JPH04166879A - Electrophotographic printing device - Google Patents

Abstract

PURPOSE:To obtain an exact temperature control characteristic by a simple adjusting operation by generating a reference signal referring to control data suited to a preliminarily measured, temperature detection characteristic inherent in the fixing device, or correcting a temperature detection signal. CONSTITUTION:A control device 15 sets control data suited to a preliminarily measured and indicated, temperature detecting characteristic inherent in the fixing device 13 in a control data storage means, generates a reference signal, or corrects a temperature detection signal referring to the control data, when the temperature of a heating roller 13a is controlled. As a result, the reference signal or temperature detection signal which becomes an object of comparison for the purpose of temperature control, can be suited to the temperature detecting characteristic inherent in the fixing device. Thus, an exact temperature control characteristic can be obtained by simple operation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrophotographic printing apparatus, and particularly to temperature control of a heating roller in a fixing device.

[Conventional technology]

An electrophotographic printing apparatus includes a fixing device that melts and fixes a toner image formed on a printing paper onto the printing paper. The fixing device has a heating element such as a halogen lamp or an infrared lamp inside it! The printer is equipped with a rotatable heating roller and a pressure roller that rotates under pressure from the heating roller, and the printing paper on which the I/toner image is formed is passed between the two rollers.

Such a fixing device reliably fuses the toner image onto the printing paper, prevents the toner from adhering to the heating roller and offset phenomenon, and controls the surface temperature of the heating roller to prevent the printing paper separation claw from melting. It is necessary to accurately detect and control the amount of heat generated by the heating element so that the surface temperature becomes a predetermined value.

For this purpose, a temperature detecting element such as a roller mister whose electrical resistance value changes depending on the temperature is provided in contact with or in close proximity to the heating roller, and a voltage dividing circuit using the temperature detecting element is used to measure the surface temperature of the heating roller. The heating element is configured to obtain a temperature detection signal having a magnitude corresponding to the temperature detection signal, compare the temperature detection signal with a reference signal, and control power supply to the heating element so that the magnitudes of both signals become equal.

However, there are individual differences in the temperature dependence characteristics of the electrical resistance value of the temperature detection element, and there are also variations in the installation status with respect to the heating roller, so it is difficult to obtain a temperature detection signal that accurately corresponds to the surface temperature of the heating roller. Therefore, in order to obtain predetermined temperature control characteristics, the adjustment resistor must be adjusted or reference signal control data must be set.

This type of device is disclosed in Japanese Patent Laid-Open No. 60-247277, Japanese Patent Laid-Open No. 63-81379, or Japanese Patent Laid-Open No. 64
There are those described in JP-A-26877 and the like.

[Problem to be solved by the invention]

To adjust the adjustment resistor and set the reference signal control data, measure the surface temperature of the heating roller after incorporating the fixing device into the electrophotographic printing device and bringing it into the operating (heating) state for adjusting the temperature control characteristics. It was both troublesome and dangerous because it was done while doing so.

In order to eliminate the need for adjustment operations after assembly into the electrophotographic printing device, an adjustment resistor is provided in the fixing device to adjust the characteristics of the temperature detection signal output from the fixing device by itself. has also been proposed. However, since the fixing device is in a high temperature state, providing adjustment parts, control circuit active parts, etc. in the fixing device poses a problem in terms of reliability.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an electrophotographic printing apparatus that eliminates temperature detection errors through simple setting (adjustment) operations and that provides highly reliable temperature control characteristics.

[Means to solve the problem]

The present invention provides a heating roller that passes a printing paper on which a toner image is formed and melts and fixes the toner image onto the printing paper, a heating element that heats the heating roller, and a temperature sensor that detects the temperature of the heating roller. a fixing device equipped with a temperature detection element for converting it into a signal; inputting the temperature detection signal and comparing it with a reference signal; controlling power supply to the heating body so that the temperature of the heating roller becomes a predetermined value; An electrophotographic device comprising a control signal generating means for generating a signal, a power supply control means for controlling power supply to the heating element based on the power supply control signal, and a control device provided separately from the fixing device. In a printing device.

control data storage means for measuring and displaying a temperature detection characteristic of the heating roller by the temperature detection element of the fixing device in advance, and storing control data for controlling the magnitude of the reference signal in the control device; $ according to temperature detection characteristics
The present invention is characterized in that it includes data setting means for setting II# data in the control data storage means, and means for generating the reference signal or correcting the temperature detection signal by referring to the control data.

[Effect]

The control device stores control data that matches the temperature detection characteristics unique to the fixing device 7, measured and displayed in advance, in the control data storage means, and generates a reference signal by referring to the control data when controlling the temperature of the heating roller. generate or correct the temperature detection signal. Therefore, the reference signal or temperature detection signal to be compared for temperature control will match the temperature detection characteristics specific to the fixing device, and accurate temperature control characteristics can be obtained with simple operations. Further, since there are no adjustment parts, control circuit active parts, etc. inside the fixing device, which is exposed to high temperatures, high reliability can also be obtained.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 4 shows a laser beam printer, in which the outer circumferential surface of a photosensitive tram 1 rotated at a constant speed is uniformly charged by a charger 2, and then exposed to light by a laser beam exposure device 3 according to print data to create an electrostatic potential. An image is formed. The developing device 4 develops the electrostatic latent image to form a toner image on the outer peripheral surface of the photosensitive drum. The extraction roller 5 extracts the printing paper 7 stored in the paper feed cassette 6 and supplies it to the registration roller 8. The registration roller 8 receives and stops the leading edge of the printing paper 7 supplied by the extraction roller 5, and controls the posture and adjusts the paper feeding timing. The printing paper 7 sent out from the registration roller 8 is conveyed via the first conveyance roller 9 so as to be in contact with the outer circumferential surface of the photosensitive drum 1, and while in contact with the outer circumferential surface of the photosensitive drum 1, the printing paper 7 is transferred from the back side to the transfer device 10. The toner image is transferred by charging. The printing paper 7 on which the toner image has been transferred is separated from the outer peripheral surface of the photosensitive tram 1 while being neutralized by a static eliminator 11, passed through a second conveyance roller 12, fixed by a fixing device 13, and discharged onto a paper discharge tray 14. be done. A control device 5 is a control device for controlling these component devices, and is provided separately from the fixing device 13.
An operation input section and a display section forming part of the operation input section and display section are installed in an operation panel 17 provided on the top surface of the housing 16.

5 and 6 show a general outline of the fixing device 13. FIG. A heating element 13b such as a halogen lamp or an infrared lamp is disposed inside the heating roller 13a, and the heating roller 13a is heated by the heating element 13b.

A rotatably provided pressure roller 13c is pressed against the heating roller 13a. The separation claw 13d is a heating roller 13a.
The printing paper 7 that has passed between the pressure roller 13c and the pressure roller 13c is prevented from being wrapped around the heating roller 13a, and the temperature detection element 13e, such as a thermocouple or thermistor, detects the The heating roller 13a is installed close to the heating roller 13a so as to have an electrical resistance value.

FIG. 1 is an electric circuit block diagram of the fixing device 13 and the control device 15. The electric circuit (conductor wire) between the heating element 13b and the temperature detection element 13e in the fixing device 13 is connected to the connectors 18a to 18a.
]-80 is connected to the electric circuit (conductor wire) of the control device 15. The resistor 1'5a of the control device 15 is connected in series with the temperature detection element 13e to form a voltage dividing circuit, and the A/D conversion circuit 15b is connected to the surface of the heating roller 13a output from the voltage dividing circuit. A temperature detection signal having a magnitude corresponding to the temperature (resistance value of the temperature detection element 13e) is converted into a digital form. The central processing unit (ePtJ) 15c stores the control data input from the operation input section 15cl in the control data storage memory 15e, and also stores the control data input from the operation input section 15cl.
The control data input from d and/or the control data and/or error message stored in the control data storage memory 15e are displayed on the display section 15f. Also,
During heating roller temperature control operation, the central processing unit 15c reads out control data stored in the control data storage memory 15e, generates a reference signal, and outputs a reference signal to the A/D conversion circuit 1.
power supply control that controls the power supply to the heating element 13b so that the temperature detection signal outputted from the heating element 13b is compared with the reference signal and the temperature detection signal is equal to the reference signal and the surface temperature of the heating roller becomes -11 to -11; Generate a signal. Then, the power supply control circuit 15g controls the amount of power supplied to the heating element 13b according to the power supply control signal.

In such an electrophotographic printing apparatus, the temperature dependence characteristics of the resistance value of the thermistor used as the temperature detection element 13e of the fixing device 13 vary from one device to another, as shown in FIG. Even if the thermistor temperature accurately corresponds to the predetermined surface temperature T of the heating roller 13a, the resistance value of the thermistor varies between R1 and R2 due to individual differences, and as a result, the temperature detection element using the thermistor A detection error occurs in the temperature detection signal obtained from the voltage dividing circuit composed of the resistor 13e and the resistor 15a. Furthermore, in reality, the heating roller 1
Since there are individual differences in the correspondence between the temperature detection element 3a and the temperature detection element 13e, this error is further aggravated.

In this embodiment, in order to eliminate this detection error and obtain more reliable temperature control characteristics, the temperature detection characteristics of the fixing device alone are measured at the test and inspection stage after the fixing bag holder 13 is assembled. The detection results are displayed (described) on the fixing device 13 itself, its packaging, or instructions. In this example, the temperature detecting element 13e of the fixing device 13 is connected to a measuring resistor having a resistance value equal to that of the resistor 15a of the control device 15 to form a measuring voltage dividing circuit, and the heating roller 13a is The heating roller 13a is heated while measuring the surface temperature.
is heated to a predetermined temperature (operating temperature when installed in an electrophotographic printing device), and when the surface temperature is a predetermined value, the value of the temperature detection signal obtained from the measuring voltage dividing circuit is measured as the value of the temperature detection signal obtained from the fixing device] 3 itself or its package. Or display (describe) in the manual.

Therefore, an assembly worker or a service person who replaces the fixing device 13 can check the information displayed on the fixing device 13 (or the packaging or the instruction manual) to the control device 15 of the electrophotographic printing device into which the fixing device 13 is installed. The operation input section 15d of the operation panel 17 uses the value of the temperature detection signal as control data.
When input from the central processing unit 15c of the control device 15
displays the control data on the display section 15f and stores it in the control data storage memory 15e.

When the electrophotographic printing apparatus assembled in this manner is put into operation for printing image information, the central processing unit 15c of the control unit 15 reads control data from the control data storage memory 15e and generates a reference signal. Furthermore, a temperature detection signal is inputted from the A/D converter circuit 15b and the magnitudes of both signals are compared. When the temperature detection signal is smaller than the reference signal (the surface temperature of the heating roller 13a is lower than a predetermined value), a power supply control signal is generated to increase the amount of heat generated by the heating element 13b, and the temperature detection signal is When the signal is larger than the reference signal (the surface temperature of the heating roller 13a is higher than a predetermined value), a power supply control signal is generated to reduce the amount of heat generated by the heating element 13b, and this signal is applied to the power supply control circuit 15g to control the heating element 13b. By controlling the amount of power supplied to heating roller 13b, the surface temperature of heating roller 13a is controlled to a predetermined value.

Next, data processing executed by the central processing unit 15c to realize such temperature control will be explained with reference to the processing flow shown in FIG. 3.

In process 101, the central processing unit 15c checks whether a control data storage process is required in connection with the fixing device installation (replacement) work. If control data storage processing is necessary, the process moves to step 102 to input the control data Tdata from the human operator section 15d, and stores the inputted control data Tdata in the control data storage memory 15e. If the process of storing control data in the control data storage memory 15e is unnecessary, the process 102 is omitted.

In process 103, the control data Tdata is read from the control data storage memory 15e and used as a reference signal (Tdat
a), the temperature detection signal Tth is inputted from the A/D conversion circuit 15b, and the magnitudes of both signals are compared. If the temperature detection signal Tth has a smaller value than the reference signal Tdata, the process proceeds to process 104, where a power supply control signal is generated to supply power to the heating element 13b, and the temperature detection signal (No. 8 T
If th is greater than or equal to the reference signal Tdata, process 105
Then, a power supply control signal is generated to cut off the power supply to the heating element 13b.

In such a control device 15, control data T data matching the value of a temperature detection signal specific to the fixing device at a predetermined temperature measured and displayed in advance is set in the control data storage memory 15e, and is used when controlling the temperature of the heating roller. The control data Tdata becomes the reference signal Tdata. Therefore, the reference signal T to be compared for temperature control
The data matches the temperature detection characteristics unique to the fixing device, and accurate temperature control characteristics can be obtained with simple operations. Furthermore, since there are no adjusting parts, #controllers, active parts, etc. inside the fixing device, which is exposed to high temperatures, high reliability can be achieved.

In the above embodiment, the temperature detection characteristic unique to the fixing device is used as the reference signal Tdata, but the temperature detection characteristic can be used to correct the error in the temperature detection signal ITth, or to use the temperature detection characteristic to compensate for the error in the temperature detection signal ITth, or to compare it with a preset fixed reference value. The difference is corrected and the reference signal T da
A similar effect can be obtained by obtaining ta.

Further, the comparison process may be performed by a comparator provided independently from the central processing unit.

=16- [Effects of the Invention] As described above, in the present invention, control data matching the temperature detection characteristics peculiar to the fixing device measured and displayed in advance is set in the control data storage means, and when controlling the temperature of the heating roller. refers to the control data to generate a reference signal or correct the temperature detection signal. Therefore, the reference signal or temperature detection signal to be compared for temperature control will match the temperature detection characteristics specific to the fixing device, and accurate temperature control characteristics can be obtained with a simple adjustment operation.

Further, since there are no adjustment parts, control circuit active parts, etc. inside the fixing device, which is exposed to high temperatures, high reliability can also be obtained.

[Brief explanation of drawings]

Fig. 1 is an electric circuit block diagram of the fixing device and control device according to the present invention, Fig. 2 is a temperature dependence characteristic of the resistance value of the thermistor used as a temperature detection element of the fixing device, and Fig. 3 is for temperature control. 4 is a longitudinal sectional side view of the laser beam printer, FIG. 5 is a schematic perspective view of the fixing device, and FIG. 6 is a side view thereof. 13...Fixing device, 13a...Heating roller, 13b...Heating element, 13a Pressure roller, 13e
...Temperature detection element, 15...Control device, 15a...
・Resistor, 15c...Central processing unit, 15d
...Operation input unit, 15e...Control data storage memory, 15f...Display unit, 19g...Power supply control circuit. ■￥6X Me View

Claims (1)

[Scope of Claims] 1. A heating roller that passes a printing paper on which a toner image is formed and melts and fixes the toner image onto the printing paper, a heating element that heats the heating roller, and a heating roller that heats the heating roller. a fixing device including a temperature detection element for converting temperature into a temperature detection signal; and a fixing device that inputs the temperature detection signal and compares it with a reference signal, and adjusts the temperature of the heating roller to a predetermined value. control signal generation means for generating a power supply control signal to the
In the electrophotographic printing apparatus, the fixing device includes a power supply control means for controlling power supply to the heating element based on the power supply control signal, and a control device provided separately from the fixing device. A temperature detection characteristic of the heating roller by a temperature detection element is measured in advance and displayed, and the control device includes a control data storage means for storing control data for controlling the magnitude of the reference signal, and a control device that stores control data for controlling the magnitude of the reference signal; 1. An electrophotographic printing apparatus comprising: a data setting means for setting control data in the control data storage means; and a reference signal generating means for generating the reference signal by referring to the control data. 2. An electrophotographic apparatus according to claim 1, wherein the control data is a temperature detection signal obtained by the temperature detection element when the heating roller of the fixing device is at a predetermined temperature. 3. In claim 1, the control data includes a preset standard value, a temperature detection signal obtained by the temperature detection element when the heating roller of the fixing device is at a predetermined temperature, and the standard value. An electrophotographic printing apparatus characterized in that the electrophotographic printing apparatus includes a difference value, and the difference value is set by the data setting means. 4. A heating roller that passes the printing paper on which the toner image is formed to melt and fix the toner image onto the printing paper, a heating element that heats the heating roller, and a temperature detection signal that converts the temperature of the heating roller into a temperature detection signal. a fixing device including a temperature detection element for converting the temperature; and a fixing device that inputs the temperature detection signal and compares it with a reference signal, and sends a power supply control signal to the heating body so that the temperature of the heating roller becomes a predetermined value. a control signal generating means for generating;
In the electrophotographic printing apparatus, the fixing device includes a power supply control means for controlling power supply to the heating element based on the power supply control signal, and a control device provided separately from the fixing device. A temperature detection characteristic of the heating roller by a temperature detection element is measured in advance and displayed, and the control device includes a control data storage memory that stores control data for controlling the magnitude of the reference signal, and a control device that controls the temperature detection characteristic according to the temperature detection characteristic. a central processing unit that stores the control data input from the data input means in the control data storage memory and reads the stored control data from the control data storage memory;
An electrophotographic printing apparatus comprising: reference signal generating means for generating the reference signal with reference to the control data. 5. In claim 4, the control device includes a display means, and the central processing unit displays the control data input from the data input means and/or the control data stored in the control data storage memory on the display means. An electrophotographic printing device characterized by displaying images. 6. A heating roller that passes the printing paper on which the toner image is formed and melts and fixes the toner image onto the printing paper, a heating element that heats the heating roller, and a temperature detection signal that converts the temperature of the heating roller into a temperature detection signal. a fixing device including a temperature detection element for converting the temperature; and a fixing device that inputs the temperature detection signal and compares it with a reference signal, and sends a power supply control signal to the heating body so that the temperature of the heating roller becomes a predetermined value. a control signal generating means for generating;
In the electrophotographic printing apparatus, the fixing device includes a power supply control means for controlling power supply to the heating element based on the power supply control signal, and a control device provided separately from the fixing device. A temperature detection characteristic of the heating roller by the temperature detection element is measured in advance and displayed, and the control device includes a control data storage means for storing control data for correcting the magnitude of the temperature detection signal, and a control data storage means for storing control data for correcting the magnitude of the temperature detection signal; An electrophotographic printing apparatus comprising: a data setting means for setting corresponding control data in the control data storage means; and a detection signal correction means for correcting the temperature detection signal with reference to the control data.