JPH1039672A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device having good fixing quality by correcting the fixing control temperature during stand-by according to the environmental temperature. SOLUTION: The fixing control temperature during operation is corrected according to the environmental temperature as shown by the operation control temperature straight line Ta. A timer means is provided to detect the environmental temperature in sequence during stand-by, and the fixing control temperature during stand-by is corrected according to the environmental temperature as shown by the stand-by control temperature straight line T wait. Even if the environmental temperature is changed during stand-by, the difference between the stand-by control temperature and operation control temperature is not increased, the fixing roller temperature can be quickly set to the desired control temperature after a job start, and an image having a good fixing property can be obtained starting from the first copy.

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 such as a copier, a printer, a facsimile, and more particularly, to an image forming apparatus having a heat fixing device.

[0002]

2. Description of the Related Art In an image forming apparatus such as a copying machine, a printer, and a facsimile, a heat fixing device for fixing an unfixed image formed by toner or the like on a recording medium (transfer paper) is well known. In an image forming apparatus provided with a conventional heat fixing device, the fixing property (fixing quality) is determined by the temperature of the fixing roller, but to a certain extent is affected by the environmental temperature, especially the transfer paper temperature.

In view of the above, many techniques have been proposed for changing the control temperature during operation of the fixing roller in accordance with the environmental temperature or the transfer paper temperature. Similarly, it has been proposed to change the standby control temperature of the fixing roller according to the environmental temperature or the transfer sheet temperature. For example, 2-11
Japanese Patent Application Publication No. 7563 discloses a heat control apparatus including a maintenance temperature setting means for setting a maintenance temperature in accordance with an output of an environmental temperature detection means, and a fixing temperature holding control means for maintaining the temperature of the fixing device at the temperature set by the maintenance temperature setting means. A fixing device is disclosed. Japanese Patent Application Laid-Open No. 4-32884 discloses a fixing device in which information on a detected fixing roller temperature and an ambient temperature is taken in, and the preheating temperature of the fixing roller is set and controlled with reference to the ambient temperature. ing.

[0004]

However, in the conventional image forming apparatus, when the apparatus is started (when the power is turned on), during the execution of the job, or at the environmental temperature at the end of the job, the standby temperature (the standby control of the fixing roller). Temperature), the standby control temperature was constant even if the ambient temperature fluctuated during standby. Therefore, if the ambient temperature fluctuates during standby, for example, if the environmental temperature drops during standby, and if the full color mode that requires a higher control temperature than normal is selected, the It takes a long time to raise the fixing roller temperature to a predetermined control temperature (for example, a control temperature corrected from a temperature corresponding to a mono color to a temperature corresponding to a full color).
There has been a problem that sufficient fixability may not be ensured at the time of forming the second image.

The present invention solves the above-mentioned problem in an image forming apparatus having a conventional heat fixing device, and quickly changes the temperature of the fixing device to a desired set temperature (control temperature) even when the environmental temperature fluctuates during standby. It is an object of the present invention to provide an image forming apparatus capable of performing temperature fixing and good fixing.

[0006]

According to the present invention, there is provided an image forming apparatus, comprising: a fixing unit having a fixing roller and a pressure roller;
An image forming apparatus having a control unit for correcting the control temperature of the fixing roller based on a detection result of the environmental temperature detecting unit, further comprising a timer unit for starting counting in association with the operation of the apparatus, and The problem is solved by successively correcting the roller control temperature at predetermined time intervals by the timer means.

According to another aspect of the present invention, there is provided an image forming apparatus comprising: a fixing unit having a fixing roller and a pressure roller;
An image forming apparatus having a control unit for correcting a control temperature of the fixing roller based on a detection result of the environmental temperature detecting unit, the image forming apparatus having a real-time clock for counting irrespective of the operation of the fixing roller; It is proposed to sequentially correct the control temperature at predetermined time intervals by the real-time clock.

Further, according to the present invention, in order to solve the above-mentioned problems, the standby fixing roller control temperature to be corrected is such that the recording medium reaches the fixing roller at least when a start key is pressed for starting an image forming operation. It is proposed that the temperature can be the operating control temperature corrected according to the environmental temperature before the operation.

Further, according to the present invention, in order to solve the above-mentioned problem, two or more control temperatures are set as the fixing roller control temperature during operation, and the standby fixing roller control temperature to be corrected is set to an environmental temperature. It is proposed that the temperature be between the two or more control temperatures corrected in accordance with

Further, in order to solve the above-mentioned problems, the present invention corrects the fixing roller control temperature during the image forming operation based on the detection result of the environmental temperature detecting means obtained at the start of the image forming operation. Suggest.

Further, according to the present invention, in order to solve the above-mentioned problem, during a predetermined time after the end of the image forming operation, a standby time is set based on the detection result of the environmental temperature detecting means obtained at the start of the image forming operation. It is proposed to correct the fusing roller control temperature.

In order to solve the above-mentioned problems, the present invention further comprises a pressure roller heating means and a pressure roller surface temperature detecting means for detecting a surface temperature of the pressure roller. It is proposed to control the roller temperature to a predetermined control temperature and to correct the pressure roller control temperature based on the detection result of the environmental temperature detecting means.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a basic configuration of a color copying machine according to an embodiment of the present invention. The copying machine shown in FIG. 1 includes a printer unit 1 for forming a color image by an electrophotographic process, and a scanner unit 2 for reading a document image and transferring image data to the printer unit 1.
A bank 3 serving as a paper feeder for supplying transfer paper to the printer unit 1; a DF4 serving as a document feeder for feeding a document to the scanner unit 2; The sorter 5 is a post-processing device for sorting paper. A general description of this copier will follow after a description relating to the present invention. The overall configuration of the copying machine is common to each embodiment of the present invention described later.

FIG. 2 is a block diagram showing a main part of the printer unit 1 in the copying machine shown in FIG. Printer unit 1
Are the developing revolver unit 2 around the photosensitive drum 10
0, an intermediate transfer belt 30, a writing unit 40, a fixing unit 52, and the like. Here, only the fixing unit 52 will be described.

In FIG. 2, the fixing unit 52 has a fixing roller 53 and a pressure roller 54. In this embodiment, both the fixing roller 53 and the pressure roller 54 have a built-in heater (the heater is not shown). In this embodiment, since the unfixed toner image is present on the upper surface of the transfer passed between the rollers, the heater capacity of the upper fixing roller is set to be larger than that of the lower pressure roller heater. Incidentally, the reason why the heater is provided in the pressure roller is mainly to prevent the heat of the fixing roller from being taken away when the two rollers are brought into contact with each other and rotated. In addition, an upper thermistor 55 and a lower thermistor 56 are provided near each of the rollers 53 and 54, and detect the temperature of each roller. The heater is controlled so that each of the rollers 53 and 54 has a predetermined temperature based on the temperature detected by each thermistor. The heater control mode includes phase control or on / off control,
In the present embodiment, both can be switched. Further, an environmental temperature detection sensor (not shown) is provided at an appropriate position in the apparatus that is not easily affected by heat generated by the fixing unit.

FIG. 3 is a circuit diagram showing a configuration of a heater control circuit. Here, only one of the heaters provided on both the fixing roller and the pressure roller and its control circuit are shown, but the other heater and its control circuit are the same. Electric power is supplied to the heater 57 from a power supply 60 via a triac 58. The triac 58 is activated by a heater control signal from the CPU described later.
Conduction is performed by a trigger pulse output when an SR (solid state relay) 59 is turned on, and power from a power supply 60 is supplied to a heater 57. In the case of the phase control mode, C
The PU outputs a PWM (pulse width modulation) heater control signal. In the case of the on / off control mode, the output is not PWM output, but the output can be switched by the CPU.

As a setting example of the fixing control temperature, there are one case where the set temperature during operation (during the fixing operation) and two cases where the set temperature is set. However, how many set temperatures are set during operation is not directly related to the gist of the present invention, and one set temperature and two set temperatures will be collectively described here as embodiments. The set temperature refers to a control temperature set at normal temperature (in the present embodiment, the ambient temperature is set to 20 ° C.). When the operating set temperature is one embodiment,
Operating set temperature: 150 ° C. On the other hand, when the operating set temperature is two embodiments, different operating control temperatures are set in the full-color mode and the mono-color (monochromatic) mode,
The set temperature in the full color mode is 160 ° C., and the set temperature in the mono color mode is 140 ° C. The set temperature of the pressure roller is set to 150 ° C. in any of the embodiments.
In both embodiments, the fixing roller control temperature during operation is corrected according to the environmental temperature. Therefore, when the environmental temperature is 20
The control temperature set at the time of ° C. is called a set temperature, and a case where the temperature is corrected by a change in the environmental temperature is called a control temperature.

By the way, in the conventional image forming apparatus, the standby control temperature is set based on the environmental temperature at startup, during job execution, or at the end of the job, so that the standby control temperature is constant. Was. For this reason, when there is an environmental change (temperature change) during standby, it may be difficult to shift the fixing roller temperature to the control temperature in each mode after the job starts. For example, when the environmental temperature decreases during standby, the fixing roller temperature does not increase to a predetermined control temperature until the transfer paper reaches the fixing device, and a fixing failure occurs on the first or second sheet. Sometimes. Therefore, in the present invention, the standby control temperature is sequentially corrected in accordance with the environmental temperature, so that the fixing roller temperature becomes a desired control temperature immediately after the start of the job so that good fixing performance can be obtained from the first sheet. Of images. Hereinafter, a process of successively correcting the standby control temperature in the present embodiment will be described with reference to the drawings.

In FIG. 4, it is determined whether or not copying has been started (S1). If the copying operation has not been started (if standby), it is determined whether or not the standby control temperature correction timing has come. (S2). The correction timing of the control temperature is determined by a correction processing management timer or a real-time clock described later. If it is not the correction timing, this processing ends. When the correction timing comes, a correction fixed flag indicating fixing of the standby control temperature: f
It is determined whether or not g static is on (S3). If this flag is not on, an environmental temperature: Tatm, which is an input from a temperature sensor (not shown), is fetched (S4), and based on the environmental temperature: Tatm. Target temperature: T is set (S5). Next, the fixing roller temperature: Troll is taken in by the thermistor 55 (see FIG. 3) (S6). Then, the acquired fixing roller temperature: Troll is compared with the set target temperature: T (S7). If the fixing roller temperature is equal to or higher than the target temperature, the fixing heater is turned off (S8). If it is lower, the fixing heater is turned on (S9). If the correction fixed flag is set in S3, the process proceeds to S6, and the processing at and after S6 is performed while the target temperature set at that time is held.

On the other hand, if the copy operation has been started in S1, a correction fixed flag fg indicating that the control temperature during standby is fixed.
The static state is set (S10), and the processing from S6 is performed. As described above, the standby control temperature is sequentially corrected according to the environmental temperature acquired at predetermined time intervals (for example, every 10 seconds) by the correction processing management timer or the real-time clock, so that the environmental temperature fluctuates during the standby. Even in this case, the fixing roller temperature can be set to a desired control temperature immediately after the start of the job, and an image having good fixability can be obtained from the first copy.

FIG. 5 is a flowchart showing a correction timing determination process using the above-described correction process management timer. When this subroutine is called, first, a correction process management timer: tcorrect is reset and started (S1). That is, the correction process management timer is a timer that starts counting in association with the operation of the apparatus. And
The operation state of the apparatus is determined (S2). If the copying operation is not being performed (standby state), the presence or absence of an abnormality is determined (S3). If there is no abnormality, the count time of the correction processing management timer is longer than a predetermined time: Time1. It is determined whether or not (S4).
If the count time of this timer is longer than a predetermined time, it is determined whether or not the correction fixed flag: fg static is set (S5). If the flag is set, the flag is turned off (S6), and the correction processing time is set. It is stopped (S7). S4
If the correction processing management timer has not reached the predetermined time in step S5, and if the flag has not been set in step S5, the process returns.
If there is an abnormality in S3, the process proceeds to S5 without looking at the correction process management timer.

On the other hand, if the copying operation is being performed in S2, it is determined whether or not the job has been completed (S8). If the job has not been completed, the process proceeds to S5, and if the job has been completed, the process returns.
Note that the correction timing may be determined by a real-time clock irrespective of the operation of the apparatus by mounting a calendar IC or the like.

FIG. 6 is a graph showing a control temperature straight line of the fixing roller according to the environmental temperature in the present embodiment.
(A) shows the case where the operating set temperature is one embodiment,
(B) shows the case where the operating temperature is set to two in each embodiment. As described above, in the present embodiment, the operating control temperature is corrected according to the environmental temperature, and as shown in the graphs, the maximum correction amount ΔT (20 deg) and the operating setting In the case of two temperatures, the maximum correction amount ΔTful (16deg) in the full color mode,
The maximum correction amount ΔTmono (12 deg) in the mono-color mode is corrected.

As shown in FIG. 6A, when the operating temperature is set to one embodiment, the operating temperature is set to 150 ° C. when the environmental temperature is 20 ° C. Then, as indicated by the operating control temperature straight line: Ta, the environmental temperature 10
The temperature is corrected to fall rightward between 30 ° C and 30 ° C. At this time, the standby control temperature is represented by a standby control temperature straight line: Twa
It is corrected as shown by it, so that the difference between the standby control temperature and the operating control temperature is small at any environmental temperature, and the transition time from the standby control temperature to the operating control temperature does not increase. Even when the ambient temperature fluctuates during standby, the temperature of the fixing roller can be quickly set to the operation control temperature after the start of the job. In addition, when the conventional control temperature during standby is constant, when the temperature decreases or rises around the environmental temperature 20 ° C., the difference from the operating control temperature increases,
The time required until the fixing roller temperature is shifted to the operation control temperature after the start of the job increases.

As shown in FIG. 6 (b), when the operating temperature is set to two, when the environmental temperature is 20 ° C.
The set temperature in the full color mode operation is set to 160 ° C., and the set temperature in the mono color mode operation is set to 140 ° C. Then, as shown as an operating control temperature straight line: Tfull or Tmono, the temperature is corrected so as to fall rightward between the ambient temperature of 10 ° C. and 30 ° C. At this time, the standby control temperature is corrected as indicated by the standby control temperature straight line: Twait. Therefore, the difference between the standby control temperature and the operating control temperature greatly increases at any environmental temperature. Therefore, the transition time from the standby control temperature to the operating control temperature does not become long, and even when the environmental temperature fluctuates during the standby, the fixing roller temperature can be quickly set to the operating control temperature after the job is started. When the conventional control temperature during standby is constant, depending on the setting method, for example, when the control temperature during standby is fixed at 150 ° C., when the temperature rises during standby, and when the temperature decreases In the mono-color mode, the difference between the standby control temperature and the operating control temperature is rather small, but conversely, in the full-color mode when the temperature drops during standby and in the mono-color mode when the temperature rises, the standby control temperature The difference between the control temperature during operation and the control temperature during operation is extremely widened, and the occurrence of defective fixing is inevitable. During standby when you do not know which color mode is selected,
Whatever the color mode is selected, it is important that the temperature of the fixing roller can be quickly shifted to the operation control temperature that does not cause a fixing failure. It should be noted that the numerical values of the temperature shown in the above description are all examples, and are not limited to the numerical values shown in the present embodiment.

By the way, if the fixing roller control temperature during standby is set to be much lower than the operating control temperature, the fixing roller is turned off when a high operating temperature (control temperature) is required after the job starts. It may be difficult to raise to that temperature. The same applies to an apparatus having a standby set temperature (a control temperature set based on a certain environmental temperature, 20 ° C. in this embodiment).

In the case where the operating temperature of the fixing roller is one embodiment, the standby control temperature which is corrected in accordance with the environmental temperature is at least transferred after the start key is pressed and the image forming operation is started. This is a temperature at which the operating control temperature (operating control temperature corrected in accordance with the environmental temperature) can be reached before the paper reaches the fixing roller.

In this embodiment, for example, it is assumed that the fixing roller temperature can be raised by 5 ° C. after the start of the job until the transfer paper reaches the fixing roller. In that case, the standby control temperature of the fixing roller is (operating control temperature) ≧
(Control temperature during standby) ≧ {(Control temperature during operation) −5 ° C.} is sequentially corrected. When the standby set temperature is set, the standby set temperature is
(Control temperature during operation) ≧ (Set temperature during standby) ≧ {(Set temperature during operation) −5 ° C.}.

This will be described with reference to FIG.
The stand-by control temperature is corrected so that the temperature is equal to or lower than the operating control temperature indicated by the straight line Ta and the temperature difference therefrom is within 5 ° C. (deg). In the example shown here, the standby control temperature is corrected so as to be (operating set temperature) −5 ° C. When the standby temperature is set based on the ambient temperature of 20 ° C., 150 ° C. ≧ (standby set temperature) ≧ (150 ° C.−5 ° C.), that is, the standby set temperature between 150 ° C. and 145 ° C. Will be provided.
Therefore, in this embodiment, the standby control temperature is maintained between the operating control temperature line Ta and the standby control temperature line Twait regardless of whether or not the standby set temperature is provided, and the correction is made according to the environmental temperature. With respect to the set operation control temperature, the fixing roller temperature can be reliably set to the operation control temperature before the transfer paper reaches the fixing roller after the job starts, and a high or low temperature is required after the job starts. Even in such a case, a copy having good fixability can be obtained from the first sheet.

Further, in the case where the operating set temperature of the fixing roller is two, when the standby control temperature is corrected in accordance with the environmental temperature, it is set so as to be within a predetermined range of the lower operating control temperature. Even if the standby control temperature is corrected, it may not be possible to cope with a case where a higher control temperature is required after the job is started. For example, even if the standby control temperature is corrected so as to cover the monocolor control temperature corrected according to the environmental temperature, if the full color mode is selected,
In some cases, it may not be possible to increase from the standby control temperature at that time to the full-color control temperature. Therefore, even when a job is started in any mode from the standby state, the fixing roller temperature is sequentially corrected according to the environmental temperature so that the fixing roller temperature can be promptly shifted to the operating control temperature corrected according to the environmental temperature. The standby control temperature is a temperature between two operating control temperatures that are corrected according to the environmental temperature.

In this embodiment, two control temperatures are set as the control temperature of the fixing roller, that is, the control temperature at full color and the control temperature at monocolor. In this case, the standby control temperature is
(Control temperature at full-color) ≧ (control temperature at standby) ≧ (control temperature at mono-color) is sequentially corrected in accordance with the environmental temperature. In addition, although the operating set temperature is set based on the ambient temperature of 20 ° C. for the two control temperatures, when the standby set temperature is also set, the standby set temperature is (full color set temperature) ≧ (standby temperature) (Set temperature in time) ≧ (set temperature in mono color).

This will be described with reference to FIG.
This is to correct the standby control temperature such that the standby control temperature line: Twait is between the full color control temperature line: Tfull and the monocolor control temperature line: Tmono. When the standby set temperature is set based on the environmental temperature of 20 ° C., 150 ° C. ≧ (standby set temperature) ≧ 140
° C, that is, the standby set temperature is set between 150 ° C and 140 ° C. Therefore, in this embodiment, the full-color control temperature straight line: Tfull and the mono-color control temperature straight line: Tmo are set regardless of whether or not the standby set temperature is provided.
The standby control temperature is maintained during no, and regardless of which mode is selected from the standby state, the fixing roller temperature is quickly adjusted after the job starts to the operating control temperature corrected according to the environmental temperature. The temperature can be set to the operation control temperature or a temperature close thereto, and a copy having good fixability can be obtained from the first sheet.

Next, another embodiment of the present invention will be described.

An environmental temperature detecting sensor for detecting the environmental temperature is provided in the printer unit 1 of FIG. 1 and detects the temperature in the apparatus main body. However, after the start of a job (image forming operation), the temperature inside the apparatus may increase, and an accurate environmental temperature may not be detected. Therefore, in the present embodiment, the data of the environmental temperature detection sensor is not used after the start of the job to correct the operation control temperature of the fixing roller.

More specifically, the control temperature during operation after the start of the job is corrected based on the data of the environmental temperature sensor acquired at the start of the job to control the temperature of the fixing roller. Then, even if the output of the environmental temperature sensor changes during a job, the correction based on the output (data) is not performed.

For this reason, it is possible to correct the control temperature during the operation of the fixing roller with accurate environmental temperature data while eliminating the influence of the rise in the temperature inside the apparatus after the start of the job, thereby obtaining a copy image with good fixability. . Note that the correction of the control temperature during standby is the same as in the above embodiment.

By the way, even if the job is completed, the temperature inside the machine is high for a while, and accurate data may not be obtained even if the environmental temperature is detected in this state. Therefore, as yet another embodiment of the present invention, it is proposed that the data of the environmental temperature detection sensor is not used for a predetermined time after the end of a job as data for correcting the fixing roller control temperature during standby. I do.

More specifically, during a certain period of time (for example, 10 minutes) after the end of the job, the control temperature at the time of standby is corrected based on the data of the environmental temperature sensor acquired at the start of the previous job to fix the fixing roller temperature. Control. Even if the output of the environmental temperature sensor changes during the fixed time, the correction based on the output (data) is not performed. Also, even if there is a next job start command during the fixed time, the fixing heater is controlled at the operating control temperature corrected by the environmental temperature sensor data acquired at the time of the previous job start, and the data detected during the job is controlled. Is not corrected.

For this reason, the influence of the temperature rise in the apparatus within a predetermined time after the end of the job is eliminated, and the standby control temperature of the fixing roller is corrected with the accurate environmental temperature data. Images can be obtained.

Next, still another embodiment of the present invention will be described. Generally, in a color image forming apparatus, a heating unit (heater) is also provided in a pressing roller in order to reduce a temperature drop of a fixing roller as much as possible. Further, a means (sensor) for detecting the surface temperature of the pressure roller is provided in order to finely control the temperature of the pressure roller. Therefore, in the present embodiment, the pressure roller can be controlled more precisely during operation and / or standby according to the environmental temperature in the same manner as the fixing roller, so that the temperature of the pressure roller can be more finely controlled. And a good copy image can be obtained. The specific correction of the control temperature is performed in the same manner as in the case of the fixing roller, and the description is omitted.

The following description is of the overall configuration and operation of the copying machine shown in FIG. FIG. 7 is a block diagram showing a control system of the copying machine shown in FIG. The control system of the copying machine mainly includes a printer control unit 100, a scanner control unit 200, a bank control unit 300, a DF control unit 400, a sorter control unit 500, a system control unit 800, and an operation unit control 900.

The printer control unit 100 is a control unit for controlling the electrophotographic process sequence and the recording paper transport process. This control unit is connected to the bank control unit 300 and the sorter control unit 500 by optical fiber serial communication, and performs control according to the image forming timing by a command.

The scanner control unit 200 controls reading of original image data and image processing control. This control unit
The DF controller 400 is connected to the DF controller 400 by optical fiber serial communication, and controls a document supply sequence by a command. In addition, since the printer control unit 100 and the scanner control unit 200 are required to have strict accuracy in the alignment at the time of image superposition and the alignment of the recording paper and the image, an optical fiber is required so that the sequence control can be directly performed. A data bus for transferring image data directly from the scanner control unit 200 to the printer control unit 100 while being connected by serial communication is also provided.

The system control unit 800 controls the entire system of the copying machine, and receives an input from the operation unit control 900 to control the printer control unit 100 and the scanner control unit 20.
It sends image forming conditions to 0, manages and controls the state of the entire apparatus, and controls display and commands. Each control unit is connected by optical fiber serial communication.

FIG. 8 is a block diagram showing the configuration of the printer control unit 100. In this figure, the CPU 10
1 performs calculation and execution of program contents. The control program is stored in the ROM 102. RAM10
Reference numeral 3 stores and saves data as the CPU 101 operates. CPU 101, ROM 102, RAM 103
Are connected by a data bus and an address bus, respectively.

The serial communication controller 104 transmits and receives commands to and from each control unit shown in FIG.
The PU 101 is connected by a data bus and an address bus.

Reference numeral 105 denotes a write control IC for performing exposure control of image data, and is connected to the CPU 101 by a data bus and an address bus. The control IC 105 is connected to and controls an exposure LD (laser diode) control unit 106 and a polygon motor 115 in the writing unit.

The I / O controller 107 controls outputs to clutches and solenoids, which will be described later, and inputs from various sensors. The fixing control 160 outputs a PWM (pulse width modulation) for controlling the fixing heater based on the A / D input value from the fixing thermistor.

The power pack control 170 controls the power pack output by PWM based on the A / D input fed back from the power pack. The outputs of the power pack unit include outputs of a charging charger, a charging grid, a developing DC bias, a developing AC bias, a belt transfer charger, and a transfer charger.

Reference numeral 180 denotes an electrometer circuit for measuring the surface potential of the photosensitive member.
Connected to input. Reference numeral 181 denotes a P sensor circuit for measuring the amount of toner adhering on the photoreceptor. The phototransistor output of the P sensor is used as an A / D input of the CPU 101, and the PWM output from the CPU is used as an LED of the P sensor.
Is connected to the drive circuit.

Reference numeral 110 denotes a main motor for driving the paper transport system, and reference numeral 111 denotes a drum motor for driving the photosensitive member and the intermediate transfer belt. Reference numeral 112 denotes a developing motor for driving the developing sleeve. An ON signal and a half-speed signal for reducing the speed by half are output from the CPU, respectively, and it is determined that the speed has reached the target speed. Lock detection signal is
Input to U.

Reference numeral 113 denotes a revolver motor for rotating a revolver unit having each color developing unit.
The four-phase output is output from the CPU to stop the designated color developing unit at the developing position.

Reference numeral 114 denotes a replenishing motor for replenishing toner from the toner cartridge into the developing device, and the ON time is controlled in accordance with the amount of adhered toner. Symbol 150
Is an intermediate transfer mark sensor serving as a reference for alignment at the time of color superposition. Since a signal from this sensor requires strict precision in timing, it is connected to an interrupt input of the CPU 101.

Reference numeral 151 denotes a revolver home position (HP) sensor serving as a reference of a stop position of the revolver unit. Since a signal requires strict precision in timing of switching output pulses during rotation of the revolver, C is required.
It is connected to the interrupt input of PU101.

FIG. 9 is a connection block diagram of the I / O controller 107 shown in FIG. As shown in the figure, the registration clutch (CL) 130, the manual feed clutch 131,
There are a manual pickup solenoid (Sol) 132, a neutralization lamp (QL) 133, a solenoid 134 for contacting and separating the intermediate transfer belt cleaning, and a lubricant application solenoid 135.

Further, there are a registration sensor 140, a manual paper end sensor 141, a black cartridge sensor 142, a color cartridge sensor 143, a door switch input 144, and a paper discharge sensor 145 for inputting signals to the controller.

Next, the main components of the printer section shown in FIG. 2 will be described. As described above, the printer unit 1
The developing revolver unit 20 around the photosensitive drum 10
It comprises an intermediate transfer belt 30, a writing unit 40, a fixing unit 52 and the like. Around the photoreceptor 10, a static elimination lamp 11, a charged scorotron charger (hereinafter, charged CH) 12, an electrometer 13, a P sensor 14, a pre-transfer static elimination lamp (hereinafter, PTL) 15, a belt transfer charger 16, A drum cleaning 17 is provided.

The developing position of the developing revolver unit 20 is as follows.
It is located between the electrometer 13 on the photoreceptor 10 and the P sensor 14, and includes four units of black, cyan, magenta, and yellow (hereinafter abbreviated as K, C, M, and Y).
Color developing units 21, 22, 23, and 24 are provided.
Then, the revolver motor 113 is rotated by the four-phase output from the CPU 101 to stop the developing device for the designated color at the developing position.

The writing unit 40 is provided with a laser diode, a polygon mirror rotated by the above-described polygon motor 115, and the like.
It is installed to expose between H12 and electrometer 13.

Around the intermediate transfer belt 30, a mark (not shown) is read from the belt transfer charger 16 in the rotation direction (clockwise in the figure), which mark is provided inside the belt and serves as a reference for alignment during color superposition. Belt mark sensor 1
50, a lubricant application unit 32 for applying a lubricant on the belt 30, a paper transfer charger 33 for transferring a toner image transferred on the belt 30 to recording paper, untransferred toner on the belt 30 and a residual A belt cleaning unit 34 for cleaning the toner is provided. The circumference of the intermediate transfer belt 30 is configured to be longer than the maximum image size plus the P sensor pattern area (including the distance from the rear end of the image and the pattern margin length).

The photosensitive member 10 and the intermediate transfer belt 30 are driven by the drum motor 111 described above. The belt cleaning unit 34 can be brought into contact with and separated from the intermediate transfer belt 30 by the solenoid 134 for cleaning the intermediate transfer belt. Further, the lubricant can be applied to the belt 30 by the lubricant application solenoid 135.

Further, a registration roller 50 is disposed upstream of the paper transfer path of the paper transfer charger 33, and a transport belt 51 and a fixing unit 52 are provided downstream. The registration roller 50, the conveyance belt 51, and the fixing roller 53 are driven by the main motor 110 described above.
The registration roller 50 is turned on / off by a registration clutch 130.

An example of the main sequence in the printer unit during image formation is shown below. In the stopped state, the developing revolver unit 20 is assumed to be stopped at the position of the developing color K.

In the case of the monochrome mode, the system control unit 800
When a start command is received, the discharge lamp 11 and the drum motor 111 are turned on. The charging CH12 is turned on when the lighting start position of the static elimination lamp on the photoconductor 10 reaches the charging position. Further, when the position where the charged CH12 is turned on reaches the developing position, the developing bias (AC + DC)
Then, the developing motor 112 is turned on. The belt transfer charger 16 is turned on when the developing bias on position on the photoconductor 10 reaches the belt transfer position.
This is the pre-rotation. However, if the developing device color at the time of stop is different from the designated color, the revolver unit 20 is rotated until the developing device of the designated color reaches the developing position after the developing bias is turned on. In this case, the preceding rotation is the pre-rotation.

When the exposure position on the photoconductor 10 is charged, a latent image can be formed on the photoconductor 10. After that timing, the printer control unit 100 sends the image data to the scanner control unit 200 so as to send the image data.
, An instruction to turn on the exposure lamp and start the scanner is transmitted by optical fiber communication.

When the scanning operation is performed, image data is transferred from the scanner control unit 200 to the writing control IC 105, converted into exposure data by the writing control IC 105, and exposed to form an electrostatic latent image on the photoconductor 10. Do.
The electrostatic latent image formed on the photoconductor 10 is developed by a developing device, and is transferred to the intermediate transfer belt 30 by a transfer charger. Immediately before the toner image transferred onto the belt 30 reaches the paper transfer position, the paper transfer charger 33 is used.
Is turned on to transfer an image to recording paper (transfer paper). The transfer paper is fed in time for the paper transfer timing. After the transfer paper is abutted against the registration roller 50 to be in a standby state, the leading edge of the image coincides with the front end of the transfer paper at the paper transfer position. Registration clutch 13
0 is turned on.

The transfer paper on which the image has been transferred is transported to a transport belt 5.
1 to the fixing unit 52 and the fixing roller 5
3. Heat is fixed when passing between the pressure rollers 54, and is discharged to a paper discharge tray (not shown).

If the paper transfer is completed and it is determined that there is no next image, the process proceeds to an end sequence. In the end sequence, first, the belt transfer charger 16 is turned off, and when the off position of the belt transfer charger 16 on the photoconductor 10 reaches the position of the charged CH12, the charged CH12 is charged.
12 is turned off, and when the position reaches the developing position, the developing bias and the developing motor 112 are turned off. From this point, the mark sensor 150 enters a reference mark detection standby state. After the mark is detected, the drum motor 111 is turned on until the reference mark is stopped at a predetermined position, and at the same time the drum motor 111 is turned off, the charge removing lamp 11 is turned off.

Next, as an example of color superposition, a full-color basic sequence of A4 size (when short in the paper transport direction) will be described. When the mark sensor 150 detects the reference mark by the rotation of the intermediate transfer belt 30 at the same time as performing the pre-rotation as in the case of the single color,
Since 0 is connected to the interrupt terminal of the CPU 101, an interrupt process is executed on the program. In this process, the revolver 20 is rotated so that the developing device 21 for the first color (K) comes to the developing position. When the belt transfer for the first color is completed, the intermediate transfer belt 30
The belt cleaning unit 34, which has been in contact with the belt, is separated so that the image on the belt is not erased.

Thereafter, when an interrupt from the mark sensor 150 is input again, a scan start command for the second color (C) is transmitted. A belt transfer is performed in the same manner as the first color, and an untransferred image is superimposed on the intermediate transfer belt 30. When the belt transfer is completed, the revolver 20 is rotated so that the developing device 23 for the third color (M) moves to the developing position. The third color (M) and the fourth color (Y) are similarly developed and superimposed on the intermediate transfer belt 30.

In order to transfer the full-color image transferred on the belt to the transfer paper, the paper transfer charger 33 is turned on immediately before the image reaches the transfer position, and the full-color image is transferred to the transfer paper. The transport of the paper is the same as in the single color mode.

When the belt transfer of the fourth color (Y) is completed,
The revolver 20 is rotated so that the developing device 21 of the first color (K) comes to the developing position to prepare for the repeat. At the same time, the belt cleaning unit 34 is changed from the separated state to the contact state, and the transfer residual toner on the belt 30 after the paper transfer is cleaned to prepare for the next image formation. The end sequence is the same as in the case of the single color.

FIG. 10 is a timing chart of a sequence for a single color, and FIGS. 11 and 12 are timing charts of a sequence for a full color. Note that FIG. 11 shows a case of A4 size (when short in the paper transport direction), and FIG. 12 shows a case of A3 size (when short in the paper transport direction). In FIG. 11 (A4 size), the image forming cycle of one color is one round of the intermediate transfer belt 30. In FIG. 12 (A3 size), the image forming cycle of one color is two rounds. This is because, in the case of this copying machine, in the A3 size, when the belt transfer is completed, the next reference mark detection timing has already come, and there is no timing to switch to the next development color in one round of the intermediate transfer belt 30. Therefore, the reference mark detection of the mark sensor 150 is set to 1
One skip for each color. Further, the timing relationship between the contact of the belt cleaning unit 34 and the paper transfer is different between A4 and A3. In the case of A4, the entire image is accommodated from the position of the belt transfer charger 16 to the position of the paper transfer charger 33. Therefore, the belt cleaning unit 34 is contacted at a timing before the paper transfer,
In A3, the belt cleaning unit 34 is brought into contact after the paper transfer in order to prevent the entire image from being accommodated within the interval and to avoid transfer failure due to the vibration of the contact of the belt cleaning unit 34 during the paper transfer. FGATE in the timing chart is a gate signal of image data, and while this signal is on, the image data is written to the photoconductor.

Although the copy sequence based on the configuration of the copying machine has been described here, when this copying machine is used as a printer, for example, when an image is formed based on image data received from the outside, an image forming operation is performed. Is the same except that a scan start command is not issued to the scanner 2. For color superimposition, image data is output with the reference mark detection of the mark sensor 150 as a trigger to output a desired print and output. It is possible to get.

[0075]

As described above, the standby control temperature of the fixing roller is sequentially corrected in accordance with the environmental temperature acquired at predetermined time intervals by the correction processing management timer or the real-time clock, etc. Even if the temperature fluctuates, the fixing roller temperature can be set to a desired control temperature immediately after the start of the job, and an image with good fixing properties can be obtained from the first copy.

The control temperature to be corrected at the time of the standby is changed to the operating control temperature (the environmental temperature from the time when the image forming operation is started by pressing at least the start key until the transfer paper reaches the fixing roller). When the image forming operation is started, the temperature of the fixing roller can be reliably shifted to the control temperature by setting the temperature at which the operation control temperature can be adjusted accordingly.

Further, when two or more operating control temperatures are set, the image forming operation is started by setting the control temperature corrected during standby to a temperature between the two or more operating control temperatures. In this case, the fixing roller temperature can be shifted to the control temperature or a temperature close to the control temperature, and an image having good fixability can be obtained from the first copy.

Further, even during the image forming operation or during a predetermined time after the end of the operation, accurate correction can be performed while eliminating the influence of the rise in the temperature inside the apparatus. Furthermore, by correcting the control temperature during standby with respect to the pressure roller, more precise temperature control becomes possible, and an image with good fixability can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a basic configuration of a copying machine according to an embodiment of the present invention.

FIG. 2 is a configuration diagram showing a main part of a printer unit in the copying machine.

FIG. 3 is a circuit diagram showing a configuration of a control circuit of a fixing heater in the copying machine.

FIG. 4 is a flowchart showing a sequential correction process of a standby fixing control temperature according to an environmental temperature in the copying machine.

FIG. 5 is a flowchart showing correction timing determination processing using a correction processing management timer in the copying machine.

6A and 6B are graphs showing a control temperature straight line of a fixing roller in the copying machine, wherein FIG. 6A shows a case where the operating set temperature is one, and FIG. 6B shows a case where the operating set temperature is two. .

FIG. 7 is a block diagram showing a control system of the copying machine shown in FIG.

FIG. 8 is a block diagram illustrating a configuration of a printer control unit illustrated in FIG. 7;

9 is a connection block diagram of the I / O controller shown in FIG.

10 is a timing chart of an image forming sequence for a single color in the copying machine shown in FIG. 1;

11 is a timing chart of an image forming sequence in full-color (A4 size) in the copying machine shown in FIG. 1;

12 is a timing chart of an image forming sequence in full color (A3 size) in the copying machine shown in FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Printer part 2 Scanner 10 Photoreceptor 20 Developing revolver unit 30 Intermediate transfer belt 40 Writing unit 52 Fixing unit 53 Fixing roller 54 Pressure roller 57 Heater 58 Triac 59 Solid state relay 60 Power supply 100 Printer control unit 200 Scanner control unit 800 System control unit

Claims (7)

[Claims] A fixing unit having a fixing roller and a pressure roller; an environmental temperature detecting unit for detecting a temperature inside the apparatus main body; and a control temperature of the fixing roller based on a detection result of the environmental temperature detecting unit. An image forming apparatus having control means for correcting, comprising: timer means for starting counting in association with operation of the apparatus;
An image forming apparatus, wherein the fixing roller control temperature during standby is sequentially corrected at predetermined time intervals by the timer means. 2. An image forming apparatus comprising: a fixing unit having a fixing roller and a pressure roller; an environmental temperature detecting unit for detecting a temperature in the apparatus main body; and a control temperature of the fixing roller based on a detection result of the environmental temperature detecting unit. An image forming apparatus having a control means for correcting, wherein a real-time clock for counting irrelevant to the operation of the apparatus is provided, and the control temperature of the fixing roller in a standby state is sequentially corrected at predetermined time intervals by the real-time clock. Image forming apparatus. 3. The standby-time fixing roller control temperature that is corrected at least during the operation corrected according to the environmental temperature from when the start key is pressed to start the image forming operation until the recording medium reaches the fixing roller. The image forming apparatus according to claim 1, wherein the temperature is a temperature that can be a control temperature. 4. The fixing roller control temperature during operation is set to two or more control temperatures, and the standby fixing roller control temperature to be corrected is corrected to the two or more control temperatures according to the environmental temperature. 3. The image forming apparatus according to claim 1, wherein the temperature is between the temperatures. 5. The fixing roller control temperature during an image forming operation according to claim 1, wherein the fixing roller control temperature during the image forming operation is corrected based on a detection result of the environmental temperature detecting unit obtained at the start of the image forming operation. Image forming device. 6. During a predetermined time after the end of the image forming operation,
3. The image forming apparatus according to claim 1, wherein a standby fixing roller control temperature is corrected based on a detection result of the environmental temperature detection unit acquired at a start of the image forming operation. 4. 7. A control device for controlling the temperature of the pressure roller to a predetermined control temperature, comprising means for heating the pressure roller and pressure roller surface temperature detection means for detecting the surface temperature of the pressure roller. The pressure roller control temperature is corrected based on the detection result of the environmental temperature detection means,
The image forming apparatus according to claim 1.