JP4337576B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus for thermally fixing an unfixed image on a recording material.

Conventionally, in a copying machine configured to heat and press a toner image transferred onto a recording sheet with a fixing roller, a temperature at which sufficient fixing performance is obtained is determined in advance as a fixing temperature (for example, 170 ° C.). The temperature adjustment control is performed to control the temperature of the fixing roller so as to maintain the fixing temperature by heating the fixing roller with a heater or the like.
In such a thermal fixing configuration, the power consumption by the heater is very large. Therefore, when the copying operation is not performed, the temperature of the fixing roller is lowered to a temperature lower than the fixing temperature (preheating temperature, for example, 60 ° C.). Many technologies for realizing energy saving by shifting to a power saving mode have been proposed (for example, Patent Document 1).
Japanese Patent Laid-Open No. 11-95622

  However, if the configuration is shifted to the power saving mode, the user must wait until the temperature of the fixing roller changes from the preheating temperature to the fixing temperature even if copying is desired. There is a problem that it is not possible to cope with work that involves. In order to reduce the waiting time, it is conceivable to set the preheating temperature to a value close to the fixing temperature, for example, a preheating temperature of 160 ° C. with respect to the fixing temperature of 170 ° C. However, it is almost impossible to expect a power saving effect.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an image forming apparatus capable of reducing power consumption and shortening waiting time for image forming operations such as copying. It is said.

In order to achieve the above object, an image forming apparatus according to the present invention is an image forming apparatus including a fixing unit that thermally fixes an unfixed image on a recording material, and the temperature of the fixing unit is maintained at a target temperature. A fixing control means for controlling the image forming apparatus, a switching instruction receiving means for receiving a switching instruction for switching the target temperature from the first temperature to a second temperature different from the first temperature during an image forming operation, and an image A fixing permission unit, and the fixing control unit controls the fixing unit upon occurrence of a predetermined event when the image forming operation is not in progress until the temperature of the fixing unit reaches the first temperature. When the temperature is raised and the switching instruction receiving means receives a switching instruction during the image forming operation , the target temperature is switched from the first temperature to the second temperature, and the switching instruction receiving means Event The image forming permission means receives the instruction for switching the target temperature until the temperature of the fixing unit reaches the target temperature until the fixing unit temperature reaches the target temperature due to the temperature increase. If the temperature of the fixing unit reaches the target temperature when the target temperature is switched from the first temperature to the temperature lower than the first temperature as the second temperature during this period, image formation is performed. The operation is permitted, and the image forming operation is started without waiting for an instruction to start the image forming operation.

In here, the The predetermined event occurs, and characterized in that indicating the start of power supply to the image forming apparatus.
A power-saving unit that executes a power-saving mode that maintains a temperature of the fixing unit at a third temperature that is lower than the first and second temperatures; and a cancellation instruction receiving unit that receives a cancellation instruction for the power-saving mode; And the occurrence of the predetermined event indicates reception of a release instruction by the release instruction receiving means.

  As a result, for example, when the occurrence of a predetermined event is the cancellation of the power saving mode, if the switch to the second temperature is instructed, the image forming operation can be started earlier than in the case of the first temperature. Thus, the waiting time can be shortened while obtaining the power saving effect by the power saving mode.

Hereinafter, an example in which an embodiment of an image forming apparatus according to the present invention is applied to a copying machine will be described with reference to the drawings.
FIG. 1 is a diagram showing the overall configuration of the copying machine 1.
As shown in FIG. 1, the copying machine 1 is roughly composed of a scanner unit 10 that reads an image of a document, and a printer unit 20 that prints and reproduces an image read by the scanner unit 10 on a recording sheet. The

The scanner unit 10 is a known image reading device that reads a placed document image by exposure scanning, and sends image data obtained by the reading to the control unit 100.
The printer unit 20 forms an image by an electrophotographic method, and includes a print head 21, a photosensitive drum 23, a paper feed cassette 30 that stores a recording sheet, a fixing unit 35, and the like. An image is formed (printed) on a recording sheet based on the data.

When the image data is input, the control unit 100 converts it into a laser diode drive signal, and drives a laser diode (not shown) inside the print head 21. The laser beam L emitted from the laser diode is deflected by the folding mirror 22 and then exposes the surface of the photosensitive drum 23 rotating in the arrow A direction in the main scanning direction.
Around the photosensitive drum 23, a cleaner 24, a charging charger 25, a developing device 26, a transfer charger 27, and the like are arranged.

Before the exposure by the laser beam L, the photosensitive drum 23 is charged with the charger 24 uniformly after the residual toner is removed by the cleaner 24. When the surface of the charged photosensitive drum 23 is exposed by the laser beam L, an electrostatic latent image is formed, and this electrostatic latent image is developed by the developing device 26 and visualized as a toner image.
On the other hand, a recording sheet is fed from a paper feed cassette 30 by a pickup roller 31 and a timing roller 32. This recording sheet is conveyed by the transfer belt 33 to a transfer position directly below the photosensitive drum 23. At the transfer position, the toner image on the photosensitive drum 23 is transferred to the recording sheet by the action of the transfer charger 27. The recording sheet on which the toner image has been transferred is further conveyed by the transfer belt 33 and the conveyance belt 34 and sent to the fixing unit 35.

The fixing unit 35 includes a fixing roller 351, a pressure roller 352 that is pressed against the surface of the fixing roller 351 by an urging unit (not shown), a heater 353 that is inserted in the fixing roller 351 and heats the fixing roller 351, and the fixing roller 351. A detection sensor 354 including a thermistor for detecting temperature is provided.
The recording sheet conveyed by the conveying belt 34 passes through the pressure contact portion between the fixing roller 351 and the pressure roller 352, and at this time, unfixed toner on the recording sheet is thermally fixed to the recording sheet by heating and pressing. . Thereafter, the recording sheet on which the toner is fixed is discharged to the discharge tray 36.

An operation panel 11 is arranged at a position on the front side of the apparatus where the user can easily operate.
FIG. 2 is a diagram illustrating a configuration of the operation panel 11.
As shown in the figure, the operation panel 11 includes a numeric keypad group 111, a clear key 112, a reset key 113, a copy start key 114, a quick start key 115, a power saving mode key 116, a switching key 117, and a display unit 118. .

The ten key group 111 is a key for the user to input the number of copies, and the clear key 112 is a key for clearing the input number of copies. The stop key 113 is a key for stopping an operation such as copying, and the copy start key 114 is a key for starting a copying operation.
The power saving mode key 116 is a key for shifting to the power saving mode. In this power saving mode, the temperature of the fixing unit 35 while the copying operation is not performed is determined in advance as a first temperature (a temperature that can sufficiently secure the fixing property even if the environment such as the type of recording sheet, temperature and humidity changes). In this mode, power is saved by lowering the temperature to a temperature (preheating temperature) lower than, for example, 170 ° C., for example, 60 ° C. The user can switch to the power saving mode by pressing the power saving mode key 116. The power saving mode can be canceled by pressing the power saving mode key 116 again. Further, when the key input by the operator is not performed for a predetermined time after the copying operation is completed, the mode automatically shifts to the power saving mode. Hereinafter, the mode in which the copying operation is performed with the temperature of the fixing unit 35 set to the first temperature with respect to the power saving mode is referred to as a normal mode.

  The quick start key 115 is a key for shifting to the quick start mode. The quick start mode is a mode in which the copying operation is performed at a second temperature, for example, 150 ° C., in which the temperature of the fixing unit 35 is lower (higher than the preheating temperature) than in the normal mode. This second temperature is a temperature at which the toner image after fixing on the recording sheet does not peel off, for example, when it is rubbed with a finger, but can be fixed to such an extent that it can be peeled off faintly when rubbed with an eraser or the like. That's it.

  In the present embodiment, when the power saving mode is canceled, the fixing unit 35 is heated by the heater 353, and in the normal mode, the temperature of the fixing unit 35 is changed from the preheating temperature T3 to the first temperature set as the target temperature. If the quick start key 115 is pressed during that time, the mode shifts to the quick start mode and the target temperature is reset to the second temperature. Thus, even if the temperature of the fixing unit 35 does not reach the first temperature, the copying operation can be started when the temperature reaches the second temperature.

This is because, depending on the user, for example, when a copier is moving to the power saving mode in a company or the like and a work involving a large amount of copying occurs just before the conference is held, a small amount of fixability may be sacrificed. Some users want to start and complete copying sooner, and this is to reduce the waiting time until the start of copying and meet such user's wishes.
FIG. 3 is a graph showing the relationship between the temperature of the fixing unit 35 and time in the normal mode and the quick start mode after the power saving mode is released. Note that T1 on the vertical axis indicating the temperature of the fixing unit indicates a first temperature, T2 indicates a second temperature, and T3 indicates a preheating temperature.

  As shown in the figure, in the normal mode (solid line 51), when the power saving mode is canceled (X time) and the temperature of the fixing unit 35 reaches the target temperature T1 (Z time), the copy operation can be started. . On the other hand, in the quick start mode (one-dot chain line 52), when the temperature of the fixing unit 35 reaches the target temperature T2 (Y time point), the copying operation is started. In both modes, since the heating is performed by the fixing heater 353, basically the same temperature rise characteristic is obtained from the time point XY. Therefore, in the example shown in the figure, the waiting time is shortened by the amount between Y and Z.

  Normally, the temperature rise characteristic of the fixing unit 35 when heated using the fixing heater 353 has a large rate of temperature rise per unit time (corresponding to the slope of the graph) immediately after the start of heating, as shown in FIG. Is a graph approximating a quadratic curve that gradually decreases and becomes minimum immediately before reaching the target temperature. Therefore, even if the difference between the temperatures T1 and T2 is small, the interval between the time Y and Z can be made relatively long, and the temperature of the fixing unit 35 can be reduced only slightly (the range in which the influence on the fixability can be reduced). ), Waiting time can be greatly reduced.

When the copy operation is started in the normal mode (after time Z), the temperature of the fixing unit 35 is maintained at the target temperature T1 as it is during the copy operation, and is started in the quick start mode (after time Y). ), The target temperature is maintained at T2. Hereinafter, the first temperature is abbreviated as T1, the second temperature as T2, and the preheating temperature as T3.
Returning to FIG. 2, the switching key 117 is a key for switching the temperature of the fixing unit 35 during the copying operation from T1 to T2 or from T2 to T1 (switching the target temperature).

  For example, when the user selects the normal mode after canceling the power saving mode (in other words, does not select the quick start mode) but wants to save power after the copy operation starts, the switching key 117 is in the copy operation. When the button is pressed, the target temperature is reset from T1 to T2, and thereafter, the fixing unit 35 is maintained at T2, so that power can be saved as compared to the case of T1. Conversely, although the quick start mode is selected, there may be a case where it is reconsidered that priority is given to the fixing property during the copying operation. In such a case, when the switching key 117 is pressed during the copying operation, the target temperature is set to T2. It is possible to meet the user's needs by changing the setting from T to T1 and maintaining the fixing unit 35 at T1.

The display unit 118 includes an LCD, and displays information such as the number of copies input by the user, various copy modes such as enlargement and reduction copy, and the operation state of the apparatus. A touch panel is stacked on the surface, and the user can select a desired copy mode and the like by touching the display screen.
FIG. 4 is a block diagram illustrating a configuration of the control unit 100.

As shown in the figure, the control unit 100 includes a CPU 101, a ROM 102, a RAM 103, and a temperature data storage unit 104 as main components.
The temperature data storage unit 104 is a non-volatile memory such as NVRAM, and stores temperature data of T1, T2, and T3 in advance.
The CPU 101 reads a necessary program from the ROM 102 and controls the scanner unit 10 and the printer unit 20 in an integrated manner so as to execute a smooth copy operation.

  In addition, an input signal of each key (including keys on the touch panel) from the operation panel 11 is received, and an operation based on the pressed key is executed. For example, when the quick start key 115 is pressed, the target temperature is switched from the first temperature to the second temperature. In this sense, it can be said that the control unit 100 and the operation panel 11 function as a switching instruction receiving unit that receives a switching instruction for switching the target temperature from the first temperature to the second temperature. In addition, a message indicating the device status or the like is displayed on the display unit 118 as necessary.

Furthermore, the detection signal from the detection sensor 354 of the fixing unit 35 is received to detect the temperature of the fixing roller 351 (the fixing unit 35). In the power saving mode, the temperature of the fixing heater 353 is maintained so that the temperature is maintained at T3. Perform lighting control. In this sense, the control unit 100, the fixing unit 35, and the like function as a power saving unit that executes the power saving mode.
Further, a target temperature (T1 or T2) for controlling the temperature of the fixing unit 35 is set according to the mode selected after the power saving mode is canceled, and the fixing heater is used until the temperature of the fixing unit 35 reaches the target temperature. The temperature of the fixing unit 35 is increased by turning on 353. Further, during the copying operation, the fixing heater 353 is controlled so that the fixing unit 35 is maintained at the target temperature.

  Here, regardless of whether the target temperature is T1 or T2, the sheet conveyance speed when passing through the fixing unit 35 is substantially the same, and the copying speed (the number of sheets that can be copied per unit time) is also the same. To be controlled. For example, when the transport speed is T2, it is possible to delay it by a predetermined amount (an amount that is acceptable if the time for the end of the entire copy operation is earlier than the case of T1 and that is acceptable within the range). is there. Further, temperature data of T1 to T3 for temperature control is read from the temperature data storage unit 104. In this sense, the control unit 100 functions as a fixing control unit that controls the fixing unit 35 and raises the temperature until the temperature reaches the target temperature.

The RAM 103 is used as a work area when the CPU 101 executes a control program.
5 and 6 are flowcharts showing the processing contents of the temperature control of the fixing unit 35 after the power saving mode is released.
As shown in FIG. 5, the control unit 100 determines whether or not there is an instruction to cancel the power saving mode from the user (step S1). This determination is made based on whether or not the power saving mode key 116 of the operation panel 11 is pressed during the power saving mode.

If it is determined that there is an instruction to cancel the power saving mode (“YES” in step S1), the target temperature of the fixing unit 35 is set to T1 (step S2). This setting is performed by setting the value of a fixing flag (not shown) in the RAM 103 to “1”.
Heating is performed by the fixing heater 353 to raise the temperature of the fixing unit 35 (step S3). Then, it is determined whether or not the quick start key 115 has been pressed (step S4).

  If it is determined that the quick start key 115 has not been pressed (“NO” in step S4), the process proceeds to step S6. On the other hand, when it is determined that the quick start key 115 is pressed (“YES” in step S4), the target temperature setting is switched from T1 to T2 (step S5), and the process proceeds to step S6. This switching is performed by changing the value of the fixing flag to “2”. In this case, a message indicating the quick start mode is displayed on the display unit 118 of the operation panel 11 (see the message display example at the bottom of the display unit 118 in FIG. 2).

  In step S6, it is determined whether or not the temperature of the fixing unit 35 has reached the set target temperature. Specifically, first, the current temperature of the fixing unit 35 is detected from the value of the detection signal from the detection sensor 354. Next, when the value of the fixing flag is “1”, the temperature data of T 1 is read from the temperature data storage unit 104. On the other hand, when the value of the fixing flag is “2”, temperature data of T2 is read. Then, it is determined whether or not the detected temperature of the fixing unit 35 is the same as the temperature indicated in the read temperature data.

  When it is determined that the set target temperature has been reached ("YES" in step S6), if the target temperature is T2 (if the fixing flag value is "2") ("YES" in step S7). The copy operation is started (step S9). On the other hand, in the case of T1 (when the value of the fixing flag is “1”) (“NO” in step S7), it waits for the copy start key 114 to be pressed and determines that it has been pressed (“ YES "), the copy operation is started (step S9). In this sense, the control unit 100 functions as an image formation permission unit that permits an image forming operation when performing the processes of steps S6 to S9.

Then, as shown in FIG. 6, it is determined whether or not the switch key 117 is pressed during the copying operation (step S10).
If it is determined that the button has been pressed (“YES” in step S10), it is determined whether or not the target temperature is T2 (step S11). This determination is made by referring to the current fixing flag value. When it is determined that it is T1, that is, when it is determined that the value of the fixing flag is “1” (“NO” in step S11), the target temperature is switched to T2 (step S12), and the process proceeds to step S14. In this case, the fixing unit 35 is maintained at T2.

FIG. 7 is a graph showing an example when the target temperature is changed during the copying operation.
In the figure, the solid line graph shows an example when the target temperature is changed from T1 to T2, and the one-dot chain line graph shows an example when the target temperature is changed from T2 to T1. The process of step S12 corresponds to an example of a solid line graph, and the temperature of the fixing unit 35 is maintained at T2 after the point P.

Returning to FIG. 6, if it is determined in step S11 that it is T2 (determining that the value of the fixing flag is “2”) (“YES” in step S11), the target temperature is switched to T1 (step S13). The process proceeds to step S14. In this case, the fixing unit 35 is maintained at T1 (see the dashed line graph in FIG. 7).
In step S14, it is determined whether or not the timing for ending the copy operation has been reached. If the copying operation is continued (“NO” in step S14), the process returns to step S10. The processing in steps S10 to S14 is repeated until the copy operation end timing is reached, and if it is determined that the copy operation end timing has been reached (“YES” in step S14), the processing ends.

  As described above, the present embodiment is configured such that the user can select from the operation panel 11 the normal mode in which the target temperature is T1 and the quick start mode in which T2 is lower than T1. . Therefore, for example, when copying after canceling the power saving mode, if the user wants to obtain a copy earlier even if the fixing property is somewhat sacrificed, the quick start mode is selected earlier than the normal mode is selected. The copying operation can be started, and the waiting time can be reduced while obtaining the power saving effect by the power saving mode (without reducing the conventional power saving effect).

  The present invention is not limited to the above-described copying machine, and may be a temperature control method for the fixing unit and a program executed by a computer. The program according to the present invention includes a magnetic disk such as a magnetic tape and a flexible disk, an optical recording medium such as DVD, CD-ROM, CD-R, MO, and PD, and a flash memory system such as Smart Media (registered trademark). It can be recorded on various computer-readable recording media such as a recording medium, and may be produced, transferred, etc. in the form of the recording medium, and various wired and wireless types including the Internet in the form of a program. In some cases, the data is transmitted and supplied via a network, broadcast, telecommunication line, satellite communication, or the like.

(Modification)
As described above, the present invention has been described based on the embodiment. However, the present invention is not limited to the above-described embodiment, and the following modifications may be considered.
(1) In the above-described embodiment, T1 (170 ° C.) and T2 (150 ° C.) can be switched and set as the target temperature for temperature control of the fixing unit 35. Absent. Usually, the fixing property of a developer such as toner on the recording sheet is improved as the temperature is increased. If the value is set to a low value, the waiting time of the user after canceling the power saving mode can be shortened accordingly.

In addition, a configuration capable of setting the target temperature, specifically, a receiving means for receiving an input of the target temperature via the operation unit or the like is provided, and the fixing unit is controlled based on the received target temperature or received. It is also possible to store the target temperature data in the storage unit and read and use it during control.
Further, the target temperature is not limited to two, but may be three or more, and a selection input from the user may be accepted. Further, the preheating temperature in the power saving mode is not limited to the above value.

  (2) In the above embodiment, the processing content of the temperature control of the fixing unit 35 after the power saving mode is released has been described. However, the temperature control is not limited to after the power saving mode is released, and a predetermined event occurs, for example, to the device This may be executed during the period from the start of power supply (such as power-on) until the temperature of the fixing unit 35 reaches the target temperature T1. Normally, since power is not supplied to the fixing heater 353 while the power is off, the temperature of the fixing unit 35 is low (about room temperature), and heating from the power on to the fixing unit 35 is started. This is because it takes a certain amount of time to reach the target temperature T1 (which is naturally longer than after the power saving is canceled). In this case, the process of step S1 may be a process of moving to step S2 when the power is turned on. Alternatively, the supply of power to the fixing unit 35 can be started.

  (3) In the above embodiment, in steps S4 and S5, only an example in which the mode is changed from the normal mode to the quick start mode after the power saving mode is released and before the copy operation is started has been described. A configuration may be adopted in which the mode can be changed to the normal mode again. In this case, for example, when the switch key 117 is pressed, the target temperature may be reset from T2 to T1.

In addition, the normal mode is automatically set in step S2 after the power saving mode is released. However, for example, the quick start mode may be automatically set and the normal mode may be switched by pressing another key.
(4) In the above embodiment, an example in which the present invention is applied to a copying machine has been described. However, the present invention is not limited to this, and a developer image such as a toner image (unfixed image) As long as the image forming apparatus includes a fixing unit that thermally fixes the printer, it can be applied to a printer, FAX, MFP (Multiple Function Peripheral), or the like.

  For example, when applied to an image forming apparatus that executes print processing in response to a print job request from an external device, the reception of the print job request is regarded as an instruction to cancel the power saving mode (occurrence of a predetermined event), and the print When the job data includes a signal for shifting to the quick start mode, the reception of the transition signal can be regarded as an instruction to switch to the second temperature. The acceptance of the print job may be regarded as both an instruction to cancel the power saving mode and an instruction to switch to the second temperature.

  The image forming apparatus according to the present invention is useful as a technique capable of realizing a reduction in waiting time of an image forming operation such as copying while reducing power consumption.

1 is a diagram illustrating an overall configuration of a copying machine 1. 2 is a diagram showing a configuration of an operation panel 11 of the copying machine 1. FIG. 7 is a graph showing the relationship between the temperature of the fixing unit 35 and time in a normal mode and a quick start mode after canceling the power saving mode. 2 is a block diagram illustrating a configuration of a control unit 100 of the copying machine 1. FIG. 5 is a flowchart showing the processing contents of temperature control of the fixing unit 35 after the power saving mode is canceled executed by the control unit 100. 5 is a flowchart showing the processing contents of temperature control of the fixing unit 35 after the power saving mode is canceled executed by the control unit 100. It is a graph which shows an example when target temperature is changed during copy operation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Copier 11 Operation panel 20 Printer part 35 Fixing part 100 Control part 115 Quick start key 116 Power saving mode key 117 Changeover key

Claims (3)

An image forming apparatus including a fixing unit that thermally fixes an unfixed image on a recording material,
Fixing control means for controlling the fixing unit so that its temperature is maintained at a target temperature;
A switching instruction receiving means for receiving a switching instruction for switching the target temperature from the first temperature to a second temperature different from the first temperature during an image forming operation;
Image forming permission means,
The fixing control means includes
When the predetermined event occurs when the image forming operation is not being performed, the fixing unit is controlled to raise the temperature of the fixing unit until the temperature reaches the first temperature, and the switching instruction receiving unit forms the image. When a switching instruction is received during operation, the target temperature is switched from the first temperature to the second temperature ,
The switching instruction receiving means
In the period from the occurrence of the predetermined event until the temperature of the fixing unit reaches the target temperature, an instruction to switch the target temperature is received,
The image formation permission unit includes:
When the target temperature is switched from the first temperature as the second temperature to a temperature lower than the first temperature until the temperature of the fixing unit reaches the target temperature due to the temperature increase. In addition, when the temperature of the fixing unit reaches the target temperature, the image forming operation is permitted, and the image forming operation is started without waiting for an instruction to start the image forming operation. Wherein the predetermined and the event occurrence, the image forming apparatus according to claim 1, characterized in that indicating the start of power supply to the image forming apparatus. Power saving means for executing a power saving mode for maintaining the temperature of the fixing unit at a third temperature lower than the first and second temperatures;
Cancellation instruction receiving means for receiving an instruction to cancel the power saving mode, and
Wherein the predetermined and the event occurrence, the image forming apparatus according to claim 1, characterized in that shows the reception of a cancellation instruction by the cancel instruction accepting means.

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