JPH10319814A - Image forming device and control method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable fixation, without the generation of a long waiting time cause by the control of the temp. of a fixing unit, when instructions to start a printing operation are issued in a state where the formation of an image is stopped by executing the control for starting the printing operation, before the temp. of a fixing means reaches a set temp. SOLUTION: A fixing temperature control part 37C is provided with a sensor for detecting the temp. of a fixing roller and the result of the detection by the sensor is transmitted to a CPU 71 as digital data. Then, in this device, the time from the issue of the instructions to start the printing operation to the start of the printing operation is changed on the basis of the temp. of the fixing means when the instructions to start the printing operation are issued, to execute the control for starting the printing operation, before the temp. of the fixing means reaches the set temp.. Therefore, the printing operation is permitted before the thermal roller temp. of the fixing unit 37 reaches the set temp. and when a recording medium after a toner image is transferred by the printing operation reaches the fixing unit 37, the temp. of the fixing unit 37 reaches the set temp.

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 having a fixing unit of a heat fixing type and an improvement of a control method thereof.

[0002]

2. Description of the Related Art In an image forming apparatus, an electrostatic latent image formed on a photoreceptor is converted into a toner image by a developer, and the toner image is transferred onto a recording medium such as transfer paper, and the toner image on the recording medium is transferred. The fixing is performed by a fixing device at a predetermined temperature.

Since a large amount of power is consumed in the fixing device to maintain a predetermined proper fixing temperature, the temperature is reduced when the printing operation is not performed, which is called idling.

[0004] In addition, if the shutdown is continued for a long time to save power, the fixing device may be kept at a temperature lower than the idling region. Then, such a temperature may be further reduced stepwise according to the time during which the apparatus is stopped.

[0005]

As described above, when an instruction to start a printing operation is issued while the temperature of the fixing device is lowered below the proper fixing temperature, the printing operation is started while increasing the temperature of the fixing device. , And the printing operation is started when the fixing proper temperature is reached.

In such a case, if a print operation is instructed in a state where the fixing unit has been stopped for a long period of time, a large amount of time is required until the fixing device reaches a proper fixing temperature. The time will be longer.

In this case, it is conceivable to start the printing operation before the temperature reaches the proper fixing temperature. However, it is expected that the recording medium reaches a fixing device that has not reached the proper fixing temperature.

Further, the proper fixing temperature differs between the case of monochrome and the case of multi-color (color), and it is necessary to control the temperature to be high in the case of color. However, there is an image forming apparatus in which both the set temperatures are the same, and there is a problem that if color fixing is performed at a temperature suitable for monochrome, the overlapping toner is not sufficiently fixed.
Conversely, if monochrome fixing is performed at a temperature suitable for color, there is a problem in that the waiting time from idling to reaching a fixing proper temperature becomes long.

The present invention solves the above-mentioned disadvantages, and achieves good fixing without a long waiting time due to temperature control of a fixing unit when an instruction to start a printing operation is given in an image forming stopped state. It is an object of the present invention to realize an image forming apparatus capable of performing the control and a control method thereof.

[0010]

That is, the present invention which constitutes means for solving the problems is as described in the following (1) to (6).

(1) The invention according to claim 1 is a fixing means for fixing a developer on a recording medium, a temperature detecting means for detecting the temperature of the fixing means, and the fixing means at the time when an instruction to start a printing operation is given. Based on the temperature of the fixing unit, the time from when the print operation start instruction is issued to when the print operation is started is changed, and control is performed so that the print operation is started before the temperature of the fixing unit reaches the set temperature. And a control unit.

In this image forming apparatus, based on the temperature of the fixing unit at the time when a print operation start instruction is given,
By changing the time from when the print operation start instruction is issued to when the print operation is started, and by performing control such that the print operation is started before the temperature of the fixing unit reaches the set temperature, the heat of the fixing unit is controlled. The printing operation is permitted before the roller temperature reaches the set temperature, and the fixing device reaches the set temperature when the recording medium onto which the toner image has been transferred by the printing operation reaches the fixing device.

As a result, when an instruction to start a printing operation is given in the image formation stopped state, it is possible to perform satisfactory fixing without generating a long and unnecessary waiting time due to the temperature control of the fixing device. Become.

(2) According to a second aspect of the present invention, there is provided a fixing means for fixing a developer on a recording medium, a temperature detecting means for detecting a temperature of the fixing means, and a control means for changing a set temperature of the fixing means. The control means, based on the temperature of the fixing means at the time when the print operation start instruction was issued, and the set temperature, the time from the print operation start instruction to the start of the print operation And controlling to start a print operation other than the fixing unit before the temperature of the fixing unit reaches a set temperature.

In this image forming apparatus, a print operation is started after a print operation start instruction is issued based on the temperature of the fixing unit at the time when the print operation start instruction is issued and the set temperature. By changing the time until the temperature of the fixing unit reaches the set temperature, the print operation is started before the temperature of the fixing unit reaches the set temperature, so that the print operation is allowed before the heat roller temperature of the fixing unit reaches the set temperature. When the recording medium onto which the toner image has been transferred by the printing operation reaches the fixing device, the fixing device reaches the set temperature.

As a result, when an instruction to start the printing operation is given in the image formation stopped state, it is possible to perform satisfactory fixing without generating a long and useless waiting time due to the temperature control of the fixing device. Become.

Further, since the time until the start of the printing operation is changed by referring to both the temperature of the fixing means and the set temperature, the set temperature may be different depending on the content of image formation and the material of the recording medium. Even when it is set, it is possible to achieve both an appropriate waiting time and good fixing.

(3) According to the third aspect of the present invention, in the first or second aspect described above, the time changed by the control means is a time required for the temperature of the fixing means to reach a set temperature. The image forming apparatus is characterized in that it is based on a time obtained by subtracting a time required for the recording medium to reach the fixing unit after starting a printing operation.

By setting the changing time in this manner, the printing operation is allowed before the heat roller temperature of the fixing device reaches the set temperature, and the recording medium onto which the toner image has been transferred by the printing operation reaches the fixing device. At this point, the fixing device reaches the set temperature.

As a result, when an instruction to start the printing operation is given in the image formation stopped state, a good fixing can be performed with an appropriate waiting time without generating a long wasteful waiting time due to the temperature control of the fixing device. Can be performed.

(4) According to a fourth aspect of the present invention, there is provided a fixing means for fixing a developer on a recording medium, a temperature detecting means for detecting a temperature of the fixing means, and a control means for controlling the temperature of the fixing means. A method of controlling the image forming apparatus comprising: a time period from when a print operation start instruction is issued to when a print operation is started, based on the temperature of the fixing unit at the time when the print operation start instruction is issued. To change
A control method for an image forming apparatus, characterized in that a print operation is started before the temperature of the fixing unit reaches a set temperature.

According to the control method of the image forming apparatus, the time from when the print operation start instruction is issued to when the print operation is started is changed based on the temperature of the fixing unit at the time when the print operation start instruction is issued. By performing control such that the printing operation is started before the temperature of the fixing unit reaches the set temperature, the printing operation is allowed before the heat roller temperature of the fixing device reaches the set temperature, and the toner is transferred by the printing operation. When the recording medium onto which the image has been transferred reaches the fixing device, the fixing device reaches the set temperature.

As a result, when an instruction to start the printing operation is given in the image forming stopped state, it is possible to perform satisfactory fixing without generating a long and unnecessary waiting time due to the temperature control of the fixing device. Become.

(5) A fixing device for fixing a developer to a recording medium, a temperature detecting device for detecting a temperature of the fixing device, and a control device for setting a set temperature of the fixing device. Controlling the image forming apparatus comprising: a print operation start instruction based on a temperature of the fixing unit at a point in time when the print operation start instruction is issued and a set temperature, based on the set temperature. A method of controlling the image forming apparatus, wherein the time until the start of printing is changed, and control is performed such that printing operations other than the fixing unit are started before the temperature of the fixing unit reaches a set temperature.

In this control method of the image forming apparatus, the print operation is started after the print operation start instruction is issued based on the temperature of the fixing unit and the set temperature at the time when the print operation start instruction is issued. Is controlled so that the printing operation is started before the temperature of the fixing unit reaches the set temperature, so that the printing operation is performed before the heat roller temperature of the fixing unit reaches the set temperature. Is allowed, and the fixing device reaches the set temperature when the recording medium onto which the toner image has been transferred by the printing operation reaches the fixing device.

As a result, when an instruction to start the printing operation is given in the image forming stopped state, it is possible to perform satisfactory fixing without generating a long and unnecessary waiting time due to the temperature control of the fixing device. Become.

Further, since the time until the start of the printing operation is changed by referring to both the temperature of the fixing means and the set temperature, the set temperature may be different depending on the content of image formation and the material of the recording medium. Even when it is set, it is possible to achieve both an appropriate waiting time and good fixing.

(6) According to the sixth aspect of the present invention, in the above-described fourth or fifth aspect, the changing time is set based on a time required for the temperature of the fixing means to reach a set temperature. A time required for the recording medium to reach the fixing unit after the start of the image forming operation.

By setting the changing time in this manner, the printing operation is allowed before the heat roller temperature of the fixing device reaches the set temperature, and the recording medium on which the toner image has been transferred by the printing operation reaches the fixing device. At this point, the fixing device reaches the set temperature.

As a result, when an instruction to start the printing operation is given in the image forming stopped state, a good fixing can be performed with an appropriate waiting time without generating a long wasteful waiting time due to the temperature control of the fixing device. Can be performed.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An image forming apparatus and a control method thereof according to the present invention will be described with reference to the drawings. <Mechanical Configuration> First, the overall mechanical configuration of the image forming apparatus to which the embodiment of the present invention is applied will be described with reference to FIG.

Here, a copying machine will be described as an example of the image forming apparatus, but a laser printer without a reading unit may be used. FIG. 2 is a cross-sectional view of the image forming apparatus used in the embodiment of the present invention.
It comprises an image forming unit 30 and a paper feeding unit 40.

The image of the document D placed on the document table is translated from a solid line position to a broken line position of the first mirror unit 11 including the illumination lamp 11A and the mirror 11B of the image reading unit 10 and a pair of opposing pairs. Second with mirror 12A
Exposure scanning is performed by the follow-up movement of the mirror unit 12 with respect to the first mirror unit 11 at a half speed.
An image obtained by the exposure scanning is formed on the image pickup device 14 via the projection lens 13, and is temporarily stored in a memory as an image signal through image processing.

Next, when the image signal is read from the memory and input to the laser writing unit 20, the laser beam generated by the semiconductor laser is rotationally scanned by the polygon mirror 22 rotated by the driving motor 21.

The projected laser beam is reflected and scanned by the movement of the rotating surface of the polygon mirror 22, passes through the fθ lens 23 and the cylindrical lens, and is exposed to the photosensitive drum 32 to which a charge is previously given by the charger 31. The surface is scanned and exposed. By this scanning exposure, an electrostatic latent image of a document image is formed on the photosensitive surface of the photosensitive drum 32. Therefore, the main scanning by the laser beam and the photosensitive drum 3
The electrostatic latent image of the original image is formed on the peripheral surface of the photoconductor drum 32 by the sub-scanning accompanying the rotation of 2. This electrostatic latent image is reversely developed by a developer carried by a developing sleeve 33A of the developing device 33 to be a toner image.

On the other hand, transfer paper P of a specified size is carried out of each paper feed cassette 41 loaded in the paper feed unit 40 by the operation of the discharge roller 41A of the paper feed cassette 41 to be stored, and is transferred via the transport roller 43. Paper is fed to the image transfer section.

The fed transfer paper P is transferred to registration rollers 44.
As a result, the toner image on the peripheral surface of the photosensitive drum 32 is adjusted, the timing is adjusted, and the toner image is synchronously fed to the transfer unit, charged by the transfer unit 34, and the toner image is transferred onto transfer paper.

Next, the transfer paper P is separated from the peripheral surface of the photosensitive drum 32 by the charge eliminating action of the separator 35, and is conveyed to the fixing device 37 via the conveying belt (conveying portion) 36, where the upper roller 37A and the lower roller 37B The toner is fused by heat and pressure.

The temperature of each of the upper roller 37A and the lower roller 37B is detected by a temperature sensor.
During the fixing operation, the temperature is controlled to be a predetermined set temperature by a temperature control described later. After the fixing, the sheet is discharged from the fixing device 37 via the conveying roller 38.

The transfer paper P discharged from the fixing device 37 is discharged onto a tray 50 via a discharge roller 45. On the other hand, the photosensitive drum 32 from which the transfer paper P has been separated removes residual toner by a blade 39A that is pressed against the cleaning device 39, cleans it, receives charge again by the charger 31, and enters the next image forming process.

<Electrical Configuration> The image forming apparatus configured as described above is electrically configured as shown in FIG.

That is, the operation of the image forming apparatus, the operation section 70 where various operations, instructions and selections are made by the user, the CPU 71 as control means for controlling the entire image forming apparatus in response to instructions from the operation section 70 And an image processing unit 73 that performs image processing such as image development in accordance with an instruction from the CPU 71.

The laser writing section 20, image forming section 30, paper feeding section 40, transport section 36, and fixing device 37 described above.
Are configured to perform a predetermined operation in accordance with an instruction from the CPU 71.

The fixing unit 37 is provided with a fixing temperature control unit 37C for controlling the fixing temperature and a fixing unit driving unit 37M for rotating and driving the upper roller 37A and the lower roller 37B. It is controlled from the.

The fixing temperature control section 37C includes a sensor for detecting the temperature of the fixing roller, and is configured to transmit the detection result of this sensor to the CPU 71 as digital data.

<Print Operation Start Time Control>
The processing procedure in the start time control of the printing operation will be described in detail with reference to the flowcharts in FIG.

When a copy start instruction is given on the operation unit 70, or when a print operation start instruction (start signal or the like) is given from an external device, the control unit 71 sends the instruction via the fixing temperature control unit 37C. The temperature of the fixing roller is detected.

In this embodiment, the fixing temperature is set to 200 ° C., and the idling area for standby is set to 120 °.
The description will be made on the assumption that the temperature is in the range of 150C to 150C. Also, 90 ° C to 120 ° C
° C in the temperature range, 60 ° C to 90 ° C in the temperature range, 30 ° C
６０60 is a temperature region, and 0 ° C.〜30 is a temperature region.

First, at the time of this temperature detection, the CPU 71 checks whether the fixing temperature is in an idling region (120 ° C. to 150 ° C.) (S1 in FIG. 3). If the fixing temperature is in the idling region, the timer is started simultaneously with the heating of the fixing roller (S2 in FIG. 3), and T1 is counted (S3 in FIG. 3).
3) Later, a printing operation other than fixing is started (FIG. 3).
S17).

This situation is shown in FIGS. 4 and 5. The fixing temperature is maintained in the idling region (120 ° C. to 150 ° C.) until time ta when there is an instruction to start the printing operation.
Then, an instruction to start the printing operation at time ta (FIG. 5)
(A)), the fixing temperature rises and the set temperature (200
At a time tb before the temperature reaches (.degree. C.), the count-up of the timer (FIG. 5C) triggers a printing operation other than fixing. Then, writing of the latent image on the photosensitive drum (FIG. 5D), development (FIG. 5E), and transfer (FIG.
(F)), conveyance immediately before the fixing device 37 is performed, and fixing is performed after the fixing temperature reaches the set temperature at time tc (see FIG. 5).
(G)) is performed.

In this case, the time required for the printing operation other than the fixing (writing of the latent image by the laser beam to the photosensitive drum to transport of the recording medium to the fixing device) is obtained in advance, and the time tb to the time tc is determined. You only have to decide.

Therefore, by starting the printing operation earlier by a necessary time until just before fixing, the fixing device 37 is started.
When the heat roller reaches the set temperature, the recording medium reaches the fixing device 37. Therefore, a long and unnecessary waiting time due to the temperature control of the fixing device 37 does not occur,
Good fixing can be performed.

In the above example, the temperature control in the case where the fixing temperature is in the idling region has been described. In addition, the fixing temperature may be lower than the idling region in order to save power in the case of a longer stop.

For example, when the fixing temperature at the time of receiving an instruction to start the printing operation is outside the above-mentioned idling region (from the temperature region to the temperature region), the printing operation is started from the start instruction according to the fixing temperature. It is desirable to change the time until the start (time set in the timer).

That is, when the temperature is outside the idling region in the temperature detection, the CPU 71 checks whether the fixing temperature is in the temperature region (90 ° C. to 120 ° C.) (S4 in FIG. 3). If the fixing temperature is in the temperature range, the timer is started simultaneously with the heating of the fixing roller (FIG. 3S
5) After the count of T2 (S6 in FIG. 3), a printing operation other than fixing is started (S17 in FIG. 3).

Similarly, if the above temperature detection indicates that the temperature is outside the temperature range, the CPU 71 checks whether the fixing temperature is within the temperature range (60 ° C. to 90 ° C.) (S7 in FIG. 3). If the fixing temperature is in the temperature range, a timer is started at the same time as the heating of the fixing roller (S8 in FIG. 3).
After counting 3 (S9 in FIG. 3), a printing operation other than fixing is started (S17 in FIG. 3).

Further, if the temperature is outside the temperature range in the above temperature detection, the CPU 71 checks whether the fixing temperature is within the temperature range (30 ° C. to 60 ° C.) (S1 in FIG. 3).
0). If the fixing temperature is in the temperature range, the timer is started simultaneously with the heating of the fixing roller (S11 in FIG. 3), and T4
After the count (S12 in FIG. 3), a printing operation other than fixing is started (S17 in FIG. 3).

If the temperature is detected outside the temperature range in the above temperature detection, the CPU 71 checks whether the fixing temperature is in the temperature range (0 ° C. to 30 ° C.) (S1 in FIG. 3).
3). If the fixing temperature is in the temperature range, the timer is started simultaneously with the heating of the fixing roller (S14 in FIG. 3), and T5
After the count (S15 in FIG. 3), a printing operation other than fixing is started (S17 in FIG. 3).

If the temperature does not belong to any of the above temperatures, the temperature is higher than the above. Therefore, the CPU 71 displays a message indicating that the temperature is higher than that on the display section 72 and stops the operation of the apparatus.

FIG. 6 shows that the fixing temperature at the time when an instruction to start the printing operation is given includes the idling area, the temperature area,
The state in each of the temperature region, the temperature region, and the temperature region is schematically shown.

In this case, the time from the start of the printing operation to the start of the printing operation is T1 in the idling area, T2 in the temperature area, T3 in the temperature area, and T3 in the temperature area. , And T5 if the temperature range.

In this case as well, the time required for the temperature rise and the time required for a printing operation other than fixing (writing of a latent image by a laser beam on a photosensitive drum to transport of a recording medium to a fixing device) are determined in advance. Here, each of T1 to T5 may be determined.

The inventors conducted experiments using an apparatus that requires about 5 seconds from writing a latent image on a photosensitive drum to transporting a recording medium to a fixing device. Good results were obtained.

Idling region: time to reach set temperature = 10 seconds: T1 = 5 seconds Temperature region: time to reach set temperature = 30 seconds: T2 = 25 seconds Temperature region: time to reach set temperature = 50 seconds: T3 = 45 Seconds Temperature range: Time to reach the set temperature = 70 seconds: T4 = 65 seconds Temperature range: Time to reach the set temperature = 90 seconds: T5 = 85 seconds Therefore, the printing operation is started earlier by the time required immediately before fixing. By doing so, the recording medium reaches the fixing device 37 when the heat roller of the fixing device 37 reaches the set temperature. Therefore, good fixing can be performed without generating a long and unnecessary waiting time due to the temperature control of the fixing device 37. Further, since T1 to T5 are changed according to the fixing temperature at the time when the start of the printing operation is instructed, it is possible to achieve both an appropriate waiting time and excellent fixing.

By the way, in the past, in most cases, the fixing temperature was the same for monochrome and color, but it is desirable to set the respective fixing temperatures separately. Therefore,
Set temperature for monochrome = 180 ° C, set temperature for color = 2
10 ° C. is set, and the time until the start of the printing operation is determined by referring to the fixing temperature when the printing operation is instructed and the set temperature of each mode.

FIG. 7 shows that the fixing temperature at the time when the start of the printing operation is instructed is the idling area, the temperature area,
In each of the temperature region, the temperature region, and the temperature region, the waiting time T1 until the start of the printing operation for each of the monochrome set temperature and the color set temperature.
To T5 and T6 to T10 are schematically shown.

In this case, the time from the instruction to start the monochrome print operation to the start of the print operation is T1 in the idling area, T2 in the temperature area, T3 in the temperature area, and temperature. It is defined as T4 in the case of an area, and T5 in the case of a temperature area.

Similarly, the time from the start of the color print operation to the start of the print operation is T6 in the idling area, T7 in the temperature area, T8 in the temperature area, and so on. The temperature range is defined as T9, and the temperature range is defined as T10.

Also in this case, the time required for the temperature rise and the time required for the printing operation other than fixing (writing of the latent image by the laser beam on the photosensitive drum to transport of the recording medium to the fixing device) (monochrome / color) May be determined in advance, and each of T1 to T10 may be determined.

The inventor conducted an experiment using an apparatus that requires about 5 seconds in the monochrome mode and about 15 seconds in the color mode for writing a latent image on the photosensitive drum and transporting the recording medium to the fixing device. As a result, good results were obtained with the following values.

Monochrome mode (Set temperature = 180 ° C.) Idling area: Time to reach set temperature = 8 seconds: T1 = 3 seconds Temperature area: Time to reach set temperature = 28 seconds: T2 = 23 seconds Temperature area: To set temperature Time to reach = 48 seconds: T3 = 43 seconds Temperature range: Time to reach the set temperature = 68 seconds: T4 = 63 seconds Temperature range: Time to reach the set temperature = 88 seconds: T5 = 83 seconds Color mode (Set temperature = 210 ° C) Idling area: time to reach set temperature = 12 seconds: T6 = 0 seconds Temperature area: time to reach set temperature = 32 seconds: T7 = 17 seconds Temperature area: time to reach set temperature = 52 seconds: T8 = 37 seconds Temperature Area: Time to reach the set temperature = 72 seconds: T9 = 57 seconds Temperature area: Time to reach the set temperature = 92 seconds: T10 = 77 seconds In this case, the set temperature in the monochrome mode is 180 ° C. By the print operation start is performed slightly shorter time than the case of 200 ° C..

In the color mode, the set temperature is set to 210
° C, the time required to reach the set temperature is slightly longer, but since the experiment was conducted with a device that performs multi-color image formation by rotating the photosensitive drum multiple times, the time until the start of printing operation is longer than in monochrome mode Has also become shorter.
As a result, the effect of shortening the time until the start of the printing operation is remarkable. In an apparatus capable of forming a multicolor image by one rotation of the photosensitive drum, it is expected that T6 to T10 will be slightly longer than this experimental value.

As described above, by starting the printing operation earlier by a necessary time until just before fixing, the recording medium reaches the fixing device 37 when the heat roller of the fixing device 37 reaches the set temperature. become. Therefore, good fixing can be performed without generating a long and unnecessary waiting time due to the temperature control of the fixing device 37. In addition, the fixing temperature, the set temperature, and the time required for the recording medium to reach the fixing device at the time when the start of the printing operation is instructed,
Since 1 to T10 are changed, it is possible to achieve both an appropriate waiting time and good fixing.

[0074]

As described above, according to the present invention, the following effects can be obtained. (1) In the image forming apparatus according to the first aspect, based on the temperature of the fixing unit at the time when the print operation start instruction is issued, the time from when the print operation start instruction is issued to when the print operation is started. Is controlled so that the print operation is started before the temperature of the fixing unit reaches the set temperature, so that the print operation is allowed before the heat roller temperature of the fixing device reaches the set temperature, and When the recording medium onto which the toner image has been transferred reaches the fixing device, the fixing device reaches the set temperature.

As a result, when an instruction to start the printing operation is given in the image formation stopped state, it is possible to perform satisfactory fixing without generating a long and unnecessary waiting time due to the temperature control of the fixing device. Become.

(2) In the image forming apparatus according to the second aspect, the instruction to start the printing operation is issued based on the temperature of the fixing means at the time when the instruction to start the printing operation is issued and the set temperature. The heat roller temperature of the fixing device reaches the set temperature by changing the time from the start to the start of the print operation and performing control such that the print operation is started before the temperature of the fixing unit reaches the set temperature. The fixing operation reaches a set temperature when the recording medium onto which the toner image has been transferred by the printing operation reaches the fixing unit.

As a result, when an instruction to start the printing operation is given in the image formation stopped state, it is possible to perform satisfactory fixing without generating a long and unnecessary waiting time due to the temperature control of the fixing device. Become.

Further, since the time until the start of the printing operation is changed with reference to both the temperature of the fixing means and the set temperature, the set temperature may be different depending on the content of image formation and the material of the recording medium. Even when it is set, it is possible to achieve both an appropriate waiting time and good fixing.

(3) In the image forming apparatus according to the third aspect of the present invention, the time changed by the control means is a time required for the temperature of the fixing means to reach the set temperature, and is recorded after the start of the printing operation. By making the time based on the time required for the media to reach the fusing means reduced,
The printing operation is allowed before the heat roller temperature of the fixing device reaches the set temperature, and the fixing device reaches the set temperature when the recording medium onto which the toner image has been transferred by the printing operation reaches the fixing device.

As a result, when an instruction to start the printing operation is given in the image formation stopped state, a good fixing can be performed with an appropriate waiting time without generating a long wasteful waiting time due to the temperature control of the fixing device. Can be performed.

(4) In the invention of the control method for an image forming apparatus according to the fourth aspect, the print operation is started after the print operation start instruction is issued based on the temperature of the fixing means at the time when the print operation start instruction is issued. By changing the time until the start of printing, and performing control so that the printing operation starts before the temperature of the fixing unit reaches the set temperature, the printing operation can be performed before the heat roller temperature of the fixing unit reaches the set temperature. The fixing device reaches the set temperature when the recording medium to which the toner image is transferred by the printing operation reaches the fixing device.

As a result, when an instruction to start the printing operation is given in the image formation stopped state, it is possible to perform excellent fixing without generating a long and unnecessary waiting time due to the temperature control of the fixing device. Become.

(5) In the control method of the image forming apparatus according to the fifth aspect, the printing operation is started based on the temperature of the fixing means at the time when the printing operation start instruction is given and the set temperature. The heat roller temperature of the fixing unit can be set by changing the time from when the instruction is issued until the start of the printing operation, and performing control so that the printing operation is started before the temperature of the fixing unit reaches the set temperature. The printing operation is allowed before the temperature reaches the temperature, and the fixing device reaches the set temperature when the recording medium onto which the toner image has been transferred by the printing operation reaches the fixing device.

As a result, when an instruction to start the printing operation is given in the image formation stopped state, it is possible to perform excellent fixing without generating a long and unnecessary waiting time due to the temperature control of the fixing device. Become.

Further, since the time until the start of the printing operation is changed with reference to both the temperature of the fixing means and the set temperature, the set temperature may be different depending on the content of the image formation and the material of the recording medium. Even when it is set, it is possible to achieve both an appropriate waiting time and good fixing.

(6) In the control method of the image forming apparatus according to the sixth aspect, the changing time is a time required for the temperature of the fixing means to reach the set temperature, and is recorded after the printing operation is started. By making the time based on the time required for the media to reach the fusing means reduced,
The printing operation is allowed before the heat roller temperature of the fixing device reaches the set temperature, and the fixing device reaches the set temperature when the recording medium onto which the toner image has been transferred by the printing operation reaches the fixing device.

As a result, when an instruction to start the printing operation is given in the image formation stopped state, a good fixing time can be achieved with an appropriate waiting time without generating a long useless waiting time due to the temperature control of the fixing device. Can be performed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an electrical configuration of an image forming apparatus used in an embodiment of the present invention for each functional block.

FIG. 2 is a cross-sectional view illustrating a mechanical cross-sectional configuration of the image forming apparatus used in the embodiment of the present invention.

FIG. 3 is a flowchart illustrating a processing procedure according to the embodiment of the present invention.

FIG. 4 is an explanatory diagram schematically showing a state of a rise in a fixing temperature and a state of a waiting time in the embodiment of the present invention.

FIG. 5 is a time chart schematically showing how a fixing temperature rises and a state of waiting time in the embodiment of the present invention.

FIG. 6 is an explanatory diagram schematically showing a state of a rise in a fixing temperature and a state of a waiting time in each embodiment of the present invention for each temperature region.

FIG. 7 is an explanatory diagram schematically showing how the fixing temperature rises and how the waiting time changes in each temperature region and the monochrome mode / color mode in the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Image reading part 20 Laser writing part 30 Image forming part 31 Charging device 32 Photoreceptor drum 33 Developing device 34 Transfer part 35 Separator 36 Conveying belt 37 Fixing device 40 Paper feeding part 41 Paper feeding cassette 44 Registration roller 50 Tray 70 Operating part 71 CPU 72 display unit 73 image processing unit P transfer paper (recording medium)

Claims (6)

[Claims] A fixing unit for fixing a developer to a recording medium; a temperature detecting unit for detecting a temperature of the fixing unit; and a printing unit based on the temperature of the fixing unit when a print operation start instruction is issued. Control means for changing the time from when the operation start instruction is issued to when the print operation is started, and performing control to start a print operation other than the fixing means before the temperature of the fixing means reaches a set temperature; An image forming apparatus comprising: 2. A fixing device for fixing a developer onto a recording medium, a temperature detecting device for detecting a temperature of the fixing device, and a control device for changing a set temperature of the fixing device. Based on the temperature of the fixing unit at the time when the print operation start instruction is issued and the set temperature, the time from when the print operation start instruction is issued until the print operation is started is changed, and the temperature of the fixing unit is changed. An image forming apparatus that performs control so as to start a printing operation other than the fixing unit before the temperature reaches a set temperature. 3. The control unit changes the time from the time required for the temperature of the fixing unit to reach a set temperature to the time required for the recording medium to reach the fixing unit after starting a printing operation. The image forming apparatus according to claim 1, wherein the image forming apparatus is based on a time obtained by subtracting a required time. 4. An image forming apparatus comprising: a fixing unit for fixing a developer onto a recording medium; a temperature detecting unit for detecting a temperature of the fixing unit; and a control unit for controlling a temperature of the fixing unit. A method, comprising: changing a time from when a print operation start instruction is issued to when a print operation is started, based on the temperature of the fixing unit at the time when the print operation start instruction is issued, and A control method for starting a printing operation before the temperature reaches a set temperature. 5. An image forming apparatus comprising: a fixing unit for fixing a developer on a recording medium; a temperature detecting unit for detecting a temperature of the fixing unit; and a control unit for setting a set temperature of the fixing unit. Changing the time from when the print operation start instruction is issued to when the print operation is started, based on the temperature of the fixing unit at the time when the print operation start instruction is issued and the set temperature. Controlling the image forming apparatus to start printing other than the fixing unit before the temperature of the fixing unit reaches a set temperature. 6. The time required for the change is from a time required for the temperature of the fixing unit to reach a set temperature to a time required for the recording medium to reach the fixing unit after a printing operation is started. The method according to claim 4, wherein the control method is based on the reduced time.