JP2002273921A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus with a simple constitution which decreases fluctuation of a position of photo-irradiation on the surface of a drum generated from fluctuation of rotation in the rotating direction of an image medium holding drum. SOLUTION: In the image forming apparatus in which a recording medium 1 forming an image by heating generated by photo-irradiation, the image medium holding drum 2 for holding the recording medium 1, a rotating position detecting means 5 such as an encoder for detecting the rotating position of the recording medium holding drum 2 and a write head 3 with a plurality of laser light sources for photo-irradiating the recording medium 1 are the minimum constitutional elements, based on positional information related to the recording medium holding member 2 from the drum position detecting means 5, an image data transferring clock to a plurality of light sources is reset.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image forming apparatus, and more particularly, to an image forming apparatus using a recording medium on which an image is formed by being heated by light irradiation. The present invention relates to an image forming apparatus capable of obtaining a high-quality image by reducing a variation in a light irradiation position on the image forming apparatus.

[0002]

2. Description of the Related Art An image forming apparatus using a recording medium on which an image is formed by being heated by light irradiation is known. For example, in the invention of Japanese Patent Application Laid-Open No. 7-23195 (method and apparatus for correcting and adjusting digital image output), a method described in U.S. Pat. A method of performing image formation by irradiating light to an appropriate position of a recording medium mounted on a drum surface by synchronizing the phase of an installed encoder output signal and a signal obtained by dividing a pixel clock using PLL control, and The device is proposed. However, since the method according to the present invention requires the same number of PLL control circuits as the number of light sources, there is a problem that the driving system of the light source becomes large and the cost required for the driving system becomes excessive. In addition, Japanese Patent Application Laid-Open No. Hei 5-23802
In the invention of Japanese Patent Application Publication No. 4 (high-resolution thermal dye transfer apparatus), a method of performing image formation by irradiating light to an appropriate position on a recording medium on which the dye is sublimated by heating disposed on the drum surface by the same control method and Although an apparatus is proposed, it has the same problems as above.

[0003]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a method for reducing the variation in the position of light irradiation on the drum surface caused by the variation in the rotation direction of the drum.
An image forming apparatus having a light source drive control system having a function of resetting an image transfer clock according to an encoder output signal installed on a drum shaft is proposed.

It is an object of the present invention to provide an image forming apparatus capable of reducing variation in pixel positions by a simple means as compared with a conventional image forming apparatus.

A second object of the present invention is to provide an image forming apparatus having less variation in pixel positions than the first embodiment.

A third object of the present invention is to provide an image forming apparatus capable of improving the stability of a data transfer control system with respect to the second invention.

A fourth object of the present invention is to provide an image forming apparatus capable of using a drum position detecting means having a lower detection accuracy than the first to third inventions. .

Another object of the present invention is to provide an image forming apparatus capable of preventing a received image from being disturbed by a signal from a drum position detecting means. .

Another object of the present invention is to provide an image forming apparatus capable of preventing disturbance of a transferred image due to a signal from a drum position detecting means. .

A seventh object of the present invention is to provide an image forming apparatus capable of preventing disturbance of a transferred image due to a reset signal from a drum position detecting means. I do.

Another object of the present invention is to provide an image forming apparatus capable of preventing transfer image disturbance due to a reset signal from a drum position detecting means.

A ninth aspect of the present invention is to provide an image forming apparatus having less variation in pixel positions than the first to eighth aspects of the present invention.

A tenth aspect of the present invention is to provide an image forming apparatus which can apply the first to ninth aspects to a printing plate material.

Another object of the present invention is to provide an image forming apparatus capable of forming an image with a lower energy amount than the invention of the tenth aspect.

A second object of the present invention is to provide an image forming apparatus which does not require the use of a liquid at the time of image formation.

A further object of the present invention is to provide an image forming apparatus capable of forming a large number of images on recording paper at a high speed with respect to the inventions of the first to twelfth aspects.

An object of a fourteenth aspect of the present invention is to provide an image forming apparatus in which a plurality of color images are superimposed to improve the positional accuracy with respect to the first to thirteenth aspects.

[0018]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above object, and the first technical means is as follows.
A recording medium on which an image is formed by heating, a recording medium holding drum for holding the recording medium, drum position detecting means for detecting the position of the recording medium holding drum, and a plurality of light sources for irradiating the recording medium with light. In the image forming apparatus provided with the write head, the image data transfer clock to the plurality of light sources is reset based on the recording medium holding drum position information from the drum position detecting means.

A second technical means is the image forming apparatus according to the first technical means, wherein the drum position detecting means comprises: a change amount of a position of the recording medium holding drum when the recording medium holding drum rotates by one pixel interval; Alternatively, it is characterized in that it is possible to detect an interval that is a fraction of the change amount of the recording medium holding drum position.

A third technical means is the image forming apparatus according to the second technical means, wherein the drum position detecting means comprises: a position change amount when the recording medium holding drum rotates by an interval of eight pixels; It is characterized in that it is possible to detect intervals that are integral multiples of the amount.

A fourth technical means is the image forming apparatus of the first to third technical means, wherein the drum position detecting means is
It is characterized by having a detection function of multiplication or more.

According to a fifth technical means, in the image forming apparatus according to the first to fourth technical means, while the unit having the image data transfer control function is receiving data from a different unit, the data transfer clock is reset. It is characterized by not being performed.

According to a sixth technical means, in the image forming apparatus according to the first to the fifth technical means, while the unit having the image data transfer control function is transmitting data to a different unit, the data transfer clock is reset. It is characterized by not being performed.

According to a seventh technical means, in the image forming apparatus according to the first to sixth technical means, the image data transfer clock is reset only once for one pulse of the output signal from the drum position detecting means. Features.

According to an eighth technical means, in the image forming apparatus of the seventh technical means, when the image data transfer clock is in the H state, the image data transfer clock is not reset.

A ninth technical means is the image forming apparatus according to the eighth technical means, wherein the driving source of the recording medium holding drum is a stepping motor.

According to a tenth technical means, in the image forming apparatus according to the first to ninth technical means, the recording medium has a property that ink adhesion characteristics are different between a heated area and a non-heated area.

According to an eleventh technical means, in the image forming apparatus according to the tenth technical means, the receding contact angle is reduced when the liquid is brought into contact with the liquid in a heated state (a lyophilic state), and the liquid does not contact the liquid. A recording medium having a surface characteristic in which the receding contact angle increases when heated in (liquid-repellent state).

According to a twelfth technical means, in the image forming apparatus of the eleventh technical means, an image is formed by heating a non-image area.

According to a thirteenth technical means, in the image forming apparatus according to the first to twelfth technical means, a developing unit for adhering ink to an image area of the recording medium; It is characterized in that an intermediate transfer member for transferring an ink image and an impression cylinder are used as constituent elements.

A fourteenth technical means is the image forming apparatus of the first to thirteenth technical means, which is a multicolor image forming apparatus having a plurality of writing units, recording medium holding units, and developing units, and The recording medium holding drum is provided with drum position detecting means.

[0032]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the embodiments shown in the drawings. FIG. 1 is a diagram showing a light source arrangement of a writing head used in an image forming apparatus according to the present invention.
Is a diagram showing an example of an image generated by a plurality of light sources,
FIG. 3 is a front view and a side view showing a relationship between a write head of the image forming apparatus and a recording medium and the like. The image forming apparatus according to the present invention uses a write head 3 having a plurality of light sources 4 as shown in FIG. 1 to perform recording on a surface of a rotating drum-shaped recording medium holding drum 2 as shown in FIG. The present invention relates to an apparatus for forming an image on a medium 1.

FIG. 2A shows an image formation by the image forming apparatus of the present invention. Each time the recording medium holding drum 2 makes one rotation, the write head 3 rotates the recording medium holding drum 2 in a direction perpendicular to the rotation direction of the recording medium holding drum 2. Writing is performed by moving one pitch in the direction. However, actually, the tooth shape of a gear or a timing belt for driving the recording medium holding drum 2 and the like,
Since the rotation of the recording medium holding drum 2 becomes uneven due to a gap error or mechanical vibration caused by a motor or the like,
Even if writing at a constant frequency is performed on the rotating recording medium holding drum 2, the writing timing is different for each rotation, an image is formed as shown on the left side of FIG. Cause.

Accordingly, the rotation position of the recording medium holding drum 2 is grasped by detecting the home position of the recording medium holding drum 2 or providing a rotation position detecting means 5 such as an encoder on the shaft of the recording medium holding drum 2. , Or control, and writing must be performed instantaneously at an appropriate position on the recording medium holding drum 2. Methods for determining the timing of writing to the recording medium 1 include a method of controlling the position of a motor that drives the recording medium holding drum 2 and a method of controlling the phase of an encoder output signal provided on the recording medium holding drum shaft and an image transfer clock. However, in the case of high-density image formation, the motor position control alone is not practical because sufficient accuracy cannot be obtained, and the control system is complicated and expensive in the phase control method of the encoder output signal and the image transfer clock. In particular, when ten or more light sources are used, the load on the data control system becomes very large.

On the other hand, in the present invention, the recording medium holding drum 2 is provided with a rotation position detecting means 5 for the recording medium holding drum such as an encoder on the shaft thereof, and the detection signal is generated based on the detection signal. By simply resetting a clock signal for transferring data to the light source 4 by a signal, the writing position on the recording medium 1 installed on the recording medium holding drum can be controlled with almost no variation.
An image can be formed as shown on the right side of FIG.

FIGS. 3, 4, and 5 show examples of the image data transfer control unit used in the image forming apparatus of the present invention. In the example of FIG. 3, a drum rotation position signal obtained from the rotation position detection means 5, a clock signal serving as a source of an image transfer clock such as an image transfer clock or a system clock, and image data are input to the image data transfer control unit 7. A signal or clock input as a signal and requesting image data;
Output the image data signal to be supplied to

FIG. 4 shows an example of a simple configuration of the image data transfer control unit. In this example, the image data transfer control unit 7
Are a plurality of image data transfer control units 7 ₁ , 7 ₂ ,
..., 7 _n has an image data transfer clock generator 8, respectively, the data receiving unit 9, the data distribution unit 10, the delay generator 11 is formed from a light source drive signal output unit 12, sequentially the image data in each unit While transmitting a request signal and receiving image data in synchronization with the request signal, a plurality of light sources are synchronized in synchronization with an input image transfer clock or an image data transfer clock obtained from a clock signal which is a source of the image transfer clock. Has a function of distributing and transferring image data. However, since the data transfer to each light source 4 is performed at the same timing by the image transfer clock except for the delay time set for each light source, the distribution of the image data to each light source is performed by the image data transfer clock. It is necessary to use a clock having a frequency sufficiently higher than that. The number of light sources controlled by the image data transfer control units 7 ₁ , 7 ₂ ,..., 7 _n (i, j, k values in FIG. 4) may be different or the same, respectively. It is desirable that all the image data transfer control units have the same specifications in terms of development efficiency and manufacturing cost.

The drum rotation position signal output from the drum rotation position detecting means 5 is input to the image data transfer clock generator 8 as shown in FIG. 5, and is used for resetting the image data transfer clock. Therefore, the phase of the image data transfer clock is corrected and controlled by the drum rotation position signal from an encoder or the like.

The delay generator 11 shown in FIG. 4 is used to correct the irradiation position variation caused by a mechanical shift of a plurality of light sources, and a delay amount unique to each light source is set. The target recording medium may be any material as long as it is heated by light irradiation to form an image. Note that the image formed on the recording medium is not limited to a visible image, and if the physical properties and molecular structure of the surface are changed by heating and the state can be detected by some method, the image is formed. And It is desirable that the eccentricity of the recording medium holding drum be as small as possible, and that the unevenness of the surface be both smooth.

The light source may be any material as long as the laser light source is desirable. However, an inexpensive and small semiconductor laser is desirable. In the case of irradiation using an optical fiber cable or the like, the light emitting portion of the optical cable is regarded as a light source. Therefore, the method of irradiating the recording medium may be to irradiate the recording medium directly from the laser light source,
A configuration in which light from a light source is irradiated on a recording medium using an optical fiber cable or the like may be used. The light source arrangement of the write head 3 used in the image forming apparatus may be perpendicular to the rotation direction of the recording drum 2 as shown in FIG. 1A, or may be the drum rotation direction as shown in FIG. The light source may be shifted to be arranged at the same position.

FIG. 6 is a diagram showing the relationship between the detection interval of the drum position detection means and the pixel interval formed on the recording medium. Since the output signal from the drum position detecting means 5 is used to correct the actually written interval, if the output signal from the drum position detecting means 5 is a plurality of pulses per rotation of the drum during image formation, , The detection interval needs to be substantially an integral multiple of the pixel pitch. Further, it is desired that the relationship be closer to an integral multiple. In the example shown in FIG. 6, resetting is performed at intervals of N pixels. However, this N is an arbitrary integer, and the optimum value differs depending on the actual device configuration and the like, and the variation in the writing position of each line is a predetermined value. Is set to fall within the value of.

FIG. 7 is a view showing an example different from FIG. 6, showing the relationship between the detection interval of the drum position detection means and the pixel interval formed on the recording medium. In the example shown in FIG. 7, resetting is performed at intervals of K times 8 pixels, but the optimum value of K differs depending on the actual device configuration and the like. For example, it may be determined based on the bus width for transferring image data, the number of bits of an IC to be used, the number of bytes that are convenient for data distribution control for each light source, and the like.
When data is distributed in units of bytes or a plurality of bytes (hereinafter referred to as bytes), resetting is performed every time data is transferred in units of bytes, so that synchronization is improved and control stability is improved. However, since the unit that transfers data to each light source transfers its byte data serially in units of bits, when resetting the clock that is transferred in units of bytes, the clock for transferring in units of bits is also reset. To have the same phase. Further K
Must be set to such a value that the writing position variation of each line falls within a predetermined value or less.

FIG. 8 is a view showing an example in which a quadruple encoder is used as the drum position detecting means. In this example, an example of multiplication by four is shown, but the number of detection heads may be three or more, and the detection density may be four or more. However, the finally obtained detection density of the drum position detection means needs to be a value which becomes a pixel density number by multiplying by an arbitrary integer. For example, when forming an image at 1270 dpi, the detection density of the drum position detection means needs to be a divisor of 1270 dpi. With the above configuration, it is possible to perform control corresponding to high density even with a head having low density detection capability.

(Explanation of the Invention of Claim 5) FIG. 9 is a diagram showing an example of the reset timing of the image transfer clock in the invention of claim 5. This figure shows the timing of the output signal of the encoder serving as the drum position detecting means, the reset signal of the image transfer clock, the image data transfer clock, and the data request signal from each data transfer control unit. While the data request signal is output from the unit and data is being acquired, the image transfer clock is not reset even if the encoder output signal is turned on. In this way, by prohibiting resetting while the image data transfer unit is receiving data, particularly image data, from the individual unit, it is possible to prevent image data from being lost. Note that the actual reset signal does not need to use the output signal of the encoder as it is, but needs to be generated from at least the encoder output signal and a signal indicating that data transfer is being performed.
The width of the N state is preferably as short as possible. Further, it is not only between ICs different from individual units. For example, in the case of a programmable IC, since a plurality of individual units can be created in the same IC, such an IC includes between individual units in the IC.

(Explanation of Claim 6) FIG. 10 is a diagram showing an example of the reset timing of the image transfer clock in the invention of claim 6. This figure shows the timing of the output signal of the encoder which is the drum position detecting means, the reset signal of the image transfer clock, the image data transfer clock, and the timing of the data acquisition signal from the data transfer control unit corresponding to each light source. As shown, while the data acquisition signal is output from each data transfer control unit and data is acquired, the image transfer clock is not reset even if the encoder output signal is turned on. In this way, the image data transfer unit transmits data to the individual unit,
In particular, by prohibiting resetting while transmitting image data, it is possible to prevent image data loss, data distribution mistakes, and the like.

The actual reset signal does not need to use the output signal of the encoder as it is, but must be generated at least from the encoder output signal and a signal indicating that data transfer is being performed. Shorter is better. Further, it is not only between ICs different from individual units. For example, in the case of a programmable IC, since a plurality of individual units can be created in the same IC, such an IC includes between individual units in the IC.

(Explanation of the invention of claim 7) As shown in FIGS. 9 and 10, one pulse is input to one encoder pulse.
This is a pulse reset signal. In the examples of FIGS. 9 and 10,
In particular, the pulse width of the reset signal in the ON state is sufficiently shorter than the pulse width of the encoder output signal. However, a plurality of reset signals are not output when the encoder output signal is in the ON state. If a plurality of reset signals are output, a difference occurs between the phase of writing the image data and the phase of the reset signal, so that the pixel interval varies every time the reset is performed, which causes a significant decrease in image quality.

As an example for preventing a plurality of pulses from being output, two D flip-flops (hereinafter, referred to as D-FFs) are prepared in series, an encoder output (assumed to be reset at H) and image data. An AND output of a signal indicating a transfer state (assuming that the H state is a non-transfer state);
The OR output with the Q output of the stage D-FF is supplied to the D input of the first stage D-FF, and the Q output of the first stage is output to the D of the second stage D-FF.
Input to the input, the Q output of the first stage D-FF and the second stage D-FF.
Take AND output with FF output. And the first stage D
An encoder output signal is supplied to the reset input of the -FF, and a clock signal having a period sufficiently shorter than the pulse width of the encoder output signal is supplied to the clock input of the first and second D-FFs, thereby shortening the time. A single pulse signal having a width can be generated.

FIG. 11 is a diagram showing the relationship between the image data transfer clock and the reset timing. If the reset of the image data transfer clock is performed while the clock is in the H state, the width of the H state of the clock may be extremely short, and in such a state, the normal image data transfer operation can be performed. Disappears. Therefore, in the generation of the reset signal of the image data transfer clock,
8. The reset signal generating method according to claim 7, wherein
This can be implemented by changing only the D input of the stage D-FF as follows. That is, an AND output of an encoder output (assumed to be reset at H), a signal indicating an image data transfer state (assuming that the H state is a non-send / receive state), an inverted signal of the image data transfer clock, and a first stage D- By supplying the OR output with the Q output of the FF to the D input of the first stage D-FF, a desired reset signal can be generated.

(Explanation of the Invention of Claim 9) In the example of the image forming apparatus shown in FIG. 3, the stepping motor 6 is used as a motor for driving the recording drum 2, so that no special control mechanism is provided. In addition, it is possible to suppress variations in pixel pitch in the drum circumferential direction. However, in practice, there is a variation in the rotation pitch of the recording drum 2 caused by an error in the meshing state between the timing belt and the pulley, or between the gears, the tooth size, the tooth spacing, and the like. The amount of movement around the drum with respect to. Therefore, when high-density image formation is performed, sufficient accuracy cannot be obtained only by the open control of the stepping motor 6. Therefore, high-density image formation is performed in combination with a means for detecting the drum rotation position such as an encoder. It is desirable to correspond to the formation.

(Explanation of the Tenth Invention) FIG. 12 is a view for explaining the ink adhesion characteristics of a recording medium. FIG. 12A shows a recording medium having a property that ink adheres to the heating area 1a, and FIG. 12B shows a recording medium having a property that ink adheres to the non-heating area 1b. These can be used as plate materials for direct printing or offset printing. For example, a light absorbing layer is provided on the surface of a material such as aluminum or PET resin, which has excellent ink adhesion, such as metal, resin, or paper. An ink-repellent material layer such as a silicone resin is formed thereon, and the image area is heated so that the ink-repellent material in the heated area is easily removed. By removing the material, a plate can be made in which the ink adheres to the heated area. In addition, a light absorbing layer is provided on the ink repellent material, a material layer having excellent ink adhesion is formed thereon, and the non-image area is heated to remove the ink adhering material. Can be produced. Since a printing plate requires high precision, it is very important to correct and control the writing position.

FIG. 13 is a view showing a recording medium used in the image forming apparatus according to the eleventh aspect. FIG. 13A shows an example in which the initial state of the recording medium 1 is set to an ink-repellent state on the entire surface and the liquid 11 is brought into contact with the surface of the recording medium to heat the image area to form an image.
Indicates the result of developing the recording medium with ink. When the recording medium 1 is brought into contact with a liquid in a heated state, the receding contact angle is reduced (lyophilic state), and when heated in a non-contact state with the liquid, the receding contact angle is increased (lyophobic state). Or) heating the image area while having surface properties and contacting the surface with a member selected from liquid, vapor, and / or solid;
Alternatively, immediately after heating the surface of the recording medium according to image information, the recording medium is brought into contact with a member selected from a liquid, a vapor, and / or a solid, so that the receding contact angle of the recording medium surface heating portion is reduced to reduce the image. It is formed and used as a plate for offset printing.

The recording medium of the present invention has a structure in which a light absorbing layer is provided on the surface of a substrate such as resin, metal, paper, etc., and a recording material layer having the above characteristics is formed thereon, or a recording medium containing a light absorbing material on the substrate. A structure in which a material layer is formed is used. Since the surface of this recording medium may not be visible when heated by irradiating laser light with an appropriate amount of energy, the irradiation position deviation of the light source should be measured using the development result with ink or using a CCD sensor. Is desirable.

FIG. 14 is a view showing a recording medium used in the image forming apparatus according to the twelfth aspect. The recording medium 1 shown in FIG. 14 has a reduced receding contact angle when it is brought into contact with a liquid in a heated state, similarly to the recording medium used in the image forming apparatus according to claim 11, and when it is heated in a non-contact state with the liquid. With surface characteristics that increase receding contact angle,
As shown in FIG. 14 (A), liquid, vapor, and / or
Heating in contact with a member selected from solids,
Or, immediately after heating the surface of the recording medium, by contacting the liquid, vapor, and / or a member selected from solids, to reduce the receding contact angle of the recording medium surface,
As shown in FIG. 14B, in the absence of the contact member, only the non-image area of the recording medium is selectively heated to form an image, and developed with ink as shown in FIG. 14C. Since the present image forming method is a device for writing a non-image portion, it is necessary to irradiate the non-image region without omission. Therefore, it is very important to correct the writing position deviation.

(Explanation of Claim 13) FIGS. 15 to 1
FIG. 7 is a diagram showing an example of a printing press embodying the invention of claim 13. FIG. 15 shows an example of a printing machine for forming an image on a belt-shaped recording medium and transferring ink images to recording paper by attaching ink to the image area. FIG. 16 shows one printing plate from a roll-shaped recording medium. FIG. 17 shows an example of an offset printing machine having a configuration in which a recording medium roll is held inside a plate cylinder, and an image is formed after a single plate is fed out while holding a recording medium roll. Is shown. The printing press described above can perform plate making and printing inside the apparatus. Although it is conceivable to sacrifice the robustness of the apparatus in order to reduce the apparatus cost, in such a case, it is particularly important to control the image formation by the rotation position detecting means of the recording drum such as an encoder.

(Explanation of Claim 14) FIGS. 18 to 20
FIG. 14 is a diagram showing an example of a printing press embodying the invention of claim 14. FIG. 18 shows an example of an offset printing press having one impression cylinder, FIG. 19 shows an example of an offset printing press having two impression cylinders,
FIG. 20 shows an example of a light source drive timing acquisition method in the case of a multicolor image forming apparatus. In the case of a multicolor printing machine, since a plurality of recording media are used, it is necessary to adjust not only the image head position for each color individually but also the image writing position so that the image position of each color matches. In the correction method, the method of matching the second color and the subsequent colors based on the image on the recording medium of the first color does not require adjustment for all colors, so that the adjustment time can be shortened. As an example of the adjustment method, a pattern image determined as shown in FIG. 20 is formed, the image position is obtained by an optical sensor or the like, the positions of the respective colors are compared, and the drive timing of the light source is adjusted.

Hereinafter, embodiments of the present invention will be described. The common conditions for each embodiment are as follows. Image forming means (light source) (1) 150 mW output, 830 nm wavelength semiconductor laser (DL-8032-001: Sanyo Tottori) × 20 1270 dpi multi-heads (2) 60 mW output, 780 nm wavelength semiconductor laser (LNC707PS: Matsushita) Electronics industry) × 20 127
0 dpi multi-head All spot shapes: φ20 μm, light source pitch 16 m
m << recording drum diameter >> φ177.854 mm << recording drum rotation speed >> (1) 67 rpm (2) 133 rpm

Example 1 (Claim 1) Recording medium (1) CTC film (having a light-absorbing layer containing a phthalocyanine dye) (2) Hot-melt ink ribbon (black: containing carbon black) + recording paper (Plain paper, synthetic paper) (3) Thermal sublimation type ink ribbon (black: 6 as light absorbing layer)
μm thick carbon black) + recording paper (PET film, synthetic paper) ● Encoder: (output) 5000 pulses / rotation First, the configuration of the image forming apparatus used is shown in FIG. Attach it to the drum as shown in Figure 3,
The common condition head (1) of the type shown in FIG. 1A was used as the image forming head, and an encoder having a 5000 p / r output was provided on the recording drum shaft as a recording drum rotational position detecting means. Next, as for the image data transfer control unit, three image data transfer control units are manufactured using a programmable IC in the image data transfer control unit as shown in FIG. 20) L
D was driven. The main input signals to the image data transfer control unit are the encoder output signal and the 20
The output signal is a system clock of MHz, image data, and other control signals, and the output signal is mainly the image data of the image data that is desired to be acquired for the image data supplier that is the first transmission destination. 1MHz clock according to the number,
For the light source drive control unit, which is the second transmission destination, a light source drive signal corresponding to each light source. The reset signal of the image data transfer clock was generated from the encoder output signal and the system clock. In the conventional image, as shown in the left side of FIG. 2B, the writing position of each line fluctuates by about 100 μm, and the pixel pitch within the same line also fluctuates. As a result, as shown in the right side of FIG. 2B, it was possible to form a high-quality image in which the variation in the writing start position of each line was several μm. Table 1 shows the result of comparing the variation in the write start position between the conventional apparatus and the apparatus of the present invention.

[0059]

[Table 1]

Embodiment 2 (Claim 2) Encoder: (output) 4000 pulses / rotation Under the same conditions as in Embodiment 1, the encoder to be used was obtained and changed as follows. The diameter of the recording drum is 17
7.854 mm, and the diameter was adjusted to 178.254 mm by the recording medium and the spacer. Thus, at 1270 dpi, 178.25 appears on the surface of the recording medium.
4 × π / 0.02 ≒ 28000 pixels can be formed, and the encoder used is 4000 p / r (pulse / rotation) that can divide 28000 by an integer.
As a result of forming an image by the above configuration, the variation in the writing start position of each line is remarkably improved to several μm, and the interval between the pixel written at the moment when the image data transfer clock is reset and the next pixel is 1270 dpi. In agreement, high quality image formation became possible. 50
Table 2 shows the result of comparing the pixel interval of the reset part between the 00p / r output and the 4000p / r output encoder.

[0061]

[Table 2]

Embodiment 3 (Claim 3) Encoder: (output) 3500 pulses / rotation Under the same conditions as in Embodiment 1, the encoder to be used was obtained and changed as follows. The diameter of the recording drum is 17
7.854 mm, and the diameter was adjusted to 178.254 mm by the recording medium and the spacer. Thus, at 1270 dpi, 178.25 appears on the surface of the recording medium.
4 × π / 0.02 ≒ 28000 pixels can be formed, and the encoder used is 3500 p / r which is a value obtained by dividing 28000 by 8. Therefore, the image data transfer control unit corresponding to each light source always resets the clock at a fixed timing after receiving one byte, thereby simplifying the circuit design and improving the stability of the control circuit. Improved. Further, as a result of forming an image with the above configuration, the variation in the writing start position of each line is remarkably improved to several μm, and high quality image formation can be performed. Table 3 shows the result of comparing the pixel interval of the reset part between the 3500 p / r output encoder and the 4000 p / r output encoder.

[0063]

[Table 3]

Embodiment 4 (Claim 4) Encoder: (output) 2000 pulses / times in quadruple mode
Rotation Under the same conditions as in Example 1, control was performed using an encoder having a quadruple output and an output of 2000 p / r, and image formation was performed. As a result, it has been confirmed that the variation in the writing start position of each line is remarkably improved to several μm, and that a high quality image can be formed with a simple encoder. 4
Table 4 shows the results of comparison of the write position variation between the 000p / r output encoder and the 2000p / r output encoder.

[0065]

[Table 4]

Fifth Embodiment (Claim 5) Under the same conditions as in the fourth embodiment, a signal which is in the L state only while all three image data transfer control units are receiving data is generated. As a result of generating and controlling the reset signal from the encoder output as described in claim 5, the noise on the image is reduced, and the variation in the writing position of each line is significantly improved to several μm. Thus, high-quality image formation can be performed.

Embodiment 6 (Claim 6) Under the same conditions as in Embodiment 5, in each image data transfer control unit, the image data received from the preceding stage is transferred to the data transfer control unit provided corresponding to each light source. As a result of generating a signal which is in the L state only while the signal is distributed to the controller and generating a reset signal from the signal and the encoder output as described in claim 6, control is performed.
The noise on the image was reduced, and the variation in the writing start position of each line was remarkably improved to several μm, making it possible to form a high quality image.

Embodiment 7 (Claim 7) Under the same conditions as in Embodiment 6, using an encoder output signal, a 2 MHz clock signal, and two D-FFs, as described in the description of Claim 7, Encoder 1
As a result of producing and controlling a circuit in which a reset signal is generated once for each pulse, noise on an image is reduced,
In addition, the variation in the writing start position of each line is remarkably improved to several μm, and high-quality image formation can be performed.

Embodiment 8 (Claim 8) Under the same conditions as in Embodiment 7, a request is made using an encoder output signal, a 2 MHz clock signal, a 31.25 kHz image data transfer clock, and two D-FFs. As described in the description of the item 8, when the image data transfer clock is in the H state, a circuit that generates a reset signal after the clock is changed to the L state is manufactured and controlled. As a result, noise on the image is reduced. In addition, the variation in the writing start position of each line is remarkably improved to several μm, and high-quality image formation can be performed.

Image results when all the controls of the inventions of claims 5 to 8 are used and when they are not used The results of image formation on a recording medium using three types of halftone pattern data are shown in Table 5. When the control according to claims 5 to 8 is not performed, a noise component is included, whereas when the control is performed, the noise component is suppressed, and it has been confirmed that normal image formation can be performed with high image quality. Table 5 shows a comparison of the image forming result of the halftone pattern data when all the controls of the inventions of claims 5 to 8 are used and when they are not used.

[0071]

[Table 5]

Embodiment 9 (Claim 9) Image data transfer in a state where the conditions of Embodiments 5 to 8 are met, that is, when the data transfer control unit is transmitting and receiving and when the data transfer clock is in the H state. Do not reset the clock, as well as encoder input 1
In a system that resets the image data transfer clock only once for a pulse, image formation was performed using the drive motor of the recording drum as a stepping motor. As a result, the control system is greatly simplified as compared with the case of using a DC motor, and at the same time, the control accuracy is improved and a high-quality image can be obtained. When image formation was performed using both of the motors without performing reset control of the image data transfer clock, it was confirmed that better results could be obtained by using a stepping motor as shown in Table 6. Table 6 shows the result of comparing the write start position variation amount between the DC motor and the stepping motor.

[0073]

[Table 6]

Embodiment 10 (Claim 10) Recording medium: 180 μm thick PET film + 10 μm
1. Carbon layer containing thick wax fine particles + 1 μm thick silicone resin layer Ink used: as shown in Table 7

[0075]

[Table 7]

The above-mentioned recording medium was used.
An image was formed under the same conditions as described above, and development was performed using the ink. As a result, good plate making with less variation in pixel position could be performed.

Embodiment 11 (Claim 11) Recording medium Material 1: Fluorine-containing acrylate material (LS317
[Asahi Glass]) ・ Material 2: Mixed material of fluorinated acrylate resin and urethane resin (RHC12 [Asahi Glass]) ・ Substrate 1: Direct mat PET film sheet (3
50 × 540 mm, 100 μm thickness) +6 μm thickness carbon layer (light absorbing layer) ・ Substrate 2: Direct mat PET film roll (3
1. 50 mm × 10 m, 50 μm thick) +6 μm thick carbon layer (light absorbing layer) Contact liquid used for image formation: water A transparent PET film that transmits laser light is disposed on the surface of the recording medium, and a thin layer of water is held between the recording medium and the film. Is LD under the same conditions as in Example 1 (however, the laser head uses (2)).
Image formation was performed with the drive timing determined, and development was performed using the ink of Example 10. As a result, good plate making with a low output LD and little pixel position variation in the sub-scanning direction could be performed.

Example 12 (Claim 12) Pretreatment of Recording Medium A polyethylene glycol # 600 heated to 90 ° C. was brought into contact with the surface of the recording medium having an ink-repellent surface state for 30 seconds, and then the recording medium was run with running water. The polyethylene glycol adhered to the surface is washed, and the polyethylene glycol and water are removed and dried to make the surface of the recording medium excellent in ink adhesion. An image is formed by using the recording medium and heating the non-image area under the same conditions as in the first embodiment (except that the laser head uses (2)) except for the LD drive timing. Example 10
As a result, it was possible to perform good plate making with a low output LD with little variation in the pixel position in the sub-scanning direction.

Example 13 (Claim 13) Recording paper: fine paper, lightly coated paper, coated paper, art paper,
Synthetic paper, plain paper Example 1 using the apparatuses shown in FIGS.
When printing was performed under the conditions of 0 and 12, good images could be obtained on the recording paper in all cases.

Embodiment 14 (Claim 14) Under the conditions of Embodiment 13, the apparatus shown in FIGS.
When the image forming position of each color plate was corrected by the method shown in FIG. 20, the position accuracy could be kept within 50 μm or less, and it was confirmed that a good multicolor image was obtained.

[0081]

According to the first aspect of the present invention, it is possible to perform pixel variation correction with a control system having a simple configuration, as compared with a conventional image forming apparatus, and to obtain a high quality image.

According to the second aspect of the present invention, it is possible to obtain an image having less pixel variation than the image forming apparatus of the first aspect.

According to the third aspect of the present invention, it is possible to improve the data transfer rate as compared with the image forming apparatus of the second aspect.

According to the fourth aspect of the present invention, the cost of the drum position detecting means can be reduced as compared with the image forming apparatuses of the first to third aspects.

According to the fifth aspect of the present invention, it is possible to prevent image disturbance as compared with the image forming apparatuses of the first to fourth aspects.

According to the sixth aspect of the present invention, it is possible to prevent image disturbance as compared with the image forming apparatuses of the first to fifth aspects.

According to the seventh aspect of the present invention, it is possible to prevent image disturbance as compared with the image forming apparatuses of the first to sixth aspects.

According to the eighth aspect of the present invention, it is possible to prevent image disturbance as compared with the image forming apparatus of the seventh aspect.

According to the ninth aspect of the present invention, it is possible to obtain an image with less pixel variation as compared with the image forming apparatuses of the first to eighth aspects.

According to the invention of claim 10, claims 1 to 9
It is possible to make a printing plate material for the image forming apparatus.

According to the eleventh aspect of the present invention, it is possible to construct a low-cost system as compared with the image forming apparatus of the tenth aspect.

According to the twelfth aspect of the present invention, it is possible to provide an apparatus having improved handling properties as compared with the image forming apparatus of the eleventh aspect.

According to the thirteenth aspect, the first to the first aspects are described.
With respect to the second image forming apparatus, a high-quality image can be obtained on recording paper.

According to the fourteenth aspect, claims 1 to 1 are provided.
For the third image forming apparatus, a high-quality multicolor image can be obtained on recording paper.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a light source arrangement of a writing head used in an image forming apparatus.

FIG. 2 is a diagram illustrating an example of an image generated by a plurality of light sources.

FIGS. 3A and 3B are a front view and a side view showing a relationship between a write head of the image forming apparatus and a recording medium and the like.

FIG. 4 is a diagram illustrating a configuration example of an image data transfer control unit.

FIG. 5 is a diagram illustrating a configuration example of an image data transfer clock generation unit.

FIG. 6 is a diagram illustrating a relationship between an encoder detection resolution and a pixel pitch.

FIG. 7 is a diagram illustrating an encoder detection resolution and a pixel pitch.
It is a figure which shows the relationship different from.

FIG. 8 is a diagram showing an example in which a quadruple encoder is used as a drum position detecting means.

FIG. 9 is a diagram illustrating an example of reset timing of an image transfer clock.

FIG. 10 is a diagram illustrating a different example of the reset timing of the image transfer clock.

FIG. 11 is a diagram illustrating a relationship between an image data transfer clock and reset timing.

FIG. 12 is a diagram for explaining ink adhesion characteristics of a recording medium.

FIG. 13 is a diagram illustrating a recording medium used in the image forming apparatus according to claim 11;

FIG. 14 is a diagram illustrating a recording medium used in the image forming apparatus according to claim 12;

FIG. 15 is a diagram illustrating an example of a printing machine that forms an image on a belt-shaped recording medium.

FIG. 16 is a diagram illustrating an example of a printing machine that holds a recording medium holding drum while forming an image for one plate from a roll-shaped recording medium.

FIG. 17 is a diagram illustrating an example of a printing press that holds a recording medium roll inside a plate cylinder and performs image formation after feeding one plate.

FIG. 18 is a diagram illustrating an example of a printing press having one impression cylinder.

FIG. 19 is a diagram illustrating an example of a printing press having two impression cylinders.

FIG. 20 is a diagram illustrating an example of a light source drive timing acquisition method of the multicolor image forming apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Recording medium, 2 ... Recording medium holding drum, 3 ... Writing head, 4 ... Light source, 5 ... Rotational position detection means, 6 ... Stepping motor, 7 ... Image data transfer control part, 8 ... Image data transfer clock generation part, 9 data receiving unit, 10 data distribution unit, 11 delay generation unit, 12 light source drive signal output unit.

Claims (14)

[Claims] 1. A recording medium on which an image is formed by heating, a recording medium holding drum for holding the recording medium, a drum position detecting means for detecting a position of the recording medium holding drum, and light irradiation on the recording medium An image forming apparatus having a write head having a plurality of light sources, wherein an image data transfer clock to the plurality of light sources is reset based on recording medium holding drum position information from the drum position detecting means. Image forming device. 2. The image forming apparatus according to claim 1, wherein the drum position detecting means changes the position of the recording medium holding drum when the recording medium holding drum rotates by one pixel interval, or the recording medium holding drum. 1 / integer of position change
An image forming apparatus capable of detecting an interval between images. 3. The image forming apparatus according to claim 2, wherein the drum position detecting unit is configured to change a position of the recording medium holding drum when the drum is rotated by an interval of eight pixels, or an interval of an integral multiple of the position change amount. An image forming apparatus characterized in that the image forming apparatus can detect an image. 4. An image forming apparatus according to claim 1, wherein said drum position detecting means has a detecting function of four times or more. 5. The image forming apparatus according to claim 1, wherein the data transfer clock is not reset while the unit having the image data transfer control function is receiving data from a different unit. Image forming apparatus. 6. The image forming apparatus according to claim 1, wherein the data transfer clock is not reset while the unit having the image data transfer control function is transmitting data to a different unit. Characteristic image forming apparatus. 7. The image forming apparatus according to claim 1, wherein the image data transfer clock is reset only once for one pulse of the output signal from the drum position detecting means. Forming equipment. 8. The image forming apparatus according to claim 7, wherein the reset of the image data transfer clock is not performed when the image data transfer clock is in the H state. 9. The image forming apparatus according to claim 8, wherein a driving source of the recording material holding drum is a stepping motor. 10. The image forming apparatus according to claim 1, wherein the recording medium has a property that ink adhesion characteristics are different between a heated area and a non-heated area. 11. The image forming apparatus according to claim 10, wherein a receding contact angle is reduced when the liquid is brought into contact with the liquid in a heated state,
And an image forming apparatus using a recording medium having a surface characteristic of increasing a receding contact angle when heated in a non-contact state with a liquid. 12. The image forming apparatus according to claim 11, wherein the non-image area is heated to form an image. 13. The image forming apparatus according to claim 1, wherein the developing unit attaches ink to an image area of the recording medium, and receives the ink image from the recording medium and transfers the ink image to recording paper. An image forming apparatus comprising: an intermediate transfer member; 14. The image forming apparatus according to claim 1, which is a multicolor image forming apparatus having a plurality of writing units, recording medium holding units, and developing units, and a recording body holding drum for each color. Wherein an image forming apparatus is provided with a drum position detecting means.