JPH04358835A - Printing error detecting apparatus - Google Patents

Abstract

PURPOSE:To detect a printing error with good accuracy even when a print just after printing is inspected. CONSTITUTION:In a printing error detecting apparatus wherein a sensor facing a moving print is provided and a reflected light from the print is received by the sensor to convert the amt. of the reflected light to a quantity of electricity and a printing error of the print is detected by utilizing this quantity of electricity, a print holding apparatus 10 is provided and both an air blowing device 13 which is provided closely to the sensor 11 and blows air to the print 30 and a control device 14 controlling a movement of the air blowing device 13 are provided on the print holding apparatus 10. In accordance with carrying condition of the print, air is intermittently blown to the print 30 to prevent the print from flapping.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] This invention detects printing errors in printed matter by using a sensor that receives reflected light from moving printed matter, converts the amount of reflected light into an amount of electricity, and uses this amount of electricity to detect printing errors in printed matter. This invention relates to a detection device.

0002

2. Description of the Related Art A printing error detection device is used to control the quality of printed matter printed by a printing press, such as a sheet-fed printing press, and to detect printing errors.

Printing errors include uneven color, oil stains, stains,
Refers to other printing defects in printed matter.

In order to detect printing errors at an early stage, it is necessary to rely on human visual inspection or to install a printing error detection device on the printing line of the printing press. When a printing error detection device is provided, it is common to inspect printed matter being fed by a feeding means such as a drum. At this time, in order to improve the inspection accuracy, it is necessary to prevent the printed matter from fluttering on the surface of the feeding means and to bring the printed matter into close contact with the surface of the feeding means.

[0005] Generally, the ink of printed matter has not completely dried immediately after printing. Therefore, it is not possible to press the printed matter against the surface of the feeding means using a contactor such as a roller in order to bring it into close contact with the surface of the feeding means.

[0006] Conventionally, therefore, a device has been proposed which charges the printed material to suppress the flapping of the printed material and brings it into close contact with the surface of the feeding means.

[0007]

SUMMARY OF THE INVENTION In an apparatus for charging printed matter, the charged state is not completely released downstream of the printing line, for example, when the printed matter is piled up, resulting in an inconvenience.

In order to solve such inconveniences, the inventor of the present invention prototyped a device that constantly blows air onto printed materials. Otherwise, there is an inconvenience that the paper enters the lower surface of the printed material (that is, between the printed material and the feeding means) from the rear end, lifting the printed material and causing a flapping phenomenon.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a printing error detection device which solves the above-mentioned drawbacks and is capable of inspecting printed matter with good accuracy even when inspecting printed matter immediately after printing.

0010

[Means for Solving the Problems] The gist of the present invention is to receive reflected light from a moving printed matter with a sensor, convert the amount of reflected light into an amount of electricity, and use this amount of electricity to prevent printing errors in printed matter. In the printing error detection device to detect, sensor 1
Air blowing means 1 that blows air toward the printed matter 30 that is provided near 1 and is being fed by the feeding means.
3, 16 and control means 14, 15 for controlling the operation of the air blowing means 13, 16, and is configured to intermittently blow air onto the printed material 30 depending on the feeding status of the printed material. This is a printing error detection device.

[0011]

[Operation] The air blowing means 1 is controlled by the control means 14 and 15.
3 and 16 and intermittently blows air onto the printed material 30 according to the feeding status of the printed material 30, thereby preventing the printed material 30 from fluttering and making it possible to bring the printed material 30 into close contact with the feeding means 21.

[0012] To give a preferable example of the timing of intermittent spraying, for example, air is not blown to the front end 30d and rear end 30b of the printed matter 30 in the feeding direction, but air is blown only to the middle part of the printed matter. Try to put it on.

[0013]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a conceptual diagram showing a part of a sheet-fed printing press equipped with a printing error detection device 9 of the present invention. Figure 2 is Figure 1
2 is a partially enlarged conceptual diagram schematically showing a printed matter holding device 10. FIG. FIG. 3 is a top view of the printing surface, and schematically shows the claws, sensors, and spraying means.

A printing error detection device 9 is provided in the middle of a printing line 20 of a normal offset sheet-fed printing press. The printing line 20 includes intermediate cylinders 22 and 23, an impression cylinder 21, and a brush cylinder 2.
5 and a plate cylinder 24. The intermediate cylinders 22, 23 and the impression cylinder are provided with claws 26 for pressing the printed matter 30.

FIG. 1 shows that the printed matter 30 is transferred to the impression cylinder 21 after printing is completed.
The figure shows a state in which the grip is changed from the middle to the intermediate barrel 23.

It should be noted that the ink supply means and other parts are not directly related to the gist of the present invention, so for the sake of brevity, they are not shown and their description will be omitted.

In the case of color printing, several similar lines are provided upstream of the lines shown in FIG. A stacking section for printed matter is provided downstream. Before the stacking section, powder or the like is appropriately supplied onto the printing surface to dry the ink.

The printing error detection device 9 includes a sensor 11, a device main body 12, and a printed matter holding device 10. The sensor 11 includes a light emitting element and a light receiving element, and is configured to irradiate light from the light emitting element onto the surface of the printed matter 30, receive the reflected light with the light receiving element, and convert it into an amount of electricity. The apparatus main body 12 is configured to detect errors in printed matter by comparing the amount of electricity obtained from the sensor 11 with a predetermined reference amount of electricity.

When the device body 12 detects an error, it
) Sound the buzzer, 2) Display on the display, 3)
The printer is configured to appropriately perform operations such as printing out the error location, 4) marking the error location, 5) stopping the printing machine, and 6) ejecting defective paper.

The sensor 11 and the device main body 12 are described in, for example, Japanese Patent Application Laid-open No. 63-47145 and No. 63-147271.
It is possible to use the one disclosed in the above publication. Therefore, it will not be described in detail herein.

The printed matter holding device 10 is for preventing the printed matter 30 from fluttering and bringing it into close contact with the impression cylinder 21. The printed matter holding device 10 includes air blowing means 13 and 16 and control means 14 and 15. The air blowing means is composed of a number of nozzles 13 and an air source 16. The control means is composed of a flow control valve 14 and a timing means 15.

As shown in FIGS. 1 to 3, a large number of nozzles 13
are arranged in a row in the lateral direction of the printed material 30 immediately in front of the sensor 11. Upstream of the nozzle 13 is the nozzle 13.
Flow rate control valve 14 for adjusting the flow rate of air supplied to
is connected. The flow control valve 14 is provided with an air source 16 that supplies compressed air to the flow control valve 14 . As will be described later, the flow control valve 14 is controlled synchronously with the impression cylinder 21 by a timing means 15.

The timing means 15 will be explained with reference to FIG.

Timing means 15 includes a cam 18 and a follower member 19. The cam 18 is provided integrally with the shaft 27 of the impression cylinder 21 and rotates together with the impression cylinder 21. cam 1
8 has two large diameter portions 18a and two small diameter portions 18b, which are arranged alternately. The large diameter portion 18a and the small diameter portion 18b are arranged to correspond to the length of the printed material in the feeding direction, as will be described later.

As shown in FIG. 4, the cam has a cam body 2.
8A and an angle adjusting member 28B. In this case, by shifting the relative positions of the cam body 28A and the angle adjusting member 28B and fixing them to the shaft 27, the ranges of the large diameter portion and the small diameter portion can be freely changed. In this way, it is made to correspond to the length of the printed matter. In addition, in order to suppress impact, the intermediate portion between the large diameter part and the small diameter part is configured to be more rounded than in the drawing.

A follower member 19 is provided above the cam 18. The follower member 19 includes a cam follower 19a that is movable in the vertical direction. cam follower 19
a is urged toward the cam 18 by a spring. When the cam 18 rotates in the direction of arrow A, the cam follower 19
a moves up and down in the direction of arrow B.

The flow rate control valve 14 is configured to be opened and closed by the vertical movement of the cam follower 19a. That is, the cam follower 19a contacts the large diameter portion 18a of the cam 18,
Valve 14 opens when callo follower 19a is in the upper position. In addition, a cam follower 19a is attached to the small diameter portion 18b of the cam 18.
When the cam follower 19a is in the lower position, the valve 14 is closed.

An example of the spraying operation will be explained with reference to FIG.

The double hatched area 30c is a printing area in the printed matter 30. The printed matter 30 is fed in the direction of the arrow. When the shaded area 30a passes under the nozzle 13, the valve 14 opens, and air is blown from the nozzle 13 to the shaded area 30a. When the sensor 11 scans other areas (including the front and rear end areas 30d and 30b of the printed material), the valve 14 is closed to prevent air from being blown. Therefore, air flows around to the bottom surface of the printed material from the front and rear ends in the feeding direction of the printed material, and the printed material does not float up from the impression cylinder 21 and flap.

Note that the present invention is not limited to the above-described embodiments. For example, the nozzle may be placed in front of the sensor. In this case, it is advantageous to tilt the nozzle 13 a little so that the air is blown directly below the sensor.

Further, the shape and number of nozzles can be changed as appropriate; for example, the outlet may be elongated.

Furthermore, a cooling means may be provided to blow air cooled to a predetermined temperature.

Further, the valve control means may be other than a cam mechanism, and it is also possible to use an electric switching means if there is no problem with the service life. Adopts a rotary valve,
The valve may be opened and closed by transmitting the rotation of the impression cylinder to the rotor.

[0035]

Effects of the Invention The present invention provides a printing method in which a sensor receives reflected light from a printed matter being sent by a feeding means, converts the amount of reflected light into an amount of electricity, and uses this amount of electricity to detect printing errors in printed matter. An error detection device is provided near the sensor (11) and controls the operation of air blowing means (13, 16) that blows air toward the printed matter (30) and the air blowing means (13, 16). Control means to control (1
4, 15), and air is intermittently blown onto the printed matter (30) according to the feeding status of the printed matter, so that it is possible to inspect the printed matter with good accuracy when inspecting the printed matter immediately after printing. can.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram showing a printing error detection device of the present invention installed in a printing line of a printing press.

FIG. 2 is an enlarged conceptual diagram showing a printed matter holding device in the printing error detection device of the present invention.

[Fig. 3] Printed matter, sensor, nozzle, in the device of the present invention,
A plan view schematically showing a nail

FIG. 4 is a plan view showing a cam of the timing means in the device of the present invention.

[Explanation of symbols]

9 Printing error detection device 10 Printed matter holding device 30 Printed matter 13 Nozzle 14 Flow control valve 15 Timing means 16 Air source 11 Sensor 12　Device body ◆

Claims (1)

[Claims] Claim 1. A printing error detection device that receives reflected light from a moving printed matter with a sensor, converts the amount of reflected light into an amount of electricity, and uses this amount of electricity to detect printing errors on printed matter. air blowing means (13, 16) that blows air toward the printed matter (30) that is provided near the air blowing means (11) and being fed by the feeding means; 1. A printing error detection device comprising control means (14, 15) for controlling the printing error, and configured to intermittently blow air onto the printed material (30) depending on the feeding status of the printed material.