JPH11258957A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately detect the presence/absence of a cartridge by detecting the presence/absence of the cartridge after the elapse of a specified time from electrification high voltage output timing by an electrification high voltage output means. SOLUTION: The device waits for a specified time until sampling is started from generating the PWM output of output PRDC in order to make an electrification generation circuit output and generating PRACC pulse output. Namely, an engine controller 600 detects the presence/absence of the cartridge at the time of starting up a power source or closing a door. The engine controller 600 drives the PRDCC and the PRACC in order to make the electrification generation circuit 200 for detecting the cartridge output. In such a case, the device has the specified waiting time until starting the sampling. The specified time is much longer than the time required for the rising electrification, for example, 500 ms.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus using an electrophotographic system, such as a page printer or a copying machine, which is characterized by means for detecting the presence or absence of a cartridge.

[0002]

2. Description of the Related Art FIG. 15 schematically shows an example of a conventional image forming apparatus. In FIG. 1, an image forming apparatus is a photosensitive drum 100 which is an electrophotographic photosensitive member for realizing an electrophotographic process, and a high voltage generating circuit for placing uniform electric charges required for the electrophotographic process on the photosensitive drum 100. A charging voltage generating circuit (generally generating a voltage obtained by superimposing a DC voltage on a sine wave) 200; a charging roller 700 serving as a charging unit for uniformly charging the charges of the charging generating circuit 200 on the photosensitive drum 100; A laser generator 300 for irradiating a laser beam according to data to form an electrostatic latent image, disposed opposite to the photosensitive drum 100,
The developing device 400 includes a developing sleeve 410 that carries toner and develops an electrostatic latent image on the photosensitive drum 100.

In this embodiment, a photosensitive drum 100, a developing device 400, and a charge roller 700 are built in, and a process cartridge (hereinafter, simply referred to as a "cartridge") 500 having a detachable main body and a detachable structure is provided.

In the image forming apparatus having the above structure, the photosensitive drum 1 uniformly charged via the charge roller 700
At 00, an electrostatic latent image is formed by irradiating a laser beam from the laser generator 300 in accordance with image data. The electrostatic latent image is developed into a toner image by the developing device 400, and is transferred to the recording medium P by the transfer device 800. The recording medium P is transported to a fixing device 900 including a heating unit 910, where the toner image is fixed as a permanent image, and further discharged outside the apparatus.

FIG. 16 shows a charge generation circuit 200 and an engine controller 600 of the image forming apparatus. In the figure, the output P from the engine controller 600
RACC is usually a square wave of about 200 Hz to 1 kHz and is determined by the process speed of the engine. In this example, the frequency is 470 Hz and the duty is 50.
%, Vpp 5 V, and the level is converted to Vpp 24 V by the transistor 502 and the resistor 503.

The power operational amplifier 501 includes a capacitor 5
04, 505 and resistors 506, 507 convert the signal PRACC from the engine controller 600 to a sine voltage of Vpp 20V. Such a sine voltage is
10 are coupled and input to the transformer 511. Transformer 5
The voltage input to 11 is changed to a voltage corresponding to the winding of the transformer 511. In the conventional example, the sine voltage is about 2 kVpp.

The diode 509 and the capacitor 508 are for peak charging the sine voltage, and this voltage is driven by the transistor 534 to superimpose a DC voltage on the sine voltage.

Output PRD of engine controller 600
CC is a PWM output for controlling a DC voltage,
In this example, the frequency is 15 kHz and the duty is 1/256 to 2
55/256, Vpp5V, and the duty is controlled by the print density. This output is rectified by the resistor 537 and the capacitor 538, and is input to the negative input terminal of the operational amplifier 531. At the same time, a voltage obtained by dividing the voltage of one terminal of the transformer 511 by the resistors 532 and 533 is input to the + input terminal of the operational amplifier 531 and drives the transistor 534 so that the values are equal.

A capacitor 519 connected to the secondary side of the transformer 511 is a capacitor for transmitting electric power to the photosensitive drum 100, and is converted into a current and a voltage by a resistor 520. Thereafter, only the positive voltage is extracted by the diode 521, and the operational amplifier 522, the capacitor 524, and the resistor 523 are extracted.
And is input to the A / D input port CRGSNS of the engine controller.

When there is a cartridge, the generated voltage is large because the current flowing through the resistor 520 is large. On the other hand, when there is no cartridge 500, the generated voltage is small because the current flowing through the resistor 520 is small. The detection voltage for judging the presence or absence of the cartridge is set between a voltage generated when the cartridge is present and a voltage generated when the cartridge is not present.

FIG. 17 is a flowchart for detecting the presence or absence of a cartridge, and FIG. 18 is a time chart for detecting the presence or absence of a cartridge.

The engine controller 600 detects the presence or absence of a cartridge when power is turned on or when a door is closed. The engine controller 600
PRDCC and PRACC are driven to output the charge generation circuit 200 for detecting the presence or absence of the cartridge (S101,
S102) While the charging output is being output at the same time, the sampling of the voltage at the CRGSNS of the A / D port in the engine controller is repeated (S103, S10).
4) The sampled data is averaged, and the average value is set as a detection voltage (S105).

Conventionally, sampling is continuously performed while the charging output is being output. If the detected voltage exceeds a specified voltage (0.7 V in this example) (S10
6), it is determined that a cartridge is present, and a print waiting state is set (S107). Conversely, when the voltage is 0.7 V or less, it is determined that there is no cartridge, and the user is notified using a display unit (not shown) (S108). After sampling, P
RDCC is set to “H” (S109), and PRACC is stopped (S110).

[0014]

However, the above-described cartridge presence / absence detecting means includes: While the output of the charge rises, a large amount of current flows through the transistor and the like, so that the input of the CRGSNS port of the engine controller 600 increases as shown in FIG. Since this voltage is also generated when there is no cartridge, the average voltage becomes large, and the presence of the cartridge is erroneously detected.

2. When the charging current in the normal image forming state is applied to cartridge detection, S / S
Since the N ratio cannot be made large, a malfunction may occur due to noise or the like.

3. The impedance component of the charge roller and the like greatly changes depending on the environment. Therefore, in a low temperature environment, it is determined that there is no cartridge despite the presence of the cartridge.

Accordingly, it is a main object of the present invention to provide an image forming apparatus capable of accurately detecting the presence or absence of a process cartridge.

Another object of the present invention is to provide an image forming apparatus capable of accurately detecting the presence or absence of a cartridge regardless of a change in environment.

[0019]

The above object is achieved by an image forming apparatus according to the present invention. In summary, the present invention provides:
At least a process cartridge including at least an electrophotographic photoreceptor and a charging unit that performs charging by contacting the electrophotographic photoreceptor is detachably mounted on a main body of the image forming apparatus, and an AC component and a DC component are superimposed on the charging unit. Charging high voltage output means for applying a high voltage, charging current detecting means for detecting a charging current flowing through the charging means, and cartridge presence / absence detection for detecting whether or not the process cartridge is mounted based on information of the charging current detecting means. Wherein the detection of the presence or absence of the cartridge is performed after a lapse of a predetermined time from the charging high voltage output timing by the charging high voltage output means.

According to another aspect of the present invention, a process cartridge including at least an electrophotographic photosensitive member and a charging unit for charging the electrophotographic photosensitive member while being in contact with the electrophotographic photosensitive member is detachably mounted on the main body of the image forming apparatus. A charging high-voltage output unit that applies a high voltage obtained by superimposing an AC component and a DC component to the charging unit; a charging current detection unit that detects a charging current that flows through the charging unit; and information based on the charging current detection unit. An image forming apparatus comprising: a cartridge presence / absence detection unit that detects presence / absence of the process cartridge; wherein the charging high voltage output unit outputs only an AC component of the charging high voltage output when detecting the presence / absence of a cartridge. An image forming apparatus is provided.

According to another aspect of the present invention, a process cartridge including at least an electrophotographic photosensitive member and a charging means for charging the electrophotographic photosensitive member by contacting the electrophotographic photosensitive member is detachably attached to an image forming apparatus main body. Attached to the charging means, a charging high voltage output means for applying a high voltage obtained by superimposing an AC component and a DC component on the charging means, a charging current detecting means for detecting a charging current flowing through the charging means, and information on the charging current detecting means. And a cartridge presence / absence detection means for detecting the presence / absence of the mounting of the process cartridge, wherein the charging high-voltage output means comprises an AC component of the charging high-voltage output between normal image formation and cartridge presence / absence detection. The image forming apparatus is characterized in that the frequency of the image is changed.

According to another aspect of the present invention, at least a process cartridge including at least an electrophotographic photosensitive member and a charging unit that contacts and charges the electrophotographic photosensitive member is detachably mounted on the main body of the image forming apparatus. A charging high-voltage output unit that applies a high voltage obtained by superimposing an AC component and a DC component to the charging unit; a charging current detection unit that detects a charging current that flows through the charging unit; and information based on the charging current detection unit. And a cartridge presence / absence detection unit for detecting the presence / absence of the process cartridge. In the image forming apparatus, the charging high voltage output unit includes a voltage of an AC component of a charging high voltage output during normal image formation and cartridge presence detection. Is provided.

According to another aspect of the present invention, a process cartridge including at least an electrophotographic photosensitive member and a charging means for charging the electrophotographic photosensitive member by contacting the electrophotographic photosensitive member is detachably attached to an image forming apparatus main body. Attached to the charging means, a charging high voltage output means for applying a high voltage obtained by superimposing an AC component and a DC component on the charging means, a charging current detecting means for detecting a charging current flowing through the charging means, and information on the charging current detecting means. An image forming apparatus including: a cartridge presence / absence detection unit that detects presence / absence of the process cartridge; and an in-machine temperature detection unit that detects a temperature in the image forming apparatus main body. Wherein the cartridge presence detecting means determines the presence or absence of the cartridge, and changes the threshold value of the charging current. Location is provided.

A heat fixing means for fixing the toner image on the recording paper by the heat generated by the heat generating element which is heated by energization, and a fixing temperature detecting means provided in the heat fixing means for detecting the temperature of the heat generating element. When the power of the apparatus is turned on, the fixing temperature detecting unit also serves as the in-machine temperature detecting unit,
It is preferable that the threshold value of the charging current is changed, and the changed state is held for a predetermined time, based on the information of the fixing temperature detecting means, wherein the cartridge presence detecting means determines the presence or absence of the cartridge.

According to another aspect of the present invention, a process cartridge including at least an electrophotographic photosensitive member and a charging means for charging the electrophotographic photosensitive member while being in contact with the electrophotographic photosensitive member is detachably attached to an image forming apparatus main body. A charging high-voltage output unit that applies a high voltage obtained by superimposing an AC component and a DC component on the charging unit, a charging current detection unit that detects a charging current flowing through the charging unit, and information based on the charging current detection unit.
A cartridge presence / absence detection means for detecting the presence / absence of the mounting of the process cartridge; a heat fixing means for fixing a toner image on a recording medium by the heat generated by a heating element which is heated by energization; Fixing temperature detecting means for detecting the temperature of the body, in the image forming apparatus, when the apparatus power is turned on, the fixing temperature detecting means,
An image, which also serves as the in-machine temperature detecting means for detecting a temperature in the image forming apparatus main body, and changes a power supply time to the heating element after power is turned on based on information of the fixing temperature detecting means. A forming device is provided.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an image forming apparatus according to the present invention will be described in more detail with reference to the drawings. In the embodiment described below, it is assumed that the present invention is embodied in the electrophotographic image forming apparatus shown in FIG. Therefore,
A description of the overall configuration and functions of the electrophotographic image forming apparatus will be omitted, and features of the present invention will be described.

Embodiment 1 A first embodiment of the present invention will be described with reference to FIGS. In this embodiment, since the charge generation circuit is generated, PR
It is characterized in that a predetermined time is waited from the generation of the DCC PWM output and the generation of the PRACC pulse output to the start of sampling. Note that the circuit configuration of this embodiment is basically the same as that of FIG. 16 described above, and the description of the components is referred to the above description. Also, output PRAC
C, output The details of the PRDCC output are the same as in the conventional example.

The engine controller 600 detects the presence or absence of the cartridge 500 when the power is turned on or when the door is closed. Engine controller 60
0 drives PRDCC and PRACC to output the charge detection circuit 200 for cartridge detection (S101, S102).

Here, as described above, there is a predetermined wait time until sampling is started (S111). This predetermined time is a time sufficiently longer than the time required for the rise of charging, and is 500 ms in this embodiment.

Referring to the time chart of FIG. 2 as well, the CRGSNS voltage input to the engine controller 600 indicates a voltage during which the rise time of charging is higher than usual, but sampling is not performed in that part, and the wait time (500 ms) Start sampling later, i.e.
Enter the cartridge detection mode.

That is, the engine controller 600 starts cartridge detection after a lapse of a predetermined time since the charging output PRACC is turned on (S103, S104). A voltage obtained by sampling and averaging the voltage at this time is set as a detection voltage (S105). When the voltage at this time is larger than 0.7V, it is determined that a cartridge is present, and a print waiting state is set (S107). If there is no cartridge, it is determined that there is no cartridge, and the user is notified using display means (not shown) (S108). PRDC after sampling is completed
C is set to "H" (S109), and PRACC is stopped (S110).

As described above, in this embodiment, the cartridge detection is performed by the cartridge presence / absence detecting means after a predetermined time has elapsed from the charging high voltage output timing by the charging high voltage output means. Overshoot of the value can be avoided, and the accuracy of cartridge detection can be improved.

Embodiment 2 Next, a second embodiment of the present invention will be described with reference to FIGS. The circuit configuration of the present embodiment is the same as that of the conventional example shown in FIG. 3, and the present embodiment is different from the conventional example in the control of the AC component output and the DC component output of the charging high voltage.

FIG. 3 is a flow chart showing charging high voltage output and cartridge presence / absence control in the electrophotographic initialization operation after the apparatus is turned on, and FIG. 4 shows a timing chart at that time. The operation will be described below with reference to the flowchart of FIG.

First, "H" is output to the PRDCC in order to set the DC component of the charging high voltage to 0 V (S201). AC
A pulse having a frequency of 470 Hz is output to PRACC to output the component (S202). At this point, a sine wave of about 2 kVpp is output as the output of the charging high voltage, and a voltage corresponding to the charging current is generated as a CRGSNS signal.

Here, since the DC component is not superimposed when the charge rises, the overshoot of the CRGSNS signal, which is generated by the current flowing into the transistor 534 (see FIG. 16), does not occur.

Subsequently, the voltage level of the CRGSNS signal is sampled for a predetermined time (S203, S204). Thereafter, an average value of the sampling values is calculated (S205), and it is determined whether or not the average value exceeds 0.7V (S205).
206) If it exceeds, it is determined that there is a cartridge and PWM output is performed to the PRDCC (S207). At this point, the DC component Vdc is superimposed on the charging high voltage output,
The normal electrophotographic initial mode is started. When the required initial rotation time has elapsed (S20)
8) Then, “H” is output to PRDCC (S209), and PR
The pulse output of the ACC is stopped (S210), the charging high voltage is set to 0 V, and the control ends.

On the other hand, if the average value of CRGSNS is 0.7 V or less in S206, it is determined that there is no cartridge, and the fact that there is no cartridge is notified to the outside (S21).
1), “H” is output to PRDCC (S209), and PR
The ACC pulse output is stopped (S210), and the control ends.

As described above, in this embodiment, the charging high voltage output means outputs only the AC component of the charging high voltage output at the time of detecting the presence or absence of the cartridge. And the accuracy of cartridge detection can be improved.

Embodiment 3 Next, a third embodiment of the present invention will be described with reference to FIGS.
This will be described below. The circuit configuration of the present embodiment is the same as that of the conventional example shown in FIG. 3, and the control of the AC component output and the DC component output of the charging high voltage is different.

FIG. 5 is a flowchart showing the charging high voltage output and the cartridge presence / absence detection control in the electrophotographic initializing operation after the apparatus is turned on, and FIG. 6 is a timing chart at that time. The operation will be described below with reference to the flowchart of FIG.

First, "H" is output to the PRDCC in order to set the DC component of the charging high voltage to 0 V (S221). Then, the frequency 520 is output to PRACC to output the AC component.
A pulse of Hz is output (S222). At this point, a sine wave of about 2 kVpp is output as a high voltage output for charging, and a voltage corresponding to the charging current is CRGSNS.
Generated as a signal.

Here, since the DC component is not superimposed when the charge rises, no overshoot of the CRGSNS signal which occurs due to the current flowing into the transistor 534 does not occur.

The frequency of the AC component is set to 4
Since the frequency is higher than that at 70 Hz, the charging current becomes larger, and the level of the CRGSNS signal becomes higher than at the normal time.

Subsequently, the voltage level of the CRGSNS signal is sampled for a predetermined time (S223, S224). Thereafter, the average value of the sampling location is calculated (S225), and it is determined whether the average value exceeds 1.2V (S226). Since the level of the CRGSNS signal is also higher than usual, the slice level of the presence or absence of the cartridge is increased to secure a noise margin.

If the average value exceeds 1.2 V, it is determined that a cartridge is present, and a pulse having a normal frequency of 470 Hz is output to PRACC (S227).
PWM output is performed to the DDC (S228).

At this point, the DC component V
The dc is superimposed, and normal electrophotographic initials are started. After the required initial rotation time has elapsed (S229), "H" is output to PRDCC (S23).
0), and stops the pulse output of PRACC (S23).
1) The charging high voltage is set to 0 V, and the control is terminated.

On the other hand, if the average value of CRGSNS is 1.2 V or less in S226, it is determined that there is no cartridge, and the fact that there is no cartridge is notified to the outside (S23).
2) Output “H” to PRDCC (S230),
The ACC pulse output is stopped (S231), and the control ends.

As described above, in the present embodiment, by changing the frequency of the AC component of the charging high-voltage output between normal image formation and detection of the presence or absence of the cartridge, the charging current at the time of detection of the presence or absence of the cartridge is increased. The S / N ratio for detecting the presence or absence of a cartridge can be improved, the noise margin can be increased, and the accuracy of detection of the presence or absence of a cartridge can be improved.

Embodiment 4 Next, a fourth embodiment of the present invention will be described with reference to FIGS. FIG. 9 shows a circuit configuration of this embodiment.

The difference between the circuit configuration of this embodiment and the circuit configuration of the conventional example shown in FIG.
D / A that outputs an analog value of 0 V to 24 V based on 8-bit data (PRA0 to PRA7) output from 0
That the circuit 201 is included. The output of the D / A circuit 201 is connected to a resistor 503, whereby the voltage of the PRACC signal after the level shift is variable, and further, the charging voltage Vpp is variable.

In this embodiment, when the voltage after the level shift is 20 V, the output of the charging high voltage is about 2 k
The circuit constant is determined so as to be Vpp. Furthermore, the output timing control of the AC component output and the DC component output is different from the conventional example.

FIG. 8 is a flowchart showing the charging high voltage output and the cartridge presence / absence detection control in the electrophotographic initializing operation after the apparatus is turned on, and FIG. 9 is a timing chart at that time. The operation will be described below with reference to the flowchart of FIG.

First, "H" is output to PRDCC in order to set the DC component of the charging high voltage to 0 V (S241). Then, in order to output the AC component, the frequency 470 is output to PRACC.
Hz pulse is output by setting the voltage after level shift with the signals PRA0 to PRA7 to be 24 Vpp (S
242).

At this point, the high voltage output of charging is about 2.4.
A sine wave of kVpp is output, and a voltage corresponding to the charging current is generated as a CRGSNS signal.

Here, since the DC component is not superimposed when the charge rises, no overshoot of the CRGSNS signal caused by the current flowing into the transistor 534 does not occur.

Further, since the frequency of the AC component is higher than that of about 2 kV in the normal state described later, the charging current is increased, and the level of the CRGSNS signal is also higher than in the normal state. Subsequently, the voltage level of the CRGSNS signal is sampled for a predetermined time (S243, S244).

Thereafter, the average value of the sampling values is calculated (S245), and whether the average value exceeds 1.2V is determined.
It is determined whether or not it is (S246). Since the level of the CRGSNS signal is also higher than usual, the slice level of the presence or absence of the cartridge is increased to secure a noise margin.

If the average value exceeds 1.2 V, it is determined that the cartridge is present, and the PRACC pulse is output from the signals PRA0 to PRA7 and the voltage after the level shift is set to 20.
Vpp and output (S247).
The PWM output is performed to the DCC (S248).
The DC voltage Vd is converted into a sine wave of about 2 kVpp for the charging high voltage output.
c is superimposed, and normal electrophotographic initials are started. When the required initial rotation time has elapsed (S249), "H" is output to PRDCC (S25).
0), the pulse output of PRACC is stopped (S251),
The charging high voltage is set to 0 V, and the control ends.

On the other hand, if the average value of CRGSNS is equal to or less than 1.2 V in S246, it is determined that there is no cartridge, and the fact is notified outside (S252), and the PRDCCC is notified.
Is output (S250), the PRACC pulse output is stopped (S251), and the control is terminated.

As described above, in this embodiment, the charging high-voltage output means changes the voltage value of the AC component of the charging high-voltage output between normal image formation and cartridge detection, thereby detecting the presence or absence of the cartridge. By changing the voltage value of the AC component of the charging high-voltage output between times, the charging current for detecting the presence or absence of the cartridge is increased, and the S / N for detecting the presence or absence of the cartridge is increased.
The ratio can be improved, the noise margin can be increased, and the accuracy of cartridge detection can be improved.

Embodiment 5 Next, a fifth embodiment of the present invention will be described with reference to FIGS.
This will be described with reference to FIG.

The engine controller 600 has a pulse output terminal PRACC and an A / D converter input terminal CRG.
It has three terminals of SNS terminal and TEMP terminal for temperature information.

The in-machine temperature detecting means 301 includes a thermistor 3
02 and the resistor 303 are connected, the side of the resistor 303 not connected to the thermistor 302 is connected to Vcc, and the side of the thermistor 302 not connected to the resistor 303 is connected to GND. Vcc is the resistance 303 and the thermistor 30
2 and the TEMP of the engine controller 600
Connected to terminal.

Since the resistance value of the thermistor 302 differs depending on the temperature, the engine controller 600 can detect the temperature by referring to the voltage input to the TEMP terminal. The voltage / temperature conversion table is stored in the engine controller 600 in advance.

On the other hand, when the engine controller 600
When a predetermined pulse is output to the ACC terminal, a high charging voltage is generated at the terminal 304 as in the above-described embodiment.

The image forming apparatus according to the present embodiment includes a charge roller 700, a developing sleeve 400, a photosensitive drum 100, and a toner cartridge 500 filled with toner (not shown) as shown in FIG. It is provided as a detachable part from.

The control when the engine controller 600 detects the presence or absence of the cartridge 500 will be described with reference to FIG.

First, when the cartridge detection sequence is started, the engine controller 600 outputs a pulse to the PRACC terminal to generate a charging high voltage (S30).
1). At this time, when the toner cartridge 500 is set in the main body, a capacitance component exists between the high voltage terminal 304 and the GND terminal 305 in FIG. Flows.

Current-voltage conversion by the capacitor 519,
Rectified by the resistor 520 and the diode 521, and the operational amplifier 522, the resistor 523, and the capacitor 524
Is charged by the engine controller 6
00 is input to the CRGSNS terminal (S301).

Next, the engine controller 600 reads and stores the temperature information input to the TEMP terminal from the temperature detecting means 301 and the voltage applied to the CRGSNS terminal (S302), and stops the charging output (S30).
3).

Next, when it is determined that the temperature inputted to the TEMP terminal is higher than a predetermined temperature, for example, 5 ° C. or higher (S304), the detected voltage and a predetermined first threshold value are determined. For example, it is compared with 0.7 V (S307). If the detected voltage is high, it is determined that a cartridge is present (S306), and if it is low, it is determined that there is no cartridge (S308).

On the other hand, if it is determined that the temperature information is lower than 5 ° C., the detected voltage is compared with a second threshold lower than a predetermined first threshold, for example, 0.2 V. (S305) If the detection voltage is high, it is determined that there is a cartridge (S306), and if it is low, it is determined that there is no cartridge (S308).

As described above, in this embodiment, the cartridge presence / absence detection means changes the threshold value of the charging current for judging the presence / absence of the cartridge based on the information of the in-machine temperature detection means. Can improve the accuracy of cartridge detection.

Embodiment 6 Next, a sixth embodiment of the present invention will be described with reference to FIGS.

The engine controller 600 has a pulse output terminal PRACC and an A / D converter input terminal CRGS.
It is provided with three terminals, ie, a TEMP terminal for NS and temperature information, and a timer 306.

As described in the fifth embodiment, the temperature detecting means 301 is connected to the thermistor 302 and the resistor 303, and the side of the resistor 303 not connected to the thermistor 302 is connected to Vcc. The side not connected is connected to the TEMP terminal. Vcc
Is divided by the resistor 303 and the thermistor 302 and connected to the TEMP terminal of the engine controller 600.

Since the resistance of the thermistor 302 varies depending on the temperature, the engine controller 600 can detect the temperature by referring to the voltage input to the TEMP terminal.

The voltage / temperature conversion table is stored in the engine controller 600 in advance.

In this embodiment, the temperature detecting means 301 is provided inside a heating means 910 for generating heat necessary for fixing a toner image carried on paper P as a recording medium, and is provided with an engine controller. When the temperature control unit 600 controls the temperature of the heating unit 910,
Using the information of

When the engine controller 600 has PRACC
When a predetermined pulse is output to the terminal, a high voltage is generated at the terminal 304 as in the fifth embodiment. The image forming apparatus according to the present embodiment includes a charge roller 401, a developing sleeve 400, and a photosensitive drum 10 as shown in FIG.
0, and a toner cartridge 500 filled with toner (not shown) is provided as a detachable component from the main body.

The control for detecting the presence or absence of the cartridge 500 by the engine controller 600 will be described with reference to FIG.

First, when the cartridge detection sequence is started, the engine controller 600 outputs a pulse to the PRACC terminal to generate a charging high voltage (S31).
0). At this time, when the toner cartridge 500 is set in the main body, a capacitance component exists between the high voltage terminal 304 and the GND terminal 305 in FIG. Flows.

The current-voltage conversion by the capacitor 519,
Rectified by the resistor 520 and the diode 521, and the operational amplifier 522, the resistor 523, and the capacitor 524
Is charged by the engine controller 6
00 is input to the CRGSNS terminal (S310).

Next, the engine controller 600 reads and stores the temperature information input to the TEMP terminal from the temperature detecting means 301 and the voltage applied to the CRGSNS terminal (S311), and stops the charging output (S31).
2). If the temperature information from the TEMP terminal is lower than a predetermined temperature, for example, 5 ° C. (S31)
3) The time counting means 306 is reset to 0, that is, the timer is started (S314), and the detection voltage inputted to the CRGSNS terminal is set to a first threshold value,
For example, the voltage is compared with 0.2 V (S315). If the detection voltage is low, it is determined that there is no cartridge (S319), and if the detection voltage is high, it is determined that there is a cartridge (S316).

On the other hand, when the temperature information input to the TEMP terminal is 5 ° C. or more, the time measured by the timer 301 is compared with a predetermined time, for example, 30 seconds (S317). If the measured time is a small value, the detected voltage is compared with 0.2 V (S315), and if the detected voltage is low, it is determined that there is no cartridge (S31).
9) If it is higher, it is determined that a cartridge is present (S31)
6).

If the value of the timer 301 is 30 seconds or more, the detected voltage is compared with a second threshold value, for example, 0.7 V, which is larger than the predetermined first threshold value (S31).
8) If the detection voltage is low, it is determined that there is no cartridge (S319), and if it is high, it is determined that there is a cartridge (S316). The timer 306 is initialized to a value of 30 seconds or more immediately after the power of the apparatus is turned on.

As described above, in this embodiment, when the apparatus is turned on, the fixing temperature detecting means is also used as the in-machine temperature detecting means, and based on the information of the fixing temperature detecting means, the cartridge presence detecting means determines whether or not the cartridge is present. By changing the threshold value of the charging current to be determined and maintaining the changed state for a predetermined time, the accuracy of detecting the presence or absence of the cartridge at the environmental temperature can be improved at a lower cost.

Seventh Embodiment Next, a seventh embodiment of the present invention will be described mainly with reference to FIG. The circuit configuration of this embodiment is the same as that of FIG.

First, when the cartridge presence / absence detection sequence is started when the power is turned on or when the door is opened, the engine controller 600 reads the temperature information from the temperature detection means 301 (S401). Next, when it is determined that the read temperature information is equal to or higher than a predetermined temperature, that is, 5 ° C. (S402), the engine controller 6
00 outputs a pulse to the PRACC terminal to generate a high charging voltage (S404).

At this time, when the toner cartridge 500 is set in the main body, the high voltage terminals 304 and G in FIG.
There will be a capacitance component between the ND terminals 305,
An alternating current flows between the high voltage terminal 304 and the GND terminal 305. Current-voltage conversion by the capacitor 519, resistance 5
The rectifier 20 is rectified by the diode 521, is peak-charged by the operational amplifier 522, the resistor 523, and the capacitor 524, and is input to the CRGSNS terminal of the engine controller 600.

Next, the detected voltage is read (S405).
After the charging output is stopped (S406), the detected voltage is compared with a predetermined value, for example, 0.7 V (S4).
07) If the detection voltage is high, it is determined that there is a cartridge (S409), and if it is low, it is determined that there is no cartridge (S408).

On the other hand, if it is determined in S402 that the temperature information is lower than 5 ° C., the heat is supplied to the heat fixing device 900 for a predetermined time to increase the temperature in the device (S403). Then,
The engine controller 600 outputs a pulse to the PRACC terminal to generate a charging high voltage (S404).

At this time, as described above, when the toner cartridge 500 is set in the main body, a capacitance component exists between the high voltage terminal 304 and the GND terminal 305 in FIG. An alternating current flows between the terminals 305. Current-voltage conversion by capacitor 519, rectification by resistor 520 and diode 521, operational amplifier 522, resistor 523, capacitor 524
Is charged by the engine controller 6
00 is input to the CRGSNS terminal. Next, the detected voltage is compared with a predetermined value, for example, 0.7 V (S407). If the detected voltage is high, it is determined that a cartridge is present (S409), and if it is low, it is determined that there is no cartridge (S408). .

As described above, in this embodiment, when the power of the apparatus is turned on, the fixing temperature detecting means is also used as the in-machine temperature detecting means, and the fixing after power-on is performed based on the information of the fixing temperature detecting means. The detection time can be set higher by changing the conduction time to the heating element of the device and raising the temperature inside the machine when the temperature inside the machine is low, and then performing cartridge detection, thereby increasing the noise margin. In addition, the possibility of erroneous detection is eliminated, and the accuracy of detecting the presence or absence of the cartridge at the environmental temperature can be improved.

[0096]

As is apparent from the above description, according to the present invention, the presence or absence of the cartridge is detected after a lapse of a predetermined time from the charging high voltage output timing by the charging high voltage detecting means, or the AC component of the charging high voltage output. By outputting only the information, it is possible to accurately detect the presence or absence of the cartridge.

The charging high voltage output means changes the frequency or voltage value of the AC component of the charging high voltage output during normal image formation and cartridge presence detection, thereby increasing the charging current at the time of cartridge presence detection. The presence / absence S / N ratio is improved, the noise margin is increased, and the presence / absence of the cartridge can be detected accurately.

Further, by changing the threshold value of the charging current, the cartridge presence / absence detection means determines the presence / absence of the cartridge based on the information of the in-machine temperature detection means.
Regardless of a change in the environment, the presence or absence of the cartridge can be accurately detected.

Further, when the power of the apparatus is turned on, the same effect as described above can be obtained by changing the power supply time to the heating element after the power is turned on based on the information of the fixing temperature detecting means and step.

[Brief description of the drawings]

FIG. 1 is a flowchart illustrating control of cartridge presence detection in a first embodiment.

FIG. 2 is a timing chart of the control shown in FIG.

FIG. 3 is a flowchart showing control of cartridge presence / absence detection in a second embodiment.

FIG. 4 is a timing chart of the control shown in FIG.

FIG. 5 is a flowchart showing control of cartridge presence detection in the third embodiment.

FIG. 6 is a timing chart of the control shown in FIG. 5;

FIG. 7 is a circuit diagram according to a fourth embodiment.

FIG. 8 is a flowchart illustrating control of cartridge presence / absence detection in a fourth embodiment.

FIG. 9 is a timing chart of the control in FIG. 8;

FIG. 10 is a circuit diagram according to a fifth embodiment.

FIG. 11 is a flowchart showing control of cartridge presence detection in the fifth embodiment.

FIG. 12 is a circuit diagram according to a sixth embodiment.

FIG. 13 is a flowchart showing control of cartridge presence / absence detection in a sixth embodiment.

FIG. 14 is a circuit diagram according to a seventh embodiment.

FIG. 15 is a schematic configuration diagram illustrating an example of a conventional image forming apparatus in which the present invention is embodied.

16 is a circuit diagram according to the image forming apparatus of FIG.

FIG. 17 is a flowchart illustrating control of conventional cartridge presence / absence detection according to the image forming apparatus of FIG. 15;

FIG. 18 is a timing chart according to the control of FIG.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 photosensitive drum (electrophotographic photosensitive member) 200 charge generation circuit 500 process cartridge 600 engine controller 700 charge roller (charging means) 900 heat fixing device 910 heating element (heater)

Continued on the front page (72) Inventor Yuki Kato 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc.

Claims (7)

[Claims] At least a process cartridge including at least an electrophotographic photosensitive member and a charging unit that contacts and charges the electrophotographic photosensitive member is detachably mounted on an image forming apparatus main body. Charging high voltage output means for applying a high voltage with a DC component superimposed thereon, charging current detecting means for detecting a charging current flowing through the charging means, and whether or not the process cartridge is mounted based on information of the charging current detecting means. An image forming apparatus comprising: a cartridge presence / absence detecting means for detecting the presence / absence of a cartridge, wherein the presence / absence of a cartridge is detected after a lapse of a predetermined time from the charging high voltage output timing by the charging high voltage output means. 2. A process cartridge including at least an electrophotographic photoreceptor and a charging unit for charging the electrophotographic photoreceptor by contacting the electrophotographic photoreceptor. The process cartridge is detachably mounted on a main body of the image forming apparatus. Charging high voltage output means for applying a high voltage with a DC component superimposed thereon, charging current detecting means for detecting a charging current flowing through the charging means, and whether or not the process cartridge is mounted based on information of the charging current detecting means. An image forming apparatus comprising: a cartridge presence / absence detection means for detecting; wherein the charging high voltage output means outputs only an AC component of the charging high voltage output when detecting the presence / absence of a cartridge. 3. A process cartridge including at least an electrophotographic photoreceptor and a charging unit for charging the electrophotographic photoreceptor by contacting the electrophotographic photoreceptor. The process cartridge is detachably mounted on the main body of the image forming apparatus. Charging high voltage output means for applying a high voltage with a DC component superimposed thereon, charging current detecting means for detecting a charging current flowing through the charging means, and whether or not the process cartridge is mounted based on information of the charging current detecting means. An image forming apparatus having a cartridge presence / absence detection means for detecting, wherein the charging high voltage output means changes the frequency of the AC component of the charging high voltage output between normal image formation and cartridge presence / absence detection. Image forming device. 4. A process cartridge including at least an electrophotographic photosensitive member and a charging means for charging the electrophotographic photosensitive member while being in contact with the electrophotographic photosensitive member, is detachably mounted on the main body of the image forming apparatus. Charging high voltage output means for applying a high voltage with a DC component superimposed thereon, charging current detecting means for detecting a charging current flowing through the charging means, and whether or not the process cartridge is mounted based on information of the charging current detecting means. An image forming apparatus having a cartridge presence / absence detection means for detecting, wherein the charging high voltage output means changes the voltage of the AC component of the charging high voltage output between normal image formation and cartridge presence / absence detection. Image forming device. 5. A process cartridge including at least an electrophotographic photoreceptor and a charging unit that contacts and charges the electrophotographic photoreceptor, is removably mounted on an image forming apparatus main body. Charging high voltage output means for applying a high voltage with a DC component superimposed thereon, charging current detecting means for detecting a charging current flowing through the charging means, and whether or not the process cartridge is mounted based on information of the charging current detecting means. An image forming apparatus comprising: a cartridge presence / absence detection means for detecting a temperature inside the image forming apparatus main body; and an internal temperature detection means for detecting a temperature inside the image forming apparatus main body. An image forming apparatus that changes a threshold value of a charging current. 6. A heat fixing means for fixing a toner image on recording paper by heat generation of a heat generating element which generates heat by energization, and a fixing temperature detecting means provided in the heat fixing means and detecting a temperature of the heat generating element. When the power of the apparatus is turned on, the fixing temperature detecting means also serves as the in-machine temperature detecting means,
6. The method according to claim 5, wherein the detection unit determines the presence or absence of the cartridge based on the information of the fixing temperature detection unit, and changes a threshold value of the charging current, and holds the changed state for a predetermined time. Image forming apparatus. 7. A process cartridge including at least an electrophotographic photosensitive member and a charging unit for charging the electrophotographic photosensitive member by contacting the electrophotographic photosensitive member is detachably mounted on the image forming apparatus main body. Charging high voltage output means for applying a high voltage with a DC component superimposed thereon, charging current detecting means for detecting a charging current flowing through the charging means, and whether or not the process cartridge is mounted based on information of the charging current detecting means. Cartridge detecting means for detecting, a heat fixing means for fixing a toner image on a recording medium by heat generation of a heat generating element which generates heat by energization, and fixing provided in the heat fixing means and detecting a temperature of the heat generating element An image forming apparatus comprising: a temperature detecting unit configured to detect a temperature in an image forming apparatus main body when the apparatus power is turned on. Combined with a temperature detecting means, based on information of the fixing temperature detecting means, the image forming apparatus characterized by varying the energization time of the heating element after power.