JP4859023B2 - Blanket cleaning method - Google Patents

Description

  The present invention relates to a method for cleaning a cylinder surface of a blanket cylinder of a rotary offset printing press, and in particular, for cleaning the cylinder surface and reducing the time resulting from the cleaning operation, generating an effective production time, improving productivity, and loss. The present invention relates to a blanket cleaning method capable of reducing paper.

  A general offset rotary printing machine includes, as main components, a web (printing paper) supply device, a plurality of sets of printing units arranged in parallel along the web traveling direction, a drying device, a cooling device, a web pass device, It is configured with a folding machine. A set of printing units is provided with an inking device, a dampening device, a plate cylinder, and a rubber cylinder in one set up and down.

  In an offset rotary printing press, ink and water supplied via an ink fountain, an ink call roller, an ink roller chain, an ink form roll, and a water fountain, a water source roll, a water form roll, or a dampening water by a spray dampener To the blanket surface of the blanket cylinder, which is transferred to a web-like printing paper and printed.

  When printing is continued for a long time, dirt such as ink and paper dust adheres to the cylinder surface of the blanket cylinder. When the printing quality is deteriorated due to such contamination of the cylinder surface, or when printing a different printed matter, it is necessary to clean the blanket cylinder when changing the printing plate. In order to remove stains such as ink and paper dust on the cylinder surface, a method of mechanically automatically washing has been conventionally performed.

  Patent Document 1 shows an example of a conventional blanket cleaning method. Conventional blanket cleaning will be described with reference to FIGS. First, the blanket cleaning device inputs a paper splicing start signal from an automatic paper splicing device (autopastor), etc., and based on this signal, the machine speed of the printing press is reduced from the normal printing speed to the blanket cleaning speed. At the blanket cleaning speed, the blanket cylinder is separated from the printing paper (web) (detached state), and the rollers of the dampening water supply device and ink supply device are separated from the plate cylinder (detached state). The cleaning waste is transferred to the cleaning cloth by pressing against the blanket cylinder, and cleaning is performed. Then, the new cleaning cloth is fed several times, and the cleaning is completed when the cleaning cloth becomes less dirty.

  Subsequently, the machine speed of the printing press was increased from the blanket cleaning speed to the normal printing speed and returned to the normal speed, and the rollers of the dampening water supply device and the ink supply device that had been removed when performing the blanket cleaning were used. Then, the blanket cylinder is brought into the original state (wearing state), the machine speed of the printing press is increased to the normal printing speed, and after performing the adjustment work such as registration, normal printing is resumed.

  In many cases, the blanket is washed at a so-called slow speed (8 to 10 rpm). Cleaning at this slow speed requires a long cleaning time and is slowed down to this speed, or it is registered by increasing the time required to attach and detach the rollers and blanket cylinders of the dampening water supply device and ink supply device, and the normal printing speed. It takes a long time to do. The printing paper (web) that runs during these operations does not become a printed matter that is produced, but is a waste paper that is discarded. In other words, as shown in FIG. 2 (3), the waste paper generated during the descending speed, the waste paper generated during the cleaning, the waste paper generated during the ascending speed, the waste paper generated during the color / register adjustment, as shown in FIG. There is.

  In this type of cylinder cleaning method, it is inevitable that the amount of waste paper increases for the above reasons. As countermeasures against this problem, a proposal (for example, see Patent Document 2) where the stabilization such as registration is accelerated by maintaining for a predetermined time at an intermediate speed in the middle of increasing the printing speed from the blanket cleaning speed to the normal printing speed, or removing the blanket cylinder. However, each roller of the dampening water supply device and the ink supply device is not in the state, and the blanket cleaning speed is set to a higher speed (about 200 rpm) to shorten the time for registration and the like. Measures have been taken to shorten and reduce waste paper.

  Furthermore, as a novel method, a shaftless type offset rotary printing press is used, the printing speed of the printing paper (web) is reduced and the blanket cylinder is rotated at a high speed with the blanket cylinder removed. A countermeasure for reducing paper has been proposed (see Patent Document 3).

  Even with these measures, it takes time to slow down to the blanket cleaning speed or to increase to the normal printing speed, it takes time to register, and a lot of paper is generated between them, so it is very efficient. There was a problem that cleaning was not possible.

  An offset rotary printing press is provided with a paper surface inspection device for detecting various defects such as printing unevenness, ink density excess / deficiency, color misregistration, part of paper surface contamination, part of printing defect, and the like. This type of paper surface inspection apparatus is proposed in Patent Documents 4 to 6, for example. However, the conventional printing paper surface inspection is only for detecting the above-mentioned various defects, and blanket cleaning has not been performed using the detection result.

No. 5-50971 JP-A-8-20104 JP 2003-246044 A JP-A-9-156080 JP-A-11-151801 JP 2004-157858 A

  An object of the present invention is to provide a blanket cleaning method capable of reducing the time required for cleaning the blanket cylinder and the time resulting from the cleaning operation and reducing waste paper in an offset rotary printing press.

In order to achieve the above object, the blanket cleaning method according to the first aspect of the present invention provides a cylinder surface of a blanket cylinder in which a web running at approximately the same speed as during printing is rotated at approximately the same speed as during printing. A primary cleaning step in which the supply of ink and dampening water to the plate cylinder is stopped in a state of being in contact with the ink, and the ink on the outer surface of the cylinder is transferred to the web for cleaning.
After detecting the end of the primary cleaning process, a cleaning fabric impregnated with a cleaning liquid having a relatively high viscosity and a low volatility is supplied from the cleaning fabric supply body, and the cleaning fabric is applied to the cylinder surface by a pressing member. Ri Do and a secondary cleaning step of cleaning the cylinder surface against,
The secondary cleaning step, the printing time and the schematic features that you start by pressing the cleaning fabric on the cylinder surface of the blanket cylinder which is rotating at the same speed.

  The invention of claim 2 is characterized in that, in claim 1, the blanket cylinder in the secondary cleaning step rotates at substantially the same speed as during printing.

  The invention of claim 3 is characterized in that in claim 1, the blanket cylinder in the secondary cleaning step includes a cleaning step of rotating while decelerating from approximately the same speed as during printing.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the feed speed of the cleaning fabric in the secondary cleaning step is controlled based on the rotational movement distance of the blanket cylinder.

  The invention of claim 5 is characterized in that, in any one of claims 1 to 4, printing is started after detecting the end of the secondary cleaning step.

  The invention of claim 6 is characterized in that, in claim 1, the primary cleaning step is carried out until it is detected that the color of the running web is equal to a predetermined coloring degree.

  A seventh aspect of the invention is characterized in that, in the sixth aspect, the coloring degree is determined from the relationship between the web running speed, the web coloring degree, and the amount of waste paper.

  The invention of claim 8 is characterized in that, in claim 5, the secondary cleaning step is performed until it is detected that the color of the running web is equal to a predetermined coloring degree.

  According to a ninth aspect of the present invention, in the eighth aspect, the coloring degree is determined from the relationship between the web running speed, the web coloring degree, and the amount of waste paper.

  The invention of claim 10 is characterized in that, in any one of claims 1 to 9, detection of completion of the primary cleaning step and the secondary cleaning step is performed by a paper surface inspection device.

  According to an eleventh aspect of the present invention, in the tenth aspect, the paper surface inspection device also serves as a paper surface inspection device for detecting dirt, fading, etc. on the printed paper surface.

According to the first aspect of the present invention, the load on the cylinder surface of the blanket cylinder is transferred to the printing paper (web) as much as possible in the primary cleaning step to reduce the load of dissolving and cleaning the ink by adding the cleaning liquid. This makes it possible to improve the productivity by reducing the cleaning time of the blanket cylinder, reduce the amount of waste paper, and reduce the amount of cleaning liquid and cleaning cloth used.After the secondary cleaning process detects the end of the primary cleaning process, A cleaning fabric impregnated with a cleaning liquid with a relatively high viscosity and a low volatility in advance is pressed against the cylinder surface in a high-speed rotation state by a pressing member so that the cleaning surface is supplied to the cleaning cloth by spraying. It is possible to reduce troubles caused by contamination and corrosion of various devices due to web breakage, blanket wear or mist. In addition, since the ink on the cylinder surface is transferred to the web as much as possible in the primary cleaning step, an effect of reducing variation in the cylinder cleaning time due to the difference in the emulsification degree of the ink can be expected.

  According to the invention of claim 2, the cleaning time is very short and the running speed of the web does not change so much so that the stability of the web tension can be secured, so that the time for registration can be shortened and the productivity is improved. The amount of waste paper is also reduced, and the risk of web breakage problems is reduced.

  According to the invention of claim 3, it can be applied to the operation of reducing the running speed of the web in order to change the printing plate of the offset rotary printing press, and the blanket cylinder rotates while decelerating from the same speed as during printing. Since cleaning is sometimes performed, the total time for cleaning can be shortened, and productivity can be improved and waste paper can be reduced.

  According to the invention of claim 4, since the feeding speed of the cleaning fabric is controlled on the basis of the rotational movement distance of the blanket cylinder, the cloth can be fed accurately even when the blanket cylinder rotates while decelerating. There is little variation in washing per feed.

  According to the invention of claim 5, since the end point of the secondary cleaning is detected instead of ending the cleaning at the predetermined number of times of cloth feeding, the cleaning time can be shortened and the productivity is improved and the waste paper is lost. Can be reduced.

  According to the invention of claim 6, since the primary cleaning process is performed until it is detected that the coloring of the running web is equal to the predetermined coloring degree, the end point of the primary cleaning is accurately determined, and thereby the cleaning time is determined. It can be shortened and productivity can be improved and waste paper can be reduced. In particular, in the primary cleaning process, the web travels at approximately the same speed as during printing, so the effect of reducing waste paper is great.

  According to the invention of claim 7, by selecting the optimum coloring degree of the web, the cleaning time can be shortened and the productivity can be improved and the waste paper can be reduced. Since it runs at the same speed, the effect of reducing waste paper is great.

  According to the eighth aspect of the present invention, it is possible to accurately determine the end point of the secondary cleaning, thereby shortening the cleaning time and improving the productivity and reducing the waste paper.

  According to the invention of claim 9, by selecting an optimum coloring degree, the washing time can be shortened, and the productivity can be improved and the waste paper can be reduced.

  According to the invention of claim 10, since the detection of the end of the primary cleaning process and the secondary cleaning process, that is, the degree of coloring of the web is performed by the paper surface inspection device, it is possible to eliminate variations in detection when performed by human vision. The end point of the primary cleaning and the secondary cleaning can be detected more accurately, the cleaning time can be shortened, the productivity can be improved, and the waste paper can be reduced.

  According to the invention of claim 11, since the paper surface inspection device for detecting the degree of coloring of the web also serves as the paper surface inspection device for detecting dirt, blurring, etc. on the surface of the printing paper, automatic detection of the degree of coloring of the web at a low cost. Is possible.

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

  FIG. 1 shows a printing unit constituting an offset rotary printing press that has performed the blanket cleaning method of the present invention. Since the upper and lower printing cylinders have the same configuration, only the upper printing cylinder will be described here with reference numerals. The offset rotary printing press includes the printing unit 1 as one set or a plurality of sets of printing units arranged in parallel along the traveling direction of the web 2. Each printing unit 1 includes, as a printing cylinder, upper and lower blanket cylinders 3 with respect to a web pass line, upper and lower plate cylinders 4, and an ink form roller that engages with the plate cylinder 4. 5 and the roller attaching / detaching mechanism portions 7 and 8, such as the swimming roller 6, the blanket cleaning mechanism portion 9, the blanket cylinder attaching / detaching mechanism portion 10, and the plate cylinder moving mechanism portion 11 are individually provided.

  In order to inspect the printing on the web surface, the color optical sensor 12 is arranged along an appropriate installation location, for example, a guide roller, where the web 2 printed by the printing unit 1 travels. The printing web surface inspection apparatus has a function of performing various printing inspections from the image data of the web surface read by the color optical sensor 12.

  The blanket cleaning control unit 20 outputs a cleaning signal that causes the blanket cleaning mechanism unit 9 disposed in the vicinity of the blanket cylinder 3 to perform a predetermined cleaning operation. The blanket cleaning apparatus includes a blanket cleaning mechanism unit 9 and a blanket cleaning control unit 20.

  The blanket cleaning mechanism unit 9 supplies the cleaning fabric from the cleaning fabric supply body based on the cleaning signal sent from the blanket cleaning control unit 10, operates the pressing member, and supplies the supplied cleaning fabric to the cylinder surface. The cleaning fabric is a cleaning fabric impregnated with a cleaning liquid having a relatively high viscosity and a low volatility in advance.

  The blanket cleaning control unit 20 includes a printing speed signal sent from a speed detecting means provided in the printing machine main body, a paper splicing start signal of an automatic splicing device, a cleaning start signal by an operator's button operation, and a paper surface inspection device. The color level signal of the paper surface is received, and the cleaning operation of the blanket cleaning mechanism is controlled, and is constituted by various circuits and programs. The detection device for the degree of coloring of the paper surface can also be configured by a paper surface coloring degree inspection device that is separate from the paper surface inspection device.

Next, the operation of the blanket cleaning control unit will be described.
When a paper splicing start signal or cleaning start signal is input, the web 2 is controlled to run at almost the printing speed, and in this state, the ink form roller 5 and the water form roller 6 are detached from the plate cylinder 4 to stain the cylinder surface. While performing primary cleaning to be transferred to the web 2, primary detection is performed based on detection of a predetermined amount of web traveling, detection of coloration of a paper surface that changes as the cleaning progresses, and coloration determination using web surface data from a known paper surface inspection device. The cleaning is terminated, then the blanket cleaning mechanism unit 9 is operated, and the secondary cleaning for cleaning the cylinder surface by pressing the supplied cleaning fabric against the cylinder surface by the pressing member is controlled. When the degree of coloring reaches a predetermined level or less, washing is terminated, and a predetermined operation is performed before starting production.

  An embodiment of the blanket cylinder cleaning method will be described.

(Specific example 1)
FIG. 2 (1) shows the barrel production rate cleaning. In this example, after printing, the web 2 running at approximately the same speed as printing is in contact with the cylinder surface of the blanket cylinder 3 rotating at approximately the same speed as printing, and ink and Stop the supply of dampening water, transfer the ink on the cylinder surface to the web 2 and perform the primary cleaning (pre-cleaning) process. After detecting the end of this pre-cleaning, the viscosity is relatively high and low volatility in advance. The cleaning fabric impregnated with the cleaning liquid is supplied from the cleaning fabric supply body, and the cleaning fabric is pressed against the cylinder surface of the blanket cylinder 3 rotating at approximately the same speed as that during printing by the pressing member and cleaned. After performing the above, the operation for starting printing is started.

(Specific example 2)
FIG. 2 (2) shows the barrel removal high-speed cleaning. In this example, after printing, the web 2 running at approximately the same speed as printing is in contact with the cylinder surface of the blanket cylinder 3 rotating at approximately the same speed as printing, and ink and Stop the supply of dampening water, transfer the ink on the cylinder surface to the web 2 and perform the primary cleaning (pre-cleaning) process. After detecting the end of this pre-cleaning, the viscosity is relatively high and low volatility in advance. A cleaning fabric impregnated with a cleaning liquid is supplied from a cleaning fabric supply body, the cleaning fabric is pressed against the cylinder surface of the blanket cylinder 3 by a pressing member, and the printing speed is reduced from a printing speed to a predetermined low speed (200 rpm). After performing a secondary cleaning by rotating at a low speed for a certain period of time, the printing speed is increased to start an operation for starting printing.

A preferred embodiment of the primary cleaning and the secondary cleaning in Specific Example 1 and Specific Example 2 will be described.
The primary cleaning is performed until it is detected that the color of the running web is equal to a predetermined coloring degree. The degree of coloring is determined from the relationship between the web running speed, the degree of web coloring and the amount of paper loss.

  Secondary cleaning controls the cleaning fabric feed rate based on the rotational travel distance of the blanket cylinder. Moreover, it is performed until it is detected that the coloring of the running web is equal to a predetermined coloring degree. The degree of coloring is determined from the relationship between the web running speed, the degree of web coloring and the amount of paper loss.

  The end of the primary cleaning process and the secondary cleaning process is detected by a paper surface inspection device. This paper surface inspection device is also used as a paper surface inspection device for detecting dirt, fading, etc. on the printed paper surface.

  The operation and effect of the present embodiment will be described. In the primary cleaning step, the cleaning liquid is originally transferred to the printing paper (web 2) as much as possible by transferring the ink removed by transferring to the cleaning cloth pressed against the cylinder surface of the blanket cylinder 3 when cleaning the blanket cylinder 3. Thus, the load of dissolving and washing the ink can be reduced. This aims at shortening the cleaning time of the blanket cylinder 3 and reducing the amount of cleaning liquid and cleaning cloth used. The supply of ink and dampening water to the plate cylinder 4 is stopped, and the blanket cylinder 3 is supplied from the plate cylinder 4 to the blanket cylinder 3. Due to the ink transfer and the ink transfer from the blanket cylinder 3 to the printing paper (web 2), the ink on the cylinder surface is reduced.

  In the secondary cleaning process, when the blanket cylinder 3 is cleaned with the blanket cylinder 3 rotating at approximately the same speed as during printing (specific example 1), the blanket cylinder 3 is decelerated from approximately the same speed as during printing. However, there is a case where the blanket cylinder 3 is washed while rotating (specific example 2).

  In the case of the specific example 1, there is an advantage that the cleaning time is short. In the specific example 1, since the running speed of the web 2 does not change so much, the tension of the web 2 can be secured, so that the time required for registration can be shortened. In the case of the specific example 2, since the traveling speed of the web 2 changes, the advantage of the specific example 1 cannot be obtained. However, in the operation of the offset rotary printing machine, the traveling speed of the web 2 is changed in order to change the printing plate as described above. It may be necessary to decelerate, which is effective for blanket cleaning performed at such timing.

  In the secondary cleaning process, a normal blanket cleaning process using a cleaning liquid and a cleaning cloth is performed. The blanket cylinder 3 is decelerated from a high-speed rotation state such as 800 to 1000 rpm or from the high-speed rotation state described above to a rotation state of about 200 rpm. While cleaning. Therefore, there are the following problems.

(1) A commonly used low-viscosity cleaning agent is blown away by centrifugal force and becomes mist, which causes troubles that contaminate and corrode various devices.
(2) When the cleaning liquid is supplied to the cleaning cloth on the printing machine, uniform coating cannot be performed sufficiently, resulting in uneven coating (unevenness of wetting), and the cleaning cloth in the portion where the cleaning liquid is small is the cylinder surface of the blanket cylinder in the high-speed rotation state. The blanket is made of rubber when it comes into contact with it, causing troubles such as partly scraping the blanket or increasing wear, and the cleaning cloth with a large amount of cleaning liquid comes into contact with the cylinder surface and then transfers to the web-like printing paper. There is a risk that the web will swell and weaken when it is transferred, and there is a risk that the paper will break, but there is a problem that this risk increases because the web is running at high speed in a high tension state.
(3) When a slight change in the rotational speed occurs in the above-mentioned high-speed rotation state, or when washing while decelerating from the high-speed rotation state to the rotation state of about 200 rpm, the batch control is performed by the timer control method. In such a case, there is a problem that variation occurs in washing per cloth feed.

  As a countermeasure for the above problems (1) and (2), a cleaning cloth (for example, described in JP-A-7-156372) in which a relatively high viscosity and low volatility cleaning liquid is uniformly impregnated in advance. The use of a cleaning fabric is preferred. This type of cleaning cloth also increases the lifetime of the blanket. On the other hand, the countermeasure for the problem (3) is solved by measuring the rotational movement distance of the blanket cylinder and controlling the cloth feed of the cleaning cloth on the basis of the measured distance. It is also effective to increase the cleaning power by widening the air pad of the cleaning device (widening the nip width and increasing the ink scraping area), thereby shortening the cleaning time.

  Determination of the end point of cleaning in the primary cleaning process and the secondary cleaning process (especially cleaning in a high-speed rotation state (800 to 1000 rpm)) is performed by detecting the color density of the printing paper (web). Although this detection can be done by human vision, it is possible if a person accustomed to this work can detect and judge at any time. Therefore, it is preferable to automatically inspect like the quality inspection of the printed paper surface. The inspection device may be a dedicated paper surface inspection device that uses a camera to obtain image data or a method that detects the ink density from reflected light using a photodiode and a transistor photosensor, but it also serves as a quality inspection device for other printed paper surfaces. be able to.

  Cleaning in the primary cleaning process involves the physical properties of the web (material, surface structure, ink transferability), ink status (type, temperature, viscosity, degree of solidification), ratio of drawn / non-drawn areas, and cylinder surface of the blanket cylinder. It is affected by the amount of paper dust adhering to the cylinder and the structure of the cylinder surface. As shown in FIG. 3, the relationship between the primary cleaning / secondary cleaning loss amount and the amount of paper loss in the primary cleaning is roughly as follows. Since it becomes difficult to transfer the ink on the blanket surface, the progress of cleaning does not progress, and the amount of waste paper tends to increase (A line in the figure). On the other hand, if the degree of progress of cleaning at the end of the primary cleaning progresses, the amount of paper loss in the secondary cleaning process decreases (B line in the figure). As described above, since the relationship shown in FIG. 3 differs depending on the physical properties of the web, the state of the ink, etc., it is preferable to investigate each printing condition, input it to the control program, and control it with feedback according to the change in the printing condition. .

  Conventionally, blanket cleaning is affected by the degree of ink emulsification, and the degree of ink emulsification varies depending on the printing conditions of the printing company. By performing the primary cleaning according to the present invention, the ink on the cylinder surface of the blanket cylinder is transferred to the web as much as possible, so that the variation in the blanket cleaning time can be optimized.

  Further, in the present invention, the cylinder is cleaned with a cleaning cloth impregnated with a relatively high viscosity and low volatility cleaning liquid. There is a possibility that ink or cleaning liquid containing water adheres. In order to prevent this, it is preferable to provide a cleaner for cleaning the chill roll for cooling the web heated by the dryer.

  Next, an experiment was conducted to compare the cleaning times of blanket cleaning shown in FIGS. An offset rotary printing press (model: Komori LR-440 / 625IIL (1000 rpm), size: A horizontal all-plate press) was used.

When printing was performed by the method of Example 1 of the present invention shown in FIG.
This is the result of blanket cleaning with the blanket cylinder rotating at approximately the same speed as during printing.
Pre-washing waste paper: 40 sheets Falling-down medium loss paper (1000 rpm to 200 rpm): 0 sheets Blanket-washing paper loss: 450 sheets Speed-up medium loss paper: 0 sheets Color / register adjustment loss paper: 100 sheets

When printing was performed by the method of Example 2 of the present invention shown in FIG.
This is the result of cleaning the blanket while the blanket cylinder rotates while decelerating from approximately the same speed as during printing.
Pre-cleaning waste paper: 40 sheets Blanket cleaning medium-loss paper: 450 sheets Speed-up medium loss paper: 250 sheets Color / register adjustment loss paper: 300 sheets

When printing is performed by the conventional method shown in FIG. Here, the number of damaged paper is the number of prints (A horizontal all plate: 625mm / sheet) converted. This is the result of washing after printing 70000 sheets.
Falling medium loss paper (1000 rpm to 200 rpm): 250 sheets Blanket cleaning paper loss: 500 sheets Speed increasing medium loss paper: 250 sheets Color / register adjustment loss paper: 300 sheets

It is a figure which shows the printing unit which comprises the offset rotary printing machine which implemented the blanket washing | cleaning method of this invention. It is a time chart which shows the operating method of the printing press at the time of blanket washing | cleaning, (1) is the specific example 1, (2) The specific example 2, (3) is a prior art example. It is a figure which shows the relationship of the amount of paper loss of primary cleaning / secondary cleaning with respect to the cleaning progress of primary cleaning.

Explanation of symbols

1 Printing unit 2 Printing paper (web)
DESCRIPTION OF SYMBOLS 3 Blanket cylinder 4 Plate cylinder 5 Ink form roller 6 Swimmer roller 7, 8 Roller desorption mechanism part 9 Blanket washing mechanism part 10 Blanket cylinder desorption mechanism part 11 Plate cylinder movement mechanism part
12 Color optical sensor 20 Blanket cleaning control unit

Claims (11)

After printing, the ink and fountain solution are supplied to the plate cylinder while the web running at approximately the same speed as printing is in contact with the cylinder surface of the blanket cylinder rotating at approximately the same speed as printing. A primary cleaning step of stopping and transferring the ink on the outer surface of the cylinder to the web for cleaning;
After detecting the end of the primary cleaning process, a cleaning fabric impregnated with a cleaning liquid having a relatively high viscosity and a low volatility is supplied from the cleaning fabric supply body, and the cleaning fabric is applied to the cylinder surface by a pressing member. Ri Do and a secondary cleaning step of cleaning the cylinder surface against,
The secondary cleaning step, the printing time of a schematic blanket washing method characterized that you start by pressing the cleaning fabric on the cylinder surface of the blanket cylinder which is rotating at the same speed.   2. The blanket cleaning method according to claim 1, wherein the blanket cylinder in the secondary cleaning step rotates at substantially the same speed as during printing.   2. The blanket cleaning method according to claim 1, further comprising a cleaning step in which the blanket cylinder in the secondary cleaning step rotates while decelerating from a speed substantially equal to that during printing.   The blanket cleaning method according to any one of claims 1 to 3, wherein a feeding speed of the cleaning fabric in the secondary cleaning step is controlled based on a rotational movement distance of the blanket cylinder.   5. The blanket cleaning method according to claim 1, wherein printing is started after detecting the end of the secondary cleaning step.   2. The blanket cleaning method according to claim 1, wherein the primary cleaning step is performed until it is detected that the color of the running web is equal to a predetermined coloring degree.   7. The blanket cleaning method according to claim 6, wherein the coloring degree is determined from the relationship between the web running speed, the web coloring degree, and the amount of damaged paper.   6. The blanket cleaning method according to claim 5, wherein the secondary cleaning step is performed until it is detected that the color of the running web is equal to a predetermined coloring degree.   9. The blanket cleaning method according to claim 8, wherein the coloring degree is determined from the relationship between the web running speed, the web coloring degree, and the amount of damaged paper.   The blanket cleaning method according to any one of claims 1 to 9, wherein detection of completion of the primary cleaning step and the secondary cleaning step is performed by a paper surface inspection device.   11. The blanket cleaning method according to claim 10, wherein the paper surface inspection device also serves as a paper surface inspection device for detecting dirt, fading, etc. on the printed paper surface.

Images