JP4456770B2 - Printing register control device for printing press - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a printing register control apparatus for a printing press that sequentially supplies multicolor liquid toners to maintain registration between colors when an image is overwritten on the surface of a photosensitive drum.
[0002]
[Background]
Conventionally, an overwritten image formed by sequentially supplying multicolor liquid toner to the surface of a photosensitive drum rotating at a constant rotation is disposed between the transfer roller and the backup roller via a transfer roller. Printing machines that transfer onto printing paper are known.
The printing machine includes a charging unit that charges the surface of the photosensitive drum to impart photosensitivity, an exposure unit that performs exposure scanning of the photosensitive drum based on the drawing data to create an electrostatic latent image, and a photosensitive unit. A developing unit that develops the electrostatic latent image on the body drum. The developing unit includes a plurality of developing rollers that sequentially supply multicolor liquid toner to the photosensitive drum.
[0003]
The liquid toner is supplied from the developing roller to the photosensitive drum by using electrophoresis that supplies the liquid toner by the difference between the potential of the exposed portion of the photosensitive drum and the other surface and the potential of the developing roller. Done. That is, the developing roller and the photosensitive drum are brought close to each other to a predetermined distance, and when the distance between the developing roller and the photosensitive drum reaches a predetermined distance, the liquid toner moves from the developing roller to the photosensitive drum, thereby forming an image. It has become.
[0004]
That is, for example, when performing image-on-image printing in which four colors of yellow, magenta, cyan, and black are sequentially stacked to form an image, firstly yellow liquid toner is supplied to the surface of the photosensitive drum. After the supply is complete, the second color magenta, the third color cyan, and finally the fourth color black liquid toner are sequentially supplied to form a multicolor image on the surface of the photosensitive drum. ing.
On the other hand, the exposure means is configured to include, for example, a laser diode, a polygon scanner, etc., and the laser light output from the laser diode is incident on the polygon scanner rotating at a constant rotation, reflected, and exposed through an fθ lens. Drawing is performed by scanning the body drum.
[0005]
[Problems to be solved by the invention]
In the printing machine as described above, the photosensitive drum and the polygon scanner of the exposure means are independently rotated at a constant rotation. Therefore, due to the phase relationship between the photosensitive drum and the polygon scanner, the registration start position of the polygon scanner that scans the surface of the photosensitive drum, that is, the registration of the first and second colors at the drawing start position is misaligned. As a result, there arises a problem that the image becomes unclear and a high-quality printed matter cannot be obtained.
[0006]
An object of the present invention is to provide a printing machine capable of maintaining a high degree of registration for each color and obtaining a high-quality printed matter when forming a multicolor image on the surface of a photosensitive drum using liquid toner. Is to provide a printing register control apparatus.
[0007]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a photosensitive drum on which an image is formed, a charging unit for charging the surface of the photosensitive drum, and the surface of the photosensitive drum after being charged by the charging unit based on drawing data. Exposure means for drawing by exposure scanning and creating an electrostatic latent image, and after exposure scanning by the exposure means, multicolor liquid toner is sequentially supplied to the surface of the photosensitive drum by electrophoresis, and the surface of the photosensitive drum is A developing means for developing the electrostatic latent image, a fog removing means for removing the fog of the image after development by the developing means, a drying means for drying the liquid toner on the surface of the photosensitive drum, and a drying means A transfer roller for receiving the image after drying, a backup roller for transferring the image on the transfer roller to printing paper, and each of these means and control means for controlling each roller And a drawing synchronization signal I / F circuit that is provided in the exposure unit and outputs a drawing synchronization signal to the exposure signal output to the exposure unit. An encoder for detecting the rotation angle of the photosensitive drum, a temporary drawing trigger signal generator for giving an approximate drawing start trigger signal generation position to the exposure means by a rotation angle detection signal output from the encoder; A first color initial rotation angle storage unit for storing an initial rotation angle of the photosensitive drum at the time of detection of the first drawing synchronization signal output from the drawing synchronization signal I / F circuit after generation of a temporary drawing trigger signal for a color; The N-th initial rotation for storing the initial rotation angle of the photosensitive drum at the time of detecting the first drawing synchronization signal output from the drawing synchronization signal I / F circuit after generation of the temporary drawing trigger signal for the color and the subsequent colors. An angle storage unit, a phase difference calculation unit that calculates a phase difference of the initial rotation angle of the photosensitive drum stored in the first color initial rotation angle storage unit and the Nth color initial rotation angle storage unit, and the phase difference calculation And a phase difference correction circuit that corrects the phase difference until an actual drawing start synchronization signal is generated based on a calculation result in the printing unit. It is.
[0008]
In the present invention, the phase difference between the initial rotation angles of the photosensitive drums stored in the first-color initial rotation angle storage unit and the N-th color initial rotation angle storage unit is calculated by the phase difference calculation unit. Based on the result, correction is performed by the phase difference correction circuit until the actual drawing start synchronization signal is generated. Therefore, even if the photosensitive drum and the exposure unit are driven independently, the first and second colors Since the actual drawing start after the color always coincides, the registration of each color when performing multicolor printing is maintained at a high level, and as a result, a high-quality printed matter can be obtained.
[0009]
According to a second aspect of the present invention, in the printing register control apparatus for a printing press according to the first aspect, the photosensitive drum is driven by a servo motor, and a feedback encoder signal from the servo motor is transmitted to the photosensitive drum. It is characterized by being used in combination with a rotation angle detection encoder.
In the present invention, since one encoder has two roles, the number of members used can be reduced.
[0010]
According to a third aspect of the present invention, in the printing register control device for a printing press according to the first or second aspect, the actual drawing of the first color is started from the first synchronization signal after the temporary drawing trigger signal of the first color is generated. The time until the synchronization signal is an integral multiple of the exposure scanning cycle.
In the present invention, since the actual drawing start synchronization signal is not output during exposure scanning, the registration of each color is more reliable.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a printing register control apparatus for a printing press according to the present invention will be described with reference to the drawings.
As shown in FIG. 1, the printing machine 1 according to the present embodiment forms an image by sequentially overlaying drawing data created based on print image data with colors such as yellow, magenta, cyan, and black. An image-on-image printing is performed, and a photosensitive drum 2 on which an image is formed is provided.
[0012]
In the vicinity of the photosensitive drum 2, a charger 3 as a charging means for charging the photosensitive drum 2 with an electrostatic charge, and light is applied to the charged photosensitive drum 2 for a certain period of time, and drawing on the photosensitive drum 2 is performed. And an exposure unit 4 as exposure means for forming an electrostatic latent image.
[0013]
For example, a developing unit 19 that develops the electrostatic latent image formed on the photosensitive drum 2 with liquid toner is provided below the photosensitive drum 2. In addition, a transfer roller 6 for pressure-transferring a print image on the surface of the photosensitive drum 2 is disposed, for example, above the photosensitive drum 2. In the vicinity of the photosensitive drum 2, a fog removing unit 13 for removing the fog of the image developed by the developing unit 19 is provided between the developing unit 19 and the transfer roller 6. A drying unit 16 is provided between the transfer roller 6 and the liquid toner on the surface of the photosensitive drum 2 after removing the fog.
The fog removing means 13 includes a fog removing roller 13A and a motor 13B that rotationally drives the roller 13A.
The image fogging means that the liquid toner adhering to the surface of the photosensitive drum 2 has a predetermined thickness or more.
[0014]
Above the transfer roller 6, there is provided a backup roller 7 that backs up from above the transfer roller 6 to prevent escape of pressing due to the deflection of the transfer roller 6, and applies strong printing pressure to the whole. 2. Control means 20 is provided for controlling the entire printing press 1 including driving of the transfer roller 6 and the like, and a printing register control device 60 (see FIG. 5) of the printing press described later.
[0015]
The photosensitive drum 2 is provided with a first servo motor 8, the transfer roller 6 is provided with a second servo motor 9, and the backup roller 7 is provided with a third servo motor 10, and these servo motors 8, 9, 10 are provided. By driving, the photosensitive drum 2, the transfer roller 6, and the backup roller 7 are configured to be driven synchronously under the control of the control means 20.
[0016]
The photosensitive drum 2 and the transfer roller 6 have the same diameter, and the backup roller 7 and the photosensitive drum 2 have the same diameter.
The transfer roller 6 can be attached to and detached from the photosensitive drum 2 by a transfer roller attaching / detaching actuator 47 (see FIG. 8), and the backup roller 7 is transferred by a backup roller actuator 48 (see FIG. 8). The roller 6 is detachable.
The backup roller 7 and the photosensitive drum 2 may have different diameters.
[0017]
As shown in FIG. 2, the exposure device 4 includes a polygon scanner 91 that rotates at a constant rotation, an fθ lens 92 that collects laser light from the polygon scanner 91, and a laser diode 93 that is incident on the polygon scanner 91. The laser beam that is configured and output from the laser diode 93 is incident on the polygon scanner 91 and reflected, and scans the photosensitive drum 2 through the fθ lens 92.
[0018]
Here, as shown in FIG. 3, a drawing area H, a non-drawing area I, and the like are formed on the photosensitive drum 2.
That is, a drawing area H having a predetermined size is formed at the center of the circumferential length G of the photosensitive drum 2, and non-drawing areas I are formed at both ends thereof. The other side end is the final drawing line B. On the other hand, a scanning width E in which scanning by the polygon scanner 91 is performed is determined with respect to the width F of the photosensitive drum 2. In the scanning width E, the drawing start line A, that is, the scanning start position of the scanning start line is the drawing origin. The scanning end position is a drawing end point D. Then, the encoder detection angle of the drawing origin C is stored in a phase synchronization control unit 40 (see FIG. 8) described later.
[0019]
When the laser light output from the laser diode 93 scans the photosensitive drum 2, a dummy signal is first output from the process control unit 35 for synchronization with the actual drawing position, as shown in FIG. A drawing synchronization signal is output from the exposure device 4 corresponding to the dummy signal, but the detection is performed by detecting the laser beam reflected by the polygon scanner 91 and reflected again by the mirror 95 through the fθ lens 92 by the synchronization detection photodetector 94. The position is output as a drawing synchronization signal. Then, after a predetermined time t has passed since the drawing synchronization signal is output, drawing is started by a drawing signal for performing drawing by rotating the polygon scanner 91, and drawing data is created.
The control circuit for the laser diode 93 and the control circuit for the polygon scanner 91 are provided in the exposure control unit 30 (see FIG. 8).
[0020]
The developing means 19 includes a developing machine main body 5 and a developing roller 15 provided in the developing machine main body 5.
The developing machine body 5 includes a base 5A and a plurality of toner storage chambers 5B, 5C, 5D, and 5E provided on the base 5A.
The toner storage chamber 5B stores, for example, a yellow color liquid toner of the four process colors, and the toner storage chamber 5C stores the second color, for example, a red color liquid toner, a toner storage chamber 5D. 3 stores a third color, for example, indigo plate liquid toner, and the toner storage chamber 5E stores a fourth color, for example, a black plate liquid toner.
[0021]
The developing roller 15 includes a first developing roller 15B provided in the toner containing chamber 5B, a second developing roller 15C provided in the toner containing chamber 5C, a third developing roller 15D provided in the toner containing chamber 5D, and a toner containing chamber. The developing roller 15E provided in 5E can supply the liquid toner in the storage chambers 5B, 5C, 5D, and 5E to the photosensitive drum 2 by the developing roller 15B and the like. ing.
[0022]
Here, the interval between the developing rollers 15B to 15E and the photosensitive drum 2 is such that when the developing rollers 15B to 15E are brought close to the photosensitive drum 2, the liquid toner moves by electrophoresis, but in the capillary phenomenon, the liquid toner moves. It is set to an optimal dimension that can form a clear image with a gap that does not occur. This interval is a dimension obtained based on experience and experiment in advance corresponding to the rotational speed of the photosensitive drum and the developing roller, the characteristics of the liquid toner, and the like, and the dimension is stored as a parameter in a predetermined place. ing.
[0023]
Each of these developing rollers 15B to 15E is selected corresponding to the electrostatic latent image of each color formed on the photosensitive drum 2. In this selection, based on a command to the developing machine moving motor 11 output from the process control unit 35 described later, the developing machine moving mechanism 12 is driven by the motor 11 and the developing rollers 15B to 15E are moved to the developing positions. It is realized by positioning.
The developing rollers 15B to 15E are driven to rotate by the developing roller drive motor 17 while maintaining a predetermined fixed speed ratio with respect to the photosensitive drum 2.
[0024]
The printing paper W is supplied between the backup roller 7 and the transfer roller 6 from a paper transport actuator 49 (see FIG. 8) constituting the printing paper transport means so that the print image on the transfer roller 6 is pressure-transferred. It has become.
[0025]
Next, the registration correction control device 60 of the printing press will be described with reference to FIGS.
The registration correction control device 60 of the printing press generates an approximate drawing start trigger signal generation position for the exposure device 4 based on the rotation angle detection signal output from the encoder 50 that detects the rotation angle of the photosensitive drum 2. A temporary drawing trigger signal generation unit 61 for providing a drawing, a drawing synchronization signal I / F 62 for outputting a drawing synchronization signal to an exposure signal provided in the exposure unit 4 and output to the exposure unit 4, and a first color initial rotation angle storage unit 63, an N-th color initial rotation angle storage unit 64, a phase difference calculation unit 65, and a phase difference correction circuit 66 provided in the phase synchronization control unit 40.
[0026]
The temporary drawing trigger signal generation unit 61 generates a temporary drawing trigger signal for the first color when the drawing origin C provided on the photosensitive drum 2 reaches the drawing start trigger signal generation position by the rotation of the photosensitive drum 2. A drawing synchronization signal from the exposure unit 4 can be passed to the color eye initial rotation angle storage unit 63. When the first drawing synchronization signal is generated, the rotation angle of the photosensitive drum 2 at that time is detected and stored in the first-color initial rotation angle storage unit 63.
[0027]
Further, n scans are performed. The drawing data during this period is dummy data. When the (n + 1) th drawing synchronization signal is generated after the provisional drawing trigger signal is generated, the exposure control unit 30 draws the drawing signal after a predetermined time t has elapsed from the synchronization signal detection position, as described above with reference to FIG. To draw one line. Then, when the drawing of one line is performed, the actual drawing starts to enter the actual drawing.
Here, the peripheral speed of the photosensitive drum 2 is set in advance so that the polygon scanner 91 moves by one dot during the one-surface scanning time, and until the drawing of the final drawing line B determined in advance. Then, drawing is executed while maintaining the two-dimensional synchronism of the circumferential length and width of the photosensitive drum 2.
[0028]
After the development of the final drawing line B for the first color is completed, the fog removal means 13 removes the fog, and after drying by the drying means 16, the development means 19 is moved to prepare for the development of the second color.
In the second color, when the drawing origin C reaches the temporary drawing trigger signal generation position, the temporary drawing trigger signal generation unit 61 generates a temporary drawing trigger signal for the second color in the same manner as the first color, and the Nth color initial rotation angle storage unit. 64, the drawing synchronization signal from the exposure device 4 can be passed. When the first drawing synchronization signal is generated, the rotation angle of the photosensitive drum 2 at that time is detected and stored in the Nth color initial rotation angle storage unit 64.
[0029]
Then, the difference between the rotation angle stored in the first color initial rotation angle storage unit 63 and the rotation angle stored in the Nth color initial rotation angle storage unit 64, that is, the phase difference is obtained by the phase difference calculation unit 65, This phase difference is given to the phase difference correction circuit 66 of the phase synchronization control unit 40. This phase difference correction is performed after the temporary drawing trigger signal for the second color is generated and before the nth drawing synchronization signal is generated.
Note that n times is an integral multiple such as 2 times, 3 times, etc.
[0030]
At this time, the phase difference correction circuit 66 is included in the DSP unit 41 (see FIG. 9) of the phase synchronization control unit 40, and as shown in FIG. 7, the generation cycle of the drawing synchronization signal output from the exposure device 4 is generated. If t is set to t seconds, it suffices to finish within the time (nt seconds) in which n drawing synchronization signals are generated. Therefore, the correction speed obtained from the phase difference and the correction time (nt) is the same as that during normal drawing for t seconds. Correction can be made by overriding the speed.
[0031]
That is, the initial rotation angle of the first color is θ1 from the temporary drawing trigger signal position of the first color, whereas the initial rotation angle of the N color is θ2 from the temporary drawing trigger signal position of the N color, which is slightly from θ1. When the position is delayed, the initial phase difference A is θ2−θ1, and the rotation of the photosensitive drum 2 is normally performed in order to correct the phase difference θ and realize the actual drawing start of the Nth color. The rotation speed may be faster than the drawing rotation speed.
On the contrary, when the initial rotation angle of the Nth color is smaller than the initial rotation angle of the first color, that is, when θ2 is smaller than θ1, the rotation of the photosensitive drum 2 is slower than the speed during normal drawing rotation. Rotate.
[0032]
Next, the control means 20 of the printing press 1 will be described with reference to FIG.
The control means 20 includes a drawing data creation unit 25, an exposure control unit 30, a process control unit 35, and a phase synchronization control unit 40.
[0033]
The drawing data creation unit 25 edits and prints drawing data to be drawn based on print image data using a small computer system such as a personal computer or a workstation to create a publication. The drawing data created using a DTP (desktop publishing) system is output using, for example, a PS file, a PDF (Portable Document Format) file, a TIFF (Tagged Image File Format) file, or the like.
The drawing data creation unit 25 possesses functions corresponding to the respective file formats, and creates drawing data to be used by the printing press 1 using the functions. Note that the drawing data creation unit 25 also performs processing for four color separation processing, RIP (Raster Image Processor) processing, and the like corresponding to the file format.
[0034]
The created drawing data is transmitted to the exposure control unit 30, and the exposure control unit 30 converts the drawing data into a signal (exposure signal) for driving the exposure unit 4, and the exposure signal is transmitted to the exposure unit 4. The
[0035]
Next, the phase synchronization control unit 40 will be described with reference to FIG.
The phase synchronization control unit 40 includes a DSP (digital signal processor) unit 41, a servo controller unit 42, and an input / output I / F 53 that operate as an integrated control unit.
The servo controller unit 42 includes a first servo controller 43, a second servo controller 44, and a third servo controller 45. Each of the servo controllers 43, 44, 45 includes the first servo motor 8 and the second servo motor. 9 and the third servo motor 10, and exchanges drive command signals and phase signals between the process control unit 35 and the exposure control unit 30 via the input / output I / F 55.
[0036]
The DSP unit 41 simultaneously gives independent position command (rotation angle) signals to the servo controllers 43, 44, 45 of the servo controller unit 42.
The position command signals output to the servo controllers 43, 44, 45 are sent to the first servo amplifier 46, the second servo amplifier 47, and the third servo amplifier 48, respectively. A drive signal corresponding to the position command signal is output to the first servo motor 8, the second servo motor 9, and the third servo motor 10, respectively, and the first encoder 50, the second encoder 51, and the third encoder 52 are output. Are input to the servo controllers 43, 44, and 45, respectively.
[0037]
The first, second, and third servo controllers 43, 44, and 45 constitute position loops 55, 56, and 57 having fixed periods (servo system sampling periods), respectively, and are software servos that control each servo system. Has function.
The DSP unit 41 maintains a time interval corresponding to the speed command during low speed operation, and continuously transmits a position command signal to each servo controller 43, 44, 45. At this time, the synchronism of the photosensitive drum 2, the transfer roller 6, and the backup roller 7 is maintained by software synchronization of the DSP unit 41.
Further, at the time of acceleration and deceleration, a position command signal is continuously transmitted while maintaining a rate of change according to an acceleration time and a deceleration time according to a predetermined target angular acceleration, and the photosensitive drum 2 is synchronized with software of the DSP unit 41. The synchronism between the transfer roller 6 and the backup roller 7 is maintained.
[0038]
The phase difference correction circuit 66 is included in the DSP unit 41. If the generation period of the drawing synchronization signal is t seconds, the phase difference correction circuit 66 may be completed within the time (nt seconds) when the n number of drawing synchronization signals are generated. The correction speed obtained from the correction time (nt) may be overridden by a normal drawing speed for t seconds.
Note that the encoder for the photosensitive drum driving motor is used for detecting the rotational angle of the photosensitive drum, but an encoder may be provided separately.
[0039]
Next, the printing procedure of this embodiment will be described based on FIG.
First, in step (hereinafter referred to as ST) 1, when the drawing origin C reaches the charging position of the charger 3, the charger 3 is turned on to charge the photosensitive drum 2. Next, in ST2, the initial rotation angle of the first color is stored in the first color initial rotation angle storage unit 63. When the drawing origin C reaches the exposure position of the exposure device 4, the exposure control unit 35 sets the drawing start position in ST3. The first color, for example, one line for drawing a yellow plate, is drawn while maintaining the above-mentioned synchronization. The peripheral speed of the photosensitive drum 2 is set in advance so that the polygon scanner 91 moves by one dot in one surface scanning time, and the photosensitive drum 2 is drawn until a predetermined final line is drawn. Drawing is executed while maintaining the two-dimensional synchrony of the circumference and width of the.
[0040]
In ST4, when the drawing origin C reaches the development position, development is performed, and the liquid toner is transferred from the first development roller 15B onto the latent image on the surface of the photosensitive drum 2 to form a print image. After the development of the final drawing line B for the first color is completed, the fog removal means 13 removes the fog of the image on the photosensitive drum 2, and then the drying means 16 removes the liquid toner on the surface of the photosensitive drum 2 after the fog removal. In step ST5, the developing unit 19 is moved for developing the second color.
[0041]
In ST6, the phase difference between the rotation angle stored in the first color initial rotation angle storage unit 63 and the rotation angle stored in the Nth color initial rotation angle storage unit 64 is obtained by the phase difference calculation unit 65, and the phase difference is calculated. The correction circuit 66 corrects the phase difference between the generation of the temporary drawing trigger signal for the second color and the generation of the nth drawing synchronization signal, and the drawing of the second color is started in ST7. Synchronization with the rotation of the photosensitive drum 2 at this time is performed in the same manner as in the first color. In ST8, after the second color development, the fog removal means 13 removes the fog of the image on the photosensitive drum 2, and then the drying means 16 dries the liquid toner on the surface of the photosensitive drum 2 after the removal of the fog. In ST9, the developing means 19 is moved for the third color development.
[0042]
In ST10, similarly to the second color, the phase difference between the rotation angle stored in the first color initial rotation angle storage unit 63 and the rotation angle of the third color stored in the Nth color initial rotation angle storage unit 64 is calculated. The phase difference is calculated by the phase difference calculation unit 65, and the phase difference is corrected by the phase difference correction circuit 66 until the nth drawing synchronization signal is generated after the provisional drawing trigger signal for the third color is generated. In ST11, the third color is corrected. Start drawing. After performing the third color development in ST12, the fog removal means 13 removes the fog on the image of the photosensitive drum 2, and then the drying means 16 dries the liquid toner on the surface of the photosensitive drum 2 after the removal of the fog. In ST13, the developing means 19 is moved for the fourth color development.
Thereafter, in the same manner as described above, the phase difference for the fourth color is corrected in ST14, the drawing of the fourth color is started in ST15, the development of the fourth color is performed in ST16, and the photosensitive drum is then removed by the fog removing means 13. Then, the fog of the image 2 is removed, and then the liquid toner on the surface of the photosensitive drum 2 after the fog removal is dried by the drying means 16.
The charger 3 is turned off after the final drawing line B for the fourth color has passed the position of the charger 3.
[0043]
As described above, a full-color print image is formed on the photosensitive drum 2 by the image-on-image. However, the development unit 19 is moved while the section between the final drawing line B and the drawing origin C is at the development position. The photosensitive drum 2 and the transfer roller 6 are attached, and the transfer roller 6 and the backup roller 7 are also attached while the interval between the final drawing line B and the drawing origin C is at the contact position of the photosensitive drum 2 and the transfer roller 6. .
[0044]
That is, after a full-color print image is formed on the surface of the photoconductive drum 2, in ST17, after the final drawing line B passes through the contact position between the photoconductive drum 2 and the transfer roller 6, the transfer roller 6 arrives and the drawing origin is reached. The print image on the photosensitive drum 2 is pressure-transferred onto the transfer roller 6 sequentially from C to the final drawing line B, and the image on the transfer roller 6 reaches the contact position with the backup roller 7 in ST17 and ST18. The position is detected by the encoder angle of the photosensitive drum 2, the printing paper W is supplied from the paper transport mechanism between the backup roller 7 and the transfer roller 6, and then transferred from the photosensitive drum to the transfer roller 6 in ST19, and transferred in ST20. The image on the roller 6 is pressure transferred onto the printing paper W.
[0045]
In the embodiment configured as described above, the following effects can be obtained.
(1) In the printing register control device 60 of the printing press, the phase difference between the initial rotation angles of the photosensitive drum 2 stored in the first color initial rotation angle storage unit 63 and the Nth color initial rotation angle storage unit 64 is the phase difference. Since it is calculated by the calculation unit 65 and is corrected by changing the rotation speed of the rotating drum 2 by the phase difference correction circuit 66 until the actual drawing start synchronization signal is generated based on the calculation result. Even if the photosensitive drum 2 and the exposure unit 4 are driven independently, the actual drawing start of the first color and the second color and the subsequent colors always coincide with each other, and registration of each color when performing multicolor printing is performed. Is maintained at a high level, and as a result, a high-quality printed matter can be obtained.
[0046]
(2) Since the photosensitive drum 2 is driven by the servo motor 8, and the feedback encoder signal from the servo motor 8 is used together with the encoder for detecting the rotation angle of the photosensitive drum 2, two encoders 50 are provided. Since it has a role, it uses less materials.
(3) Since the time from the first synchronization signal after the temporary drawing trigger signal for the first color is generated to the actual drawing start synchronization signal for the first color is an integral multiple of the exposure scanning period, actual drawing starts during the exposure scanning. The synchronization signal is not output, and each color is more reliably registered.
[0047]
(4) The transfer roller 6 is disengaged from the photosensitive drum 2, and the transfer roller 6 is disengaged from the photosensitive drum 2 until the development of the photosensitive drum 2 by the developing means 19 is completed. Since the mutual engagement is disengaged until the printing paper W is disposed between the backup roller 7 and the transfer roller 6 with respect to the transfer roller 6, the development of multicolor printing on the surface of the photosensitive drum 2 is performed by the transfer roller. 6, and the printing paper W can be fed without being interrupted by the backup roller 7. As a result, smooth printing can be performed.
[0048]
(5) Since the fog of the image after the development by the developing means 19 is removed, the thickness becomes uniform, and since it is dried by the drying means 16 in that state, quick drying is possible, and the second and subsequent colors are possible. Smooth transition to development.
(6) Liquid toner corresponding to the printing color can be stored for each color in the toner storage chambers 5B to 5E, and the developing rollers 15B to 15E are provided in the storage chambers 5B to 5E, so that the colors are not mixed. Multi-color printing is possible and can meet the needs of various customers.
[0049]
(7) Since the developing machine body 5 and the developing roller 15 are moved using the non-drawing area I, this movement does not affect the drawing, and the drawing of the next color can be quickly performed. Further, since the drawing area H and the non-drawing area I are provided, the size of the printing paper can be dealt with by changing the range of the non-drawing area I. Accordingly, the single photosensitive drum 2 and the transfer roller 6 can handle various types of printing paper, and the production and installation of the photosensitive drum and the like are facilitated.
[0050]
In addition, this invention is not limited to the said embodiment, The following modifications may be sufficient as long as the objective of this invention can be achieved.
That is, in the above embodiment, the feedback encoder signal from the servo motor 8 is used together with the encoder for detecting the rotation angle of the photosensitive drum 2, but these may be provided separately.
In the embodiment, the printing machine 1 is used for printing. However, the printing machine 1 can also be used for test printing, that is, for calibration.
[0051]
【The invention's effect】
According to the printing register control apparatus of the printing press of the present invention, the phase difference calculation unit calculates the phase difference between the initial rotation angles of the photosensitive drums stored in the first color initial rotation angle storage unit and the Nth color initial rotation angle storage unit. Since it is calculated and corrected by the phase difference correction circuit until the actual drawing start synchronization signal is generated based on the calculation result, the photosensitive drum and the exposure means are driven independently. Even so, the actual drawing start of the first color and the second and subsequent colors always coincide, and the registration of each color when performing multicolor printing is maintained at a high level, and as a result, a high-quality printed matter can be obtained. become.
[Brief description of the drawings]
FIG. 1 is an overall view showing an embodiment of a printing register control apparatus for a printing press according to the present invention.
FIG. 2 is a view showing an example of an exposure system of the embodiment.
FIG. 3 is a diagram illustrating a drawing area, a non-drawing area, a drawing origin, and the like on the photosensitive drum according to the embodiment.
FIG. 4 is a diagram illustrating an example of synchronization detection timing at the start of drawing according to the embodiment.
FIG. 5 is a diagram illustrating a configuration of a printing register control device of the printing machine according to the embodiment.
FIG. 6 is a diagram showing a positional relationship such as a drawing origin and an exposure position in the embodiment.
FIG. 7 is a diagram illustrating a timing example of a temporary drawing trigger signal and a drawing synchronization signal according to the embodiment.
FIG. 8 is a diagram illustrating a control mechanism in the printing press according to the embodiment.
FIG. 9 is a diagram showing a phase synchronous drive system of the embodiment.
FIG. 10 is a flowchart of processing of the embodiment.
[Explanation of symbols]
1 Printing machine
2 Photosensitive drum
3 Charger
4 Exposure unit as exposure means
5. Developing machine main body constituting developing means
5B-5E Toner storage chamber
6 Transfer roller
7 Backup roller
13 Fog removal means
15 Development roller
15B to 15E First to fourth developing rollers
16 Drying means
19 Development means
20 Control means
25 Drawing data generator
30 Exposure control unit
35 Process control unit
40 Phase synchronization controller
45 storage unit
60 Printing register control device for printing press
61 Temporary drawing trigger signal generator
62 Drawing synchronization signal I / F
63 First color initial rotation angle storage unit
64 Second color initial rotation angle storage unit
65 Phase difference calculator
66 Phase Correction Circuit

Claims (3)

A photosensitive drum on which an image is formed, a charging unit for charging the surface of the photosensitive drum, and after charging by the charging unit based on drawing data, the surface of the photosensitive drum is exposed and scanned to perform drawing. An exposure unit for creating a latent image, and a development for developing the electrostatic latent image on the surface of the photosensitive drum by sequentially supplying multicolor liquid toner to the surface of the photosensitive drum by electrophoresis after exposure scanning by the exposure unit. Means, a fog removing means for removing the fog of the image after development by the developing means, a drying means for drying the liquid toner on the surface of the photosensitive drum, and a transfer roller for receiving the image dried by the drying means. And a backup roller for transferring the image on the transfer roller to the printing paper, and each of these means and a control means for controlling each of the rollers. A register control system,
A drawing synchronization signal I / F circuit that is provided in the exposure unit and outputs a drawing synchronization signal to the exposure signal output to the exposure unit;
An encoder for detecting a rotation angle of the photosensitive drum;
A temporary drawing trigger signal generation unit for giving an approximate drawing start trigger signal generation position to the exposure means by a rotation angle detection signal output from the encoder;
A first color initial rotation angle storage unit that stores an initial rotation angle of the photosensitive drum at the time of detection of the first drawing synchronization signal output from the drawing synchronization signal I / F circuit after the first color temporary drawing trigger signal is generated;
An N-th color initial rotation angle storage unit for storing an initial rotation angle of the photosensitive drum at the time of detection of the first drawing synchronization signal output from the drawing synchronization signal I / F circuit after generation of a temporary drawing trigger signal for the second and subsequent colors; ,
A phase difference calculation unit for calculating a phase difference between the initial rotation angles of the photosensitive drums stored in the first color initial rotation angle storage unit and the Nth color initial rotation angle storage unit;
A phase difference correction circuit configured to correct the phase difference until an actual drawing start synchronization signal is generated based on a calculation result in the phase difference calculation unit. Printing register control device. 2. The printing register control apparatus for a printing press according to claim 1, wherein the photosensitive drum is driven by a servo motor, and a feedback encoder signal from the servo motor is used in combination with an encoder for detecting the rotation angle of the photosensitive drum. A printing register control device for a printing press. 3. The printing register control apparatus for a printing press according to claim 1 or 2, wherein the time from the first drawing synchronization signal after generation of the temporary drawing trigger signal for the first color to the actual drawing start synchronization signal for the first color is exposure. A printing register control apparatus for a printing press, characterized by being an integral multiple of a scanning cycle.

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