of a recording paper skew detection device as follows. That is, a sensor lever that moves when the recording paper is conveyed due to a paper edge shift, a slit setting means that moves in synchronization with the sensor lever for measuring the amount of paper edge deviation of a semicircle or a fan, and the slit setting means The gist of the present invention is to provide a counting means for measuring the provided slit and a means for judging whether or not the slit measurement amount by the counting means is larger than a reference value.

Further, in this skew feeding detection device for the recording paper, the sensor lever and the slit setting means for measuring the deviation amount of the semi-circular or fan-shaped paper edge make a rotational movement with the center position of the semi-circle or the fan shape as the fulcrum. It is characterized in that the reference value is set with a position, which is pushed by a predetermined amount of slits by the paper edge when the recording paper is conveyed, as a reference point.

Further, in these skew feeding detection devices for recording paper, a photo interrupter is used as a slit counting means for measuring the amount of paper edge deviation.

[0009]

According to the above construction, when the recording paper is normally conveyed at the standard position, the paper edge is not displaced and the sensor lever does not move. However, when the recording paper skews and a paper edge shift occurs, the sensor lever moves, and at the same time when the sensor lever moves, a semi-circular or fan-shaped slit setting means in which a slit is set to measure the paper edge shift amount is also provided. Move. As a result, the count number of the number of slits varies depending on the paper edge deviation amount, a reference value is set in advance for the count number of this slit, and when the count value becomes equal to or greater than this reference value, skew of the recording paper occurs. To detect that there is.

Further, the sensor lever and the slit setting means for measuring the amount of paper edge deviation of a semicircle or a fan are integrally configured, and the sensor lever and the slit setting means determine the center position of the semicircle or a fan. It is provided as a fulcrum so as to make a rotational movement. Then, when the recording paper is normally conveyed to the standard position, the sensor lever is slightly pressed, and the reference value is set with the position pressed by a predetermined amount of the slit by the paper edge as the reference point. Since the setting is made, it is possible to detect whether the recording paper is normally conveyed at the standard position, and whether the paper edge shift occurs in the pushing direction or the pulling direction.

Further, since the photo interrupter is used as the slit counting means for measuring the amount of paper edge deviation,
The slit can be detected reliably.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of an embodiment of a skew feeding detection device for recording paper according to the present invention. In FIG. 1, the recording paper 1 is set on the platen at a position indicated by a line S, and is conveyed in a direction indicated by an arrow L by a conveying means (not shown) so that the standard sheet edge 1a passes through the line S. A sensor lever 2 which is a part of the recording paper skew detection device is in contact with the paper edge 1a.
Further, the sensor lever 2 is integrally formed with the slit setting means 3 having a semicircular shape, and the slit setting means 3
The semicircular center 4 is used as a fulcrum for rotational movement. The semicircular slit setting means 3 has slits set at predetermined intervals in order to measure the amount of paper edge deviation. This slit is counted by the photo interrupter 5 and fed back to the control unit on the apparatus main body side.

FIG. 2 is a more concrete view of the structure of the skew feeding detection device for the recording paper. In FIG. 2, the sensor lever 2 is shown with a part omitted, but it is designed to rotate integrally with the slit setting means 3 with a semicircular center 4 as a fulcrum. The paper edge 1a of the recording paper 1 is in contact with the sensor lever 2, and this contact state is such that the sensor lever 2 is slightly pushed when the paper edge 1a is conveyed along the line S which is normal, that is, the standard state. Is set so that Therefore, unlike the extension M of the sensor lever 2 of the semicircular slit setting means 3, the reference point N of the slit setting means 3 is provided at a position slightly displaced in the direction in which the sensor lever 2 is pressed. By doing so, it is possible to detect both the case where the paper edge 1a of the recording paper 1 moves in the direction 6 in which the sensor lever 2 is pushed from the line S which is the standard state, and the case where the sensor lever 2 moves in the direction 7 in which the sensor lever 2 is pulled. Will be able to. Therefore, reference values, which are allowable values for the amount of paper edge deviation, are provided in both the pushing direction 6 and the pulling direction 7 with the reference point N as the center. The reference value T is a mark in the pushing direction 6 and the reference value H is a mark in the pulling direction 7. In FIG. 2, a slit, which is thicker than a normal slit, is attached to the third slit from the reference point N as an allowable value. usually,
The recording paper 1 is conveyed as much as 300 mm, and if the paper edge deviation amount of ± 1 mm or more is detected as skewing, the above setting is made. Therefore, when the photo interrupter 5 detects the mark of the reference value T or H, the control unit on the apparatus main body side detects and displays the skew, and activates the skew correction mechanism.

Next, the operation / action of the skew feeding detection of the recording paper of this embodiment will be described with reference to the flow chart of FIG. When the skew detection operation is started (step 300), first,
Set recording paper (paper) 1 on the platen (step 301)
) Do. The recording paper 1 is set so that the paper edge 1a is conveyed on the line S as described above. Then, the slit counter of the photo interrupter 5 is reset (step 302
), And the conveyance of the recording paper 1 is started (step 303).
In this case, if the recording paper 1 is not yet conveyed (NO), the process returns to step 302. Slits are counted by the photo interrupter 5 while the recording paper 1 is being conveyed (step 304)
To do. Next, it is judged whether or not the recording paper 1 is conveyed by a constant amount (step 305). As a result, when the predetermined amount is not conveyed (NO), the process returns to step 304, and when the predetermined amount is conveyed (YES), it is determined whether or not the count value of the photo interrupter 5 exceeds the reference value (step 306). ) Do. If the reference value is not exceeded (NO), skew feeding is not detected, so image formation continues (RET). If the count value exceeds the reference value (YES), the slit is counted by the photo interrupter 5 and skewed. The line amount is calculated (step 307), the skew detection is displayed, and the skew correction mechanism is activated.

In the above-mentioned embodiment, the slit setting means 3 is shown as an example of a semicircular shape, but the slit setting means 3 is not limited to a semicircular shape and may be a fan shape. What is essential is that the slit can be set and the deviation of the paper edge can be detected. In the above embodiment, the standard S of the paper edge 1a is set in the direction in which the sensor lever 2 is slightly pushed, but the present invention is not limited to this example. It is also possible to set the reference point N on the extension line M of the sensor lever 2 without setting it as in the above embodiment. In this case, the contact state between the sensor lever 2 and the paper edge 1a of the recording paper 1 must be set so that the sensor lever 2 has a tilting habit toward the paper edge 1a. Otherwise, the paper edge shift in the pulling direction 7 in the above embodiment cannot be detected.

[0016]

As described above, according to the skew feeding detection apparatus for a recording sheet of the present invention, even if the sheet edge detection operation is not performed by the two carriage scans, the sheet is conveyed once with a simple mechanical structure. The skew detection can be performed, and the skew detection operation does not take time. Furthermore, since skew feeding can be detected independently of carriage scanning, skew feeding can be detected as needed even during printing, that is, during image formation.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of a skew feeding detection device for a recording sheet of the present invention.

FIG. 2 is a diagram for explaining a mechanical configuration of a recording sheet skew detection device of the present invention.

FIG. 3 is a view showing a flowchart of a skew feeding detection device for a recording sheet of the present invention.

[Explanation of symbols]

 1 recording paper 1a paper edge 2 sensor lever 3 slit setting means 4 fulcrum 5 photo interrupter 6 pushing direction by paper edge 7 pulling direction by paper edge

Claims (3)

[Claims] 1. A sensor lever that moves due to a paper edge shift when a recording sheet is conveyed, a semi-circular or fan-shaped slit edge setting means that moves in synchronization with the sensor lever, and slits. A skew feeding detection device for recording paper, comprising: count means provided in the setting means for measuring a slit; and means for judging whether or not the slit measurement amount by the count means is larger than a reference value. 2. The sensor lever and the slit setting means for measuring a semi-circular or fan-shaped sheet edge shift amount are provided so as to make a rotational movement with a semi-circular or fan-shaped center position as a fulcrum. A skew detection device for a recording sheet, wherein the reference value is set with a reference point being a position where a predetermined amount of a slit is pressed by a sheet edge when the recording sheet is conveyed. 3. A skew feeding detecting device for a recording sheet according to claim 1, wherein a photo interrupter is used as a slit counting means for measuring a sheet edge shift amount.