JP2002260823A - Controlling method and controlling device of heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To heat a substance to be heated like a printing plate at a constant temperature, regardless of the inputted alternating current voltage. SOLUTION: A heat controller reads an input voltage by a voltage sensor, and calculates a voltage correction factor Q, depending on an input voltage V and a standard voltage Vs set in advance (step 120, 122). Then, the cutting ratio C is calculated based on the voltage correction factor Q (step 124). At this time, the cutting ratio C is calculated, for example, up to one decimal place, by rounding to one decimal place. After that, a controlling period for a cycle control corresponding to the cutting ratio, and timing of off-cycle are set (step 126, 128). By performing a cycle control of a halogen lamp heater depending on the result of the above setting, a printing plate can be heated with a constant temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a heating heater that generates heat in accordance with a supplied AC voltage, and a method for developing a printing plate on which an electrostatic latent image is formed by charging exposure with a liquid developer. The present invention relates to a heating heater control device for performing a heating process using a heating heater.

[0002]

2. Description of the Related Art A photosensitive lithographic printing plate used for newspaper printing includes an OPC (Organic Photoconductor) having a photosensitive layer formed on a conductive support such as aluminum using an organic photoconductor.
uctor) There is a printing plate (hereinafter referred to as “printing plate”). In a direct plate-making system for producing a printing plate using this printing plate, an electrostatic latent image is formed on the printing plate by charging and exposure, and then developed with a liquid developer including toner particles and a carrier liquid in a developing process. After 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 at this time, a heating heater such as a halogen lamp heater is used as a fixing heater, and AC power of a predetermined voltage is supplied to the fixing heater to generate heat and adhere to the printing plate. The toner particles in the liquid developer are melted and fixed by heating to a predetermined temperature (for example, about 80 ° C. to 140 ° C.).

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 order to prevent such a change in the heating efficiency of the fixing heater, lighting control of the fixing heater is performed in the fixing process.

[0005] The phase control method and the cycle control method are generally used as the lighting control method of the fixing heater. However, in the phase control method, the occurrence of harmonic interference becomes a problem. In Japanese Patent No. 342250, for example, an input voltage (power supply voltage) is detected, a cut rate (cut ratio) is set based on the input voltage, and an AC voltage for turning on the fixing heater is intermittently determined based on the cut ratio. A cycle control system that shuts off is used.

In this cycle control, the fixing heater is turned off between one cycle and a plurality of cycles of the input AC voltage to change the effective value of the electric power supplied to the fixing heater, thereby changing the effective value of the fixing heater. The fever is controlled.

However, in this cycle control method, an off time (off cycle) for a predetermined period set in advance must be set based on the cut ratio. In some cases, the off time of the fixing heater becomes longer or the off time becomes shorter for the cut ratio, and the heating temperature of the printing plate by the fixing heater changes.

On the other hand, in order to suppress the change in the heating temperature using such a fixing heater, in addition to the cycle control,
A method of controlling the number of lighting of the fixing heater according to the input voltage is also being studied. That is, the number of lighting of the fixing heaters is controlled in accordance with the input AC voltage, and the cycle control is performed by setting the cut ratio in accordance with the number of lighting heaters and the AC voltage.

However, even if the number of lightings and the cut ratio are set based on the AC voltage, and the AC power supplied to the fixing heater is intermittently cut off based on the setting result, it is set in advance. Since an off cycle of the fixing heater is provided within a certain period, a region where a desired effective value cannot be obtained occurs. In such a voltage range, it is difficult to suppress a change in the heating temperature of the printing plate.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described circumstances, and is intended to reduce a heating target such as a printing plate even when an AC voltage supplied to a heating heater such as a halogen lamp heater changes. It is an object of the present invention to propose a method of controlling a heater for heating which can be appropriately heated at a substantially constant temperature, and a control device for a heater for heating a printing plate to a constant temperature for processing.

[0011]

According to the present invention, there is provided a method for controlling a heater for heating, the method comprising: controlling a heater for heating an object to be heated by the heater for generating heat in accordance with the voltage of AC power. A method comprising: detecting a voltage of the AC power supplied to the heating heater, calculating a cut ratio of a predetermined number of digits from a voltage correction rate for setting the AC voltage as a reference voltage, and calculating the cut ratio from the cut ratio. After setting a control cycle for controlling the AC power supplied to the heater for heating, power supply to the heater for heating is controlled based on the cut ratio and the control cycle.

According to the present invention, when performing cycle control of the heating heater, a voltage correction rate is calculated based on a preset reference voltage and an input AC voltage, and based on the voltage correction value. Calculate the cut ratio when performing cycle control. When performing the cycle control, the control cycle is set based on the calculated cut ratio.

As described above, by setting the control cycle based on the cut ratio, it is possible to apply power of an appropriate voltage according to the cut ratio to the heater for heating, and to apply heat to the object to be heated such as a printing plate. Can be heated to a desired temperature.

According to the present invention, a voltage correction rate for setting the input AC voltage as a preset reference voltage is set, and a cut ratio is calculated based on the voltage correction rate. For example, the voltage correction rate Q is as follows: Q = {1− (Vs / V) ² } × 100 (%) from the reference voltage Vs and the input voltage V. From this, the cut ratio C can be obtained as C = 100 / Q.

From the cut ratio C thus obtained, a control cycle for turning on and off the heating heater is set. By setting the control cycle based on the cut ratio C, even if the cut ratio C is not limited to an integer and is a plurality of digits after the decimal point, the control cycle for turning on and off the heating heater based on the cut ratio C can be appropriately set. Cycle control can be performed by setting.

In such a method of controlling a heater for heating according to the present invention, it is preferable that the number of digits of the cut ratio is obtained at least to one digit below the decimal point. It is preferable that one off cycle of the heater is set to be equal to or more than a predetermined number of on cycles.

As a result, in the present invention, the object to be heated can be uniformly heated to prevent uneven heating.

The control device of the fixing heater to which the present invention is applied uses a heating heater that generates heat in accordance with the voltage of AC power, forms an electrostatic latent image by charging exposure, and then forms a liquid developer. A heating heater control device for heating the printing plate developed by the heating heater by the heating heater, wherein the voltage detection unit detects an input voltage that is a voltage of AC power supplied to the heating heater; A cut ratio setting unit configured to set a cut ratio of AC power supplied to the heating heater from a voltage correction ratio calculated based on an input voltage detected by a voltage detection unit and a predetermined reference voltage, based on the cut ratio. Cycle setting means for setting a control cycle for performing lighting control of the heater for heating, and the heating heater based on setting results of the cut ratio setting means and the cycle setting means. Characterized in that it comprises a lighting control means for controlling the lighting, the.

According to the present invention, the voltage correction rate is calculated based on the AC voltage detected by the voltage detection means and a preset reference voltage, and the cut ratio is calculated from the voltage correction rate. Thereafter, a control cycle is set based on the cut ratio, and lighting control of the fixing heater is performed based on the cut ratio and the control cycle.

[0020] Thus, the printing plate can be heated to a predetermined constant temperature, and the printing plate to be subjected to the heat treatment can be reliably prevented from having a defective finish such as fixing unevenness and drying unevenness due to heating unevenness. can do.

[0021]

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 the direct plate making system, a so-called OPC in which a photosensitive layer using an organic photoconductor is formed on one surface of a conductive support formed of aluminum or the like.
Using a printing plate (hereinafter referred to as “printing plate 12”), the photosensitive layer of the printing plate 12 is uniformly charged by a charger of a drawing apparatus, and then exposed to light based on image data using a laser beam of a predetermined wavelength. The layer is scanned and exposed. Thereby, the printing plate 12
Then, an electrostatic latent image corresponding to the image data is formed. The printing plate 12 on which the electrostatic latent image is formed is sent to the developing and fixing device 10.

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 The toner particles are melted and fixed to the printing plate 12 by a heater used as a 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 has been 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. In the developing and fixing device 10, the printing plate 12 performs the 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 / fixing device 10 includes a developing unit 16, a drying unit 18, a fixing unit 20, a cooling unit 22, and an edge processing unit along the transport direction of the printing plate 12 in the machine frame 14. A part 24 is provided.

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. Thereby, the toner particles adhere to the printing plate 12 according to the electrostatic image. The squeeze roller 28 sends out excess liquid developer from the printing plate 12 while squeezing the liquid developer. The auxiliary electrode plate 32 and the electrode plate 30 promote adhesion of toner particles to the printing plate 12 when a predetermined voltage is applied.

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. A mounting bar (not shown) is stretched between the chains 44 at a predetermined interval.
2 is placed. The driving force of the transport motor 46 is transmitted to the sprocket 42.

As a result, the printing plate 12 sent from the developing unit 16 while being squeezed 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 conveyor 38. In the fixing unit 60, a predetermined number of halogen lamp heaters 62 are arranged as a heater for heating in 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 8
(0 ° C to about 140 ° C). Thereby, in the printing plate 12, the toner particles adhered to the surface of the photosensitive layer in accordance with the electrostatic latent image are melted and fixed to the printing plate 12 to form a toner image.

The cooling section 22 is provided with a plurality of rollers 52 facing the conveyor 38,
Is transported in the cooling unit 22 while being sandwiched between the transport conveyor 38 and the rollers 52. The cooling section 22 is provided with a temperature sensor 68 for detecting the temperature of the printing plate 12 discharged from the fixing section 20 in a non-contact manner. The fixing section 20 detects the temperature of the printing plate 12 with the temperature sensor 68 to detect a fixing failure of the printing plate 12.

The cooling unit 22 blows cooling air from a nozzle (not shown) toward the printing plate 12 so that the temperature of the printing plate 12 heated by the fixing unit 20 is reduced.

In the edge processing unit 24 on the downstream side of the cooling unit 22, the both ends in the width direction of the printing plate 12 are chamfered by cutting blades (not shown) provided opposite to both ends in the width direction of the printing plate 12. 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 and developing device 10 is provided with a discharge roller pair 56 adjacent to the discharge port 54, and the printing plate 12 on which edge processing and front and rear surface cleaning have been performed is nipped by the discharge roller pair 56. Then, it is sent out from the outlet 54 toward the dissolution apparatus.

By the way, as shown in FIG.
A fixed number of halogen lamp heaters 62 as heating heaters are provided in a fixing unit 60 provided in the cover 66.
Is 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 having a rated power of 1 kW with an AC power of 200 V
(Halogen lamp heaters 62A, 62B) and four 2kW halogen lamp heaters 62 (Halogen lamp heaters 62C, 62D, 62E, 62F) and about 1 newspaper.
A printing plate 12 of 2L1W size (vertical × horizontal about 1100 mm × about 400 mm) which can print images of pages vertically.
Is to be processed.

The halogen lamp heaters 62A to 62F are
The printing plates 12 are arranged at predetermined intervals along the transport direction, so that the printing plates 12 are heated by electric power of about 10 kW.

The fixing unit 60 has a cover 66.
A spare halogen lamp heater (not shown in FIGS. 2 and 3) is provided therein, and when the shortage of the heating temperature of the printing plate 12 or the like is detected from the temperature detected by the temperature sensor 68, for example, the halogen lamp heater 62 is disconnected. Is determined, and the occurrence of the heating failure is notified, and the spare halogen lamp heater is turned on, so that the occurrence of the fixing failure due to the insufficient heating temperature of the printing plate 12 is minimized. . 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. 3, the fixing section 20 is provided with a heating controller 70 to which the present invention is applied. The heating controller 70 includes a CPU 72, R
A microcomputer (microcomputer 82) having a general configuration 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 an AC voltage (input voltage V) supplied to the power supply 2. Also,
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 sensor 8 via the input interface 90.
4 and the plate detection sensor 86 are connected.

In the heating controller 70, the voltage sensor 8
The input voltage V for turning on the halogen lamp heater 62 is detected by 4, and the timing when the printing plate 12 passes through the fixing unit 60 is detected by the plate detection sensor 86. 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. Further, the plate detection sensor 86 is provided at a position where the fixing unit 60 can be detected so as to reach a predetermined temperature state before the printing plate 12 reaches a position facing the fixing unit 60.
0 may be provided near the upstream side, or may be provided near the insertion port 36.

A zero-cross detection circuit 88 for detecting a zero-cross 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, 94D, 9
4E, 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.

In the fixing unit 60, by turning on the halogen lamp heaters 62A to 62F at a relatively low input voltage (for example, 180 V) set in advance, a predetermined temperature (for example, about 8
(A predetermined temperature in a range of 0 ° C. to 140 ° C.). That is, in the fixing unit 20, by turning on the halogen lamp heater 62 at this temperature,
The printing plate 12 can be appropriately heated.

The heating controller 70 sets and stores this voltage as the reference voltage Vs. Further, the heating controller 70 turns on / off the halogen lamp heater 62 according to the input voltage V with respect to the reference voltage Vs. That is, the heating controller 70 sets the reference voltage Vs
The lighting time of the halogen lamp heater 62 is controlled based on the input voltage V and the halogen lamp heater 6.
2 has the same heating value as when it is lit at the reference voltage Vs.
2 is heated to a constant temperature.

When the SSR 94 is turned on, it is energized and supplies AC power to the halogen lamp heater 62. The heating controller 70 turns on the SSR 94
By turning off the power, the power to the halogen lamp heater 62 is supplied and cut off, so that the effective value of the power supplied to the halogen lamp heater 62 becomes the reference voltage Vs.

At this time, the heating controller 70 turns off the SSR 94 based on the zero cross point of the input voltage detected by the zero cross detection circuit 88. As a result, the supply of power to the halogen lamp heater 62 is cut off for one cycle of the input voltage V.

When executing the cycle control, the heating controller 70 first detects the input voltage V by the voltage sensor 84, and based on the detection result, determines the effective value of the voltage supplied to the halogen lamp heater 62 to the reference voltage Vs. Calculate a voltage correction ratio for matching. This voltage correction factor Q
Can be obtained from the reference voltage Vs and the input voltage V as Q = {1− (Vs / V) ² } × 100 (%). That is, by turning off the halogen lamp heater 62 for a time corresponding to the voltage correction rate Q during the predetermined time, the AC power of the reference voltage Vs is substantially supplied to the halogen lamp heater 62.

On the other hand, when the ratio of one off cycle in which power is cut off in a predetermined cycle of the AC voltage is set as a cut ratio, the cut ratio C is C = 100 / Q.

The heating controller 70 sets a control cycle for turning on and off the halogen lamp heater 62 based on the cut ratio C calculated as described above, and sets a timing for turning off the halogen lamp heater 62 (hereinafter referred to as “off cycle”). ) Is set. At this time, the heating controller 70 sets an off cycle so that the halogen lamp heater 62 does not turn off continuously over a plurality of cycles.

That is, as shown in FIG. 4, the off-cycle timing is set such that one off-cycle is arranged between a plurality of on-cycles (regions of the AC voltage waveform indicated by solid lines in FIG. 4). Power is supplied to the halogen lamp heater 62 during this ON cycle, and power supply to the halogen lamp heater 62 is cut off during the OFF cycle. At this time, by preventing the off cycle from continuing, the amount of movement of the printing plate 12 when the halogen lamp heater 62 is turned off is suppressed, and the printing plate 12 is prevented from being heated unevenly. ing.

The heating controller 70 turns on and off the halogen lamp heater 62 at a control cycle and timing based on the cut ratio C by operating the SSR 94 based on the control cycle and the timing of the off cycle.

On the other hand, when the printing plate 12 passes through the fixing unit 60, the temperature inside the fixing unit 60 may gradually increase. At this time, as shown by the broken line in FIG. 5, the heating temperature of the printing plate 12 is higher at the rear end side than at the front end side in the transport direction. In the heating controller 70, in order to prevent such a change in the heating temperature of the printing plate 12, when the leading end of the printing plate 12 is detected by the plate detection sensor 86, at a predetermined timing,
In order to reduce the heating temperature of the printing plate 12, the cut ratio is corrected so as to gradually increase, so that the heat generated by the halogen lamp heater 62 is suppressed.

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

In the fixing section 20 of the developing and fixing device 10, the halogen lamp heater 6 provided in the fixing unit 60 is provided.
The printing plate 12 is heated while controlling the halogen lamp heater 62 on / off based on the measurement result. In the present embodiment, the fixing process is performed while the printing plate 12 having a length of about 1100 mm along the transport direction is transported at a speed of 83.7 mm / sec.

Here, the printing plate 1 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 developing and fixing device 10 starts operating, the operation is started, the flowchart shown in FIG. 6 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.

In the next step 102, it is checked whether or not the plate detection sensor 86 has detected the printing plate 12 to be subjected to the heat fixing process in the fixing unit 20. That is, the developing and fixing device 1
It is confirmed whether or not the printing plate 12 on which the electrostatic latent image is formed at 0 is 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 the process proceeds to step 104. In this step 104, when the printing plate 12 reaches a position facing the fixing unit 60, the printing plate 12
Preheating is started so that can be heated to a predetermined temperature.

At the same time, in step 106, heating conditions for the printing plate 12 are set. FIG. 7 shows a heating condition setting routine. In the first step 120 of the flowchart, the input voltage V is detected using the voltage sensor 84, and the detection result is read.

In the next step 122, a voltage correction rate Q is calculated from the reference voltage Vs set and stored in advance and the input voltage V. This voltage correction rate Q is equal to the reference voltage Vs
And the input voltage V, the following equation can be used.

Q = {1− (Vs / V) ² } × 100 (%) Accordingly, for example, when the reference voltage Vs is 180 V and the input voltage V is 200 V, the voltage correction rate Q is Q = 19 (%).

In step 124, a cut ratio C is calculated from the voltage correction rate Q. Since the cut ratio C is C = 100 / Q, for example, when the voltage correction rate Q is 19 (%), C = 100 / Q = 5.2631. At this time, the microcomputer 8 of the heating controller 70
2 rounds off the second digit after the decimal point and 1
Calculate up to digits. Therefore, in this case, the cut ratio C
Becomes C = 5.3.

Thereafter, in step 126, a control cycle for performing on / off control of the halogen lamp heater 62 is set based on the cut ratio C, and an off cycle timing is set (step 128).

The control cycle is, for example, when the cut ratio C is 5.
If it is 3, it will be 53 cycles. Further, the timing of the off cycle is set so that the off cycle is not continuous, and the off cycle is continuous, so that the off time of the halogen lamp heater 62 becomes longer, and the moving amount of the printing plate 12 in the non-heating state becomes longer. Prevent from becoming.

For example, if the cut ratio C is 5.3, the number N of off cycles in the control cycle f is 10 cycles (N = 10) of the AC voltage V from the cut ratio C and the control cycle f. ).

Here, an example of setting the off-cycle timing will be described. When f / N = 53/10, 5 (q =
5) Since the remainder becomes 3 (r = 3) and Nr = 10−3 = 7, after repeating 4 (q−1 = 4) cycles on and 1 cycle off seven times, 5 ( (q = 5) It is set so that on and off of one cycle are repeated 3 (r = 3) times.

That is, since the cut ratio C is a cycle in which one off cycle is provided, if the cut ratio C × X is an integer, the number of off cycles in the CX cycle is X.

If CX / X is the remainder q, then
One off cycle is repeated (Xr) times for every (q-1) on cycles, and one off cycle is repeated r times for every q on cycles. Thus, the number N of off cycles in the control cycle f according to the cut ratio C can be set.

As described above, by preventing the off cycle from continuing, it is possible to minimize the movement of the printing plate 12 when the halogen lamp heater 62 does not generate heat. Cycle (50H
z, one time within 0.2 seconds), the printing plate 12
This can prevent partial heating unevenness from occurring.

When the heating condition of the printing plate 12 is set in this way, the process proceeds to step 108 in the flowchart shown in FIG.
, The lighting control of the halogen lamp heater 62 based on the set heating condition is started. At the same time, in step 110, a timer (not shown) is started to measure the elapsed time t.

The fixing unit 60 starts heating the printing plate 12 by performing on / off (on / off) control of the halogen lamp heater 62 at a cut ratio C set based on the input voltage V.

At this time, the heating controller 70 turns off the SSR 94 at the timing set based on the cut ratio C while detecting the zero cross point of the voltage waveform by the zero cross detection circuit 88. Thereby, SSR94
Is turned off, 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, it is confirmed whether or not the time t measured by a timer (not shown) has reached a predetermined time ts. If the time t measured by the timer has reached the predetermined time ts, an affirmative decision is made and a step 114 is made. Move to. In this step 114, the heating condition is corrected. FIG. 8 shows an outline of the correction of the heating condition.

In this flowchart, first, the cut ratio C already set in the first step 130 is increased in accordance with the preset ratio α (1 ≦ α).

That is, assuming that C = C × α, a new cut ratio C is calculated. Thereafter, in step 132 (corresponding to step 126 in FIG. 7), the control cycle f of the halogen lamp heater 62 is set based on the corrected cut ratio C, and step 134 (step 1 in FIG. 7) is performed.
28), the off-cycle timing is set based on the cut ratio C and the control cycle f. It should be noted that the timing (predetermined time ts) for correcting the cut ratio C and the correction rate α can use values set in advance by a test or the like. Further, when a substantial temperature rise does not occur in the fixing unit 20, the correction of the cut ratio C can be omitted.

When the correction conditions are set as described above,
In the flowchart shown in FIG. 6, the process proceeds to step 108 to start lighting control of the halogen lamp heater 62 based on the set heating conditions. Thereby, the temperature rise in the fixing unit 20 due to the heating of the halogen lamp heater 62 is suppressed, and the printing plate 12 can be heated to a constant temperature.

Thus, the halogen lamp heater 62
By heating and fixing the printing plate 12 while performing the lighting control of, the heating temperature of the printing plate 12 rises more than necessary,
It is possible to prevent the image from being blurred due to swelling of a halftone dot for forming an image or the like on the printing plate 12 or unevenness in image density.

On the other hand, in step 116, it is confirmed whether or not the rear end of the printing plate 12 has reached the timing of passing through the fixing unit 60. That is, it is confirmed whether or not the heating of the printing plate 12 is to be ended. Here, when the timing at which the rear end of the printing plate 12 passes the fixing unit 60 has been reached, an affirmative determination is made in step 116 and the process proceeds to step 102.
The fixing unit 20 enters a standby state. That is, the heating of the printing plate 12 is terminated, and the process shifts to a standby state for heating a new printing plate 12.

As described above, the heating controller 70 sets the voltage correction factor Q from the input voltage V with respect to the preset reference voltage Vs, and sets the halogen lamp based on the cut ratio C calculated from the voltage correction factor Q. A control cycle f for controlling the lighting of the heater 62 and an off timing are set. As a result, it is possible to perform control with higher precision as compared with the conventional case where the lighting control is performed at a fixed period set in advance.

For example, when the control cycle is set to 2 sec for an AC voltage of 50 Hz, and the lighting control of the halogen lamp heater 62 is performed based on the cut ratio within this control cycle, the cut ratio is an integer. There is a need.

For this reason, for example, when the input voltage V is 200
In the range from v to 204v, the cut ratio is 5. By controlling the halogen lamp heater 62 based on the cut ratio set in this way, the halogen lamp heater 62
The effective value of the voltage applied to the
v, 201v, 202v, 203v, 204v, respectively, 178.9v, 179.8v, 180.7v, 1
81.6v, 182.5v, -1.1v to +2.
It will change in the range of 5v.

On the other hand, the cut ratio C is set to one decimal place.
The calculation is performed up to the digits (the second decimal place is rounded off), and the control cycle f is set based on the cut ratio C, so that the input voltage V is applied to the halogen lamp heater 62 when the input voltage V is in the range of 200 V to 204 V. The effective value of the AC voltage is in the range of 180.1v to 179.9v.

That is, when the input voltage V is 200 v, 20
In each of 1v, 202v, 203v, and 204v,
Cut ratio C is 5.3, 5.1, 4.9, 4.7, 4.5
And the control cycle f is 53 cycles, 51 cycles,
There are 49 cycles, 47 cycles, and 45 cycles.

By controlling the lighting of the halogen heater 62 based on the cut ratio C and the control period f set in this way, the effective value of the AC voltage applied to the halogen lamp heater 62 is such that the input voltage V is 200 V, 201v, 2
02v, 203v, and 204v, 180.
1, 180.2v, 180.2v, 180.1v, 17
9.9v. Therefore, the halogen lamp heater 6
2, a substantially desired voltage (reference voltage Vs) can be applied. Therefore, it is possible to heat the printing plate 12 to a predetermined appropriate temperature.

That is, as shown in FIG.
Assuming that s is 180 v and the voltage of the 50 Hz AC power supply (input voltage V) is in the range of 180 v to 240 v, the cut ratio
When C is an integer (the first decimal place is rounded off), the range of the voltage applied to the halogen lamp heater 62 is 164.8.
v to 189.4v, the cut ratio C is calculated to one digit after the decimal point (the second digit after the decimal point is rounded off), so that the change range of the voltage is 181.3v.
１７178.9v.

Thus, as shown in FIG. 10, when the cut ratio is set to an integer, the temperature of the printing plate 12 heated by the fixing unit 60 is reduced when the change in the cut ratio is reduced. ₁ (shown by a broken line in FIG. 10) and a predetermined temperature (the temperature when the halogen lamp heater 62 is turned on by the reference voltage Vs) Ts become large.

On the other hand, by using the cut ratio C obtained to one digit after the decimal point, the heating temperature T ₂ of the printing plate 12 (shown by a solid line in FIG. 10) can be changed regardless of the change in the input voltage V. It becomes a substantially constant temperature (predetermined temperature Ts).

Thus, the halogen lamp heater 62
By suppressing the change in the voltage supplied to the fixing unit 60, the temperature of the printing plate 12 moving while facing the fixing unit 60 can be made substantially constant.

In the present embodiment, the cut ratio C is calculated to one digit after the decimal point by calculation. However, the cut ratio C is calculated, for example, to two digits after the decimal point (3 digits after the decimal point).
The digit may be rounded down to the nearest whole number. This allows more accurate temperature control using the halogen lamp heater 62.

That is, as shown in FIG.
May be calculated to two digits after the decimal point, a control cycle f may be set based on the cut ratio C, and cycle control may be performed based on the cut ratio C and the control cycle f.

In this case, for example, when the reference voltage Vs is 180
v, and the input voltage V is 200 v, the cut ratio C is
C = 5.26. From this, the control cycle f is 526
Cycle (f = 526) and 1 out of 526 cycles
An off cycle for 00 cycles is set (N = 10
0).

Since q = 5 and r = 26, 4
One off cycle for each cycle may be repeated 74 times, and one off cycle for every 5 cycles may be repeated 26 times.

Since the greatest common divisor between the control cycle f (f = 526) and the number of off cycles N (N = 100) is 2, the control cycle f is 263 and the off cycle N is 5
The timing of the off cycle may be set as 0.

As described above, by calculating the cut ratio C to two decimal places and setting the control cycle f based on the cut ratio C, a constant voltage can be applied to the halogen lamp heater 62. Thereby, the printing plate 12
Since the entire surface is heated to a constant temperature, it is possible to reliably prevent the printed matter using the printing plate 12 that has been subjected to the heat-fixing process from having a density non-uniformity as well as a defective finish such as blurred image.

Note that the present embodiment described above does not limit the configuration of the present invention. In the present embodiment,
Although the fixing unit 60 of the fixing unit 20 has been described using the six halogen lamp heaters 62, the configurations of the fixing unit and the fixing unit to which the present invention is applied are not limited thereto, and the configuration of the input AC power is not limited thereto. The present invention is applied to a fixing device having an arbitrary configuration including a heater for heating a printing plate to which a liquid developer is adhered according to an electrostatic latent image by generating heat in accordance with a voltage or a control device of the heater. Can be.

In the present embodiment, the halogen lamp heater 62 has been described as the heater for heating. However, the heater for heating to which the present invention is applied generates heat in accordance with the voltage of the supplied AC power. As long as the heater is not limited to the halogen lamp heater, a heater having an arbitrary configuration can be applied.

Further, in the present embodiment, the fixing section 20 of the developing and fixing device 10 for heating and fixing the printing plate 12 has been described as an example. However, the present invention is not limited to the heating and fixing of the printing plate 12, but may be applied to a heating target. Can be applied to a heating device or a heating / drying device having an arbitrary configuration for heating to a constant temperature regardless of an input AC voltage.

[0100]

As described above, according to the present invention, the cut ratio is calculated from the voltage correction rate calculated from the reference voltage and the input voltage, and the control cycle is set from the cut ratio, so that the control cycle can be performed regardless of the input voltage. In addition, it is possible to supply a substantially constant voltage to the heater for heating. Thus, the object to be heated can be uniformly heated to a constant temperature.

In the present invention, a printing plate is used as an object to be heated, and when the liquid developer adhered to the printing plate in accordance with the electrostatic latent image is melt-fixed or dried, the printing plate is used. Since heating can be performed at a constant temperature without unevenness, an excellent effect that an image free from fixing unevenness and drying unevenness can be formed on a printing plate can be obtained.

[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 of the developing and fixing device.

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

FIG. 4 is a diagram schematically illustrating a voltage waveform of electric power supplied to a halogen lamp heater by performing cycle control.

FIG. 5 is a diagram illustrating an example of a change in a heating temperature of a printing plate with respect to a heating time by a halogen lamp heater.

FIG. 6 is a flowchart showing an outline of lighting control of a halogen lamp heater by a heating controller.

FIG. 7 is a diagram schematically illustrating setting of heating conditions for controlling a halogen lamp heater.

FIG. 8 is a flowchart showing an outline of correction of a heating condition according to a heating time.

FIG. 9 is a table showing the number of digits of a cut ratio when a reference voltage is set to 180 V, and a heating temperature obtained by performing cycle control based on each cut ratio and a control cycle set in accordance with the cut ratio. It is.

FIG. 10 is a diagram illustrating a change in heating temperature with respect to an input voltage according to the number of digits after the decimal point of the cut ratio C, where a solid line indicates a case where the cut ratio is calculated to one digit below the decimal point, and a broken line indicates a cut ratio. Is an integer.

[Explanation of symbols]

Reference Signs List 10 developing / fixing device 12 printing plate (heated body) 20 fixing unit 60 fixing unit 62 halogen lamp heater (heating heater) 70 heating controller (control device) 82 microcomputer (cut ratio setting means, cycle setting means,
Lighting control means) 84 Voltage sensor (voltage detection means) 88 Zero cross detection circuit 94 SSR (Lighting control means)

Claims (4)

[Claims] 1. A method for controlling a heating heater for heating an object to be heated by a heating heater that generates heat in accordance with the voltage of the AC power, comprising detecting a voltage of the AC power supplied to the heating heater. Calculating a cut ratio of a predetermined number of digits from a voltage correction rate for using the AC voltage as a reference voltage, and setting a control cycle for controlling AC power supplied to the heating heater from the cut ratio, A method for controlling a heater for heating, comprising controlling power supply to the heater for heating based on a ratio and the control cycle. 2. The method according to claim 1, wherein the number of digits of the cut ratio is calculated to at least one digit below the decimal point. 3. The control cycle and the cut ratio are set so that one off cycle of the heating heater is at least every predetermined number of on cycles. 3. The method for controlling a heater for heating according to item 1. 4. After forming an electrostatic latent image by charging exposure using a heating heater that generates heat in accordance with the voltage of the AC power,
What is claimed is: 1. A heater control device for heating a printing plate developed by a liquid developer using said heater, comprising: a voltage detecting means for detecting an input voltage which is a voltage of AC power supplied to said heater. A cut ratio setting unit configured to set a cut ratio of AC power supplied to the heating heater from a voltage correction rate calculated based on an input voltage detected by the voltage detection unit and a predetermined reference voltage; Cycle setting means for setting a control cycle for performing lighting control of the heating heater based on a ratio; lighting control for controlling lighting of the heating heater based on setting results of the cut ratio setting means and the cycle setting means Means for controlling a heater for heating.