JP2003316200A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus in which completion of image formation can be made earlier by efficiently controlling a fixing device. <P>SOLUTION: The image forming apparatus is provided with: a fixing device 157 for carrying out fixing at a specified temperature by using a heater receiving power supply; a temperature detecting means 157S for detecting the temperature of the fixing device; and a control means 101 for performing temperature control of a heater and control of the processing speed according to the detection result of the temperature detecting means so that the target fixing temperature is maintained. The processing speed is varied by the control means when the temperature of the fixing device is not the target fixing temperature by referring to the detection result of the temperature detecting means. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to efficient operation control of an image forming apparatus using a heater for fixing an image.

[0002]

2. Description of the Related Art Generally, in an electrophotographic image forming apparatus, in order to thermally fix a toner image transferred on one surface of an image support such as a transfer paper to the image support, the image support of the image support is fixed. A fixing heating roller in contact with one surface,
A fixing device including a pressure roller arranged so as to be pressed against the fixing heating roller is widely used.

In a certain type of fixing device, a heater lamp such as a halogen lamp (hereinafter, simply referred to as "heater") is provided in the roller as a heating source of the fixing heating roller.

[0004]

By the way, it takes a certain amount of time from the power-on of the image forming apparatus until the heater is heated to a predetermined temperature (hereinafter, referred to as "fixing target temperature") to enable image formation. Requires. The period until the image can be formed is the warm-up period.

Further, when a large amount of images are formed, the heat of the fixing device is taken by the recording paper, and the fixing device may fall below the fixing target temperature. In this case, control is performed so that image formation is temporarily suspended until the fixing device returns to the fixing target temperature.

If the fixing device is below the target fixing temperature at the time of starting the image formation, the fixing device reaches the fixing target temperature by performing warm-up even if one image is formed. I have to wait until.

A large amount of time may be required from the control of the fixing device as described above to the completion of image formation. In particular, the problem becomes serious in a high-speed copying machine having a long warm-up period.

The present invention has been made to solve the above problems, and an object of the present invention is to enable efficient control of a fixing device to accelerate the completion of image formation. To provide a forming apparatus.

[0009]

The present invention for solving the above problems is as described below. (1) According to a first aspect of the invention, a fixing device for fixing a predetermined temperature by a heater supplied with electric power, a temperature detecting means for detecting a temperature of the fixing device, and a detection result of the temperature detecting means are provided. Temperature control of the heater so as to maintain the target fixing temperature and control means for controlling the process speed, the control means refers to the detection result of the temperature detection means, and determines the temperature of the fixing device. The image forming apparatus is characterized in that the process speed is changed when is not the fixing target temperature.

In the present invention, the control means refers to the detection result of the temperature detection means and controls so as to change the process speed and execute image formation when the temperature of the fixing device is not the fixing target temperature. For example, when the temperature of the fixing device becomes lower than the fixing target temperature, the process speed is set to a low speed and the image formation is executed. The efficient control of the fixing device makes it possible to accelerate the completion of image formation.

(2) According to a second aspect of the present invention, the control means, when the number of jobs is within a predetermined number, during the warm-up of the fixing device and before the target fixing temperature is reached, the control speed is higher than a normal speed. 2. The image forming apparatus according to claim 1, wherein the process speed is changed to a low speed at which the fixing property of the fixing device can be ensured and image forming is started.

According to the present invention, when the temperature of the fixing device is not the target fixing temperature in the above (1) and the image formation is executed by changing the process speed, if the job is within a predetermined quantity, the warming up is performed. Before the fixing target temperature is reached, the process speed is changed to a lower speed, which is slower than the first speed and is capable of ensuring the fixability of the fixing device, and image formation is started. Such efficient control of the fixing device makes it possible to accelerate the completion of image formation.

(3) According to a third aspect of the present invention, the control means controls the process speed to a first speed when the temperature of the fixing device is the fixing target temperature, and is less than the fixing target temperature. In the case of, the process speed is changed to a second speed slower than the first speed and capable of securing the fixing property in the fixing device.
The image forming apparatus according to any one of 1.

According to the present invention, in the above (1) or (2), when the temperature of the fixing device is the fixing target temperature, the process speed is controlled to the first speed (high speed or normal speed), and the fixing is performed. When the temperature of the fixing device is lower than the fixing target temperature, the process speed is changed to the second speed (low speed) which is slower than the first speed and can secure the fixing property in the fixing device. Such efficient control of the fixing device makes it possible to accelerate the completion of image formation.

(4) According to a fourth aspect of the present invention, the control means controls the process speed to a first speed when the temperature of the fixing device is the fixing target temperature, and the process speed is controlled during execution of image formation. When it is detected that the temperature of the fixing device has dropped below the fixing target temperature, the image is detected after detecting that the temperature of the fixing device has returned to the fixing target temperature after temporarily suspending image formation. 4. The control according to claim 1, wherein control is performed to select either restarting the formation or changing the process speed to a second speed lower than the first speed. The image forming apparatus described above.

According to the present invention, when it is detected that the temperature of the fixing device is lower than the fixing target temperature during the image formation, the temperature of the fixing device is temporarily changed after the image formation is temporarily stopped. Either the image formation is restarted after detecting the return to the fixing target temperature, or the process speed is changed to the second speed slower than the first speed without interruption. Take control.

In this case, the amount of jobs to be image-formed is referred to, and if the image formation is for a small amount of jobs, the process speed is changed and the image formation is executed without interruption.
Such efficient control of the fixing device makes it possible to accelerate the completion of image formation.

(5) According to a fifth aspect of the present invention, the control means selects the maximum speed within the range in which the fixability of the fixing device can be secured from a plurality of speed candidates as the second speed. The image forming apparatus according to claim 4, wherein the image forming apparatus is selected.

According to the present invention, when it is detected that the temperature of the fixing device has dropped below the fixing target temperature during the execution of image formation, the process speed is changed to the second speed lower than the first speed. When it is selected to do so, the maximum speed at which the fixability of the fixing device can be secured is selected from a plurality of speed candidates as the second speed.

In this case, referring to the amount of jobs to be image-formed and the like, if the image formation is for a small amount of jobs, the image formation is interrupted by changing to the highest process speed within the range where the fixability can be secured. Run without. By performing such efficient control of the fixing device, it becomes possible to complete the image formation as early as possible while maintaining the image quality.

(6) The invention according to claim 6 is characterized in that the control means refers to the set remaining amount of the job, and makes the selection so that the job is completed sooner. The image forming apparatus according to claim 4 or claim 5.

In the present invention, the above (4) or (5)
Then, the image formation is restarted after detecting that the temperature of the fixing device has returned to the fixing target temperature after the image formation is temporarily interrupted, or it is slower than the first speed without interrupting the image formation. For either selection of changing the process speed to the second speed that can secure the fixing property in the fixing device,
The set remaining amount of the job is referred to, and the control is performed so that the job ends earlier.

That is, with reference to the remaining amount of the job to be image-formed, it is selected whether to suspend / resume the job or continue at a low speed. Such efficient control of the fixing device makes it possible to accelerate the completion of image formation.

(7) According to a seventh aspect of the invention, the control means controls the rotation of the fixing roller to be decelerated or stopped during a period in which the recording paper does not pass through the fixing roller in the fixing device. The image forming apparatus according to any one of claims 1 to 6, wherein:

According to the present invention, when the recording paper does not pass through the fixing roller in the fixing device, the rotation of the fixing roller is controlled to be decelerated or stopped so that one fixing roller having a heater does not have a heater. The heat conduction to the other fixing roller is suppressed.

By controlling the fixing device as described above, it is possible to prevent the temperature of the fixing device from lowering, prevent the interruption of the image formation and the decrease of the process speed in advance, and accelerate the completion of the image formation. .

(8) The invention according to claim 8 is characterized in that the control means controls to a plurality of process speeds in accordance with the temperature of the fixing device. The image forming apparatus according to claim 1.

According to the present invention, when the temperature of the fixing device is not the target fixing temperature, the process speed is changed so as to execute the image formation, so that the fixing property can be secured by the fixing device. The process speed is controlled in multiple stages according to the temperature.

By controlling the fixing device as described above, when the temperature of the fixing device is lowered, the image formation can be executed at a slow process speed according to the lowered temperature, so that the interruption of the image formation is prevented. In the end, it is possible to speed up the completion of image formation.

(9) The invention according to claim 9 is an image forming apparatus capable of reading the next job during execution of image formation, wherein the control means is a process slower than a standard process depending on the temperature of the fixing device. The next job reading is not performed when image formation is being executed at a speed.
The image forming apparatus according to claim 8.

According to the present invention, in an apparatus capable of reading the next job during execution of image formation, when the image formation is being executed at a process speed slower than the standard according to the temperature drop of the fixing device, the next job is read. It is controlled not to do.

By such control, the image formation at the process speed lower than the standard during execution is completed, and after the fixing device recovers to the fixing target temperature, the next job is read and executed, and the fixing device is executed. Since it is possible to prevent the next job from being continuously executed at a low speed in the state where the temperature is lowered, it is possible to finally complete the image formation earlier.

(10) An invention according to claim 10 is an image forming apparatus comprising display means for displaying a state, wherein the control means is performing image formation at a process speed slower than a standard and 10. The image forming apparatus according to claim 9, wherein a message indicating that the next job is not read is displayed when the job is not read.

According to the present invention, in an apparatus capable of reading the next job during execution of image formation, when the image formation is being executed at a process speed slower than the standard according to the temperature drop of the fixing device, the next job is read. The control is performed so as not to perform, and the control is displayed.

By such control, it is possible to prevent the next job from being continuously executed at a low speed in the state where the temperature of the fixing device is lowered, and finally it is possible to accelerate the completion of image formation. It becomes possible to inform the user of the state.

(11) The invention according to claim 11 is an image forming apparatus comprising a second heater as a heat source of the fixing device, wherein the control means is slower than a standard according to the temperature of the fixing device. 11. When the image formation is being performed at the process speed, the second heater is turned on to prevent the temperature of the fixing device from decreasing. The image forming apparatus described above.

According to the present invention, when image formation is being executed at a process speed lower than the standard depending on the temperature of the fixing device,
By turning on the second heater (preliminary heater), the temperature of the fixing device is prevented from further lowering. By such control, it is possible to prevent interruption of the image formation being executed and further decrease of the process speed, and finally it is possible to accelerate the completion of the image formation.

[0038]

BEST MODE FOR CARRYING OUT THE INVENTION An image forming apparatus according to an embodiment of the present invention will be described in detail below with reference to the drawings.
Although not described in the claims, the operation method or control method of the image forming apparatus of the present embodiment is also a part of the present embodiment.

<First Embodiment> FIG. 1 is a circuit configuration diagram showing a first embodiment of the image forming apparatus of the present embodiment. 3 is a schematic cross-sectional view showing the mechanical structure of the image forming apparatus of this embodiment. In addition,
In FIG. 1 and FIG. 3, only the parts necessary for explaining the operation of the present embodiment are described, and other known parts are omitted.

This image forming apparatus 100 is AC (alternating current).
Electric power is supplied from a commercial power supply of about 100 V or AC200 V, and the AC from the commercial power supply is used as it is for the fixing device, and a direct current having a necessary voltage is generated inside the device and supplied to each part.

Reference numeral 101 denotes a control section as control means for controlling each section, which controls the following (1) to (11). (1) Referring to the detection result of the temperature detecting means, the process speed is changed when the temperature of the fixing device is not the fixing target temperature. (2) When the fixing device is warming up and before the fixing target temperature is reached, the process speed is changed to a lower speed that is slower than the normal speed and the fixing property of the fixing device can be secured, and image formation is started. (3) When the temperature of the fixing device is the fixing target temperature, the process speed is controlled to the first speed, and when it is lower than the fixing target temperature, it is slower than the first speed and the fixability in the fixing device can be secured. Change the process speed to the second speed. (4) When it is detected that the temperature of the fixing device has dropped below the target fixing temperature during image formation, it is possible that the temperature of the fixing device returns to the target fixing temperature after the image formation is temporarily interrupted. Control is performed to select either restarting image formation after detection or changing the process speed to a second speed lower than the first speed without interruption. (5) When it is detected that the temperature of the fixing device has dropped below the target fixing temperature during execution of image formation, and when the process speed is changed to a second speed lower than the first speed As the second speed, the maximum speed that can secure the fixability in the fixing device is selected from a plurality of speed candidates. (6) The set remaining amount of the job is referred to, and the selection of the above (4) or (5) is performed so that the job is completed sooner. (7) The rotation of the fixing roller is controlled to be decelerated or stopped during a period in which the recording paper does not pass through the fixing roller in the fixing device. (8) A plurality of process speeds are controlled according to the temperature of the fixing device. (9) When image formation is being executed at a process speed lower than the standard depending on the temperature of the fixing device, the next job reading is not performed. (10) When image formation is being executed at a process speed lower than the standard and the next job is not read, a message indicating that the next job will not be read is displayed. (11) When image formation is being executed at a process speed lower than the standard according to the temperature of the fixing device, the second heater is turned on to prevent the temperature of the fixing device from decreasing.

The control section 101 may be a dedicated control means for executing heater control based on the fixing temperature,
It may also be used as a control unit that controls the entire image forming apparatus.

Reference numeral 110 denotes a power source section as a power source means,
Power is supplied from a commercial power source of 100 V or AC 200 V, and DC is generated by rectifying AC in order to generate direct current of a required voltage inside the device.

Reference numeral 120 denotes an operation display unit, on which various operation inputs are made by the user to the image forming apparatus 100, and various states and messages of the image forming apparatus 100 are displayed.

Reference numeral 130 denotes an image processing unit that performs necessary predetermined image processing on image data from an external device or a scanner unit (not shown), and the processed image data is sent to a print engine, which will be described later. Sent.

Reference numeral 140 denotes a paper feeding / conveying unit that feeds the recording paper p to a print engine, which will be described later, and conveys the recording paper p during image formation at a predetermined speed under the control of the control unit 101. The paper feeding / conveying unit 140 includes a paper feeding roller 141 for feeding paper, a registration roller 142 for feeding the recording paper p at a timing when forming an image,
A transport belt 143 that transports the recording paper on which the toner image is transferred to the fixing unit, and an output roller 144 that outputs the fixed recording paper p to the outside of the machine are configured.

Reference numeral 150 denotes a print engine for forming an image according to image data on the recording paper p, and a band electrode 152.
An image writing unit 153 that writes an electrostatic latent image according to image data on the image carrier to which static electricity has been applied by the developing unit 15 that develops the electrostatic latent image on the image carrier into a toner image.
4, a transfer unit 155 that transfers the toner image on the image carrier onto the recording paper p, a cleaning unit 156 that removes the residual toner on the image carrier, and the toner image on the recording paper p is stabilized by heat and pressure. A fixing temperature sensor 157S as a temperature detecting unit that detects the surface temperature of the fixing unit 157 and the fixing heating roller of the fixing unit 157 and transmits the detection result to the control unit 101.
It has and.

Reference numeral 157 denotes a fixing unit for thermally fixing the toner image transferred on the transfer paper, and a fixing heater serving as a main heater as a heating source is a fixing roller 157.
Similarly, a fixing heater serving as a sub-heater as a heating source is provided inside the fixing roller 157b.

The image forming apparatus of this embodiment is
It is assumed that image formation can be performed at a plurality of process speeds (speeds of electrostatic latent image formation, development, transfer, and fixing). That is, not only at the maximum or standard process speed (“first speed” in the claims) but also at a slower process speed (“second speed” in claims), the conveyance of the recording paper, the electrostatic latent image Forming, developing, transferring, and fixing can be performed.

The control operation relating to the fixing of the image forming apparatus of the present embodiment configured as described above will be described in detail for each embodiment with reference to the flowcharts of FIG. 3 and thereafter.

<Process speed control during continuous image formation> First, when the image forming apparatus is powered on, the control unit 10
In No. 1, the fixing heater is turned on, and the surface temperature of the fixing heating roller heated by the heater is monitored by the fixing temperature sensor 157S. When the temperature of the fixing heating roller reaches the fixing target temperature by the heating of the fixing heater, the control unit 1
01 controls each unit to start image formation. The warm-up period is from when the heater is turned on to when the fixing target temperature is reached and image formation is started.

When images are continuously formed on a plurality of recording papers, the control unit 101 periodically checks with the fixing temperature sensor 157S whether the temperature of the fixing roller can be maintained near the fixing target temperature. (Fig. 3S
1).

When the fixing roller maintains the fixing target temperature by this temperature check of the fixing roller (S2 in FIG. 3).
N), the image formation is continued at the maximum or standard process speed (electrostatic latent image formation, development, transfer, and fixing speed) (S3 in FIG. 3).

If the fixing roller does not maintain the fixing target temperature by the temperature check of the fixing roller and is below the fixing target temperature (Y in FIG. 3 S2), the control unit 1
01 displays a warning that the temperature of the fixing unit has decreased on the operation display unit 120 (S4 in FIG. 3).

Then, with reference to the detected temperature of the fixing roller at the present time and the remaining amount of the job being executed, a slow process speed for ensuring the fixability is calculated by the present fixing temperature, and the slow process speed is calculated. Either the job is completed at the process speed or the image is formed at the maximum or standard process speed after the image formation is temporarily interrupted and the fixing target temperature is restored, whichever comes first. Whether to do it is calculated.

If the remaining amount of the job being executed is small, completion is faster if image formation is performed at a slow process speed without interrupting image formation (continuation at low speed in S3 in FIG. 3). Image formation is performed at a process speed according to temperature (S6 in FIG. 3).

Further, when the remaining amount of the job being executed is not small, the image formation is not executed at a low speed, but the image formation is interrupted and the image formation is executed at a high process speed because the completion is faster ( In step S5 of FIG. 3, restarting after interruption), image formation is temporarily interrupted until the fixing roller recovers to the fixing target temperature (steps S7 and S8 in FIG. 3), and image formation is executed (restarted) at the maximum or standard process speed (FIG. 3). 3S9).

That is, in this embodiment, the fixing device can be efficiently controlled by changing the process speed according to the fixing temperature lower than the fixing target temperature and continuing the image formation. It is possible to accelerate the completion of formation. Also, when the remaining amount of the job is large, instead of continuing the image formation at a slow process speed, the image formation is temporarily stopped and the fixing temperature is recovered, and then the image formation is performed at the maximum or standard process speed. By restarting, the end of image formation is not delayed.

In the above embodiment, when the slow process speed is set in accordance with the detected temperature of the fixing device, controlling the slow process speed to a plurality of speeds deteriorates the fixability. It is desirable in that the image formation can be continued without performing the process.

For example, it is assumed that the process speed of 65 sheets / minute at the target fixing temperature (first fixing target temperature) is a standard or maximum condition ("first speed" in claims). Then, a plurality of candidates are set in advance as the second speed lower than the first speed, and, for example, a process speed of 45 sheets / minute (second speed) is set at a second target fixing temperature lower than the first fixing target temperature. 2), a process speed (second speed) of 30 sheets / min at a third fixing target temperature lower than the second fixing target temperature, and 20 sheets / min at a fourth fixing target temperature lower than the third fixing target temperature. The process speed (second speed), and so on.

From the plurality of candidates for the second speed, it is most desirable to select the highest speed that can secure the fixability and execute the image formation, as a result, in order to improve the productivity.

<Process speed control during warm-up>
First, when the image forming apparatus is powered on, the control unit 1
In 01, the fixing heater is turned on, and the surface temperature of the fixing heating roller heated by the heater is monitored by the fixing temperature sensor 157S. Then, in the case of normal control, after the temperature of the fixing heating roller reaches the fixing target temperature by the heating of the fixing heater, the control unit 101 controls each unit to start image formation. In other words, the warm-up period is from the lighting of the heater to the start of image formation after the fixing target temperature is reached, and image formation was not executed.

In this embodiment, if there is an unexecuted job at the time of warming up, the control unit 101
The amount of jobs is checked (S1 in FIG. 4). In this case, the amount of jobs becomes a boundary between whether the image formation is completed faster when the image formation is started earlier at the slow process speed, or when the image formation is started later even at the high process speed. It is an amount.

If the job is less than the predetermined amount (Y in FIG. 4 S1), the fixing target temperature (first fixing target temperature)
When the lower second fixing target temperature is reached (Y in FIG. 4S2), image formation is executed at a slow process speed (FIG. 4S).
3). In this case, for a small amount of jobs, it is faster to start image formation earlier even if the process speed is slow.

If the job is equal to or more than the predetermined amount (N in FIG. 4S1), the high-speed process is reached after the first fixing target temperature higher than the second fixing target temperature is reached (Y in FIG. 4S4). Image formation is executed at a speed (S5 in FIG. 4). In this case, for a large number of jobs, starting the image formation at a high process speed will result in faster completion even if the start is slow.

As described above, this embodiment is an image forming apparatus capable of executing image formation by changing the process speed when the temperature of the fixing device is not the fixing target temperature (first fixing target temperature). If the job is within the specified quantity,
During warming up and before the fixing target temperature is reached, the process speed is changed to a lower speed, which is slower than the first speed and at which the fixing property of the fixing device can be secured, and image formation is started to be executed. Can be efficiently controlled, and the completion of image formation can be accelerated.

Also in this case, the third fixing target temperature and the fourth fixing target temperature lower than the second fixing target temperature are set, and the completion is the earliest according to the job amount and the process speed. It is desirable to start image formation so that

<Control of Fixing Device During Paper Interval> When continuous image formation is executed based on a large number of jobs, the fixing roller may lose heat by the recording paper p and maintain the target fixing temperature. It can be difficult. Therefore, in each of the above-described embodiments, the process speed is changed to continue the image formation. In this embodiment, a method for minimizing the temperature drop of the fixing device even during image formation will be described.

During execution of image formation, the control section 101 executes the routine for fixing the fixing device at the time of sheet feeding shown in FIG. First, the heater is turned on during image formation to keep the fixing roller warm (heating) (FIG. 5S1).

Then, it is checked whether or not the job is being executed (is it not interrupted) (FIG. 5 S2). Further, it is checked whether or not the recording paper p to which the toner image is transferred is present and the paper discharge sensor is turned on (FIG. 5S3). If the paper discharge sensor is turned on while the job is being executed (see FIG. 5S
2 is Y, S3 is Y), and the fixing roller is rotating.

Here, the process waits until the time set for each discharged recording paper size (paper discharge size) elapses (see FIG. 5S).
4) That is, after waiting for the recording paper p to pass through the fixing device, the control unit 101 stops or decelerates the rotation of the fixing roller (S5 in FIG. 5). Then, the deceleration or stop of the fixing roller is continued until the deceleration / stop time set according to the sheet interval time at the time of passing the sheet passes (N in S5 and S6 in FIG. 5).

Then, after the deceleration / stop time determined according to the sheet interval time during sheet passing (Y in S6 in FIG. 5), the normal operation is resumed and the deceleration or stop of the fixing roller is released (FIG. 5S7).

As described above, in this embodiment, while the recording paper does not pass through the fixing roller in the fixing device, the rotation of the fixing roller is controlled so as to be decelerated or stopped so that the heater is provided. The heat conduction from the fixing roller (heat roller) to the other fixing roller (pressure roller) having no heater is suppressed, and the temperature decrease is suppressed.
For this reason, the frequency of interruption of image formation and reduction of the process speed is reduced, and the image formation can be executed quickly.

<Job Reservation Acceptance Control> There is an image forming apparatus capable of accepting reservations for other jobs during job execution. In the above embodiment, when a large number of jobs are continuously executed, when the temperature falls below the target fixing temperature, the process speed is changed to the low speed side to continue the image formation.

Therefore, in this embodiment, when there is a job being executed and a reservation for another job occurs, the reservation is accepted or temporarily stopped to fix the job. It is possible to selectively control whether to recover the temperature of the vessel.

Here, if a reservation for another job is made from the operation display unit 120 while a certain job is being executed, the control unit 101 confirms whether the fixing roller maintains the fixing target temperature (S1 in FIG. 6). . Here, if the fixing roller has the fixing target temperature (Y in FIG. 6S1), the reservation of the job is accepted without any problem (FIG. 6S2).

If the fixing roller temperature is lower than the target fixing temperature (N in FIG. 6S1), the sub-heaters other than the main heater are turned on (FIG. 6S3). Then, the control unit 101 checks again whether the fixing roller maintains the fixing target temperature (S4 in FIG. 6). If the fixing roller has the fixing target temperature (Y in FIG. 6S4), the reservation of the job is accepted (FIG. 6S2).

If the fixing roller is below the target fixing temperature (N in FIG. 6S4) despite the sub-heater lighting, the control unit 101 stops accepting the reservation of the job (S5 in FIG. 6), and The operation display unit 120 displays that the acceptance of the reservation has been stopped (S6 in FIG. 6).

By such control, even when the job being executed is image formation at a process speed slower than the standard, the job is terminated and the next job is started after the fixing device is restored to the fixing target temperature. It is possible to prevent the next job from being continuously executed at a low speed in a state where the temperature of the fixing device is lowered by executing the reading and execution of the image, so that it is possible to finally complete the image formation earlier. . Further, by displaying the job acceptance stop on the operation display unit 120, the user is notified of the state of the apparatus. In this display, it may be notified that the reason is the temperature drop of the fixing device.

<Job Reservation Acceptance Control> In the above job reservation acceptance control, the reserved job is accepted when the target fixing temperature is maintained. On the other hand, the job reservation acceptance control is slightly modified.

Here, if a reservation for another job is made from the operation display unit 120 while a certain job is being executed, the control unit 101 confirms whether the fixing roller maintains the fixing target temperature (S1 in FIG. 7). . If the fixing roller has the fixing target temperature (Y in FIG. 7S1), the reservation of the job is accepted without any problem (FIG. 7S2).

If the fixing roller is below the fixing target temperature (N in FIG. 7S1), the sub-heaters other than the main heater are turned on (FIG. 7S3). Then, the control unit 101 checks again whether the fixing roller maintains the fixing target temperature (S4 in FIG. 7). Here, if the fixing roller has a second fixing target temperature lower than the fixing target temperature (see FIG. 7).
The job reservation is accepted (Y in S4) (S2 in FIG. 7).

If the fixing roller is below the second target fixing temperature despite the lighting of the sub-heater (S4 in FIG. 7).
N), the control unit 101 stops accepting the reservation of the job (FIG. 7S5) and also displays on the operation display unit 120 that the acceptance of the job reservation is stopped (FIG. 7S).
6).

Since the preliminary heater is turned on as described above, it is difficult for the temperature to fall below the second fixing target temperature, and the process speed of the job being executed or the reserved job does not drop further.

That is, in the present embodiment, when image formation is being executed at a process speed slower than the standard according to the temperature of the fixing device, the fixing device is turned on by turning on the second heater (preliminary heater). It is designed to prevent further temperature drop. By such control, it is possible to prevent interruption of the image formation being executed and further decrease of the process speed, and finally it is possible to accelerate the completion of the image formation.

[0086]

As described above, according to the present invention, the following effects can be obtained. (1) According to the first aspect of the invention, referring to the detection result of the temperature detecting means, when the temperature of the fixing device is not the target fixing temperature, the process speed is changed so as to execute the image formation. For example, when the temperature of the fixing device becomes lower than the fixing target temperature, the process speed is set to a low speed and the image formation is executed. The efficient control of the fixing device makes it possible to accelerate the completion of image formation.

(2) In the invention according to claim 2, when the temperature of the fixing device is not the fixing target temperature in the above (1) and the image formation is executed by changing the process speed, the number of jobs is within the predetermined number. If there is, before the fixing target temperature is reached during warming up, the process speed is changed to a lower speed that is slower than the first speed and is capable of ensuring the fixability in the fixing device, and image formation is started. Such efficient control of the fixing device makes it possible to accelerate the completion of image formation.

(3) In the invention described in claim 3, in the above (1) or (2), when the temperature of the fixing device is the fixing target temperature, the process speed is set to the first speed (high speed,
Alternatively, the process speed is changed to a second speed (low speed) which is slower than the first speed and can secure the fixability in the fixing device when the fixing device is below the target fixing temperature. Such efficient control of the fixing device makes it possible to accelerate the completion of image formation.

(4) In the invention described in claim 4, in the above (1) to (3), when it is detected that the temperature of the fixing device has dropped below the target fixing temperature during image formation, the image is Whether the image formation is restarted after detecting that the temperature of the fixing device has returned to the fixing target temperature after the formation is temporarily interrupted, or the process speed is changed to the second speed lower than the first speed. Control to select either one. In this case, the amount of jobs to be image-formed, etc. is referred to, and if the image formation of a small amount of jobs is performed, the process speed is changed and the image formation is executed without interruption. Such efficient control of the fixing device makes it possible to accelerate the completion of image formation.

(5) In the invention according to claim 5, in the above (4), it is detected that the temperature of the fixing device has dropped below the target fixing temperature during the image formation.
When it is selected to change the process speed to the second speed, which is slower than the first speed, the highest speed that can secure the fixability in the fixing device is selected from the plurality of speed candidates for the second speed. Select a speed. In this case, referring to the amount of jobs to be image-formed, if the image formation of a small amount of jobs,
The image forming process is executed without interruption by changing the process speed to the highest process speed that can secure the fixing property. By performing such efficient control of the fixing device, it becomes possible to complete the image formation as early as possible while maintaining the image quality.

(6) In the invention described in claim 6, in the above (4) or (5), after detecting that the temperature of the fixing device has returned to the target fixing temperature after the image formation is temporarily interrupted, Selection of either restarting image formation or changing the process speed to a second speed which is slower than the first speed and which can secure the fixability in the fixing device without interrupting the image formation , Refer to the remaining amount of the set job,
The control is performed so that the job ends earlier. That is,
By referring to the remaining amount of the job to be image-formed, it is possible to select whether to suspend / resume the job or continue at a low speed. Such efficient control of the fixing device makes it possible to accelerate the completion of image formation.

(7) In the invention described in claim 7, in the above (1) to (6), the rotation of the fixing roller is decelerated or stopped during the period when the recording paper does not pass through the fixing roller in the fixing device. By controlling, heat conduction from one fixing roller having a heater to the other fixing roller not having a heater is suppressed. By controlling the fixing device in this way, the temperature of the fixing device is prevented from lowering, interruption of image formation and reduction of the process speed can be prevented in advance, and the completion of image formation can be accelerated.

(8) In the invention described in claim 8, in the above (1) to (7), when the temperature of the fixing device is not the target fixing temperature, the process speed is changed so that the image formation is executed. Therefore, the process speed is controlled in a plurality of stages according to the temperature of the fixing device so that the fixing property can be secured in the fixing device. By controlling the fixing device in this way, when the temperature of the fixing device is lowered, image formation can be executed at a slow process speed according to the lowered temperature, so that interruption of image formation can be prevented and It is possible to accelerate the completion of image formation.

(9) In the invention described in claim 9, in the above-mentioned (1) to (8), in the apparatus capable of reading the next job during the execution of image formation, it is slower than the standard according to the temperature drop of the fixing device. When image formation is being executed at the process speed, control is performed so that the next job reading is not performed. By such control, the image formation at the process speed lower than the standard during execution is completed, the fixing device is restored to the fixing target temperature, and the next job is read and executed, and the temperature of the fixing device is changed. Since it is possible to prevent the next job from being continuously executed at a low speed in the lowered state, it is possible to speed up the completion of image formation in the end.

(10) According to the tenth aspect of the present invention, in the above (9), in the apparatus capable of reading the next job during the execution of the image formation, the image is formed at a process speed slower than the standard according to the temperature decrease of the fixing device. When the formation is being executed, the control is performed so that the next job reading is not performed, and the control is displayed. By such control, it is possible to prevent the next job from being continuously executed at a low speed when the temperature of the fixing device is lowered, and finally it is possible to accelerate the completion of image formation. It becomes possible to inform the user.

(11) In the invention described in claim 11, in the above (1) to (10), when the image formation is being executed at a process speed slower than the standard according to the temperature of the fixing device, the second
By turning on the heater (preliminary heater), the temperature of the fixing device is prevented from further lowering. By such control, it is possible to prevent interruption of the image formation being executed and further decrease of the process speed, and finally it is possible to accelerate the completion of the image formation.

[Brief description of drawings]

FIG. 1 is a configuration diagram illustrating an example of an electrical configuration of an image forming apparatus according to an exemplary embodiment of the present invention.

FIG. 2 is a configuration diagram showing an example of a mechanical configuration of the image forming apparatus according to the embodiment of the present invention.

FIG. 3 is a flowchart showing an operation of the image forming apparatus according to the embodiment of the present invention.

FIG. 4 is a flowchart showing an operation of the image forming apparatus according to the exemplary embodiment of the present invention.

FIG. 5 is a flowchart showing an operation of the image forming apparatus according to the exemplary embodiment of the present invention.

FIG. 6 is a flowchart showing an operation of the image forming apparatus according to the exemplary embodiment of the present invention.

FIG. 7 is a flowchart showing an operation of the image forming apparatus according to the exemplary embodiment of the present invention.

[Explanation of symbols]

100 image forming apparatus 101 control unit 110 power supply 120 Operation display section 130 Image processing unit 140 Paper Feed Conveyor 150 print engine

Continued front page    (72) Inventor Ichimichi Yamauchi             2970 Ishikawa-cho, Hachioji-shi, Tokyo Konica stock             Inside the company (72) Inventor Tokio Shiroichi             2970 Ishikawa-cho, Hachioji-shi, Tokyo Konica stock             Inside the company (72) Inventor Nori Sasamoto             2970 Ishikawa-cho, Hachioji-shi, Tokyo Konica stock             Inside the company (72) Inventor Akifumi Isobe             2970 Ishikawa-cho, Hachioji-shi, Tokyo Konica stock             Inside the company F term (reference) 2H027 DA12 DE07 ED02 ED08 ED24                       ED25 EE03 EE07 EH10                 2H033 AA20 AA30 BA25 BA30 BB18                       CA01 CA03 CA04 CA07 CA26                       CA28 CA30 CA36 CA40 CA45                       CA58

Claims (11)

[Claims] 1. A fixing device for fixing at a predetermined temperature by a heater supplied with electric power, a temperature detecting device for detecting a temperature of the fixing device, and a fixing target temperature maintained according to a detection result of the temperature detecting device. The temperature control of the heater and the control means for controlling the speed of electrostatic latent image formation, development, transfer, and fixing (hereinafter referred to as process speed). An image forming apparatus, wherein the process speed is changed when the temperature of the fixing device is not the fixing target temperature with reference to the detection result. 2. The control means, in the case of a job within a predetermined quantity, is slower than a normal speed, and the fixing property in the fixing device is lower than a normal speed during warming up of the fixing device and before reaching the fixing target temperature. 2. The image forming apparatus according to claim 1, wherein the process speed is changed to a storable low speed and the image formation is started. 3. The control means controls the process speed to a first speed when the temperature of the fixing device is the target fixing temperature, and controls the process speed to be lower than the first speed when the temperature is lower than the target fixing temperature. 3. The image forming apparatus according to claim 1, wherein the process speed is changed to a second speed that is slow and at which the fixing property of the fixing device can be secured. 4. The control means controls the process speed to a first speed when the temperature of the fixing device is the fixing target temperature, and the temperature of the fixing device is changed to the fixing target temperature during execution of image formation. When it is detected that the temperature of the fixing device has returned to the fixing target temperature after the image formation is temporarily interrupted, the image formation is restarted, or the first image formation is resumed. 4. The image forming apparatus according to claim 1, wherein control is performed to select any one of changing the process speed to a second speed slower than the above speed. 5. The control means selects, as the second speed, from among a plurality of speed candidates, a maximum speed in a range in which fixability of the fixing device can be secured. Item 4. The image forming apparatus according to item 4. 6. The method according to claim 4, wherein the control unit refers to the set remaining amount of the job, and performs the selection so that the job is completed sooner. The image forming apparatus described. 7. The control means controls the rotation of the fixing roller to be decelerated or stopped during a period in which the recording paper does not pass through the fixing roller in the fixing device. The image forming apparatus according to claim 6. 8. The image forming apparatus according to claim 1, wherein the control unit controls to a plurality of process speeds according to the temperature of the fixing device. 9. An image forming apparatus capable of reading a next job during execution of image formation, wherein the control unit is executing image formation at a process speed slower than standard according to the temperature of the fixing device. 9. The image forming apparatus according to claim 1, wherein the next job reading is not performed. 10. An image forming apparatus comprising display means for displaying a status, wherein the control means is performing image formation at a process speed slower than standard and does not read the next job, 10. The image forming apparatus according to claim 9, wherein a display indicating that the next job is not read is displayed. 11. An image forming apparatus comprising a second heater as a heat source of the fixing device, wherein the control means is performing image formation at a process speed slower than a standard according to the temperature of the fixing device. In this case, the temperature of the fixing device is prevented from lowering by turning on the second heater.
The image forming apparatus according to any one of 1.