JP2002361835A - Plate roll sensing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plate roll sensing apparatus capable of printing in a state in which a used plate roll is not mounted by automatically judging the presence or absence of the roll based on a relatively simple constitution. SOLUTION: The plate roll sensing apparatus comprises a plate cylinder 2 capable of mounting a plurality of plate rolls 10, and an image forming unit 7 for forming an image on a plate film 1 supplied from the roll 10 to an outer peripheral surface of the cylinder 2 to sense the presence or absence of the roll 10. The sensing apparatus comprises a signal originating unit for originating a detection signal to a mounting position of the roll 10 at the cylinder 2, a signal receiving unit for receiving a reflected signal of the detection signal, and a controller for judging the presence or absence of the roll 2 based on information obtained from the originating unit and the receiving unit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital printing press having an imaging unit, and more particularly to a plate roll detecting device for detecting the presence or absence of a plate roll in a printing unit of a digital printing press.

[0002]

2. Description of the Related Art As shown in FIG. 7, a printing unit of an offset printing press winds a plate film 1 around an outer peripheral surface thereof and rotates the plate cylinder 2 and supplies ink to the plate film 1 on the plate cylinder 2. An inking unit 3, a blanket cylinder (not shown) onto which an image is transferred from the plate film 1, and an impression cylinder (not shown) for sandwiching printing paper between the blanket cylinder and transferring an image on the blanket cylinder to the printing paper ( (Not shown).

The printing press shown in FIG. 7 is a digital printing press.
A roll-shaped plate film 1 (plate roll) having a length capable of continuously forming a plurality of images is configured to be set on the plate cylinder 2. Specifically, a roll-shaped plate film 1 is mounted in a concave portion 4 formed on the outer peripheral surface of the plate cylinder 2, and a supply reel 5 for feeding an unused portion of the plate film 1 to the outer peripheral surface; There is provided a take-up reel 6 for holding the starting end 1a of the film 1 and winding the used portion of the plate film 1 from the outer peripheral surface of the plate cylinder 2.

When a new plate film 1 is set on the plate cylinder 2, a new plate roll is mounted on the supply reel 5, the starting end 1a of the mounted plate roll is pulled out from the recess 4, and the starting end 1a is grasped. By pulling with
While applying tension to the plate film 1, the plate cylinder 2 is rotated in the direction of arrow P in FIG. By the rotation of the plate cylinder 2, the plate film 1 is gradually wound around the outer peripheral surface of the plate cylinder 2, and after the winding at a predetermined angle is completed, the start end 1a is held by the take-up reel 6. In this way, plate cylinder 2
The setting of a new plate film 1 is completed.

When the plate film 1 is set, the plate wound around the outer peripheral surface of the plate cylinder 2 by the imaging unit 7 fixedly arranged with a predetermined gap between the plate film 2 and the outer peripheral surface. An image is formed on the film 1, and the plate film 1 is used as a printing plate. The image is printed by supplying the ink from the ink unit 3 to the plate film 1, and when the printing is completed, the take-up reel 6 removes the used portion of the plate film 1 from the outer peripheral surface of the plate cylinder 2. From the supply reel 5 and the plate film 1
Unused portions are sequentially fed out. That is, in an offset printing press having the printing unit shown in FIG.
Using the imaging unit 7, a new image can be formed on the fed-out plate film 1 again. Therefore, until the plate film 1 forming the plate roll has no unused portions, the plate is removed. The image formation and the printing can be repeatedly performed without performing the complicated processing of.

In the printing unit constructed as described above, when the unused portion of the plate film 1 is eliminated and the plate film 1 is completely taken up by the take-up reel 6, as shown in FIG. End portion 1b comes out.
The terminal portion 1b of the plate film 1 is a portion which is inserted into and wound around a hole (not shown) formed in the supply reel 5, and is formed in a tongue shape. And this FIG.
When the printing unit is driven in a state in which the end portion 1b of the plate film 1 is protruded as shown in FIG. It becomes dirty or dirty.

Therefore, in the prior art, in order to prevent the above-mentioned dirt and the like, the unused portion is eliminated and the terminal portion 1b is removed.
The plate cylinder 2 is configured not to rotate until the plate film 1 (plate roll) from which is projected is removed and a new plate roll is attached.

[0008]

As shown in FIGS. 7 and 8, two plate rolls are mounted on the plate cylinder 2 constituting the printing unit described above, and the plate film 1 is transferred from each plate roll. After being pulled out, the drawn-out plate film 1 is used as a printing plate. That is, usually, printing is performed using two plate films 1 attached to the plate cylinder 2.

However, in a situation where there is no spare plate roll, for example, the printing unit must be driven only with another color (using only the remaining plate rolls) without mounting one of the plate rolls. You may have to. In such a case, the printing process on the printing paper must be performed using the plate film 1 supplied from one plate roll so that the end portion 1b of the wound plate roll does not hit the surrounding elements. Must. Specifically, it is necessary to remove the used plate roll, drive the plate cylinder 2 and the like after recognizing that the printing press has removed the plate roll.

However, the printing unit according to the prior art is not provided with a detecting device for judging whether or not the used plate roll has been removed from the plate cylinder 2 without fail. The presence or absence could not be determined. This is because it was technically difficult to provide a sensor or the like inside the concave portion 4 of the plate cylinder 2 on which the plate roll is mounted to detect the presence or absence of the plate roll. That is, if a sensor or the like is to be provided inside the concave portion 4 of the plate cylinder 2, wiring must be necessarily provided on or inside the rotation axis of the plate cylinder 2. Since it rotates at a high speed, it is technically difficult to implement such a wiring or the like to realize a detection device.

As described above, in the prior art, it cannot be determined whether or not the plate roll has been removed, and the rotation of the plate cylinder 2 with the end portion 1b of the plate film 1 protruding is prevented. Therefore, the plate cylinder 2 cannot be rotated until a new plate roll is mounted. Therefore, in the conventional printing unit, the printing process using one plate roll could not be performed.

Accordingly, the present invention has been made to solve the above-mentioned problems of the prior art, and automatically determines the presence or absence of a plate roll based on a relatively simple structure, and uses the used plate. An object of the present invention is to provide a plate roll detection device that enables printing processing in a state where a roll is not mounted.

[0013]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and comprises a plate cylinder on which a plurality of plate rolls can be mounted, and a plate roll on an outer peripheral surface of the plate cylinder. A printing unit provided with an image forming unit that forms an image on a plate film supplied from a printing press, a plate roll detecting device that detects the presence or absence of the plate roll, and detects the mounting position of the plate roll on the plate cylinder. A signal transmitting unit that transmits a signal, a signal receiving unit that receives a reflected signal of the detection signal, the signal transmitting unit, and a control unit that determines the presence or absence of the plate roll based on information obtained from the signal receiving unit. It is characterized by having.

As described above, according to the present invention, a signal transmitting section for transmitting a detection signal, a signal receiving section for receiving a reflected signal of the detection signal, and controlling these, based on information obtained therefrom, Since the plate roll detecting device is configured by using the control unit that determines the presence or absence of the plate roll, without providing complicated wiring and the like in the plate cylinder, in a non-contact state with the plate cylinder, The presence or absence can be detected. Therefore, according to the present invention, the presence or absence of a plate roll is automatically determined based on a relatively simple configuration, and in a state where a used plate roll is not mounted, based on information to that effect, Normal printing processing can be performed by enabling high-speed rotation of the plate cylinder.

Further, the plate roll detecting device according to the present invention has a rotation angle detection unit for detecting a rotation angle of the plate cylinder, and the control unit receives the rotation angle detection unit based on information obtained by the rotation angle detection unit. It is preferable that the mounting position of the plate roll be recognized.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic view of a printing unit of a printing press provided with a plate roll detecting device according to an embodiment of the present invention. Since the printing unit in this embodiment is for two colors, the plate cylinder 2 is configured to wind the plate films 1 for two colors on the outer peripheral surface thereof. That is, the plate roll 10 that supplies the plate film 1 for each color is
It is configured so that it can be mounted at two places, and for that purpose, two sets of a supply reel 5 and a take-up reel 6 are provided. It should be noted that two sets of ink units 3 each composed of a plurality of ink rollers for supplying ink for each color are also provided.

A recess 4 is formed on the outer peripheral surface of the plate cylinder 2 at a position facing approximately 180 degrees. The concave portion 4 is formed along the axial direction of the plate cylinder 2 and has a concave groove shape as a whole. The outer peripheral surface of the plate cylinder 2 is divided into two regions by the concave portions 4, and the plate film 1 is wound around each region. A plate roll 10 for supplying the plate film 1 can be mounted in each recess 4.

Each recess 4 has one area (for one color)
And a take-up reel 6 for taking up the used plate film 1 in the other area (for the other color). , Supply reel 5 and take-up reel 6
Are provided along the axial direction of the plate cylinder 2. Also,
In each recess 4, the take-up reel 6 is connected to the supply reel 5.
And the back side of the plate film 1 supplied from the plate roll 10 slides against the edges 13 and 14 of the outer peripheral surface facing the recess 4. .

The imaging unit 7 (corresponding to the "image forming section" of the present invention) is fixedly arranged at a position above the plate cylinder 2, and is provided between the lower end thereof and the outer peripheral surface of the plate cylinder 2. A predetermined gap is provided. A predetermined space 8 required for setting a new plate film 1 on the plate cylinder 2 is provided in front of the imaging unit 7, and a light shielding plate 9 is provided in front of the space 8 in an upright state. It is arranged.

In the printing unit configured as shown in FIG. 1, when a new plate film 1 is set on the plate cylinder 2, a new plate roll 10 is mounted on the supply reel 5,
The starting end 1a of the mounted plate roll 10 is pulled out from the concave portion 4, and the starting end 1a is gripped and pulled to apply tension to the plate film 1 and rotate the plate cylinder 2 in the direction of arrow P (see FIG. 1). . By the rotation of the plate cylinder 2,
The plate film 1 is gradually wound around the outer peripheral surface of the plate cylinder 2. Then, after the winding at the predetermined angle is completed, the starting end 1 a of the plate film 1 is held on the take-up reel 6.
Through these steps, the setting of the plate roll 10 and the plate film 1 on the plate cylinder 2 is completed.

When the plate film 1 is set in this manner, the outer peripheral surface of the plate cylinder 2 is fixed by the imaging unit 7 fixedly arranged with a predetermined gap between the plate film 2 and the outer peripheral surface. An image is formed on the plate film 1 wound on the plate film 1, and the plate film 1 on which the image is formed is used as a printing plate. Then, by supplying ink from the ink unit 3 to the plate film 1, a printing process using an image formed on the plate film 1 is performed. When this printing process is completed, the used portion of the plate film 1 is taken up from the outer peripheral surface of the plate cylinder 2 using the take-up reel 6, and the unprinted portion of the plate film 1 is taken out of the plate roll 10 mounted on the supply reel 5. The used part is sequentially fed out. That is,
Automatic plate exchange is performed.

In the printing unit according to this embodiment, the printing plate supplied from the plate roll 10 (automatic plate replacement).
New images can be sequentially formed on the plate film 1 by using the imaging unit 7. Therefore, according to the present embodiment, while the plate roll 10 has an unused portion of the plate film 1, image formation on the plate film 1 and printing are repeatedly performed without performing complicated processing such as removal of a printing plate. And printing processing on paper.

In the printing unit constructed and operated as described above, a plate roll detecting device for detecting the presence or absence of the plate roll 10 is provided. Specifically,
This plate roll detecting device includes a photoelectric sensor 21 having a light emitting unit (corresponding to a “signal transmitting unit” of the present invention) and a light receiving unit (corresponding to a “signal receiving unit” of the present invention), It is configured using a rotary encoder (corresponding to the “rotation angle detection unit” of the present invention) and the like. The plate roll detection device will be described later in detail.

Next, the operation of replacing the plate film 1 (so-called automatic plate exchange) in the printing unit configured as described above will be described with reference to FIGS. Here, FIG. 2 is a schematic diagram showing a relationship between a set of supply reel 5 and a take-up reel 6 provided on the plate cylinder 2 shown in FIG. 1, and FIG. 3 is a flowchart when the above is performed.

As shown in FIG. 2, in the present embodiment, a motor 26 for driving the take-up reel 6 is used.
Is configured to transmit a driving force to a gear 23 provided at an end of the take-up reel 6 via a gear 22.
The take-up reel 6 has a plurality of sheets (4 in this case).
Wings 24 having wings are attached,
A blade sensor 25 including a photocoupler or the like is provided near the blade portion 24. Further, a fixing device (not shown) capable of switching between rotation and fixing of the supply reel 5 is provided at an end of the supply reel 5. In other words, in the present embodiment, the plate film 1 is supplied from the plate roll 10 using these motors 26, fixing devices, and the like to perform automatic plate replacement and the like. Hereinafter, the automatic plate exchange will be specifically described with reference to FIG. 2 and based on the flowchart of FIG.

As shown in FIG. 3, when performing automatic plate exchange in the printing unit according to the present embodiment, first, the fixing state of the fixing device provided at the end of the supply reel 5 is released ( In step S301, the motor 26 is driven (step S302). As described above, when the motor 26 is driven with the fixing device released, the rotation of the motor 26 causes the take-up reel 6 via the gears 22 and 23 to rotate.
Is rotated, and the used plate film 1 is taken up on the take-up reel 6.

When the take-up reel 6 rotates, the blade 24 provided on the take-up reel 6 rotates (step S303), and the blade sensor 25 detects the number of rotations of the blade 24. (Step S30
4).

Then, based on the detection signal from the blade sensor 25, the blade 24 is controlled by the specified number of times (for example, 5
(00 times) is determined (step S30).
5) If the specified number of times has been reached (if "Yes" is determined in step S305), the supply reel 5 is fixed by the fixing device (step S306). Here, the “designated number” is a number that is calculated in advance based on the length of the plate film 1 provided on the plate cylinder 2.
That is, in this embodiment, the number of rotations of the take-up reel 6 to supply a new plate film 1 by an appropriate length from the plate roll 10 is defined by the specified number of times. Have been. Further, the fixing of the supply reel 5 by the fixing device after reaching the designated number of times is performed.
This is to prevent the plate film 1 from being supplied more than necessary.

Now, even after performing the step S306, the detection by the blade sensor 25 is continuously performed, and it is determined whether or not the rotation of the blade 24 is detected after the fixing by the fixing device (step S306). S307).

When the rotation of the blade 24 is detected by the blade sensor 25 ("Ye" in step S307).
s "), it is determined whether the number of detections has reached twice the specified number of times (step S30).
8). If it is determined in step S308 that the number of detections by the blade sensor 25 has reached twice the specified number of times (“Yes” in step S308).
Is determined), an error is displayed (step S309). In the above step S308, “Ye
That is, it is considered that the take-up reel 6 continues to rotate by the drive of the motor 26 even though the supply reel 5 is fixed by the fixing device. Therefore, in this case, in the present embodiment, it is determined that all the plate films 1 constituting the plate roll 10 have been wound on the take-up reel 6 side, and an error message is displayed (step S309). ), And after the error display, the driving of the motor 26 is stopped (step S312).

On the other hand, "No" in step S307.
Is determined, the blade sensor 25 detects the blade 2
It is determined whether two seconds have elapsed since the detection of No. 4 was stopped (step S310). If two seconds have elapsed (if "Yes" is determined in step S310), it is determined that the plate exchange has been completed normally (step S311), and the driving of the motor 26 is stopped (step S311). Step S312). The determination of "Yes" in step S310 means that the supply reel 5 is fixed by the fixing device, so that the take-up reel 6 does not rotate even when the motor 26 is driven. Conceivable. Therefore, in this embodiment, in such a case, both ends of the plate film 1 are connected to the supply reel 5.
And the take-up reel 6 (step S311), and the driving of the motor 26 is stopped as described above (step S312).

As shown in FIG. 3, the driving of the motor 26 is stopped both when the automatic plate exchange is normally completed (step S311) and when an error is displayed (step S309). Then, in the case of normal termination, the next print processing is started.

However, if the motor 26 is stopped via step S309, one plate roll 1
0 is in the used state, so that conventionally, even if the other plate roll 10 remains, the plate cylinder 2 is driven until the other plate roll 10 is replaced unless another plate roll 10 is replaced. The printing process could not be performed only with the plate roll 10. The reason for this is the above [Problems to be solved by the invention]
It is as described above.

Therefore, in the printing unit according to the present embodiment, if another plate roll 10 remains, the printing process using the plate film 1 of the plate roll can be performed as necessary. For this purpose (to enable high-speed rotation of the plate cylinder 2), a plate roll detecting device is provided. That is, the presence or absence of the plate roll 10 on the plate cylinder 2 is appropriately determined by the plate roll detection device, and when the used plate roll is removed based on the detection signal of the plate roll detection device, The plate cylinder 2 constituting the printing unit according to the present embodiment is configured to be able to rotate at high speed during printing.

Hereinafter, with reference to FIGS. 4, 5 and 6,
The plate roll detection device and the high-speed rotation possibility determination processing based on the detection signal will be specifically described. FIG. 4 is a schematic perspective view of the plate cylinder 2 constituting the printing unit according to the present embodiment, and FIG. 5 is a relationship between the rotation state of the plate cylinder 2 and a plate roll detecting device (a photoelectric sensor constituting the plate roll). FIG. FIG. 6 shows a flowchart for determining whether or not high-speed rotation of the plate cylinder is possible based on the detection signal of the plate roll detection device.

As shown in FIG. 4, a photoelectric sensor 21 serving as a plate roll detecting device is provided near the outer peripheral portion of the plate cylinder 2, and based on a control signal from a control unit (not shown), a plate sensor is provided. Light as a detection signal is emitted from the light emitting portion to the concave portion 4 of the body 2, and a reflected signal (reflected light) of the light is received by the light receiving portion. Then, the reflected signal is transmitted to the control unit. In the present embodiment, the rotation angle of the plate cylinder 2 is detected by a rotary encoder (not shown) provided near the shaft portion 2a, and a detection signal related to the rotation angle is also transmitted to the control unit. Is done.

As shown in FIG. 5, in this embodiment, the rotation angle of the plate cylinder 2 is detected by using a rotary encoder provided near the shaft portion 2a of the plate cylinder 2, and The relative relationship between the position of the plate roll 10 in the formed recess 4 and the position of the photoelectric sensor 21 is grasped by the control unit. Therefore, in this embodiment,
Based on the detection signal of the rotary encoder, when the plate roll 10 is not yet in the irradiation range of the photoelectric sensor 21, the input signal from the photoelectric sensor 21 is ignored (FIG. 5A).
When the plate roll 10 enters the irradiation range of the photoelectric sensor 21 (see FIG. 5B), the input of the photoelectric sensor 21 is monitored. This monitoring is performed when the plate roll 10 is out of the irradiation range of the photoelectric sensor. (See FIG. 5C).

Here, the concave portion 4 according to the present embodiment is coated in black, and the outer surface of the plate roll 10 is generally silver or the like. That is, when the concave portion 4 is irradiated with light, the light is absorbed and the amount of reflected light is reduced. When the plate roll 10 is irradiated with light, the amount of reflected light is
It becomes larger than when the concave portion 4 is irradiated. Therefore, in the present embodiment, by transmitting these amounts of received light to the control unit, the control unit can easily determine whether or not the plate roll 10 exists in the recess 4.

Next, referring to FIGS. 4 and 5, FIG.
Will be described. FIG. 6 shows, as described above, whether or not high-speed rotation is possible using the plate roll detection device according to the present embodiment (whether or not used plate rolls are appropriately removed). It shows a flowchart for making a determination. In this embodiment, when "error display" is performed in step S309 (see FIG. 3), as long as the display is continued, the plate cylinder 2 cannot rotate at high speed for performing the printing process. When the "error display" is performed as described above, the plate cylinder 2 is in a state in which the plate cylinder 2 can rotate slowly. Here, “slow rotation” means that the printing drum 2 is rotated at a low speed based on an operation of a button by the operator, and “low speed” means that the printing drum 2 rotates at about 5 rpm or less. is there. In the present embodiment, the configuration is such that the high-speed rotation is possible if the “error display” is canceled.

In FIG. 6, first, it is determined whether or not an error display (see step S309 in FIG. 3) is performed for one plate cylinder 2 (step S601).
If there is an error display ("Y" in step S601)
If “es” is determined), the process of step S602 is performed. If there is no error display (if “No” is determined in step S601), the process of step S605 described below is performed.

In step S 602, it is determined whether or not it is time to position the plate roll 10 on the photoelectric sensor 21 based on the detection signal of the rotary encoder. The photoelectric sensor 21 emits and receives light at the timing described with reference to FIG. If it is the timing at which the plate roll 10 is positioned on the photoelectric sensor 21 (if “Yes” is determined in step S602), the control unit based on the detection signals of the rotary encoder and the photoelectric sensor 21 performs It is determined whether or not the plate roll 10 exists in the printer (step S).
603), when it is determined that there is no plate roll 10 (when “No” is determined in step S603), the error display is canceled (step S604).
Then, when it is determined that the plate roll 10 is present in the concave portion 4 (when “Yes” is determined in step S603), the process of step S605 is performed.

In step S605, it is determined whether or not an error display is displayed for all plate cylinders constituting the printing unit. If no error is displayed ("Yes" in step S605) If it is determined), it is determined that high speed rotation of the plate cylinder is possible (step S606), and if there is a plate cylinder for which an error is still displayed (if “No” is determined in step S605). It is determined that high-speed rotation of the plate cylinder is impossible (step S607). In the printing unit (see FIG. 1) according to the present embodiment, the configuration having one plate cylinder 2 has been described. However, the above-described plate roll detection device may be provided for each of a plurality of plate cylinders. Therefore, even when a plurality of plate cylinders are provided, this step S60 is performed.
5 will work.

As described above, by using the plate roll detecting device according to the present embodiment, without providing complicated wiring and the like in the plate cylinder 2, the plate roll 2 It is possible to detect the presence or absence of the plate roll 10 in. And, in the printing unit, the plate roll 1
If 0 has been properly removed, it is determined that high-speed rotation is possible (step S606), and one plate roll 1 is placed on the plate cylinder 2.
The printing process can be performed even in a state having only 0. That is, according to the present embodiment, the presence or absence of the plate roll 10 is automatically determined based on a relatively simple configuration, and the printing process can be performed in a state where the used plate roll 10 is not mounted. Can be.

The present invention is not limited to the above embodiment, and various changes other than those described above can be made without departing from the gist of the present invention.
For example, in the present embodiment, a case where two plate rolls are mounted on one plate cylinder 2 has been described, but the present invention is not limited to this configuration, and one or three plate rolls are mounted on one plate cylinder. At least one plate roll is configured to be attachable,
The presence / absence of each plate roll may be detected using the plate roll detection device described in the present embodiment, and a determination may be made as to whether or not high speed rotation of the plate cylinder is possible based on the detection signal.

In the present embodiment, when the plate roll detecting device is constituted by using the photoelectric sensor,
Although the case where “light” is used as the transmission / reception signal has been described, the present invention is not limited to this configuration. For example, an ultrasonic wave, static electricity, or the like may be used as the transmission / reception signal.

In this embodiment, when the plate roll detecting device is constituted by using a rotary encoder,
That is, the case where the rotary encoder is used as the rotation angle detecting unit has been described, but the present invention is not limited to this configuration, and for example, a cam switch, a proximity switch, or the like may be used.

[0048]

As described above, according to the present invention, the presence or absence of a plate roll is automatically determined based on a relatively simple configuration, and the printing process is performed in a state where a used plate roll is not mounted. Can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a printing unit of a sheet-fed printing press provided with a plate roll detection device according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a relationship between a set of supply reels and a take-up reel which constitute the printing unit of FIG. 1;

FIG. 3 is a flowchart when an automatic plate exchange is performed by the printing unit according to the embodiment;

FIG. 4 is a schematic perspective view of a plate cylinder constituting the printing unit of FIG. 1;

FIG. 5 is a schematic view showing the rotational state of the plate cylinder shown in FIG. 4, the positional relationship with the plate roll detection device,

FIG. 6 is a flowchart for determining whether or not high-speed rotation of the plate cylinder is possible based on a detection signal of the plate roll detection device according to the embodiment;

FIG. 7 is a schematic diagram of a main part of a printing unit according to the related art.

FIG. 8 is a schematic perspective view of a plate cylinder constituting a printing unit according to the related art.

[Description of Signs] 1 ... Plate Film 2 ... Plate Cylinder 3 ... Ink Unit 4 ... Recess 5 ... Supply Reel 6 ... Take-Up Reel 7 ... Imaging Unit (Image Forming Unit) 10 ... Plate Roll 21 ... Photoelectric Sensor

Claims (2)

[Claims] 1. A printing unit comprising: a plate cylinder to which a plurality of plate rolls can be mounted; and an image forming unit that forms an image on a plate film supplied from the plate roll on an outer peripheral surface of the plate cylinder. A plate roll detection device that detects the presence or absence of a plate roll, a signal transmitting unit that transmits a detection signal to a mounting position of the plate roll on the plate cylinder, a signal receiving unit that receives a reflection signal of the detection signal, A plate roll detection device comprising: a signal transmission unit; and a control unit that determines the presence or absence of the plate roll based on information obtained from the signal reception unit. 2. The apparatus according to claim 1, further comprising: a rotation angle detection unit configured to detect a rotation angle of the plate cylinder, wherein the control unit recognizes a mounting position of the plate roll based on information obtained by the rotation angle detection unit. Claim 1
A plate roll detection device according to item 1.