JP2001100573A - Controller for fixing heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To heat a printing plate at an approximately fixed temperature independently of the voltage of an AC power supplied to a fixing heater. SOLUTION: A heating controller sets the number of halogen lamp heaters to be lit based on voltage V0, V1, and V2, which are preliminarily stepwise set as a reference voltage, and sets a correction rate based on the reference voltage corresponding to the number of halogen lamp heaters and the AC voltage and controls lighting of halogen lamp heaters. Thus, the heating temperature of a printing plate 12 is kept approximately fixed independently of the AC voltage to heat the printing plate 12 at a proper temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a fixing heater, which heats and fixes a printing plate, on which an electrostatic latent image is formed by charge exposure, with a liquid developer, and then heats and fixes the printing plate. More specifically, the present invention relates to a fixing heater control device that turns on the fixing heater with AC power.

[0002]

2. Description of the Related Art A photosensitive lithographic printing plate used for newspaper printing includes an organic photoconductor (OPC) using an organic photoconductor for a photosensitive layer formed on a conductive support such as aluminum.
ductor) There is a printing plate (hereinafter referred to as “printing plate”). In a direct plate making system that uses the printing plate to make a printing plate, an electrostatic latent image is formed on the printing plate by charging and exposure in a drawing process, and then a liquid developer including toner particles and a carrier liquid is used in a developing process. After developing and drying, the toner is heated and fixed in a fixing step to form a toner image corresponding to the electrostatic latent image.

In the fixing step, an AC power of a predetermined voltage is supplied to a fixing heater such as a halogen lamp heater to cause the fixing heater to generate heat and to remove toner particles in the liquid developer adhering to the printing plate by a predetermined amount. Temperature (e.g., about
(° C.) to be melt-fixed.

When the fixing heater is heated using AC power, the heating temperature changes due to a change in the voltage of the AC power. In addition, when the printing plate is processed intermittently or continuously, the heating efficiency of the fixing heater changes.

For this purpose, Japanese Unexamined Patent Publication No. Hei 6-342250 discloses that an input voltage (power supply voltage) is detected, a cut rate is set on the basis of the power supply voltage, and an intermittent power supply is performed based on the set cut rate. We are trying to shut it off.
In this publication, the power cut rate is set based on continuous processing or intermittent processing of a printing plate.

However, when the AC power to be supplied to the fixing heater is intermittently cut off based on the cut rate, the AC power is increased in units of cycles at predetermined time intervals. When it becomes large, there is a voltage region where the actual correction amount does not change, and in this voltage region, there is a problem that the heating temperature becomes high.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and appropriately heats a printing plate at a substantially constant temperature even when an AC voltage supplied to a heating means such as a halogen lamp heater is different. It is an object of the present invention to propose a control device for a fixing heater which can perform the fixing.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a control device for a fixing heater for heating and fixing a printing plate on which an electrostatic latent image has been formed by charging and exposure with a liquid developer. A heating unit provided with a plurality of fixing heaters that generate heat when AC power is supplied,
Voltage detecting means for detecting the voltage of the AC power, and the AC power so as to reduce the number of lighting of the fixing heater in accordance with the rise of the AC voltage based on the AC voltage detected by the voltage detecting means. A first setting unit for setting the number of fixing heaters for supplying a voltage, and a heating temperature that is decreased in accordance with an increase in the AC voltage based on a setting result of the setting unit and a detection result of the voltage detection unit. A second setting unit that sets a cut rate of power supplied to the fixing heater; and supplying the AC power to the fixing heater of the heating unit based on a setting result of the first and second setting units. And heating control means for heating the printing plate passing through the heating section.

According to the present invention, the number of lighting of the fixing heater is set based on the AC voltage detected by the voltage detecting means, and the fixing heater is supplied to the fixing heater based on the number of lighting of the fixing heater and the AC voltage. Set the cut rate of AC power to be applied. At this time, when the AC voltage is high, the setting is made so that the number of lighting of the fixing heater is reduced.

Thus, even if the AC voltage is high, the difference between the reference voltage for setting the cut rate and the AC voltage can be reduced. By setting the cut rate based on this difference and turning on the fixing heater, The printing plate can be heated to a substantially constant temperature regardless of the AC voltage.

In the invention according to a second aspect, the first setting means sets the number of lights in a stepwise manner for each preset reference voltage, and the second setting means sets the lighting number. The cut ratio is set based on a reference voltage corresponding to the number and the AC voltage detected by the voltage detection means.

According to the present invention, the reference voltage is set in advance in a plurality of stages, and the number of lighting heaters and the cut rate of the fixing heater are set based on the reference voltage and the AC voltage.

Thus, only by detecting the AC voltage,
The lighting number of the fixing heater and the cut rate can be easily set, and the lighting control of the fixing heater can be easily and accurately performed.

According to the present invention, as described in claim 3, the number of lighting of the fixing heater according to the AC voltage and the cut rate according to the AC voltage and the number of lighting of the fixing heater are determined. It is preferable to include storage means for storing.

According to a fourth aspect of the present invention, there is provided a control device for a fixing heater for heating and fixing a printing plate on which an electrostatic latent image has been formed by charging and exposing with a liquid developer, wherein AC power is supplied. A heating unit provided with a plurality of fixing heaters that generate heat by the heating unit, a printing plate detection unit that detects a leading end of the printing plate conveyed to the heating unit, and a printing plate detection unit based on a detection result of the printing plate detection unit. A time measuring unit for measuring a heating time of the printing plate in the heating unit, and a process of measuring the cutoff rate of the AC power set at least based on the AC voltage supplied to the fixing heater by the time measuring unit. A correcting unit that corrects the temperature in accordance with time, and supplying the AC power to the fixing heater of the heating unit based on the cut ratio corrected by the correcting unit and passing the heating unit. Characterized in that it comprises a heating control means for heating the plate, the.

According to the present invention, the cut rate set based on the AC voltage supplied to the heater for heating is changed to the elapsed time from the start of heating, which is the passage time of the printing plate passing through the heating section while being conveyed. Correction is made to increase accordingly.

By controlling the lighting of the fixing heater based on the corrected cut rate, it is possible to suppress an increase in the heating temperature of the printing plate with the passage of time, and to make the printing plate substantially uniform along the transport direction. It can be heated at any temperature.

[0018]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a schematic configuration of a developing and fixing device 10 applied to the present embodiment. The developing and fixing device 10 is provided in a direct plate making system. In a direct plate-making system in which the developing and fixing device 10 is provided, a so-called OPC printing plate (hereinafter, “printing plate 12”) in which a photosensitive layer using an organic photoconductor is formed on one surface of a conductive support formed of aluminum or the like. After the photosensitive layer of the printing plate 12 is uniformly charged by the charger of the drawing apparatus, scanning exposure corresponding to image data is performed using laser light of a predetermined wavelength. Thus, an electrostatic latent image is formed on the printing plate 12. Developing and fixing device 1
The printing plate 12 on which the electrostatic latent image has been formed is fed to 0.

In the developing and fixing device 10, the printing plate 12 is developed with a liquid developer composed of toner particles, a carrier liquid and the like, the toner particles are attached to the image portion, the wet toner image is dried, and Then, the toner particles are melted and fixed to the printing plate 12 by the fixing heater.

In the direct plate making system, an elution device, a drying device and a punch / plate bending device are provided on the downstream side of the developing and fixing device 10, and the printing plate 12 on which the toner image is formed is fed to the elution device. The photosensitive layer in the non-image area where the toner is not adhered is eluted by exposure to the eluate. The printing plate 12 subjected to the elution treatment is applied with a gum solution for plate surface protection, dried, and sent to a punch / plate bending device.

In the punch / plate bending apparatus, punch holes and notches are formed at both ends in the longitudinal direction of the printing plate 12 as positioning references when the printing plate 12 is mounted on a rotary press for printing.
When the printing plate 12 is mounted on a plate cylinder of a rotary press, a plate bending process for hooking is performed. Printing plate 12 after plate bending
Are accumulated in, for example, a stocker and conveyed to a printing process.

On the other hand, in the developing and fixing device 10, the printing plate 12
Performs processing while transporting the printing plate 12 along the longitudinal direction based on one end side in the width direction.

As shown in FIG. 1, the developing and fixing device 10
The developing unit 16, the drying unit 18, the fixing unit 20, the cooling unit 22, and the edge processing unit 24 are formed in the machine frame 14 along the transport direction of the printing plate 12.

The developing section 16 includes a guide plate 26 and a squeeze roller 28. In the developing unit 16, an electrode plate 30 and an auxiliary electrode plate 32 are arranged to face the guide plate 26, and a nozzle 34 is provided above the auxiliary electrode plate 32. The printing plate 12 fed from the insertion port 36 is transported between the guide plate 26, the auxiliary electrode plate 32, and the electrode plate 30 with the surface on the photosensitive layer side facing upward. At this time, the developing unit 16 causes the liquid developer containing the charged toner particles from the nozzle 34 to flow onto the printing plate 12 for development. Thereby, the toner particles adhere to the printing plate 12 according to the electrostatic image. Squeeze roller 28
Sends the excess liquid developer from the printing plate 12 while squeezing it. The auxiliary electrode plate 32 and the electrode plate 3
0 indicates that the printing plate 12
Promotes adhesion of toner particles to the toner.

A conveyor 38 is provided between the drying section 18 and the cooling section 22. In the conveyor 38, a chain 44 is wound around a sprocket 40 on the drying unit 18 side and a sprocket 42 on the cooling unit 22 side. Placed bars (not shown) are arranged at predetermined intervals between the chains 44.
Is placed. The driving force of the transport motor 46 is transmitted to the sprocket 42.

As a result, the printing plate 12 sent out of the developing unit 16 by the squeeze roller 28 is placed on the conveyor 38, and is conveyed from the drying unit 18 to the cooling unit 22 via the fixing unit 20.

The drying section 18 has a blower 4 on the developing section 16 side.
8, a plurality of (for example, two) heaters 50 and fans 49 are provided on the fixing unit 20 side. Printing plate 12
When transported through the drying unit 18, pre-drying is performed by air blown by the blower 48, and the air heated by the heater 50 is blown by the fan 49 to be dried.

In the fixing section 20, a fixing unit 60 is provided above the transport conveyor 38. In the fixing unit 60, a plurality of halogen lamp heaters 62 are arranged inside a cover 66.

In the fixing section 20, the halogen lamp heater 6
2 is turned on, and the printing plate 12 transported on the transport conveyor 38 is uniformly heated at a predetermined temperature (for example, about 1
(20 ° C to about 140 ° C). Thus, the toner particles adhered to the surface of the printing plate 12 are melted and fixed to the printing plate 12, and a toner image corresponding to the electrostatic latent image is formed.

The cooling section 22 is provided with a plurality of rollers 52 facing the conveyor 38,
Is conveyed while being held between the conveyor 38 and the rollers 52. The cooling unit 22 is provided with a temperature sensor 68, which detects the temperature of the printing plate 12 discharged from the fixing unit 20 in a non-contact manner, and prevents the printing plate 12 from being poorly heated by the fixing unit 20. In the cooling unit 22, a cooling air is blown from a nozzle (not shown) toward the printing plate 12 so as to lower the temperature of the printing plate 12 heated by the fixing unit 20.

In the edge processing unit 24 on the downstream side of the cooling unit 22, both ends of the printing plate 12 in the width direction are chamfered by cutting blades (not shown) provided opposite to both ends of the printing plate 12 in the width direction. By this chamfering, unnecessary toner attached to both ends in the width direction of the printing plate 12 is scraped off. This prevents the toner adhering to both ends in the width direction of the printing plate 12 during printing from causing printing stains. Further, the edge processing unit 24 removes attached matter such as toner residue from the printing plate 12 by a brush 55 provided so as to face both end surfaces in the width direction of the printing plate 12 and the front and back surfaces. Another purpose of chamfering the edge of the printing plate 12 is to prevent the printing ink from adhering to the edge during printing.

The fixing / developing device 10 is provided with a discharge roller pair 56 adjacent to the discharge port 54. The printing plate 12 on which edge processing and front and rear surface cleaning have been performed is sandwiched between the discharge roller pair 56. Then, it is sent out from the outlet 54 toward the dissolution apparatus.

As shown in FIG. 2, a fixing unit 60 provided in the fixing section 20 includes a plurality of halogen lamp heaters 6 as fixing heaters in a cover 66.
2 are provided. Each of the halogen lamp heaters 62 has a longitudinal direction arranged along the width direction of the printing plate 12 and is surrounded by the reflection plate 64, and each can uniformly heat the printing plate 12 along the width direction. I have.
In the present embodiment, as an example, two halogen lamp heaters 62 (halogen lamp heaters 62A and 62B) having a rated power of 1 kW with an AC power of 200 v and 2 kW
4H halogen lamp heaters 62C, 62D, 62E, 62F, and 2L1W size (approximately 1100mm x 400mm in height x width) that can print images of about 1 page of newspaper vertically Printing plate 12
Is to be processed. Halogen lamp heater 62
A to 62F are arranged at predetermined intervals along the transport direction of the printing plate 12, so that the printing plate 12
It is heated by the electric power of w.

The fixing unit 60 is provided with a spare halogen lamp heater 62 (not shown in FIGS. 2 and 3) inside the cover 66, and the temperature sensor 68 detects the halogen lamp heater due to insufficient heating temperature of the printing plate 12. When the disconnection of the heater 62 is detected, an alarm is issued to notify the user, and the spare halogen lamp heater is turned on to minimize the occurrence of fixing failure due to insufficient heating temperature. Note that the control of the heating temperature of the printing plate 12 based on the temperature detected by the temperature sensor 68 can use a conventionally known control method, and a detailed description thereof will be omitted in the present embodiment.

On the other hand, as shown in FIG.
Is provided with a heating controller 70 to which the present invention is applied, and the halogen lamp heater 62 (62A to 62A).
F) is controlled on / off by the heating controller 70.

The heating controller 70 includes a CPU 72, R
A microcomputer (microcomputer 82) in which a memory 74 such as an OM or a RAM, an input port 76, and an output port 78 are connected by a bus 80 is provided.

The fixing unit 20 includes a halogen lamp heater 6
A voltage sensor 84 is provided as voltage detection means for detecting the voltage of the AC power supplied to the power supply 2. Further, the developing and fixing device 10 is provided with a plate detection sensor 86 for detecting the passage of the printing plate 12 sent to the fixing unit 60, and the microcomputer 82 of the heating controller 70 receives the voltage from the input interface 90 through the input interface 90. The sensor 84 and the plate detection sensor 86 are connected.

In the heating controller 70, the voltage sensor 8
4 by measuring the AC voltage V _S to light the halogen lamp heater 62, the printing plate 12 by the plate detecting sensor 86
The timing at which the image passes through the fixing unit 60 is detected.
As the plate detection sensor 86, a conventionally known sensor that detects the printing plate 12 in a non-contact manner, such as a photoelectric switch or a proximity switch, can be used.
May be provided in the vicinity of the upstream side, or may be provided in the vicinity of the insertion port 36.

A zero-crossing detection circuit 88 for detecting a zero-crossing point of an AC voltage for lighting the halogen lamp heater 62 is connected to the heating controller 70 via an input interface 90.

Further, an output interface 92 is connected to an output port 78 of the heating controller 70. The output interface 92 is connected to a solid state relay (SSR 94) provided for each halogen lamp heater 62. The microcomputer 82 includes SSRs 94A, 94B, 94C, 94
D, 94E, and 94F), the halogen lamp heaters 62A to 62F are individually turned on and off. Further, by controlling the SSR 94, the microcomputer 82 can instantaneously switch on / off the halogen lamp heater 62, and can cut off power supply for, for example, one cycle of AC voltage.

The heating controller 70 controls the number of lighting of the halogen lamp heater 62 based on the AC voltage. That is, as shown in FIG. 4A, the heating controller 70 sets the lowest voltage in the operation range to the reference voltage V _0, and when the AC voltage V _S exceeds the reference voltage V ₀ , Then, the number n of lighting of the halogen lamp heater 62 is reduced.

In this embodiment, when the reference voltage V ₀ (for example, 180 V) is used and the AC voltage V _S is the reference voltage V ₀ , the six halogen lamp heaters 62A to 62F (n =
N = 6) is lit, the AC voltage V _S is the voltage V ₁ (e.g. 2
00v), the halogen lamp heater 62A
Are turned off (n = N-1 = 5), and the AC voltage V _S
Exceeds the voltage V ₂ (for example, 220 V), the halogen lamp heater 62B
Are turned off (n = N−2 = 4).

[0043] That is, in the fixing unit 60, when the AC voltage V _S is, for example, 180V～199v, by lighting the halogen lamp heaters 62a to 62f,
Toner has become possible to heat the printing plate 12 to a predetermined temperature which is optimally fixed, also the AC voltage V _S is 200v~219v sometimes, a halogen lamp heater 62B～62F (approximately 9 kW), further AC voltage V _S
Is between 220v and 240v, the halogen lamp heaters 62C-62F (about 8 kw) are turned on, so that the printing plate 12 can be heated to a predetermined temperature at which the toner is optimally fixed.

On the other hand, the heating controller 70 controls the voltage V ₀ for switching the number N of lighting of the halogen lamp heater 62,
Using V ₁ and V ₂ as reference voltages, the reference voltages V ₀ , V ₁ and V
And it corrects the lighting time of the halogen lamp heater 62 on the basis of the AC voltage V _S for _2.

That is, even when the number n of lighting of the halogen lamp heaters 62 is the same, when the AC voltage V _S increases, the heating temperature of the printing plate 12 by the halogen lamp heaters 62 also increases. For this, as shown in FIG. 4 (B), the heating controller 70, according to the AC voltage is increased by lowering the power supply rate to the halogen lamp heater 62, regardless of the AC voltage V _S, The printing plate 12 is heated to a substantially constant temperature.

The heating controller 70 uses the decrease in the power supply rate as a correction rate, and controls the lighting time of the halogen lamp heater 62 based on the correction rate. That is,
When the power supply rate is 90%, the correction rate is set at about 20%, and the halogen lamp heater 62 is turned on intermittently so that the lighting time of the halogen lamp heater 62 at every predetermined time is cut by about 20%.

At this time, the heating controller 70 detects a zero-cross point of the voltage waveform of the AC voltage V _S and turns on / off the SSR 94 based on the zero-cross point, thereby providing a halogen lamp for a cycle corresponding to the correction rate. Cycle control for interrupting the AC power to the heater 62 is performed.

In this cycle control, the SSR 94 is momentarily turned off. Thereby, the halogen lamp heater 62
Is turned off for a cycle corresponding to the correction rate during all cycles (for example, 100 cycles / 50 Hz) during a predetermined time (for example, 2 seconds). That is, as shown in FIG. 5, when the correction rate is 20%, the AC voltage V
_The halogen lamp heater 62 is turned off for one cycle in the five cycles of _S.

On the other hand, when the printing plate 12 passes through the fixing unit 60, the temperature inside the fixing unit 60 gradually increases. For this reason, as shown by the broken line in FIG. 6, the temperature of the printing plate 12 at the rear end side is higher than that at the front end side in the transport direction. In the heating controller 70, the printing plate 1
In order to prevent such a change from occurring in the heating temperature 2, when the leading edge of the printing plate 12 is detected by the plate detection sensor 86, the correction rate is reduced at a predetermined timing in order to lower the heating temperature of the printing plate 12. Is corrected so that is gradually increased. Note that, in the cycle control, the AC power is cut in units of one cycle. Therefore, in the supply efficiency shown in FIG. 4B, the two-dot chain line is ideal, but in reality, it is close to the solid line.

Memory 74 provided in microcomputer 82
(For example, ROM) _SHalogen according to
The lighting number n of the lamp heaters 62 and the number of the halogen lamps 62
Lighting number n and AC voltage V_SCorrection rate based on the printing plate 1
Correction rate etc. according to the passing time of 2 are stored in advance as a map
Have been. The microcomputer 82 heats and fixes the printing plate 12.
When you use the halogen lamp
The lighting of the data 62 is controlled.

In this embodiment, the printing plate 12 having a length of about 1100 mm along the transport direction is moved at a speed of 83 mm / sec.
The fixing process is performed while transporting. At this time, the printing plate 12
Is 13 seconds, and the halogen lamp heater 62 is turned on for 2 seconds.
It is to be corrected at intervals.

Next, the operation of the present embodiment will be described.

In the fixing section 24 provided in the developing and fixing device 10, the AC voltage V _S supplied to the halogen lamp heater 62 provided in the fixing unit 60 is measured, and based on the measurement result, the halogen lamp heater 62 is used. Of the printing plate 12 is heated to an appropriate temperature set in advance.

Hereinafter, the printing plate 12 by the heating controller 70 will be described with reference to the flowcharts shown in FIGS.
The lighting control of the halogen lamp heater 62 will be described.

The heating controller 70 includes the developing and fixing device 1
When the power supply switch (not shown) is turned on and the operation of the developing and fixing device 10 is started, the operation starts, the flowchart shown in FIG. 7 is executed, and the execution is ended when the power of the developing and fixing device 10 is turned off. .

First step 10 in this flowchart
In the case of 0, for example, initialization such as resetting a timer counter (not shown) is performed. When the initial setting is completed,
In the next step 102, it is determined whether or not the plate detection sensor 86 has detected the printing plate 12 on which the heat fixing process is performed by the fixing unit 20, that is, the printing plate 12 on which the electrostatic latent image is formed Check whether it has been inserted.

Here, when the printing plate 12 is inserted into the insertion opening 36 of the developing and fixing device 10 and the plate detection sensor 86 is turned on, an affirmative determination is made in step 102 and a step 104 is performed.
Then, the heating condition of the printing plate 12 is set.

FIG. 8 shows a routine for setting heating conditions. In the first step 120 of this flowchart, the halogen lamp heater 6 is operated by using the voltage sensor 84.
Read the AC voltage V _S to turn on the 2.

[0059] In the next step 122, to set the lighting number n of the halogen lamp heater 62 at the time of heating the printing plate 12 from the AC voltage V _S read the map stored in the memory 74. In step 124, the set lighting number n of the halogen lamp heater 62 and the AC voltage V
_The correction rate r is set from _S.

When the heating conditions of the printing plate 12 are set in this manner, the process proceeds to step 106 in the flowchart shown in FIG. 7, and the printing plate 12 reaches the fixing unit 20 and the halogen lamp heater 62 is turned on. Sometimes, the fixing unit 60 is heated so that the printing plate 12 can be heated to an appropriate temperature.
Start the play heat inside.

Thereafter, at step 108, the printing plate 12
At the timing when the tip of the printer reaches the fixing unit 60, a timer (not shown) is started, and
The halogen lamp 62 is turned on based on the heating condition set at 0.

Thus, in the fixing unit 60, the halogen lamp heaters 62 of the number n of lightings set based on the AC voltage V _S are replaced with the reference voltage (voltage V ₀ ) set for each number n of the lightings of the halogen lamp heaters 62. , V _1, V ₂₎ and an AC voltage V _S correction factor r on-off based on (lit or
While the light is turned off), the heating of the printing plate 12 is started.

At this time, the heating controller 70 turns off the SSR 94 at a predetermined timing according to the correction rate r while detecting the zero cross point of the voltage waveform by the zero cross detection circuit 88. Thus, the supply of power for one cycle of the voltage waveform to the halogen lamp heater 62 is stopped.

On the other hand, in step 112, the time t measured by a timer (not shown) is equal to a predetermined time T ₁ (T ₁ = 2 sec).
It is checked whether or not the time has reached.
_When it reaches ₁ , the routine proceeds to step 114, where the heating conditions are corrected. The correction of the heating condition is performed by counting up the correction rate r, for example, by increasing the correction rate r set in step 104 by a predetermined rate.

When the heating conditions are corrected, step 108
Then, the timer is reset / started again, and the process proceeds to step 110 to control the lighting of the halogen lamp heater 62 based on the corrected heating condition.

As described above, in the fixing unit 20, the printing plate 12
When heating and fixing the printing plate 12, the heating condition is corrected at predetermined time intervals, so that the heating temperature of the printing plate 12 is substantially constant irrespective of the lapse of the processing time of the printing plate 12, as shown by the solid line in FIG. I am trying to be. Thereby, it is possible to prevent the image from being blurred or uneven in image density due to an increase in the heating temperature of the printing plate 12 and expansion of halftone dots for forming an image or the like on the printing plate 12. .

On the other hand, in step 116, it is confirmed whether or not the rear end of the printing plate 12 has passed the fixing unit 60. In the fixing unit 20, when the rear end of the printing plate 12 reaches the timing of passing the fixing unit 60 while correcting the heating conditions of the printing plate 12 at predetermined time intervals in this manner, an affirmative determination is made in step 116. As a result, the fixing unit 60 operates until the processing of the next printing plate 12 is started.
It goes into a standby state.

As described above, in the fixing unit 20, the printing plate 12
Based on the AC voltage V _S to light the halogen lamp heater 62 for heating the halogen lamp heater 62
And the correction rate r based on the reference voltages (voltages V ₀ , V ₁ , V ₂ ) and the AC voltage V _S which are set for each number n of the halogen lamp heaters 62. are doing.

As a result, as shown by the solid line in FIG. 9, the heating temperature of the printing plate 12 in the fixing unit 60 can be kept substantially constant regardless of the AC voltage V _S.

That is, when the halogen lamp heater 62 is simply turned on regardless of the AC voltage V _S , the heating temperature of the printing plate 12 increases as the AC voltage V _S increases, as shown by the dashed line in FIG. . Also, the halogen lamp heater 6
2 and one reference voltage (for example, 180
v) and the correction rate is set based on the AC voltage V _S ,
Since the halogen lamp heater 62 can be cut only in cycle units of the AC voltage waveform, the AC voltage V _S
Rises and the correction rate r increases, a voltage region where the heating temperature of the printing plate 12 increases as shown by a broken line in FIG. 9 occurs.

On the other hand, the fixing unit 20 changes the reference voltage, which is the reference of the correction rate r, in steps by changing the number n of the halogen lamp heaters 62 to be turned on based on the AC voltage. As a result, the correction rate r at the time of performing the cycle control for turning on / off the halogen lamp heater 62 is suppressed to be low, and the printing plate 12 is controlled regardless of the AC voltage V _S.
Can be heated to a substantially constant temperature.

As described above, by heating the entire area of the printing plate 12 at a substantially constant level, it is possible to surely prevent the printed matter using the printing plate 12 from having a density unevenness and a defective image such as blurred image. be able to.

The embodiment described above does not limit the configuration of the present invention. In the present embodiment,
Voltage V ₀ , using six halogen lamp heaters 62,
The lighting number n and the correction rate r are set in three stages of V ₁ and V _2. By setting the lighting number n and the correction ratio r in three or more stages by using six or more halogen lamp heaters 62. Thus, the printing plate 12 can be heated with a further reduced temperature change.

Further, based on the processing interval of the printing plate 12,
Further, the correction rate r may be corrected. That is, in a continuous process in which the processing interval of the printing plate 12 is short, the heating temperature of the printing plate 12 is easily increased because the temperature in the fixing unit 60 is increased. By correcting the correction rate r, the printing plate 1 due to such a temperature rise in the fixing unit 60 can be obtained.
2 can suppress an increase in the heating temperature. Accordingly, even when a large number of printing plates 12 are continuously processed, the printing plates 12 can be heated and fixed at a substantially constant temperature so as to obtain a uniform printed matter.

Further, in the present embodiment, the printing plate 12 of a single size has been described as an example, but the developing and fixing device 10 and the fixing unit 20 may process the printing plates 12 of different sizes. . In this case, the halogen lamp heater to be lit for each size of the printing plate, the number of lit halogen lamp heaters, and the correction rate may be set.

[0076]

As described above, according to the present invention, the number of lighting of the fixing heater is set based on the AC voltage, and the AC power to the fixing heater is cut based on the number of lighting and the AC voltage. Since the lighting of the fixing heater is controlled by setting the rate, an excellent effect that the printing plate can be more accurately heated to a more constant temperature regardless of the AC voltage can be obtained.

Further, according to the present invention, the printing plate is heated at a substantially constant temperature from the front end to the rear end in the transport direction by further correcting the cut rate based on the elapsed time when heating the printing plate. Can be.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a developing and fixing device applied to an embodiment.

FIG. 2 is a schematic perspective view illustrating an example of a fixing unit provided in a fixing unit to which the present invention is applied.

FIG. 3 is a block diagram showing a schematic configuration of a heating controller to which the present invention is applied.

FIG. 4A is an example of a diagram showing the number of lighting of halogen lamp heaters based on an AC voltage, and FIG. 4B is the number of lighting of halogen lamp heaters when a printing plate is heated to a predetermined temperature. FIG. 4 is an example of a diagram showing the efficiency of supplying AC power to a halogen lamp heater based on AC voltage and AC voltage.

FIG. 5 is a diagram illustrating an example of a voltage waveform of AC power supplied to a halogen lamp heater according to a correction factor.

FIG. 6 is a diagram schematically showing elapsed time and heating temperature when heating the printing plate.

FIG. 7 is a flowchart showing an outline of lighting control of a halogen lamp heater by a heating controller.

FIG. 8 is a flowchart showing an outline of setting of the number of lighting of a halogen lamp heater and a correction rate based on an AC voltage.

FIG. 9 is a diagram schematically illustrating a heating temperature of a printing plate according to an AC voltage by a fixing unit to which the present invention is applied.

[Explanation of symbols]

Reference Signs List 10 developing / fixing device 12 printing plate 20 fixing unit 60 fixing unit (heating unit) 62 (62A to 62F) halogen lamp heater (fixing heater) 70 heating controller (fixing heater control device) 72 microcomputer (control means, first unit) And second setting means, correction means, measurement means) 74 memory (storage means) 84 voltage sensor (voltage detection means) 86 plate detection sensor (printing plate detection means)

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) H05B 3/00 310 H05B 3/00 310C // G03F 7/40 501 G03F 7/40 501 (72) Inventor Koichi Okitsu Kanagawa 1250 Takematsu, Minami Ashigara City, F-term (reference) 2H033 BA25 BA58 BA59 CA22 CA23 CA30 CA48 2H070 EE04 EE07 2H096 AA06 BA20 LA30 3K058 AA71 BA18 CA03 CB02 CB05 CB14 DA02 GA06 CB09 CB09 FF01 HH02 JJ03 KK05 KK09 MM08 MM14 MM20

Claims (4)

[Claims] 1. A control device for a fixing heater for heating and fixing a printing plate on which an electrostatic latent image has been formed by charging and exposing with a liquid developer, wherein the heating device is configured to generate heat when supplied with AC power. A heating unit provided with a fixing heater, a voltage detecting means for detecting a voltage of the AC power, and the fixing in response to an increase in the AC voltage based on the AC voltage detected by the voltage detecting means. Setting means for setting the number of fixing heaters for supplying the AC power so as to reduce the number of lighting heaters for the heater, and the AC based on the setting result of the setting means and the detection result of the voltage detecting means. A second setting unit that sets a cut rate of power supplied to the fixing heater so as to lower a heating temperature in accordance with an increase in voltage; and a setting result of the first and second setting units. Control device for fixing heater which comprises a heating control means for heating the printing plate whose serial the AC power supply to the fixing heater of the heating unit through the the heating unit. 2. The method according to claim 1, wherein the first setting means sets the number of lightings stepwise for each preset reference voltage, and the second setting means sets a reference voltage corresponding to the set number of lightings. 2. The control device for a fixing heater according to claim 1, wherein the cut rate is set based on the AC voltage detected by the voltage detection unit. 3. A storage unit for storing the number of lighting of the fixing heater according to the AC voltage, and the cut rate according to the number of lighting of the AC voltage and the fixing heater. The control device for a fixing heater according to claim 1. 4. A control device for a fixing heater for heating and fixing a printing plate on which an electrostatic latent image has been formed by charging exposure after developing with a liquid developer, wherein the plurality of heating plates generate heat when supplied with AC power. A heating unit provided with a fixing heater, a printing plate detection unit for detecting a leading end of a printing plate conveyed to the heating unit, and printing in the heating unit based on a detection result of the printing plate detection unit. A time measuring means for measuring a heating time of the plate; and a cutoff rate of an AC power set at least based on an AC voltage supplied to the fixing heater is increased according to an elapsed time measured by the time measuring means. And a heating unit that supplies the AC power to the fixing heater of the heating unit to heat the printing plate passing through the heating unit based on the cut rate corrected by the correction unit. Control device for the fixing heater, which comprises a control means.