JP3425041B2 - Image forming device - Google Patents

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 copying machine, a printer and a facsimile, and more specifically to an image forming apparatus including a heat fixing device.

[0002]

2. Description of the Related Art In image forming apparatuses such as copiers, printers, and facsimiles, a heat fixing device for fixing an unfixed image formed by toner or the like onto a recording medium (transfer paper) is well known. In an image forming apparatus equipped with a conventional heat fixing device, the fixing quality is determined by the temperature of the fixing roller, but a certain part is influenced by the environmental temperature, especially the transfer paper temperature.

Therefore, a number of techniques for changing the control temperature of the fixing roller according to the environmental temperature have been proposed.

[0004]

However, in the full-color image forming apparatus, since the toner adhesion amount, which is another factor that affects the fixing quality, greatly changes depending on the mode, the fixing control temperature is set according to the environmental temperature. It has become difficult to obtain sufficient fixing quality just by changing it. In other words, if the conventional control is performed, when trying to satisfy the fixability in the full color mode, in the mono color mode in which the toner adhesion amount is smaller than in the full color mode,
Alternatively, there is a problem that the glossiness becomes too high due to the excessive heat quantity in the character mode in which the toner adhesion amount is smaller.

The present invention provides an image forming apparatus which solves the above-mentioned problems in an image forming apparatus having a conventional thermal fixing device and can obtain satisfactory fixing quality in all modes even when the environmental temperature changes. The task is to do.

[0006]

According to the present invention, there is provided an environmental temperature detecting means for detecting a temperature in an apparatus main body, comprising: a fixing means having a fixing roller and a pressure roller.
In a full-color image forming apparatus having a control unit that corrects the control temperature of the fixing roller based on the detection result of the environmental temperature detecting unit, the control temperature of the fixing roller is set between full-color mode operation and other mode operation. The problem can be solved by correcting so that the degree of change in the control temperature with respect to the change in the detection result is different.

According to the present invention, the above-mentioned problem is based on the environmental temperature detecting means for detecting the temperature in the main body of the apparatus, including the fixing means having the fixing roller and the pressure roller, and the detection result of the environmental temperature detecting means. A full-color image forming apparatus having a control means for correcting the control temperature of the fixing roller has an automatic color selection mode for automatically discriminating whether the original is a color original or a black-and-white original, and the mode is designated. If the original is a color original or a black-and-white original, the correction is started under the correction condition in which the corrected fixing roller control temperature becomes higher, and after the mode determination of the color original or the black-and-white original by the mode, This is solved by correcting the control temperature of the fixing roller according to the correction condition of the determined mode.

According to the present invention, the above-mentioned problem is based on the environmental temperature detecting means for detecting the temperature in the main body of the apparatus, including the fixing means having the fixing roller and the pressure roller, and the detection result of the environmental temperature detecting means. The full-color image forming apparatus having the control means for correcting the control temperature of the fixing roller has an automatic character photograph mode for automatically discriminating whether the manuscript is a character manuscript or a photo manuscript, and the mode is designated. If the original is a text original or a photographic original, the correction is started under the correction condition in which the fixing roller control temperature after correction is higher, and after the mode determination of the text original or the photographic original by the mode, This is solved by correcting the control temperature of the fixing roller according to the correction condition of the determined mode.

Further, in order to solve the above-mentioned problems, the present invention is such that the other mode is a monochromatic mode, and the correction amount of the fixing roller control temperature obtained by the correction condition during the monochromatic mode operation is the full color mode operation. It is proposed that the correction amount be smaller than the correction amount obtained by the correction condition at that time. Further, according to the present invention, in order to solve the above problem, the other mode is a character mode, and the correction amount of the fixing roller control temperature obtained by the correction condition during the character mode operation is the correction amount during the full color mode operation. It is proposed that the correction amount be smaller than the correction amount obtained by the condition.

Further, in order to solve the above-mentioned problems, the present invention has a monochromatic mode and a character mode as the other modes, and the fixing roller control temperature of the fixing roller control temperature obtained by the correction condition in the monochromatic mode or the character mode operation. The correction amount is less than the correction amount obtained by the correction condition in the full color mode operation, and the correction amount obtained by the correction condition in the character mode operation is less than the correction amount obtained by the correction condition in the single color mode operation. suggest.

Further, according to the present invention, in order to solve the above-mentioned problems, the other mode is a thick paper mode, and the correction amount of the fixing roller control temperature obtained by the correction condition in the thick paper mode operation is the full color mode operation. It is proposed that the correction amount be smaller than the correction amount obtained by the correction condition at that time.

Further, in order to solve the above-mentioned problems, the present invention has a monochromatic mode, a character mode and a cardboard mode as the other modes, which are obtained by a correction condition in the monochromatic mode or the character mode or the cardboard mode operation. The correction amount of the fixing roller control temperature that is obtained is less than the correction amount obtained by the correction condition in the full color mode operation, and the correction amount obtained by the correction condition in the character mode operation is obtained by the correction condition in the single color mode operation It is proposed that the correction amount is less than the amount, and the correction amount obtained by the correction condition in the thick paper mode operation is less than the correction amount obtained by the correction condition in the character mode operation.

Further, in order to solve the above-mentioned problems, the present invention comprises means for heating the pressure roller and pressure roller surface temperature detecting means for detecting the surface temperature of the pressure roller. It is proposed that the roller temperature is controlled to a predetermined control temperature and that the pressure roller control temperature is corrected under a correction condition different from the fixing roller control temperature correction condition based on the detection result of the environmental temperature detection means. To do.

Further, in order to solve the above-mentioned problems, the present invention comprises a means for heating the pressure roller and a pressure roller surface temperature detecting means for detecting the surface temperature of the pressure roller. The roller temperature is controlled to a predetermined control temperature, and the pressure roller control temperature is corrected based on the detection result of the environmental temperature detection means under different correction conditions during full color mode operation and during other mode operation. Suggest to do.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION 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 which is an embodiment of the present invention. The copying machine shown in this figure 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 which is a paper feeding device for feeding a transfer sheet to the printer unit 1, a document feeding device DF4 which feeds a document to the scanner unit 2, and a transfer unit ejected from the printer unit 1. It comprises a sorter 5, which is a post-processing device for sorting paper. A general description of this copier will follow the description relating to the present invention. The overall structure of this copying machine is common to each embodiment of the present invention described later.

FIG. 2 is a block diagram showing the main part of the printer unit 1 in the copying machine shown in FIG. Printer section 1
Is the developing revolver unit 2 centered on the photoconductor drum 10.
0, the intermediate transfer belt 30, a writing unit 40, a fixing unit 52 and the like. Here, the description will focus on the fixing unit 52.

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 the present embodiment, since the unfixed toner image is on the upper surface of the transfer that is passed between both rollers, the heater capacity of the upper fixing roller is larger than that of the lower pressure roller heater. By the way, the reason why the pressure roller is equipped with a heater is mainly to prevent heat from being removed from the fixing roller when the rollers are brought into contact with each other and rotated. Further, an upper thermistor 55 and a lower thermistor 56 are arranged close to the rollers 53 and 54 to detect the temperature of each roller. The heaters are controlled so that the rollers 53 and 54 reach a predetermined temperature based on the temperature detected by each thermistor. The heater control mode includes phase control or on / off control,
In this embodiment, both can be switched. Further, an environmental temperature detection sensor (not shown) is arranged at an appropriate position in the apparatus where it is not easily affected by heat generated by the fixing unit.

FIG. 3 is a circuit diagram showing the structure of the heater control circuit. Here, only one of the heaters provided on both the fixing roller and the pressure roller and its control circuit is shown, but the other heater and its control circuit are similar. Electric power is supplied to the heater 57 from a power source 60 via a triac 58. The triac 58 is S by a heater control signal from a CPU described later.
A trigger pulse generated when the SR (solid state relay) 59 is turned on causes conduction, and power from the power source 60 is supplied to the heater 57. C in phase control mode
The PU outputs the heater control signal by PWM (pulse width modulation). In the on / off control mode, the PWM output does not occur, but the output can be switched by the CPU.

The fixing control temperature in this embodiment is set as follows. In this embodiment, since the fixing roller control temperature is corrected according to the environmental temperature,
The control temperature shown here is the control temperature when the environmental temperature is 20 ° C. Fixing roller control temperature during standby: 150 ° C Fixing roller control temperature during full color mode: 160 ° C Fixing roller control temperature during mono-color (single color) mode: 14
Fixing roller control temperature in the 0 ° C thick paper mode: 140 ° C Pressure roller control temperature: 150 ° C The controlling temperature of the pressure roller is the same in each mode, but there is a big difference between the single color mode and the full color mode for the fixing roller. Attached. In addition, an intermediate value between the full-color mode and the single-color mode is set so that a good fixing operation can be executed no matter which mode the image formation is started during standby. In addition, the control temperature in the single color mode is low,
This is mainly because the amount of toner adhered per unit area is small, and the control temperature in the full color mode is high. Since the colors are superimposed and colors are developed, the amount of toner adhered per unit area is large and more heat is required. This is because. The pressure roller is set to a temperature that does not allow the temperature of the fixing roller to escape when forming a full-color image.

By the way, in the case of an apparatus having different (two or more) fixing roller control temperatures in the full color mode and other modes as in the present embodiment, when the control temperature is corrected according to the environmental temperature, the conventional As described above, when the value obtained by performing the calculation according to a certain law based on the detected environmental temperature is added to or subtracted from the control temperature,
It is considered that the control will be as shown in. In the example shown in this figure, the full color mode fixing roller control temperature is set to 160 ° C. and the monocolor (single color) mode and thick paper mode fixing roller control temperature is set to 140 ° C. at the environmental temperature of 20 ° C. The control temperature is corrected according to the ambient temperature, and is shown in the figure as a control temperature straight line for operating in full color mode: Ta and a control temperature straight line for operating in other modes: Text. The fixing roller control temperature during standby is not corrected,
Shown as Twait, a horizontal, stand-by control temperature line constant at 150 ° C. Here, the fixing roller control temperature when the environmental temperature is 20 ° C. is referred to as a set temperature. That is, the full color mode setting temperature: 160 ° C., the other mode setting temperature: 140 ° C., and the standby setting temperature: 150 ° C. No specific temperature is set for the character mode.

In the case of the example shown in FIG. 13, the maximum correction amount: ΔT is set so that the fixing failure does not occur in the full color mode.
= 16 deg is corrected according to the ambient temperature. However, in the modes other than the full color mode, the same maximum correction amount: ΔT = 16 deg is corrected, and in a region where the ambient temperature is low, there is a fixing defect that the glossiness is too high due to an excessive amount of heat, and the ambient temperature is also high. In a high area, there is a possibility that fixing failure such as poor fixability may occur.

Therefore, in this embodiment, the control temperature in another mode is corrected under a correction condition different from that in the full color mode. Hereinafter, correction of the fixing roller control temperature according to the environmental temperature in the present embodiment will be described with reference to FIG.

As shown in FIG. 4, in the present embodiment, the fixing roller control temperature when the environmental temperature is 20 ° C., that is, the fixing roller set temperature is the full color mode set temperature: 160 ° C. and the other mode set temperature: 140. C, standby set temperature: 150C. The control temperature in full color mode is the control temperature line during full color mode operation: Tfull
Maximum correction amount: ΔTfull = 16deg
Is corrected according to the ambient temperature. On the other hand, the control temperature in the mono color mode is the maximum correction amount: ΔTm as shown by the control temperature line in the mono color mode operation: Tmono.
The correction of ono = 12deg is performed according to the environmental temperature. Further, the control temperature in the character mode is the maximum correction amount: Δ as shown by the control temperature line during the character mode operation: Tchar.
The correction of Tchar = 8 deg is performed according to the environmental temperature. Further, the control temperature in the thick paper mode is the maximum correction amount as shown by the control temperature straight line in the thick paper mode operation: Tthic:
The correction of ΔTthic = 4 deg is performed according to the environmental temperature.
The relationship of the maximum correction amount in each mode is ΔTfull> ΔT
mono>ΔTchar> ΔTthic. The standby control temperature is not corrected according to the ambient temperature, and is controlled to a constant temperature as indicated by the standby control temperature straight line: Twait.

As described above, in the present embodiment, when the fixing roller control temperature is corrected according to the ambient temperature, the correction condition is changed between the full color mode operation and the other mode operation, and the correction amount in the full color mode is used. The correction amount for other modes is reduced. Therefore, it is possible to obtain a copy image with good fixing quality even when the environmental temperature changes. For example, when the environmental temperature decreases, in the full-color mode requiring a larger amount of heat, the fixing property is secured by correcting the fixing roller control temperature with a large correction amount, and the mono-color mode in which the toner adhesion amount is small, or In the character mode in which the toner adhesion amount is smaller, by correcting the control temperature with a small correction amount, it is possible to prevent the problem that the glossiness becomes too high due to an excessive amount of heat. Further, when the environmental temperature rises, the control temperature does not become too low in the modes other than the full color mode (since the correction amount for lowering the control temperature is small), it is possible to prevent the fixing property from deteriorating.

The values of the maximum correction amounts in the modes other than the full color mode may be the same. In that case, the relationship between the maximum correction amounts in each mode is ΔTfull> ΔTmo
no = ΔTchar = ΔTthic. Alternatively, the correction amount in the monochrome mode and the correction amount in the character mode may be the same, and only the correction amount in the thick paper mode may be reduced. In that case, the relationship between the maximum correction amounts in each mode is ΔTfull> ΔTmo
no = ΔTchar> ΔTthic. Further, the correction amount in the character mode may be set smaller than the correction amount in the mono color mode, and the correction amount in the character mode may be the same as the correction amount in the thick paper mode. In that case, the relationship between the maximum correction amounts in each mode is Δ
Tfull>ΔTmono> ΔTchar = ΔTthic. That is, when the relationship of the maximum correction amount in each mode is collectively shown, ΔTfull> ΔTmono ≧ ΔTchar ≧ ΔTthic.

Next, another embodiment of the present invention will be described. The copying machine according to the present embodiment automatically determines whether the original is a color original or a black-and-white original, and automatically determines whether the original is a text original or a photo original. It has an automatic character photo mode. Generally, in such a mode, the fixing control temperature is corrected after the document is discriminated. In that case, even if a high operating temperature of the fixing roller is required after the document is determined, it may be difficult to make the rise of the roller temperature in time with the arrival of the transfer paper. When the user specifies the mode instead of the automatic determination, the document is scanned after the mode is specified. Therefore, it is necessary to correct the control temperature while performing the current scan. There is a margin, and it is possible to correct the roller temperature required for the specified mode.

Therefore, in this embodiment, when the automatic color selection mode or the automatic character photography mode is selected, the corrected fixing roller control temperature is adjusted so that the highest control temperature required in that mode can be dealt with. The correction is started under the higher correction condition.
Since the mode is determined after the first scan by the scanner, the control temperature may be corrected under the correction condition of the determined mode.

The determination of specific correction conditions when the automatic color selection mode or the automatic character / photo mode is selected will be described with reference to FIG. The correction conditions of the fixing roller control temperature for each mode in this embodiment are the same as those in the above embodiment, and the control temperature straight line in each mode is the same as that shown in FIG. Then, the control temperature straight line having the highest temperature is selected from among the modes that can be present when the automatic color selection mode or the automatic character photography mode is selected, and the correction is started.

For example, when the automatic color selection mode is designated and the automatic character photograph mode is designated, the photograph mode of the full color mode is the mode that requires the highest control temperature among the possible modes. Therefore, when the automatic color selection mode is specified and the automatic character photo mode is also specified, the correction condition for which the corrected fixing roller control temperature becomes higher, that is, the control temperature straight line in full color mode operation: Tfull is selected. Then, the correction of the control temperature is started (by selecting the correction condition that is the control temperature straight line). I don't know whether it is the character mode (black and white copy) or the photo mode (full color copy) at the time of starting the discrimination, but for the time being, if the control temperature straight line: Tfull that gives the highest control temperature is selected, the original is in the photo mode. Even in the case, the roller temperature can be corrected to a high control temperature in time for the arrival of the transfer paper. Therefore, fixing failure can be avoided.

Further, for example, when the automatic color selection mode is designated and the character mode is further designated, the character mode is a black-and-white copy. As the mode that can be designated, a normal monocolor mode or more toner adhesion is used. It is a character mode with a small amount. Therefore, if the control temperature is the highest among the mono-color mode and the character mode, that is, if the environmental temperature is 20 ° C or higher, the control temperature straight line in the character mode operation: Tchar is selected, and the environmental temperature is 20 ° C or lower. In this case, the control temperature straight line during operation in the mono color mode: Tmono is selected to start the correction of the control temperature.

Although detailed description of other combinations of mode designations is omitted, Table 1 below shows combinations of mode designations in this embodiment and control temperature straight lines selected at that time.

[0032]

[Table 1]

Although the thick paper mode is not included in this table, the thick paper mode has priority over the other modes. Therefore, when the thick paper mode is designated, how the other modes are designated. However, the control temperature straight line: Tthic during the thick paper mode operation is selected and the correction of the control temperature is started.

Next, another embodiment of the present invention will be described. In this embodiment, not only the fixing roller,
The control temperature of the pressure roller is also corrected according to the environmental temperature.
The conditions for correcting the control temperature of the pressure roller are different from the conditions for correcting the fixing roller control temperature. The control temperature straight line of the pressure roller in this embodiment is shown in FIG.

That is, in FIG. 5, the control temperature straight line: K of the pressure roller is shown by a broken line. Here, the pressure roller control temperature when the environmental temperature is 20 ° C. is set to 150 ° C. The correction condition of the pressure roller and the correction condition of the fixing roller are different, and the maximum correction amount ΔK of the pressure roller control temperature is different from the maximum correction amount of the fixing roller control temperature. Therefore, the slope of the control temperature line of the fixing roller shown by the solid line and the control temperature line of the pressure roller shown by the broken line are different.

By correcting the control temperature of the pressure roller according to the environmental temperature under a correction condition different from that of the fixing roller,
The correction can be performed under the correction condition suitable for the pressure roller, the finer temperature control can be performed, and the copy image with good fixing quality can be obtained.

Next, still another embodiment of the present invention will be described. FIG. 6 is a graph showing a control temperature straight line of the pressure roller in the present embodiment. As shown in this figure, in the present embodiment, the control temperature of the pressure roller has a different control temperature line for each designated mode,
That is, the pressure roller control temperature is corrected under different correction conditions for each mode.

In the full color mode, the maximum correction amount: ΔKfull is corrected in accordance with the ambient temperature as indicated by the control temperature line during full color mode operation: Kfull. In the mono color mode, the maximum correction amount: ΔKmono is corrected according to the environmental temperature as indicated by the control temperature line during the mono color mode operation: Kmono. Further, the control temperature in the character mode is the maximum correction amount: Δ as shown by the control temperature line during the character mode operation: Kchar.
The correction of Kchar is performed according to the environmental temperature. Further, the control temperature in the thick paper mode is the maximum correction amount: ΔKthi as indicated by the control temperature straight line in the thick paper mode operation: Kthic.
The correction of c is performed according to the ambient temperature. In the example shown here, the maximum correction amount of the pressure roller control temperature in each mode is the same as the maximum correction amount of the fixing roller control temperature in the corresponding mode (see FIG. 4) (ΔKfull = ΔTfull, Δ
Kmono = ΔTmono, ΔKchar = ΔTchar)
Different amounts may be used for each.

As described above, by correcting the control temperature of the pressure roller according to the environmental temperature under the correction condition which differs for each mode, it becomes possible to perform the correction under the correction condition suitable for each mode, and more precise temperature control can be performed. This makes it possible to obtain a copy image with good fixing quality.

The following description is for the overall structure 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 this 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 section 100 is a control section for controlling the electrophotographic process sequence and the recording sheet conveying 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 controller is
It is connected to the DF control unit 400 by optical fiber serial communication, and controls the document supply sequence by a command. Further, 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 between the recording paper and the image, the optical fiber is directly controlled so that the sequence control can be performed. It is connected by serial communication and is equipped with a data bus for directly transferring image data from the scanner control unit 200 to the printer control unit 100.

The system control unit 800 controls the entire system of the copying machine, and the printer control unit 100 and the scanner control unit 20 are operated by an input from the operation unit control 900.
It sends image forming conditions to 0, manages and controls the state of the entire device, 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
3 stores and saves data in accordance with the operation of the CPU 101. CPU 101, ROM 102, RAM 103
Are connected by a data bus and an address bus, respectively.

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

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

The I / O controller 107 controls outputs to clutches, solenoids and the like, which will be described later, and inputs from respective sensors and the like. The fixing control 160 outputs 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. 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 is an electrometer circuit for measuring the surface potential of the photosensitive member, the output of which is the A / D of the CPU 101.
Connected to input. Reference numeral 181 denotes a P sensor circuit for measuring the amount of toner adhering to the photosensitive member. The phototransistor output of the P sensor is the A / D input of the CPU 101, and the PWM output from the CPU is the LED of the P sensor.
Connected to the drive circuit.

Reference numeral 110 is a main motor for driving the paper carrying system, and reference numeral 111 is a drum motor for driving the photoconductor and the intermediate transfer belt. Further, reference numeral 112 is a developing motor for driving the developing sleeve, and an ON signal and a half speed signal for reducing the speed to half are output from the CPU respectively, and it is determined that the speed has reached the target speed. The lock detection signal for
Input to U.

Reference numeral 113 is a revolver motor for rotating a revolver unit equipped with each color developing device,
The 4-phase output is output from the CPU, and the developing device for the designated color is stopped at the developing position.

Reference numeral 114 is a replenishing motor for replenishing the toner from the toner cartridge into the developing device, and the on-time is controlled according to the toner adhesion amount. Reference numeral 150
Is an intermediate transfer mark sensor that serves as a reference for alignment during color superposition. Since signals from this sensor require strict timing accuracy, they are connected to the interrupt input of the CPU 101.

Reference numeral 151 is a revolver home position (HP) sensor that serves as a reference for the stop position of the revolver unit, and the signal requires a strict timing accuracy of switching output pulses during the revolver rotation.
It is connected to the interrupt input of the PU 101.

FIG. 9 is a connection block diagram of the I / O controller 107 shown in FIG. As shown in this figure, the registration clutch (CL) 130, the manual feed clutch 131,
There are a manual feed pickup solenoid (Sol) 132, a static elimination 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 feed 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 as a device for inputting a signal 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
Development revolver unit 20 centering on the photoconductor drum 10,
The intermediate transfer belt 30, a writing unit 40, and a fixing unit 52 are included. Around the photoconductor 10, a static elimination lamp 11, a charging scorotron charger (hereinafter referred to as charging CH) 12, an electrometer 13, a P sensor 14, a pre-transfer static elimination lamp (hereinafter referred to as PTL) 15, a belt transfer charger 16, A drum cleaning 17 is provided.

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

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

Around the intermediate transfer belt 30, a mark (not shown) is read from the belt transfer charger 16 in the rotating direction (clockwise in the figure), which is a reference for the alignment at the time of color superposition and is provided inside the belt. 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 the toner image transferred on the belt 30 to a recording paper, an untransferred toner on the belt 30, and a residual toner. A belt cleaning unit 34 for cleaning toner is provided. The circumference of the intermediate transfer belt 30 is 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 photoconductor 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 applying solenoid 135.

Further, a registration roller 50 is provided upstream of the paper transfer path of the paper transfer charger 33, and a transfer belt 51 and a fixing unit 52 are provided downstream thereof. 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 the registration clutch 130.

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

In the monochrome mode, the system control unit 800
When the start command comes further, the static elimination lamp 11 and the drum motor 111 are turned on. When the charge removal lamp lighting start position on the photoconductor 10 reaches the charging position, the charging CH 12 is turned on. Further, when the position where the charging CH12 is turned on reaches the developing position, the developing bias (AC + DC)
And the developing motor 112 is turned on. Further, 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 front rotation. However, when the color of the developing device when stopped is different from the designated color, the revolver unit 20 is rotated after the developing bias is turned on until the developing device of the designated color reaches the developing position. In this case, up to this point is the front rotation.

If the exposure position on the photoconductor 10 is in a charged state, 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.
A command to turn on the exposure lamp and to start the scanner is sent to the optical fiber communication.

When the scanning operation is performed, the image data is transferred from the scanner control section 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. To do.
The electrostatic latent image formed on the photoconductor 10 is developed by the developing device and transferred to the intermediate transfer belt 30 by the transfer charger. Then, immediately before the toner image transferred onto the belt 30 reaches the paper transfer position, the paper transfer charger 33
Turn on to transfer the image to the recording paper (transfer paper). It should be noted that the transfer paper is being fed in time for the paper transfer timing, and after the transfer paper front end is abutted against the registration roller 50 to enter the standby state, the image front end and the transfer paper front end match at the paper transfer position. Register clutch 13 at the timing
0 is turned on.

The transfer paper on which the image is transferred is the conveyor belt 5
1 is conveyed to the fixing unit 52, and the fixing roller 5
3. When passing between the pressure roller 54 and the pressure roller 54, it is thermally fixed and discharged to a paper discharge tray (not shown).

When it is determined that the paper transfer has been completed and there is no next image formation, the sequence proceeds to the end sequence. In the termination sequence, first, the belt transfer charger 16 is turned off, and when the position where the belt transfer charger 16 on the photoconductor 10 is turned off reaches the position of the charging CH 12, the charging CH 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 in time, the mark sensor 150 enters the reference mark detection standby state, and 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 static elimination lamp 11 is turned off.

Next, as a color overlapping example, a basic full-color sequence of A4 size (when it is short in the sheet conveying 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 while performing the same pre-rotation as in the case of a single color, the mark sensor 15
Since 0 is connected to the interrupt terminal of the CPU 101, interrupt processing is executed on the program. In the process, the revolver 20 is rotated so that the developing device 21 for the first color (K) comes to the developing position. When the transfer of the first color belt is completed, the intermediate transfer belt 30
The belt cleaning unit 34 that has been in contact with is separated so that the image on the belt is not erased.

After that, when the interrupt from the mark sensor 150 is input again, the scan start command for the second color (C) is transmitted. Belt transfer is performed in the same manner as for 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 belt-transferred full-color image onto the transfer paper, the paper transfer charger 33 is turned on immediately before the image reaches the transfer position to transfer the full-color image onto the transfer paper. The paper conveyance is the same as the single color mode.

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

FIG. 10 shows a timing chart of the sequence in the case of a single color, and FIGS. 11 and 12 show timing charts of the sequence in the case of a full color. Note that FIG. 11 shows the case of A4 size (when it is short in the sheet conveyance direction), and FIG. 12 shows the case of A3 size (when it is short in the sheet conveyance direction). In FIG. 11 (A4 size), one color image forming cycle is one round of the intermediate transfer belt 30, but in FIG. 12 (A3 size), one color image forming cycle is two rounds. This is because in the case of this copying machine, the next reference mark detection timing has already come when the belt transfer is completed in the A3 size, 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 1
I fly once 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, but in the case of A4, the entire image is contained between the position of the belt transfer charger 16 and the position of the paper transfer charger 33. Therefore, the belt cleaning unit 34 is contacted at a timing before the paper transfer,
At A3, the belt cleaning unit 34 is brought into contact with the sheet after the sheet is transferred in order to prevent all the images from being accommodated within the interval and to avoid transfer failure due to vibration of the contact of the belt cleaning unit 34 during the sheet transfer. Note that FGATE in the timing chart is a gate signal of image data, and while this is on, the image data is written in the photoconductor.

Although a copy sequence based on the structure of the copying machine is described here, when the copying machine is used as, for example, a printer, an image is formed when forming an image with image data received from the outside. Regarding the above, the same is true except that the scan start command is not issued to the scanner 2. For color superimposition, the reference mark detection of the mark sensor 150 is used as a trigger to output the image data so that the desired pudding and output can be obtained. It is possible to obtain.

[0074]

As described above, by correcting the fixing control temperature in accordance with the environmental temperature under the correction condition suitable for each operation mode, an image of good fixing quality can be obtained even when the environmental temperature changes. You can

Further, when the automatic color selection mode or the automatic character / photo selection mode is designated, at least in any operation mode, fixing failure due to insufficient heat amount can be prevented, and an image of good fixing quality can be obtained. it can.

Further, by correcting the control temperature of the pressure roller under the correction condition suitable for the pressure roller, fine temperature control is performed, and an image with good fixing quality can be obtained.

Furthermore, by correcting the pressure roller control temperature under the correction condition suitable for each operation mode, more detailed temperature control is performed, and an image with good fixing quality can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a basic configuration of a copying machine that is 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 fixing heater control circuit in the copying machine.

FIG. 4 is a graph showing a fixing roller control temperature curve for each mode in the copying machine.

FIG. 5 is a graph showing a control temperature straight line of a pressure roller according to another embodiment of the present invention.

FIG. 6 is a graph showing a control temperature straight line of a pressure roller according to still another embodiment of the present invention.

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

FIG. 8 is a block diagram showing a configuration of a printer control unit shown in FIG.

9 is a connection block diagram of the I / O controller shown in FIG. 8. FIG.

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

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

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

FIG. 13 is a graph for explaining the conventional correction of the fixing control temperature according to the environmental temperature.

[Explanation of symbols]

1 Printer section 2 scanner 10 photoconductor 20 Development 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 100 Printer control unit 200 Scanner control unit 800 System control unit

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-7-77893 (JP, A) JP-A-61-70571 (JP, A) JP-A-6-278308 (JP, A) JP-A-7- 319238 (JP, A) JP 60-263173 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03G 13/20 G03G 15/20 G03G 21/00 370-502

Claims (10)

(57) [Claims] 1. An environmental temperature detecting means for detecting a temperature in an apparatus main body, comprising a fixing means having a fixing roller and a pressure roller, and a control temperature of the fixing roller based on a detection result of the environmental temperature detecting means. In a full-color image forming apparatus having a correction means, the control temperature of the fixing roller is different in the degree of change in the control temperature with respect to the change in the detection result between the full-color mode operation and the other mode operation. The image forming apparatus is characterized by performing the correction as described above. 2. An environmental temperature detecting means for detecting the temperature inside the apparatus main body, comprising a fixing means having a fixing roller and a pressure roller, and a control temperature of the fixing roller based on a detection result of the environmental temperature detecting means. A full-color image forming apparatus having a control unit for correction has an automatic color selection mode for automatically discriminating whether an original is a color original or a black-and-white original. When the mode is designated, the original is a color original. Correction condition for which the fixing roller control temperature after correction is higher than that of the color document or the monochrome document An image forming apparatus characterized in that the control temperature of the fixing roller is corrected by. 3. An environment temperature detecting means for detecting the temperature inside the apparatus main body, comprising a fixing means having a fixing roller and a pressure roller, and a control temperature of the fixing roller based on a detection result of the environment temperature detecting means. A full-color image forming apparatus having a control unit for correction has an automatic character / photo mode for automatically determining whether a manuscript is a text manuscript or a photo manuscript. When the mode is designated, the manuscript is a character manuscript. Correction condition for which the fixing roller control temperature after correction is higher than that of the original document or the photographic document An image forming apparatus characterized in that the control temperature of the fixing roller is corrected by. 4. The other mode is a single color mode, and the correction amount of the fixing roller control temperature obtained by the correction condition in the single color mode operation is smaller than the correction amount obtained by the correction condition in the full color mode operation. The image forming apparatus according to claim 1, which is characterized in that. 5. The other mode is a character mode, and the correction amount of the fixing roller control temperature obtained by the correction condition in the character mode operation is smaller than the correction amount obtained by the correction condition in the full color mode operation. The image forming apparatus according to claim 1, which is characterized in that. 6. The other mode includes a monochromatic mode and a character mode, and the correction amount of the fixing roller control temperature obtained by the correction condition in the monochromatic mode or the character mode operation is obtained by the correction condition in the full color mode operation. The correction amount is less than the correction amount, and the correction amount obtained by the correction condition in the character mode operation is less than or equal to the correction amount obtained by the correction condition in the single color mode operation.
The image forming apparatus according to item 1. 7. The other mode is a thick paper mode, and the correction amount of the fixing roller control temperature obtained by the correction condition in the thick paper mode operation is smaller than the correction amount obtained by the correction condition in the full color mode operation. The image forming apparatus according to claim 1, which is characterized in that. 8. The other modes include a monochromatic mode, a character mode, and a thick paper mode, and the correction amount of the fixing roller control temperature obtained by the correction condition in the monochromatic mode, the character mode, or the thick paper mode is in the full color mode. Is less than the correction amount obtained by the correction conditions of, and the correction amount obtained by the correction conditions of the character mode operation is less than the correction amount obtained by the correction conditions of the single color mode operation. The image forming apparatus according to claim 1, wherein the correction amount obtained is equal to or less than the correction amount obtained by the correction condition during the character mode operation. 9. A pressure roller surface temperature detecting means for detecting the surface temperature of the pressure roller and a means for heating the pressure roller are provided to control the pressure roller temperature to a predetermined control temperature, and The image forming apparatus according to claim 1, wherein the pressure roller control temperature is corrected under a correction condition different from the fixing roller control temperature correction condition based on the detection result of the environmental temperature detection unit. 10. A pressure roller surface temperature detecting means for detecting the surface temperature of the pressure roller and a means for heating the pressure roller are provided to control the pressure roller temperature to a predetermined control temperature, and The pressure roller control temperature is corrected based on a detection result of the environmental temperature detection means under different correction conditions between a full color mode operation and another mode operation. Image forming apparatus.