JP2022174505A - Printer - Google Patents

Abstract

To provide a printer capable of accurately detecting a front edge of a sheet.SOLUTION: There is provided a printer, including: a sheet feeding unit 2; a registration unit 3 for aligning a front edge of a sheet of paper fed and conveyed from the sheet feeding unit 2 in a conveying direction of a sheet-like printed material; a main unit that prints on the sheets aligned by the registration unit 3; a paper discharge unit that discharges the sheet printed by the main unit; and a controller, the registration unit 3 including a sensor 8 for detecting the sheet conveyed to the registration unit 3, the sensor 8 including a light source that irradiates the sheet with light from below; and imaging means for imaging from below an area included in at least an irradiation area of the sheet that is irradiated with the light source, and the controller being configured to detect a front edge of the sheet based on a brightness of the captured image captured by the imaging means.SELECTED DRAWING: Figure 1

Description

The present invention relates to printing presses.

The printing press is provided with a registration section (positioning section) for positioning the conveyed sheet-like material (sheet paper) in the conveying direction and in the horizontal direction orthogonal to the conveying direction. The registration portion first stops the front end of the sheet which is conveyed in a scale-like pile by the feeder device constituting the sheet feeding device, so that the sheet is conveyed in the conveying direction (vertical direction). ) for positioning. Next, the horizontal needles are used to move the sheet in one of the left and right directions, thereby positioning the sheet in the left and right direction.

Next, the swing gripper is swung to a position (sheet gripping position) where the swing claw grips the front end of the sheet that is positioned and stopped by the front rest. When the front end of the sheet is gripped by the swing claws of the swing gripper that has moved to the sheet gripping position, the front support is moved to the retracted position, and then the swing gripper moves to the transfer position with the first intermediate cylinder (transport cylinder). to convey the sheet material. The swing gripper accelerates the sheet material from a stopped state to the peripheral speed of the first intermediate cylinder, and transfers the sheet material to the claws provided on the first intermediate cylinder.

After gripping the front end of the sheet-like article by the swing claw, the front rest and the horizontal needles return to their original positions for positioning the next sheet-like article. The returning front contact pushes up the tail side of the sheet-like material being conveyed by the swing gripper. Then, the front edge (front end) of the next sheet-like material reaches the front part when the returned front part is covered by the tail side of the sheet-like material being conveyed by the swing gripper. The swing gripper also returns to its original position (sheet gripping position) after transferring the sheet to the first intermediate cylinder.

In the above configuration, when the timing (arrival timing) at which the sheet-like object abuts against the front rest is greatly delayed, or when the sheet-like object is tilted obliquely and is stopped in contact with the front rest, the swing gripper swings. The claws may not be able to grip the sheet correctly. For this reason, a sensor (register detector) is arranged to detect the positioning state of the sheet in the front rest (see, for example, Patent Document 1).

As the sensor, a reflective photoelectric sensor is used as disclosed in Patent Document 2. This photoelectric sensor includes a light emitting section that irradiates the lower surface of the sheet with light, and a light receiving section that reflects the light from the light emitting section on the lower surface of the sheet and receives the reflected light. Then, based on the amount of light received by the light receiving portion, it is determined that the front edge of the sheet-like object is positioned at the front rest.

By the way, the front end of the sheet does not always extend straight, and for example, the sheet may be conveyed to the front support with the front end curved upward. In this case, the amount of light received by the light-receiving portion at the front end portion of the sheet-like object is extremely small. Therefore, even though the front edge of the sheet has moved to the front rest, the sheet cannot be detected, and the front edge of the sheet cannot be detected with high accuracy. rice field.

Japanese Patent No. 3712547 Japanese Utility Model Laid-Open No. 4-100150

SUMMARY OF THE INVENTION An object of the present invention is to provide a printing press capable of accurately detecting the front edge of a sheet.

In order to achieve the above object, a printing press according to the present invention comprises: a sheet feeding unit for feeding sheets; A registration unit for aligning the front edge of the main unit, a main unit that prints on the sheets that have been registered in the registration unit, and a paper discharge for discharging the sheets printed by the main unit. and a control unit, wherein the registration unit includes a sensor for detecting a sheet conveyed to the registration unit, the sensor applying light to the sheet from below. and imaging means for imaging from below at least an area included in the irradiation area irradiated by the light source on the sheet, and the control unit controls the image pickup image picked up by the imaging means. It is characterized by the detection of the front edge of the sheet on the basis of the contrast.

According to the above configuration, when the light source irradiates the sheet with light from below, a shadow is produced by the steps of the front edge of the sheet. Therefore, in the image of the area included in the irradiation area of the sheet, which is captured by the imaging means, the front edge of the sheet is darker than the other parts, and the boundary between the front edge and the other parts can be seen. Therefore, even if the front edge of the sheet is warped upward, the front edge of the sheet can be detected by detecting the front edge of the sheet based on the contrast of the captured image captured by the imaging means. can be detected with high accuracy.

Further, in the printing press according to the present invention, it is preferable that the light source is arranged on the upstream side in the transport direction or the downstream side in the transport direction with respect to the imaging means.

As described above, by arranging the light source on the upstream side or the downstream side in the transport direction with respect to the imaging means, a shadow can be clearly formed on the front edge of the sheet, so that the boundary between light and dark can be clearly recognized. .

Further, in the printing press according to the present invention, the control unit includes acquisition means for acquiring a brightness value from the captured image of the imaging means, and the brightness value acquired by the acquisition means matches a preset threshold value. a determination means for determining the position of the image corresponding to the matched brightness value as the front edge.

According to the above configuration, when the brightness value acquired by the acquiring means matches a preset threshold value, the position of the image corresponding to the matching brightness value is determined as the front edge, thereby accurately determining the front edge. can be detected well.

Further, in the printing press according to the present invention, the control unit sets a plurality of detection points in the conveying direction of the sheet within an imageable angle of view of the imaging unit, and the captured image detected at each detection point The front edge of the sheet may also be detected on the basis of the brightness of the .

According to the above configuration, the control unit sets a plurality of detection points in the conveying direction of the sheet within the angle of view that can be picked up by the image pickup means, and detects the light and shade of the picked-up image detected at each detection point. By detecting the front edge of the sheet, it is detected that the sheet is slanted, and processing is performed to correct the posture of the sheet, or the front edge of the sheet reaches the register. It can be utilized for performing various processes such as detecting the timing and adjusting the conveying speed of the sheets so as to achieve the desired timing.

According to the present invention, there is provided a printing press that can accurately detect the front edge of a sheet by detecting the front edge of the sheet based on the brightness and darkness of the captured image captured by the imaging means. be able to.

It is a top view which shows the registration part of a printing press. FIG. 4 is a longitudinal side view of a sensor that detects a sheet conveyed to the registration section; FIG. 10 is a side view showing movement in the vicinity of the registration section when the sheet arrives at the registration section; FIG. 5 is a side view showing a state immediately before the swing gripper moves the sheet to transfer it to the first intermediate cylinder; FIG. 5 is a side view of the rollers of the swing gripper device guiding the trailing edge of the sheet transferred to the impression cylinder; FIG. 4 is a longitudinal side view showing a state in which a sensor detects front edges of two sheets conveyed in an overlapping state; 3 is a block diagram showing control of the printing press; FIG.

A printer according to an embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the printing machine includes a paper feed section for feeding sheets (including printing paper and synthetic resin printing film) from a paper stacking table (not shown) by a feeder device 1. 2, a registration section 3 for aligning the position of the front edge of the sheet conveyed from the sheet feeding section 2 in the conveying direction and the position of the left and right edges of the sheet in the horizontal direction perpendicular to the conveying direction, and a register section 3. a main unit (not shown) for printing on the sheets aligned by the main unit, and a paper discharge unit (not shown) for discharging the sheets printed by the main unit. ing.

The sheet feeding unit 2 sequentially feeds the sheets such that the leading edge in the conveying direction of the succeeding sheet overlaps the trailing edge in the conveying direction (bottom edge) of the preceding sheet. do. A feeder device 1 provided in the paper feeding unit 2 includes an endless conveying belt 4 driven and rotated by a drive roller (not shown). The conveying belt 4 has a plurality of holes 4A along its entire length, and functions as a suction belt for sucking and conveying sheets by an air suction force from a suction box (not shown).

The registration unit 3 includes a front contact unit 5 for aligning the front ends of the sheets in the transport direction by contacting the front ends (starting ends) of the sheets in the transport direction to temporarily prevent the transport of the sheets. A contact mechanism 6 (see FIG. 3) and needles (horizontal needles) provided with horizontal needles for moving the sheet in one of the left and right (horizontal) directions to align the positions of the left and right (width direction) edges of the sheet. and a mechanism 7 (see FIG. 1). Needle (horizontal needle) mechanisms 7 are provided on the left and right sides, and one of the left and right needle (horizontal needle) mechanisms 7, 7 is used to move the sheet in one (or the other) of the left and right (horizontal) directions. position.

Also, as shown in FIG. 1, the registration unit 3 includes first front contact detecting means (front edge) for detecting the position (front edge) of the front edge in the conveying direction of the sheets aligned by the front contact mechanism 6 (see FIG. 3). needle detection means (second sensor) 9 for detecting the position of the right and left edges of the sheets aligned by the needle (horizontal needle) mechanism 7; sensor 8, has the same function as the first sensor 8, and detects the position (front edge) of the front end in the conveying direction of the sheets aligned by the front contact mechanism 6 (see FIG. 3). A second front contact detecting means (third sensor) 10 and a passing register detecting means (fourth sensor) 11 for detecting that the sheet has passed over the front contact portion 5 are provided. In order for the second front contact detection means (third sensor) 10 to detect a sheet with a small width that cannot be detected by the first front contact detection means (first sensor) 8, Then, the position of the front end of the sheet in the conveying direction (front edge) is detected by switching to either front contact detection means 10 or 8. FIG.

As shown in FIG. 2, the front contact portion 5 includes a front contact 5A that extends upward and abuts against the front end of the sheet P, and a separate member from the front contact 5A. , and a total of six eaves 5B are provided at intervals in the left-right direction as shown in FIG. The front contact portion 5 interferes with the sheet P conveyed by the swing gripper device 12 (see FIG. 3) and the positioning position F1 projecting upward from the conveying surface of the feeder device 1 to position the sheet. In order to prevent this from happening, it reciprocates between the front contact retraction position F2 positioned below the conveying surface of the feeder device 1 . The sheet contacting the front contact portion 5 at the positioning position F<b>1 is gripped by the swing gripper device 12 and moved to the first intermediate cylinder 13 while speeding up to the peripheral speed of the first intermediate cylinder 13 . As shown in FIG. 3, the swing gripper device 12 has a swing pawl seat 12A and a swing pawl 12B. 4) and a transfer position (not shown) for transferring the gripped sheet to the claws of the first intermediate cylinder 13.

A first sensor 8 and a third sensor 10 are arranged on both left and right sides, respectively, to detect whether the front end of the sheet is in contact with the front contact portion 5 and to check whether the posture in the conveying direction is normal ( within the tolerance). The detection result is input to the control unit S, which will be described later. If the control unit S determines that there is an abnormality, it issues an abnormality signal and stops the paper feeding. continue.

The second sensor 9 is arranged on each of the left and right sides, and detects whether or not the position of one of the left and right ends of the sheet is normal. The detected result is input to the control unit S, which will be described later. If the control unit S determines that the position is abnormal, an error signal is issued and the paper feed is stopped. Continue paper. Even when the controller S determines that the sheet is in an abnormal position, it is possible to issue an alarm while continuing the sheet feeding.

Further, the fourth sensor 11 is arranged at a substantially central position in the left-right direction, and when the sheet passes over the front contact portion 5, the light emitted upward from the light emitting portion is blocked and the light receiving portion receives the reflected light. Then, it detects that the sheet has passed over the front contact portion 5, issues an error signal, stops the paper feeding, and stops the printing press.

Also, although not shown, a fifth sensor is provided. The fifth sensor is arranged above and below the passing sheet, and the amount of received light (light transmission amount), it detects that a plurality of sheets have been conveyed in an overlapping manner, issues an error signal, and stops paper feeding.

As described above, the sheets are conveyed so that the leading edge in the conveying direction of the sheet is positioned below the trailing edge in the conveying direction of the preceding sheet (the arrow in FIG. is the direction in which the leaf is conveyed). The first sensor 8 (or the third sensor 10) is provided with a light source (not shown) that irradiates light from below onto an area including the front edge of the sheet that has been transported and comes into contact with the front rest. imaging means (not shown) for imaging a region included in the irradiated area (area including the front edge) from below. Note that the irradiation area and the imaging area may be set to areas of the same size, or may be set to an area in which the irradiation area is larger than the imaging area. The imaging means has a CMOS image sensor (not shown, hereinafter simply referred to as an image sensor) in which a plurality of elements for converting the brightness of light into an electric signal are arranged in a plane. The first sensor 8 (or the third sensor 10) configured in this manner detects the front edge (front end) of the sheet based on the contrast of the captured image captured by the image sensor. That is, as shown in FIG. 6, when the sheet is irradiated with light H from below by a light source, a bright and dark boundary is formed at the position of the front edge E of the sheet P on the lower side. Specifically, the front edge E becomes darker than the other portions, and the boundary between the front edge E and the other portions can be seen. Therefore, even if the front edge of the sheet is warped upward, for example, the front edge E of the sheet can be detected by detecting the front edge E of the sheet based on the brightness of the image picked up by the image sensor. The front edge E can be detected with high accuracy. Although FIG. 6 shows a state in which the sheets P are overlapped, the front edge E can be detected in the same manner even if the upper sheet P does not exist. Also, in FIG. 6, the thickness of the sheet P is drawn thicker than the actual thickness in order to make the front edge E easier to understand.

Further, the light sources of the first sensor 8 and the third sensor 10 are arranged downstream in the transport direction (or upstream in the transport direction) with respect to the image sensor. Then, as shown in FIG. 6, the light source irradiates light H obliquely upward from the downstream side in the conveying direction toward the upstream side in the conveying direction, and the irradiated light H is reflected by the sheet P, and the reflected light is received by the elements of the image sensor. By arranging the light source on the downstream side in the transport direction (or on the upstream side in the transport direction) with respect to the image sensor in this way, the boundary between the light and dark at the front edge E of the lower sheet P can be more reliably determined. Recognize.

The controller S binarizes the brightness of the light received by each element of the image sensor and inputs the binarized brightness value to the controller S. In addition, the control unit S compares the input brightness value with a preset threshold value to determine the brightness. This dark determined brightness value is determined to be the front edge of the sheet. Specifically, as shown in FIG. 7, the control unit S includes an acquisition unit 14 that acquires a brightness value by binarizing an image captured by the image sensor, and a brightness value acquired by the acquisition unit 14 is set in advance. and determination means 15 for determining the position of the image corresponding to the matched brightness value as the front edge when the threshold value is matched. In this way, the front edge can be accurately detected by determining the brightness value that matches the preset threshold value as the front edge. The image sensor may take images continuously or intermittently. Further, the acquisition unit 14 may acquire the data of the captured image at only one position in the conveying direction of the sheet, or may acquire the data of the captured image at a plurality of positions in the conveying direction.

The control unit S sets a plurality of detection points in the conveying direction of the sheet within an imageable angle of view of the image sensor, and detects the front edge of the sheet based on the brightness of the captured image captured at each detection point. By detecting the slanting of the sheet, processing for correcting the posture of the sheet is performed, or the timing at which the front edge of the sheet reaches the registration section 3 is detected. It can be used to perform various processes such as adjusting the conveying speed of sheets so as to achieve desired timing.

Specifically, the image sensor captures images at a predetermined cycle (for example, a cycle of 0.5 msec), and the angle at the moment when the front edge of the sheet can be imaged within the imaged angle of view is detected, for example, by an impression cylinder (another conveyance It can be grasped by correlating it with the number of pulses of the encoder that detects the rotation of the body. When the control unit S provided in the printing press receives the angle of the impression cylinder corresponding to the front edge of the sheet at the time of imaging, the control unit S determines the amount of deviation from the ideal angle (preset target angle). calculate. The sheet conveying speed or conveying timing of the feeder device 1 is adjusted according to the calculated amount of deviation.

The main unit includes a plurality of printing units (not shown) for printing patterns of special colors other than a plurality of colors (including gold, silver, fluorescent colors, etc.). Each printing unit includes a plate cylinder (not shown) on which a plate is wound, a blanket cylinder (not shown, also called a blanket cylinder) to which ink is transferred from the plate cylinder, and a sheet of paper pressed together by the blanket cylinder. an impression cylinder 16 (see FIG. 5) for transferring the ink on the blanket cylinder to the sheet; A cylinder (also referred to as a feed cylinder, see FIG. 5) and a transfer cylinder (not shown) positioned between the impression cylinders for transferring sheets from the impression cylinder of the previous printing unit to the impression cylinder of the next printing unit. ) and . The first intermediate cylinder, the impression cylinder and the transfer cylinder are collectively referred to as a transfer cylinder. In order to hold the sheet, the transport cylinder is provided with a claw and a claw rest for clamping the front edge of the sheet.

In FIG. 3, the gripping position shown in FIG. 2 where the sheet P is gripped with the front end abutting against the front contact portion 5 and the retracted position after the sheet is delivered to the first intermediate cylinder 13 are moved. A movement locus G1 of the swing gripper device 12 is shown. FIG. 4 shows a state in which the swing gripper device 12 has been swung from the retracted position in FIG. The swing gripper device 12 is swung in the direction opposite to the above so that the sheet gripped by the plurality of pairs of swing claw seats 12A and swing claws 12B provided in the swing gripper device 12 is moved to the first intermediate cylinder 13 . FIG. 5 shows a state in which the sheet P transferred to the first intermediate cylinder 13 is transferred to the impression cylinder 16 and conveyed by the impression cylinder 16 . At this time, the trailing edge of the conveyed sheet P is guided by a rotatable roller 17 provided in the swing gripper device 12 .

It should be noted that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention.

In the above embodiment, the printing press is provided with a plurality of printing units that print spot colors other than colors (including gold, silver, fluorescent colors, etc.), but an arbitrary number of units greater than or equal to one is provided. It may be a printer.

Moreover, in the above embodiment, a CMOS image sensor is used as an imaging means, but a CCD image sensor may be used.

Further, in the above-described embodiment, a pair of left and right first sensors 8 (or third sensors 10) are provided, but three or more sensors may be provided, or only one sensor may be provided. If only one is provided, it is only detected whether or not the front end of the sheet is in contact with the front contact portion 5, and it is not detected whether or not the posture in the conveying direction is normal (whether it is within the allowable range).

Further, in the above-described embodiment, the registration portion for aligning the front edge position in the sheet conveying direction and the left and right edge positions in the sheet conveying direction perpendicular to the sheet conveying direction is shown. It may be a registration portion that aligns only the front end position of. In this case, the left and right edges of the sheet are aligned in the left and right direction and sent to the registration section.

In the above-described embodiment, the light source is arranged downstream in the transport direction (or may be upstream in the transport direction) with respect to the imaging means. good.

DESCRIPTION OF SYMBOLS 1... Feeder apparatus 2... Paper feed part 3... Register part 4... Conveyor belt 4A... Hole 5... Front contact part 5A... Front contact part 5B... Eaves part 6... Front contact mechanism 7... Needle (horizontal needle) mechanism 8 first front contact detection means (first sensor) 9 needle detection means (second sensor) 10 second front contact detection means (third sensor) 11 travel register Detection Means (Fourth Sensor) 12 Swing Gripper Device 12A Swing Claw Seat 12B Swing Claw 12C Swing Axis 13 First Intermediate Cylinder (Paper Feed Cylinder) 14 Acquisition Means 15 Judgment Means 16 Impression cylinder 17 Roller E Front edge F1 Positioning position H Light P Sheet S Control unit

Claims (4)

A paper feeding unit for feeding sheets, a registration unit for aligning the front edge of the sheets fed and conveyed from the paper feeding unit in the conveying direction of the sheet-like printed material, and the registration unit A printing machine comprising: a main unit for printing on aligned sheets; a paper discharge unit for discharging the sheets printed by the main unit; and a control unit. ,
The registration section includes a sensor for detecting the sheet conveyed to the registration section, and the sensor includes a light source for irradiating the sheet with light from below and a sheet irradiated with at least the light source. and an imaging means for imaging the area included in the irradiation area from below,
The printing machine according to claim 1, wherein the control section detects the front edge of the sheet based on the brightness of the captured image captured by the imaging means. 2. The printing press according to claim 1, wherein the light source is arranged on the upstream side in the transport direction or the downstream side in the transport direction with respect to the imaging means. The control unit includes an acquisition unit that acquires a brightness value from the captured image of the imaging unit, and, when the brightness value acquired by the acquisition unit matches a preset threshold value, corresponds to the matching brightness value. 3. The printing press according to claim 1, further comprising a judgment means for judging the position of the image to be printed as the front edge. The control unit sets a plurality of detection points in the sheet conveying direction within an imageable angle of view of the imaging means, and detects the front side of the sheet based on the brightness of the image captured at each detection point. 4. A printing press as claimed in any one of claims 1 to 3, characterized in that it detects edges.

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