JPS6022162A - Temperature controller of recorder - Google Patents

Abstract

PURPOSE:To control properly the temperature of a fixing roll to improve the fixability by varying the quantity of electric conduction to a heating means in accordace with the size of a recording paper. CONSTITUTION:The temperature detection signal from a thermistor 103 is inputted to an input terminal A1 of a microcomputer 100 and is converted digitally to control the temperature. A pulse signal is inputted to an interrupt terminal INT throught a full-wave rectifying circuit 101 and an inverting amplifying circuit 102; and if the microcomputer is in the interrupt permission state at this time, an interrupt program is executed by the rise of this pulse signal. In a halogen heater driving circuit 104, when the signal from a driver 105 connected to an output port R1 of the microcomputer 100 is inputted to a photocoupler 113, the photocoupler 113 is made conductive, and a triac 114 is made conductive to supply the power to a hologen heater H1. Thus, since the quantity of electric conduction to the heating means is varied in accordance with the size of the recording paper, the temperature of the fixing roll is controlled properly to improve the fixability.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a temperature control device for a recording device, and more particularly to a temperature control device for a printer in a recording device for copying or laser printing.

(Prior art) Conventionally, the temperature of the fuser in this type of recording device is generally detected by a temperature sensing element such as a thermistor, and the temperature is set at a preset temperature level. -In the heat of the evening, etc., I controlled the heater. For example, if the set temperature level is 180°C, 180°C
When the detected temperature was lower than 180°C, the heater was turned on (ON), and when the detected temperature was higher than 180°C, the heater was turned off (OFF).

However, the heater used for temperature control in conventional recording apparatuses of this type has generally been one piece. Therefore, depending on the size of the transfer paper that is conveyed to the fuser during copying or recording operations, transfer paper that takes a long time to be conveyed to the fuser roller, such as A3 size, may be If the temperature of the fixing device roller is too low and the amount of heat generated by the heat source is small, the temperature of the fixing device roller will not rise to a predetermined temperature easily, resulting in poor fixing. However, if a heater with a large amount of heat is used from the beginning, overshoot and ripples will become large when the size of the transfer paper is small.
In addition, there was a problem in that it caused adverse effects such as temperature rise on the entire device.

(Objective) Therefore, it is an object of the present invention to provide a temperature control device for a recording device that eliminates the above-mentioned drawbacks and can most efficiently supply power to fixing.

In order to achieve this object, the present invention controls the energization of the heat source according to the size of the transfer paper conveyed into the recording apparatus. For example, when the size of the transfer paper is relatively large such as A3 size In this case, increase the energizing time per unit time,
Control is performed so that as the size becomes smaller, the energization time per unit time is also reduced.

(Example) Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an example of the internal configuration of a copying machine to which the present invention is applied,
Here, l is a document mounting table made of a transparent member, and reciprocates in the direction of the arrow in the figure. Reference numeral 2 denotes a short-focus, small-diameter imaging element array (for example, a CCD array), and the image of the original document (not shown) placed on the original table l is reflected by the light source 2a. Slit sea light is applied onto the photosensitive drum 3. Further, numeral 4 denotes a charger, which charges the photosensitive drum 3 uniformly. The drum 3, which is uniformly charged by the charger 4, is subjected to image fogging by the imaging element array 2, and an electrostatic image corresponding to the original image is formed. Next, this electrostatic image is developed by the developing device 5.

On the other hand, the transfer paper P that is manually fed from the manual feed table ca is detected by a detection means 6b that detects that the transfer paper P is manually fed.
The image on the photosensitive drum 3 is fed onto the drum 3 by a feeding roller 6, which rotates in response to a detection signal from the photosensitive drum 3, and a registration roller 7, which rotates at a timing such that the image on the photosensitive drum 3'2 comes to the proper position on the transfer paper. Next, the toner image on the photosensitive drum 3 is transferred onto the transfer paper P by the transfer charger 8. Thereafter, the transfer paper P separated from the drum 3 by the separating means 8a is guided to the fixing device 1O by the guide 9, and the toner image on the transfer paper P is fixed at 0° IOa.
After the paper is fixed by
2 is discharged on top. 8b is a cleaning means, and 8c is a cooling fan.

The fixing device 10 includes a fixing roller lOa having a halogen heater H1 whose temperature is controlled by a temperature control device described later.
and a pressure roller 10b that comes into pressure contact with the fixing roller 10a.
It consists of The fixing roller lOa has a layer of tetrafluoroethylene resin on the surface of the metal roller. On the other hand, the pressure roller fob has a sponge layer adhered to a core metal serving as a central axis, and further has an elastic coating layer on the sponge layer. A contact type thermistor TH is disposed on the dead surface of the fixing roller 10a, and the surface temperature of the fixing roller lOa is detected by the thermistor TH.

The copying machine of this example has a built-in manual feeding device 6a that can feed only one sheet of transfer paper P, but due to an increase in the amount of copying used, it is necessary to continuously copy a large number of sheets of transfer paper P. In this case, continuous feeding by the paper feed cassette 14 becomes possible by connecting an accumulator 13 to the lower part of the main body of the copying machine.

FIG. 2(A) shows an example of the configuration of the hot one control device of the copying machine shown in FIG. 1, where 100 is F! , a well-known one-chip microcomputer with built-in OM (read-only memory), RAM (random access memory), etc.
For example, an 8-bit A/D (analog
It consists of Texas Instruments' 7MS2300 with a built-in digital) converter. 101 is an aftereffect rectifier circuit constituted by a transformer 110 and diodes '111 and 112, and 102 is an inverting amplifier circuit for inverting and amplifying the output signal from the full-wave rectifier circuit 101. A thermistor 103 detects the temperature of the fixing roller 10a, and corresponds to 1 in FIG. 10
4 is a drive circuit for the halogen heater H□ which drives the fixing roller 10a; 105 is a dryer/heater for driving the halogen heater drive circuit 104; Furthermore, R7,
R2 and R3 are resistors that set a reference voltage when A/D converting the temperature detection signal from the thermistor 103.

The temperature detection signal from the thermistor 103 is input to the analog input terminal A1 of the microcomputer 100 and converted into a digital value.
1 and an inverting amplifier circuit 102, a pulse signal that becomes a logic level "H" (high) near the zero-crossing point of the AC power supply (hereinafter referred to as a zero-crossing pulse signal)
is input to the interrupt terminal INT of the microcomputer 100, and if the microcomputer 100 is in an interrupt enabled state at that time, the interrupt program is executed at the rising edge of the pulse signal. Although not shown, signals from various sensors such as manual jam detection, keys, etc. are input to other input ports of the microcomputer 100. Furthermore, an exposure lamp is connected to the output port of the microcomputer 100.

Control signals are output to various parts of the copying machine, such as the paper feed roller and the optical system 9 display.

-The above-mentioned input capo-1-(analog input terminal) The temperature detection signal inputted manually to A1 is AID-converted by the microcomputer 100 in the following manner. That is, if the voltage value input to the input port A+ is X (, V), and the quasi-voltages set at ports IO and 11 of the microcomputer 100 are V and VREF, the following equation (1 ) and (2) to calculate b.

(vAsSVREF) /255 = a (1) (X
-VREF) /a = b-(2) Then this b
Convert the value into hex code and input the analog value X(v)
Get the digital one for the first one. In this example, the A/D (analog-digital) conversion value of the thermistor 103 in the 1JIi kl state is 'FF', and the thermistor 10
The A/D conversion value in the short-circuited 5 insects of 3 is “00°”
Set in advance so that

In this way, since the temperature detection number 455 from one thermistor 103 is A/D converted, a wide range of temperature levels can be included.

A cassette size signal circuit 108 has two microswitches for detecting the size of the transfer paper, and the open/closed states of these microswitches are input to the microcomputer 100 as a cassette size signal. When both of these microswitches are closed (ON), the large size signal is output, when either one is closed, the middle size signal is output, and when both edges are open (OFF), the small size signal is output from the cassette size signal circuit 1'. 08 to the input port of the microcomputer 100.

FIG. 2(B) shows a configuration example of the halogen heater drive 1/1 path 104 of FIG. 2(A), where 113 is a photocoupler and 114 is an I.Liac. When a signal from the driver 105 connected to the output port R1 of the microcomputer 100 is input to the photocoupler 113, the photocoupler 113 becomes conductive, and due to the conduction of the photocoupler 113, the triac 114 becomes conductive, and the halogen heater Hl
AClooV is also included.

FIG. 3 shows an example of the signal waveforms of the output signal B of the aftermath rectifier circuit 102 and the output signal C of the inverting amplifier circuit 103 in FIG. 2(A).

Figures 84 (A) to (D) are similar to Figure 2 (A) and Figure 2 (B).
) is a flowchart showing an example of the operation of the apparatus of the present invention shown in FIG. As described later, in this example, when the power is turned on 11jj
According to the temperature detected from the thermistor 103, the energization state of the Haloken heaters H, , H, and H3 is switched from energization (iE) to energization every 1 cycle,
Change the switching temperature of the halogen heater H1. In other words,
1 cycle is ON (energized), next 1 cycle is 0FF
(de-energized) is repeated to prepare for power supply, and the energization state is changed according to the size of the transfer paper passing through the conveyance path during 99 copies.

Next, an example of the operation of the apparatus of the present invention shown in FIGS. 2(A) and 2(B) will be described in detail with reference to the flowcharts in FIGS. 4(A) and 4(B). . After turning on the power, necessary initial settings of memory, flags, etc. are performed in step 201. Next, in step 202, the temperature detection signal A from the thermistor 103 is input from the human-powered boat A, and A/D conversion is performed as described above to obtain digital signal A. In the next steps 203 to 208, this Based on the digital value, the surface temperature of the fixing roller 10a is 50°C or less, 80°C or less,
It is determined whether the temperature is 100°C or lower, 1306°C or lower, 150°C or lower, or 170°C or lower. Fixing roller 10
The surface temperature of a is 50°C or less, 80°C or less, 100°C
Below 130℃, 150℃ or less, or 170℃
If it is below, in the corresponding next steps 209 to 214, the flag F150. F/8
0. F/100. F/130. F/150 or F/1
Set 70 to 1゛.

On the other hand, if the surface temperature of the fixing roller 1θa is not below 170°C, the process advances to step 215 and the flag F/180 is set.
is set to °l''. When the flag F/180 is set to °1''', the state becomes ready for copying. Furthermore, in this example, the flag for temperatures lower than the fixing roller surface temperature detected by the thermistor 103 is always set to 1''. Thereafter, when zero-crossing interrupts are permitted in step 216, the main program is executed in step 217. When the above-mentioned zero-cross pulse signal is input to the interrupt terminal INT while the main program is being executed, the interrupt program shown in FIG. 4<8) is executed.

Next, the interrupt program (processing procedure) shown in FIG. 4(B)
Explain. First, the flag F/'180. F/170. F/150. F/130.
F/100. Determine whether the flag F/130 is set to "1". If the flag F/180 is set to "1", it is assumed that the wait is already in the wait-up (standby completion) state, and the process is executed in step 227. Execute the heater control program shown in Figure 4 (C) below/\
Controls the supply of electricity to the logon baboon 103.

If flag F/180 is not set to 1°,
In step 222, it is determined whether or not the flag F/170 is set to yant. If it is set to yant, then in step 228, a thermistor 1037'l- Judgment is made based on the detected signals. Laura Hikino's surface blood temperature is 170.
If the temperature is below .degree. C., the heater drive signal is turned on (energized) by the step 229, and cyclic energization is performed. On the other hand, if the fixing roller surface temperature is not below 170°C, the flag F/180 is set to 1 in step 230 to change to the weight-up state, and step 227 described above is performed.
Proceed to.

Similarly, if the flag F/1'50 is set to °1'', it is determined in step 231 whether the fixing roller surface temperature is 165°C or less, and if it is 185°C.
If it is up to that point, then the aftereffect energization is performed in step 228, and thereafter energization control is performed every other cycle, with one cycle on and one cycle off. In addition, if the flag F/130 is set to °l'', it is determined in step 232 whether or not the fixing roller surface temperature is 155°C or less, and even if it is up to 155°C, For example, aftereffect energization is performed in step 229, and thereafter energization control is performed every l cycle.
If flag F/100 is set to 1',
In step 2233, it is determined whether the surface temperature of the fixing roller is 145° C. or below or below 145° C. If it is up to 145° C., aftereffect energization is performed in step 228, and thereafter energization control is performed every other cycle. Also, the flag F/80 is 1°
.

If it is set to
Full-wave energization is performed at step 9, and energization control is performed every other cycle thereafter. Furthermore, if the flag F/80 is not set to 1", that is, if the flag F150 is set to 1", then in step 235 the constant J'10-ra surface temperature is set to 130°. It is determined whether the temperature is below C or not, and if it is up to 130° C., then in step 228, aftereffect energization is performed, and thereafter energization control is performed every other cycle.

On the other hand, if the above-described steps 231 to 235 for determining the fixing roller surface temperature are negative, that is, if the fixing roller surface temperature is not below the set predetermined temperature, the flag F/180 is set to 1° in each step 230.
' to change to the weight amplifier type 3t1, and proceed to the heater control process of step 227.

Thereafter, the process proceeds from step 228 or step 227 to step 23B, and after turning off (deenergizing) the heater drive signal in step 236, the next step 237 reads the fixing roller surface temperature again, as shown in FIG. ) returns to the main routine.

Next, referring to the flowchart in FIG. 4(C),
B) in step 227 of the hit control program (
(processing procedure) will be explained in detail. First, in this example, 1
Since the temperature is controlled at 80℃, step 30
Table 1J'l! of the fixing roller 10a in 1! 'JI+
The temperature detected by the thermistor 103 that detects A degree is 180°
It is determined whether the value is C or higher. The detected temperature is 180
If the temperature is below .degree. C., it is determined in the next step 302 whether or not a copying operation is in progress. Preparing for copying (standby)
Then, in step 306, 1 cycle 0, which will be described later
Intermittent energization of N-1 cycle OFF is performed until the temperature detected by the thermistor 103 reaches 180°C.

On the other hand, when the copying operation is in progress, the steps start from step 302.
In step 307, it is determined whether the size of the transfer paper is large size or not based on the cassette i size signal from the cassette size signal circuit 108. If the size of the transfer paper is a large size such as A3, move to step 308.
-J and perform a full pass (see (A) in Figure 5).

When it is determined that the size of the transfer paper is not large size, in the next step 309, it is determined whether the size of the transfer paper is medium size or not based on the above-mentioned cassette size (ij number. In the case of medium size, the flag F/TI is set in step 310.
It is determined whether or not it is set to "1", and if the determination is negative, the flag F/Tl is set to "l" in step 311, and the halogen heater H is energized.For the next interrupt control, step Step 310 moves to step 312, where it is determined whether flag F/T2 is set to "1", and if the determination is negative, flag F is set at step 313.
/T2: energize Seriton and Haloken heater Hl to ``1''.

At the time of the next interrupt control, in step 312, the flag F
/T,2 is determined to be l'', so the process moves from step 312 to step 306, and one cycle is turned ON.
-Perform intermittent energization with 1 cycle OFF. At that time, as described later, in the process of step 30B, the flag F/
Since T I and F/T2 have been reset, the processing from step 311 is repeated again during subsequent interrupt control. In this way, when the size of the transfer paper is middle size, the heater is turned on for one cycle in step 311 and step 313, and then in step 30, depending on the set state of flags F/Tl and F/T2.
In step 6, the energization control of the 2-cycle heater 0N-1 cycle heaters OF and F is repeated, in which 1 cycle of the heater is turned on and 1 cycle of the heater is turned off (see (B) in FIG. 5).

When the size of the transfer paper is a small size such as A4 size, the above-mentioned step 309 becomes a negative determination and the process moves to step 306, where one cycle of 0N is performed as in the preparation for copying.
-1 cycle OFF intermittent energization detection temperature is 180°C
(See (C) in Figure 5). In this way, when the temperature detected by the thermistor 103 exceeds 180'O, step 301 to step 236 is performed.
Then, energization of the halogen heater H is stopped until the detected temperature becomes 180° C. or less.

FIG. 4(D) shows the connection to the halogen heater H for every other cycle in step 306 of FIG. 4(C).
Detailed processing procedures regarding control are shown below. First step 3
In 08-1 and 30B-2, it is determined whether flag F/1st and flag F/2nd are set to 1". Flag F/1st and flag F/2nd are each AC l cycle. This flag is used to energize the first half cycle and the next half cycle.

If both flag F/1st and flag F/2nd are not set, steps 308-2 to 308-
Proceed to step 3, turn on (energize) the heater drive signal, and turn on AC 1.
Start energizing the first half of the cycle.

At the same time, the flag F/2nd is set to 'l'. During the next interrupt control, step 1. Step 306-1 to Step 30G
Proceed to step -2, and since Frac F/mu'52 is set to l, step 5. Proceeding to step 306-4, the heater drive signal is turned on to start energizing the next half cycle of the alternating current cycle.

At the same time, flag F/1st is set to °°1°'. During the next interrupt control, flag F/1 and flag F/2 are both set to l'', so step 308-
1 Car step 30B-5; i-3 step 3
Proceed to 0Ei-8 and reset flag F/2. When the next interrupt LE J is controlled, step 3 is changed from step 30B-5.
Proceed to oθ-7 and reset flag F/1. In other words, the halogen heater H1 is not energized during one AC cycle in which the flag F/second and flag F/first are reset.

Furthermore, after resetting flag F/1 in step 308-7, both flag F/Tl and flag F/T2 are reset in step 30B-8. Note that the flags F/TI and F/T2 are involved only when copying is performed on medium-sized transfer paper as described above.

FIG. 5 shows the halogen heater H! when the detected temperature falls below 180'O according to the flowchart shown in FIGS. 4(A) to 4(D). An example of a state in which an alternating current is applied to is shown.

In Figure 5, (A) shows the fully energized state during copying when the transfer paper is large size such as A3 size, and (B)
) shows the state of 2/3 copies when copying when the transfer paper is medium size like 84 size, and (C) shows the state when copying preparation or transfer is small size like A4 size. This shows the state of 1/2 energization when copying. In this way, in this example, how much energy is applied to the halogen heater H, per unit time? li Mfi-4) is changed depending on the size of the transfer paper, the surface temperature of the fixing roller is always maintained at an appropriate temperature, and defective fixing can be prevented.

Note that the present invention is not limited to temperature control by intermittent energization as in this example, but may be such that, for example, a plurality of heaters are prepared and the heater to be passed through is selected depending on the size of the recording paper.

(Effects) As explained above, according to the present invention, since the amount of electricity applied to the heating means is made variable according to the size of the recording paper, the temperature of the fixing roller is appropriately controlled, and the You can do this by improving your sexuality.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of the internal configuration of a copying area to which the present invention is applied, FIG. B) is Figure 2 (A)
3 is a signal waveform diagram showing an example of the signal waveform at each part of FIG. 2(A), and FIGS. A flowchart showing an example of the operation of the device δ shown in FIGS. FIG. 3 is a waveform diagram showing an example of a 1L state. DESCRIPTION OF SYMBOLS 1... Document placement table, 2... Imaging element array, 3... Photosensitive drum, 4... Charger, 5... Developing device, 6a... Manual feed stand, 7... Resist Roller, 8...Transfer charger, '8a...Separation means. 9... Guide, 10... Fixing device, 10a... Fixing roller, 10b... Pressure roller, 11... Paper ejection roller, 12... Tray, 13... Attachment, 14... Cassette, 100... Microcomputer, 201... Full wave rectifier 1 & circuit, 102... Inverting amplifier circuit, 103,'T)l... Thermistor, 104... Halogen heater drive circuit , 105... Driver, 106... Cassette size signal circuit, 110... Transformer, Ill, 112... Diode, 113... Photocoupler, +14... Triac, Hl... Halogen heater, R1+ "2 +R3...Resistance. Patent applicant: Canon Co., Ltd. Figure 3C Figure 4 (A)

Claims (1)

[Scope of Claims] (1) Temperature detection means for detecting the temperature of the heating means of the recording device, and energization control means for controlling the energization of the heating means according to the temperature detected by the pH degree detection means; A temperature control device for a recording apparatus, characterized in that the energization control means varies the level of energization to the heating means in accordance with the size of recording paper conveyed to the heating means. 1. A temperature control device for a recording apparatus, characterized in that a time period for energization is made variable in accordance with the size of the recording paper by intermittent energization.