WO2007055127A1

WO2007055127A1 - Image forming apparatus, cooling control program, and computer readable recording medium

Info

Publication number: WO2007055127A1
Application number: PCT/JP2006/321760
Authority: WO
Inventors: Kazutoshi Ishikawa
Original assignee: Sharp Kabushiki Kaisha
Priority date: 2005-11-10
Filing date: 2006-10-31
Publication date: 2007-05-18
Also published as: JP2007133174A

Abstract

Temperature control of the fixing unit in an image forming apparatus is performed efficiently. The image forming apparatus (100) has two modes, i.e. a print mode for transferring toner to a recording sheet which is fed in from a sheet feed tray by means of a sheet feed roller (1) in response to reception of a print instruction from a receiving section (37) and fixing the toner by means of a fixing unit (6) heated by a heater lamp (34), and a mode for waiting reception of the print instruction. The image forming apparatus (100) is provided with a POUT1 sensor (22) for detecting arrival of the recording sheet at the fixing unit (6) in the downstream of the sheet feed roller (1) in the carrying direction of recording sheet. A cooling control section (32) stops operation of a cooling fan (9) in the waiting mode, and starts driving of the cooling fan (9) in response to detection by the POUT1 sensor (22) in the print mode.

Description

Specification

Image forming apparatus, cooling control program, and computer-readable recording medium

Technical field

The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus that fixes a developer onto a recording sheet by a heated fixing unit.

Background art

[0002] Examples of an image forming apparatus using an electrophotographic system include a copying machine, a printer, and a facsimile. In these image forming apparatuses, for example, an image is formed on a recording sheet based on image data input from a peripheral device.

A general image forming process in such an image forming apparatus will be described as follows. FIG. 4 is a diagram showing a recording paper conveyance path. When the image forming apparatus receives the image data, first, the paper feeding roller 1 pulls the recording paper one by one from a paper feeding tray (not shown) and conveys the recording paper in the direction of the registration roller 2. A PIN sensor 21 is installed adjacent to the registration roller 2, and is detected by the PIN sensor 21 when the leading edge of the recording paper is conveyed to the registration roller 2.

[0004] When the PIN sensor 21 detects the leading edge of the recording paper, the charger is based on the timing.

The exposure optical system 5 is exposed by laser light to the surface of the photoconductor 4 charged by 7 to form an electrostatic latent image. A toner image is formed on the photoreceptor 4 on which the electrostatic latent image has been formed by the developing device 3 developing with a toner (developer).

[0005] Then, the toner image developed on the photoreceptor 4 is transferred onto the recording paper conveyed from the registration roller. The recording paper on which the toner image has been transferred is conveyed to the fixing device 6 and is pressed by the heated heating roller 13 and the pressure roller 14 in the fixing device 6. This

The toner image is fixed on the recording paper. The recording paper on which the toner image is fixed is then discharged from the image forming apparatus main body.

In such an image forming apparatus, when the recording paper starts to pass through the heating roller 13 and the pressure roller 14 of the fixing device 6, the recording paper takes heat from the heating roller 13 and the pressure roller 14. ,, Through It is known that the temperature of the heating roller 13 and the pressure roller 14 decreases with excess. For this reason, in order to maintain a sufficient fixing force until the passing of the recording paper is completed, it is necessary to take sufficient warm-up time (time for heating the heating roller 13 and the pressure roller 14). In order to shorten the warm-up time, it is necessary to efficiently control the temperature of the heating roller 13 and the pressure roller 14.

From this point of view, Patent Document 1 describes an image forming apparatus that increases the cooling capacity of a cooling fan after a predetermined time in response to an instruction output instructing an image forming operation.

[0008] Further, Patent Document 2 discloses an image forming apparatus that stops rotation of a cooling fan when recording paper enters a fixing device and starts driving the fan again after the recording paper passes through the fixing device. Are listed.

However, the conventional image forming apparatus still has a problem that the temperature control of the heating roller 13 and the pressure roller 14 (that is, the fixing device 6) is not efficient.

For example, in the image forming apparatus described in Patent Document 1, the timing for increasing the cooling capacity of the cooling fan is determined according to an instruction output for instructing an image forming operation. Therefore, when the instruction output is received, even if a recording paper pull-in error occurs before the recording paper is transported to the fixing device, the cooling capacity of the cooling fan automatically increases after a predetermined time. Resulting in. As a result, the temperature of the fuser drops at the time of reprinting after error recovery, and it is necessary to warm up again over a long period of time.

On the other hand, in the image forming apparatus described in Patent Document 2, the cooling fan rotates at the same time as the power is turned on, and the driving of the cooling fan is stopped only when the recording paper passes through the fixing device. . For this reason, the cooling fan is in a driven state before receiving a print instruction. Therefore, the temperature of the fuser has dropped when the print instruction is received, so it cannot be warmed up quickly. This problem becomes particularly noticeable immediately after the power is turned on (for example, when an image forming operation is performed in the first morning).

Patent Document 1: Japanese Patent Publication “JP-A-6-274001 (published on September 30, 1994)” Patent Document 2: Japanese Patent Publication “JP-A-9 114288 (published on May 2, 1997)” Disclosure of the invention

The present invention has been made in view of the above problems, and an object thereof is to provide an image forming apparatus capable of efficiently performing temperature control of a fixing unit (fixing device).

In order to solve the above-described problems, the present invention provides a receiving unit that receives an image forming command, a paper feeding / conveying unit that draws and conveys recording paper from a paper feeding tray, and a developer that fixes the developer on the recording paper. A heating unit that heats the fixing unit, a cooling unit that cools the fixing unit, and a cooling control unit that controls the operation of the cooling unit, in response to reception of an image forming command by the receiving unit. The image forming mode in which the developer is transferred to the recording paper that has been pulled in by the paper feed conveyance unit, and the developer is fixed on the recording paper by the fixing unit heated by the heating unit, and the image forming command An image forming apparatus having two modes, i.e., a standby mode for waiting for reception, and further comprising a recording paper detection unit for detecting that the recording paper has been drawn by the paper feeding / conveying unit, The cooling control unit It stops the operation of the cooling unit in the standby mode, wherein the improved than before detecting the cooling power of the cooling unit in accordance with detection by the recording sheet detector in the image forming mode.

[0014] According to the above configuration, in the standby mode, the cooling control unit stops the operation of the cooling unit.

Therefore, it is possible to prevent the temperature in the apparatus from excessively decreasing in the standby mode and to quickly warm up. Further, in the print mode, the cooling control unit improves the cooling power of the cooling control unit in response to detection by the recording paper detection unit that detects that the recording paper has been pulled in. Therefore, when the recording paper pull-in fails in the paper feeding / conveying unit, the cooling control unit should not improve the cooling power of the cooling unit. Therefore, it is possible to prevent the temperature in the apparatus from decreasing before reprinting, and to quickly warm up. As described above, the image forming apparatus of the present invention can efficiently control the temperature of the fixing unit.

Incidentally, the cooling control unit of the image forming apparatus may be realized by hardware, or may be realized by causing a computer to execute a program. Specifically, the cooling control program according to the present invention is a program that causes a computer to operate as the cooling control unit, and the program is recorded in the recording medium according to the present invention. When these programs are executed by a computer, the computer operates as the cooling control unit. Therefore, the image forming apparatus can efficiently control the temperature of the fixing unit.

[0017] Further objects, features, and advantages of the present invention will be fully understood from the following description. The benefits of the present invention will become apparent from the following description with reference to the accompanying drawings.

Brief Description of Drawings

FIG. 1, showing an embodiment of the present invention, is a functional block diagram showing a main configuration relating to temperature control of an image forming apparatus.

FIG. 2, showing an embodiment of the present invention, is a cross-sectional view showing a schematic structure of an image forming apparatus.

FIG. 3, showing an embodiment of the present invention, is a cross-sectional view showing a schematic structure of an image forming apparatus.

FIG. 4 is a diagram showing a recording paper conveyance path.

FIG. 5, showing one embodiment of the present invention, is a diagram showing a state of temperature control of the image forming apparatus.

FIG. 6, showing an embodiment of the present invention, is a flow diagram illustrating a flow in controlling a cooling fan. BEST MODE FOR CARRYING OUT THE INVENTION

One embodiment of the present invention is described below with reference to FIGS. 1 to 6. 2 and 3 are longitudinal sectional views showing a schematic configuration of the image forming apparatus 100 of the present embodiment. FIG. 4 is a diagram showing a recording paper conveyance path. As shown in FIG. 2, the image forming apparatus 100 includes a paper feeding roller (paper feeding / conveying unit) 1, a registration roller 2, a developing unit 3, a photosensitive member 4, an exposure optical system 5, a fixing unit (fixing unit) 6, A charger 7 and a transfer roller 8 are provided.

[0020] The paper feed roller 1 is for drawing recording sheets one by one from a paper feed tray (not shown). In this specification, “pulling in” means that the paper feed roller (paper feed transport unit) 1 is rotated downstream of the paper feed tray in the recording paper transport direction (that is, the photoreceptor 4 or the fixing device) by the rotation of the roller. This means that the recording paper is transported to the 6th side. The registration roller 2 conveys the recording paper drawn by the paper feeding roller 1 to a photoconductor 4 described later, and also determines timing for forming an image on the recording paper. In order to determine this timing, as shown in FIG. 4, a PIN sensor 21 is provided adjacent to the registration roller 2 on the downstream side in the recording paper conveyance direction. The PIN sensor 21 is a sensor for detecting the leading edge of the recording paper, whereby the timing at which the leading edge of the recording paper passes through the registration roller 2 can be detected.

The charger 7 is for charging the surface of the photoreceptor 4 with electric charges. The exposure optical system 5 performs scanning exposure on the surface of the photoreceptor 4 charged by the charger 7 to form an electrostatic latent image. The developing device 3 is for developing the surface of the photoreceptor 4 on which the electrostatic latent image is formed with toner (developer).

The transfer roller 8 is for transferring the toner image to the recording paper by sandwiching the recording paper with the photoreceptor 4 on which the toner image is formed. The fixing device 6 includes a heating roller 13 and a pressure roller 14, and these roller forces S are sandwiched and pressed by being heated by a built-in heater lamp (heating unit). In order to fix the toner image transferred on the recording paper.

Further, as shown in FIG. 4, a POUT1 sensor 22 is provided on the downstream side of the fixing device 6 in the recording paper conveyance direction. The POUT1 sensor 22 is used to detect the passage of the leading and trailing edges of the recording paper, thereby detecting the timing when the recording paper reaches the fixing device 6 and the completion timing of the passing. it can. Specifically, the POUT1 sensor 22 changes from OFF to ON when the leading edge of the recording paper reaches the POUT1 sensor 22, and the ON force changes to OFF when the trailing edge of the recording paper passes the POUT1 sensor 22. . Further, the image forming apparatus 100 is provided with a POUT2 sensor 23 in a discharge unit that discharges the recording paper to the outside of the apparatus. This POUT2 sensor 23 is used to detect the passage of the leading edge and trailing edge of the recording paper in the same manner as the POUT1 sensor 22, and as a result, the recording paper is discharged out of the image forming apparatus 100. Can be detected.

The image forming apparatus 100 further includes a cooling fan 9, a main motor 10, and a sub motor 11, as shown in FIG.

The cooling P fan 9 is mainly used for the temperature in the image forming apparatus, which has been raised by heating the fixing device 6. It is for lowering by ventilating the inside of the device. The main motor 10 is for generating a driving force for rotating the resist roller 2, the photoconductor 4, the heating roller 13 and the pressure roller 14 included in the fixing device 6. The sub motor 11 is for generating a driving force to rotate the paper feed roller 1.

A printing operation in such an image forming apparatus will be described as follows. When a later-described receiving unit 37 of the image forming apparatus receives the image data, the image forming apparatus 100 changes from the standby mode to the print mode (image forming mode). In the printing mode, first, the sheet feeding roller 1 pulls recording sheets one by one from a sheet feeding tray (not shown) and conveys the recording sheet in the direction of the registration roller 2.

[0028] Then, when the PIN sensor 21 provided adjacent to the registration roller 2 detects the leading edge of the recording paper, the photosensitive timing is used as a reference so that an image is formed at an accurate position on the recording paper. The body 4 is subjected to scanning exposure. More specifically, when the main motor 10 for transporting the recording paper is driven by a predetermined number of steps Sn from the reference timing (or time required for the main motor 10 to be driven by the predetermined number of steps Sn). When Tsn elapses), the exposure optical system 5 starts scanning exposure with laser light on the surface of the photoconductor 4 charged in advance by the charger 7. By scanning exposure, an electrostatic latent image is formed on the surface of the photoreceptor 4. The developing device 3 develops the photoreceptor 4 on which the electrostatic latent image is formed with a toner, and a toner image is formed.

Then, the recording sheet conveyed by the registration roller 2 is sandwiched between the photoconductor 4 and the transfer roller 8, whereby the developed toner image is transferred onto the photoconductor 4. The recording paper on which the toner image has been transferred is conveyed to the fixing device 6 and is pressed by the heated heating roller 13 and the pressure roller 14 in the fixing device 6. As a result, the toner image is fixed on the recording paper.

[0030] After that, the main body of the image forming apparatus 100 is discharged from the recording paper on which the toner image is fixed.

A POUT2 sensor 23 is provided in the vicinity of the discharge portion of the image forming apparatus 100, so that it can be detected that the recording paper has been discharged. Here, when the next recording sheet is not conveyed in the image forming apparatus, the image forming apparatus 100 ends the printing mode and enters the standby mode. In the standby mode, the image forming apparatus 100 waits for reception of a print command. In the image forming apparatus as described above, the temperature control of the fixing device 6 (the heating roller 13 and the pressure roller 14) will be described as follows. The temperature control of the fixing device 6 is performed by controlling the heating power of the heater lamp 34 built in the heating roller 13 and the pressure roller 14 and the cooling power of the cooling fan 9 that cools the inside of the apparatus.

[0032] FIG. 1 is a functional block diagram showing the relationship of each block related to temperature control. As shown in FIG. 1, the temperature control for the fixing device 6 of the image forming apparatus 100 is as follows: a temperature control unit 30, a POUT1 sensor (recording paper detection unit) 22, a sheet count unit 33, a heater lamp 34, a cooling fan 9, This is realized by the temperature detection unit 35, the timer 36, the reception unit 37, and the like.

As described above, the heater lamp 34 is for heating the fixing device 6 (the heating roller 13 and the pressure roller 14), and the cooling fan 9 cools the fixing device 6 by ventilating the inside of the apparatus. Is to do. The temperature control unit 30 includes a temperature control unit 31 that controls the on / off of the heater lamp 34 and a cooling control unit 32 that controls the on / off of the cooling fan 9. Temperature can be controlled.

[0034] As described above, the POUT1 sensor 22 is capable of detecting the recording paper passing through the fixing device 6. More specifically, the detection signal of the POUT1 sensor 22 is turned on when the leading edge of the recording paper reaches, and then the detection signal is turned off when the trailing edge of the recording paper passes. As a result, when the detection signal of the POUT1 sensor 22 changes from OFF to ON, it is known that the recording paper has reached the fixing device 6, and when the ON force changes to OFF, the recording paper is fixed to the fixing device 6. It can be seen that the passage of has been completed.

[0035] Further, the sheet count unit 33 counts the number of recording sheets that have passed through the POUT1 sensor continuously. Here, “passing continuously” means, for example, that the time from the passage of one recording sheet to the passage of the next recording sheet is a predetermined time or less.

The temperature detection unit 35 is provided in the image forming apparatus 100 and is for detecting the temperature of the fixing device 6 (heating roller 13). Timer 36 is for counting time. The receiving unit 37 is for receiving a print command from a personal computer or the like.

Next, control of the heater lamp 34 by the temperature control unit 31 will be described with reference to FIG. As shown in FIG. 5, the temperature control unit 31 has two modes of off and on. . The off mode is a mode in which the temperature control unit 31 is stopped and the heater lamp 34 is not controlled to be turned on / off. Also, the on-mode means that the temperature control unit 31 is connected to the heater lamp 34 by the fixing device 6 (the heating roller 13 and the heating roller 13) so that the fixing device 6 has an appropriate temperature (tl) for fixing the toner onto the recording paper. This refers to the mode in which the pressure roller 14) is heated appropriately.

In the standby mode, the temperature control unit 31 is in the off mode. Here, when the receiving unit 37 receives the print command, the image forming apparatus 100 enters the print mode. Along with this, the temperature control unit 31 enters the on mode. In the on mode, the temperature control unit 31 controls on / off of the heater lamp 34 so that the heating roller 13 has an appropriate temperature tl. As a result, when the heater lamp 34 starts heating the heating roller 13 and then the recording paper passes through the fixing device 6, the heat deprived from the fixing device 6 by the recording paper is appropriately compensated, and the temperature of the heating roller 13 is increased. Keep tl. Note that the temperature control at this time is performed based on the temperature detected by the temperature detector 35.

Then, when the recording paper force passes through the SPOUT1 sensor 22 (that is, when the POUT1 sensor 22 changes from on to off), the image forming apparatus 100 enters the standby mode. Along with this, the temperature control unit 31 also enters the off mode. When continuously printing on a plurality of recording sheets, the image forming apparatus 100 enters the standby mode when the last recording sheet passes the POUT1 sensor 22, and the temperature control unit 31 Enters the off mode.

Next, the control of the cooling fan 9 by the cooling control unit 32 will be described with reference to FIGS. In this embodiment, on / off control of the cooling fan 9 is performed in response to the detection signal of the POUT1 sensor 22. In the following description, unless otherwise specified, it is assumed that the cooling control unit 32 performs each process.

In the standby mode when the power is turned on, the cooling control unit 32 stops the driving of the cooling fan 9. Here, when the receiving unit 37 receives the print command (S11), the image forming apparatus 100 enters the print mode and proceeds to step S12. On the other hand, when the receiving unit 37 has not received the print command, the image forming apparatus 100 stands by in the standby mode.

In step S12, it is determined whether or not the temperature t detected by the temperature detector 35 is higher than a predetermined temperature t2. Here, if the detected temperature t is higher than the predetermined temperature t2, the cooling control unit 32 proceeds to step S19 and drives the cooling fan. Also, the predetermined temperature t2 If it is the following, proceed to Step S13.

Subsequently, in step S 13, it is determined whether or not the number p counted by the number counting unit 33 has reached a predetermined number pl. Here, if the number P is less than the predetermined number pl, the process proceeds to step S20 to determine whether or not the printing is completed. In the present embodiment, the end of printing is determined by the POUT 1 sensor 22 detecting that the last recording sheet among the continuously printed recording sheets passes. When the printing is finished in step S20, the process proceeds to step S23, and the cooling control is finished while the cooling fan is stopped. If printing has not been completed, the process returns to step S13 again to determine whether or not the number p counted by the number counting unit 33 is a predetermined number pl.

On the other hand, if it is determined in step S13 that the predetermined number pl is reached, the process proceeds to step S14. In step S14, the timer 36 is reset, and the process proceeds to step S15. In step S15, it is determined whether or not the detection signal of the POUT1 sensor 22 has changed from OFF to ON.

[0045] If the detection signal of the POUT1 sensor 22 is turned on in step S15 (that is, if the plth sheet of recording paper reaches the fixing unit 6), the process proceeds to step S16. Then, timer 36 starts counting up. On the other hand, if it has not changed from off to on, the process returns to step S15 to determine again whether or not the detection signal of the POUT1 sensor 22 has turned off.

In step S16, after the timer 36 starts counting up, the process proceeds to step S17, and it is determined whether or not the time T force counted by the timer 36 exceeds a predetermined time T1. Here, if the counted time T does not exceed the predetermined time T1, the process proceeds to step S21, and it is determined whether or not the printing is finished. If printing has not ended, the process returns to step S17, and it is determined again whether or not the counted time T has exceeded a predetermined time T1. On the other hand, when printing is finished, the timer 36 stops counting up (S22), and the cooling fan is stopped (S23), and the cooling control is finished.

[0047] If the predetermined time T1 is exceeded in step S17, the process proceeds to step S18 to stop the count-up of the timer 36, and then the cooling fan is started to be driven in step S19. Thereby, the driving of the cooling fan is started and the cooling control is ended.

As described above, the image forming apparatus 100 according to the present embodiment is provided adjacent to the fixing device 6. In response to the detection of the passage of the recording paper by the POUTl sensor 22, the cooling control unit 32 starts driving the cooling fan after a predetermined time. Therefore, if the recording paper does not reach the fixing device 6 due to clogging of the conveyance path from the paper feed roller 1 to the fixing device 6 and the recording paper is jammed, the cooling control unit 32 sets the cooling fan 9 It will never start driving. As a result, when reprinting is performed after an error has occurred, it is possible to shorten the warm-up time without causing the temperature of the fixing device 6 to decrease.

[0049] It should be noted that the predetermined temperature t2 in the above step S12 may be determined on the basis of the temperature at which each part in the apparatus can be damaged. According to step S12, the heated fixing device 6 can prevent the temperature inside the apparatus from rising abnormally and damage each part due to heat. At this time, the cooling control unit 32 starts driving the cooling fan 9 only when the temperature is equal to or higher than the predetermined temperature, so the driving of the cooling fan 9 is not started even though the temperature of the fixing device 6 is low. . Therefore, before the recording paper reaches the fixing device 6, the temperature of the fixing device 6 is not decreased more than necessary, and the temperature increase of the fixing device 6 is not hindered.

[0050] In addition, the predetermined number pi in step S13 is preferably determined as appropriate according to the characteristics of the fixing device 6, the content of the heating control, and the like. It is possible to determine based on the number of sheets after checking whether the inside of the apparatus is overheated when printing is continuously performed. In this way, the cooling control unit 32 starts driving the cooling fan 9 after a predetermined number of recording sheets have been printed, so the cooling fan 9 is driven even though the temperature inside the apparatus has not risen sufficiently. By doing so, it is possible to prevent the temperature of the fixing device 6 from being lowered or preventing the temperature of the fixing device 6 from being hindered when fixing the subsequent recording paper.

In the present embodiment, the number counting unit 33 is configured to count the number of recording sheets detected by the POUT1 sensor 22, but the present invention is not limited to this, and instead of the POUT1 sensor 22. The number of recording sheets detected by other sensors such as POUT2 sensor 23 and PIN sensor 21 may be counted. If the image forming apparatus 100 supports double-sided printing, the number of printed pages may be counted instead of counting the number of recording sheets. In addition, even if the number of pages is the same as the number of pages, the amount of printing varies depending on the size of the recording paper. As a configuration that counts, etc.

[0052] In addition, it is preferable that the cooling control unit 32 appropriately adjust the predetermined number pi according to various conditions during printing. As an example, the cooling control unit 32 may adjust the predetermined number pi according to the temperature in the apparatus detected by the temperature detection unit 35. In this configuration, when the temperature inside the device is high, the value of pi is reduced, and when the temperature inside the device is low, the value of pi is increased, so that cooling control considering the temperature inside the device can be performed. it can. The timing at which the temperature detection unit 35 detects the temperature is not particularly limited, but may be, for example, the timing at which the reception unit 37 receives a print command. According to this, since the predetermined number of sheets pi can be determined based on the temperature at the time when the print command is received and the mode is switched to the print mode, how much the temperature in the apparatus rises thereafter in the print mode. Can be determined more accurately.

As another example, the cooling control unit 32 may adjust the predetermined number pi according to the time of the standby mode. The standby mode time corresponds to the time from the end of one print mode to the start of the next print mode. In this embodiment, this is because the POUT2 sensor 23 detects that the trailing edge of the last recording sheet has passed in the previous print mode, and the time when the receiving unit 37 receives the print command in the next print mode. It corresponds to the time until. When the standby mode is long, it is expected that the temperature inside the device has been sufficiently lowered.On the other hand, when the standby mode is short, the temperature inside the device is not sufficiently lowered and is expected to be high. Is done. Therefore, it is possible to control the cooling appropriately by increasing the value of pi when the standby mode is long, and decreasing the value of pi when the standby mode is short.

[0054] As yet another example, the cooling control unit 32 may adjust a predetermined number pi according to the type of recording paper. For example, when the size of the recording paper is large, the amount of heat that one recording paper takes away from the fixing device 6 also increases. Therefore, when the size of the recording paper is large, the value of pi is increased to delay the driving of the cooling fan 9, and when the size of the recording paper is small, the driving of the cooling fan is accelerated by decreasing the value of pi. Is preferred. Thereby, it is possible to appropriately control the cooling in consideration of the size of the recording paper. In addition, the predetermined number pi may be adjusted according to the weight or material of the recording paper as well as the size of the recording paper. In these cases, Information on the type of recording paper can be sent to the image forming apparatus 100 by the user or a computer used by the user. The size of the recording paper is detected by measuring the time from when each sensor 2:! To 23 is turned from OFF to ON until the timing from ON to OFF. The size may be estimated based on that.

It should be noted that the predetermined time T1 in the above step S17 can be made equal to or less than the time required for the trailing edge of the recording paper to pass through the fixing device after the leading edge of the recording paper reaches the fixing device 6. .

[0056] Usually, when the recording paper passes through the fixing device, the heat of the fixing device is taken away by the recording paper, so that the fixing device needs to be heated. As a result, after the recording paper passes through the fixing device 6, the temperature of the fixing device 6 tends to rise. Here, according to the above configuration, the cooling fan 9 starts to be driven from when the recording paper reaches the fixing device 6 until the recording paper is completely passed. Therefore, after completion of passing the recording paper, the fixing device 6 can be surely cooled, and the next recording paper force S can be prevented from curling.

[0057] In this case, since the passing time varies depending on the size of the recording paper (A3, A4, A5, etc.), the cooling control unit 32 adjusts the predetermined time T1 according to the size of the recording paper. That power S favored.

In this embodiment, the timer 36 starts counting up when the detection signal of the POUT1 sensor 22 changes from OFF to ON (ie, when the leading edge of the recording paper reaches the fixing unit 6). The force at which the cooling control unit 32 starts driving the cooling fan 9 after a predetermined time T1 has passed. Instead, if the POUT1 sensor 22 is installed upstream of the fixing unit 6, the detection of the POUT1 sensor 22 When the signal changes from ON to OFF (that is, when the trailing edge of the recording paper passes through the fixing unit 6), the cooling fan 9 may be started immediately without counting up the timer. . That is, the cooling control unit 32 may start driving the cooling fan 9 in response to the POUT1 sensor 22 detecting that the trailing edge of the recording paper has passed the fixing unit 6. In this case, the cooling fan 9 is started at the same time as the recording paper completes passing through the fixing device 6, so that the temperature of the fixing device 6 is prevented from decreasing before the toner is fixed, and the recording paper is used. It is possible to prevent overheating that occurs after passing through. In the present embodiment, the cooling fan is driven when the number of continuously printed recording sheets reaches a predetermined number pi. However, the present invention is not limited to this, and one sheet is used. The timer 36 may be configured to start power-up of the timer 36 when the leading edge of the recording paper printed on the eye is detected by the POUT1 sensor 22. In this case, in the cooling control process described above, if the temperature t detected by the temperature detector 35 does not exceed t2 in step S12, the configuration may be changed to proceed to step S14.

[0060] In this case, it is preferable that the predetermined time T1 is appropriately determined according to the characteristics of the fixing device, the contents of the heating control, and the like. It is possible to investigate whether the inside of the device is overheated when printing, and to make a decision based on the time.

Also in this case, it is preferable that the cooling control unit 32 adjust T1 as appropriate according to various conditions during printing, as in the case of pi described above. That is, it is preferable that the cooling control unit 32 adjust the predetermined time T1 according to the temperature detected by the temperature detection unit 35. The timing at which the temperature detection unit 35 detects the temperature is not particularly limited, but may be, for example, the timing at which the reception unit 37 receives a print command. Further, the cooling control unit 32 may adjust the predetermined time T1 according to the time in the standby mode, or may adjust according to the type of recording paper. With these configurations, it is possible to obtain substantially the same effect as in the case of adjusting pi described above.

By the way, when driving of the cooling fan 9 is started in step S19, the cooling control unit

Examples of the timing at which 32 stops the driving of the cooling fan 9 include one of the following two timings. First, the first timing may be a predetermined time after the print mode ends. In this case, the predetermined time should be determined based on the time required for the cooling fan 9 to sufficiently reduce the temperature in the apparatus after the printing mode. Can do. Instead of using the end of the printing mode as a base point, the base point may be the time when the last recording paper is ejected from the image forming apparatus 100 (that is, the point when the POUT2 sensor 23 is turned off from on). ,.

[0063] Further, as the second timing, after the cooling fan 9 is driven, the temperature detector 35 The timing force S when the temperature is detected at any time and the detected temperature falls below (below) the specified temperature can be mentioned. In this case, it is desirable that the predetermined temperature is a temperature that is low enough not to damage each part in the apparatus and high enough that the fixing device 6 can be quickly warmed up.

As described above, the image forming apparatus 100 of the present embodiment stops the cooling fan 9 in the standby mode immediately after the power is turned on. Even when the cooling fan 9 is driven in the standby mode after printing, the driving of the cooling fan 9 is stopped based on a predetermined time or a predetermined temperature. As a result, the warm-up can be quickly performed at the time of the next printing in which the fixing device 6 is not excessively cooled in the standby mode.

Note that the image forming apparatus 100 of the present embodiment further includes an abnormality detection unit (not shown) as a more preferable form. This anomaly detection unit is for detecting an error when the recording paper is pulled in by the paper feed roller 1 and an error thereafter. The cooling control unit 32 refers to the temperature detected by the temperature detecting unit 35 when an error such as a paper jam is notified from the abnormality detecting unit in the printing mode, and if this temperature exceeds a predetermined temperature, the cooling control unit 32 Start driving fan 9.

[0066] According to such a configuration, when an error occurs before the recording paper reaches the fixing device 6, it is possible to prevent a fire or damage to each part due to an excessive increase in the temperature in the apparatus. That power S. In this case, since the cooling control unit 32 stops the driving of the cooling fan 9 based on the temperature inside the device, not simply stopping the driving of the cooling fan 9, the temperature inside the device is too low and the warming-up is stopped. There is no risk of hindrance.

In the present embodiment, a PO provided adjacent to the fixing device 6 is used as a recording paper detection unit for detecting that the recording paper has been drawn by the paper supply roller 1. A UT1 sensor 22 was used. Here, “the drawing is completed” means that in this embodiment, the trailing edge of the recording paper conveyed by the paper supply roller 1 is separated from the paper supply roller 1 to the downstream side in the recording paper conveyance direction. Therefore, it is intended that the recording paper in a state where the drawing by the paper feed roller 1 is completed does not cause an error such as a paper jam when it is in contact with the paper feed roller 1. By the way, the recording paper detection unit in the present invention is not limited to the configuration of the POUT 1 sensor 22 provided adjacent to the fixing device 6, and may be a sensor provided at another position. Les. For example, the PIN sensor 21 provided adjacent to the registration roller 2 or the POUT2 sensor 23 provided near the discharge unit may be used, or another sensor may be provided separately. In other words, the recording paper detection unit that detects that the recording paper has been drawn in by the paper feeding / conveying unit has a conveyance direction longer than the length of the recording paper in the conveyance direction. A sensor provided on the downstream side can be used. According to this configuration, the recording paper detection unit can detect the recording paper after it is normally pulled by the paper feed roller 1, and the cooling fan 9 is activated when at least the recording paper pull-in by the paper feed roller 1 fails. Driving can be avoided.

[0069] Finally, the temperature control unit 31 and the cooling control unit 32 of the image forming apparatus 100 may be configured by a hard logic, or may be realized by software using a CPU as follows.

That is, the image forming apparatus 100 includes a CPU (central processing unit) that executes instructions of a temperature control program and a cooling control program that realize each function, a ROM (read only memory) that stores the program, and the above It is equipped with a random access memory (RAM) for expanding the program, a storage device (recording medium) such as a memory for storing the program and various data. The object of the present invention is to record the program code (execution format program, intermediate code program, source program) of each control program of the image forming apparatus 100, which is software that realizes the above-described functions, in a computer-readable manner. This can also be achieved by supplying the recording medium to the image forming apparatus 100 and reading and executing the program code recorded on the recording medium by the computer (or CPU or MPU).

[0071] Examples of the recording medium include disks such as magnetic tapes and cassette tapes, magnetic disks such as floppy (registered trademark) disks / hard disks, and optical disks such as CD-ROMZMO / MD / DVDZCD-R. System, IC card (including memory card) Z optical card, etc. or semiconductor memory system such as mask RM / EPROMZEEPR〇MZ flash ROM can be used. Alternatively, the image forming apparatus 100 may be configured to be connectable to a communication network, and the program code may be supplied via the communication network. The communication network is not particularly limited. For example, the Internet, intranet, extranet, LAN, ISDN, VAN, CATV communication network, virtual private network, telephone line network, mobile communication network, satellite communication A net or the like is available. The transmission medium constituting the communication network is not particularly limited. For example, IEEE 1394, USB, power line carrier, cable TV line, telephone line, ADSL line, etc. It can also be used with radio such as Bluetooth (registered trademark), 802.11 radio, HDR, mobile phone network, satellite line, terrestrial digital network. The present invention can also be realized in the form of a computer data signal carried in a carrier wave, in which the program code is embodied by electronic transmission.

The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope shown in the claims. That is, embodiments obtained by combining technical means appropriately modified within the scope of the claims are also included in the technical scope of the present invention.

As described above, the image forming apparatus according to the present invention includes the recording paper detection unit that detects that the recording paper has been drawn in by the paper feed conveyance unit, and includes a cooling control unit. However, the operation of the cooling unit is stopped in the standby mode, and the cooling power of the cooling unit is improved compared to that before detection in response to the detection by the recording paper detection unit in the image forming mode. . Therefore, as described above, there is an effect that the temperature control of the fixing unit can be performed efficiently.

[0075] Further, it is preferable that the recording paper detection unit is provided adjacent to the fixing unit and detects that the leading edge of the recording paper has been conveyed to the fixing unit.

According to the above configuration, the cooling control unit improves the cooling power of the cooling unit in response to the leading edge of the recording paper being conveyed to the fixing unit. Therefore, even if an error occurs in the conveyance path from the paper feed conveyance unit to the fixing unit, it is possible to prevent the temperature in the apparatus from being lowered.

[0077] The cooling control unit may be configured to improve the cooling power of the cooling unit between the time when the recording paper reaches the fixing unit and the time when the passage is completed. Inspection It is preferable to improve the cooling power of the cooling section after a predetermined time has elapsed from the time of taking out.

It is known that the recording paper takes heat of the fixing unit when passing through the fixing unit. Here, according to the configuration of the present invention, the cooling power of the cooling section is not improved until the recording paper reaches the fixing section. As a result, it is possible to prevent the temperature of the fixing unit from being lowered below an appropriate temperature due to the recording paper reaching the fixing unit while the cooling power is improved. As a result, it is possible to prevent deterioration of fixing of the developer transferred to the recording paper.

[0079] Further, normally, while the recording paper passes through the fixing unit, the fixing device is heated for the purpose of compensating for heat taken away by the recording paper. Tends to increase. Here, when the fixing unit is overheated, the next recording sheet conveyed to the fixing unit is curled by the heat of the fixing unit. However, according to the configuration of the present invention, since the cooling power is reliably improved before the recording paper passes through the fixing unit, the temperature of the fixing unit increases excessively after the recording paper completes passing through the fixing unit. It can be kept at an appropriate temperature. This prevents the next recording paper from curling.

[0080] The image forming apparatus further includes a temperature detection unit that is provided in the image forming apparatus and detects the temperature of the fixing unit, and the cooling control unit sets the predetermined time to the temperature detection unit. It is preferable to adjust according to the temperature detected by the part.

When the temperature of the fixing unit is high, it is desirable to improve the cooling power of the cooling unit early. Conversely, when the temperature of the fixing unit is low, it is desirable to improve the cooling power of the cooling unit later. According to the above configuration, since the cooling control unit adjusts the timing for improving the cooling power in accordance with the temperature of the fixing unit, more efficient temperature control can be performed.

[0082] Further, it is preferable that the cooling control unit adjusts the predetermined time according to a temperature detected by the temperature detecting unit when an image forming command is received by the receiving unit.

According to the above configuration, the cooling control unit adjusts the “predetermined time” described above according to the temperature of the fixing unit at the time when the printing mode is started. Accordingly, it is possible to accurately determine how long the fixing unit S in the print mode is in the overheat state. [0084] The cooling control unit may adjust the predetermined time according to the time of the standby mode.

[0085] For example, when the standby mode time is long, it is considered that the temperature of the fixing unit is sufficiently lowered. Therefore, it is desirable to improve the cooling power later. On the contrary, when the standby mode time is short, it is considered that the temperature of the fixing portion that has risen during the previous image formation is not sufficiently lowered, so it is desirable to improve the cooling power as soon as possible. According to the above configuration, the cooling control unit adjusts the timing for improving the cooling power according to the time of the standby mode, so that more efficient temperature control can be performed.

[0086] The cooling control unit may adjust the predetermined time according to the type of the recording paper.

The amount of heat taken away from the fixing unit by the recording paper varies depending on the type of the recording paper. Therefore, according to the above configuration, more efficient temperature control can be performed by adjusting the timing at which the cooling control unit improves the cooling power in accordance with the type of recording paper. Here, the type of recording paper includes, for example, the size of the recording paper, the weight of the recording paper, and the material of the recording paper. The cooling control unit may adjust the timing in consideration of all of these, or may adjust the timing in consideration of only a part such as one or two.

[0088] The image forming apparatus further includes a recording paper counting unit that counts the amount of recording paper on which images are continuously formed, and the cooling control unit is configured to record the recording paper in the image forming mode. When the amount of recording paper counted by the counting unit is a predetermined amount of recording paper, it is preferable that the cooling power of the cooling unit is improved from that before detection according to the detection by the recording paper detection unit. .

According to the above configuration, when the image forming apparatus is configured to continuously form an image on a plurality of recording sheets, the amount of the recording sheet on which the image is formed becomes a predetermined amount. When it reaches, the cooling power can be improved. Therefore, for example, even when an image is formed only on one sheet of recording paper, the inside of the apparatus is not overheated, and the fixing unit is overheated only when an image is formed on a plurality of sheets of recording paper. It is possible to control the temperature appropriately. The image forming apparatus further includes a temperature detection unit that is provided in the image forming apparatus and detects a temperature, and the cooling control unit determines the amount of the predetermined recording sheet from the temperature detection unit. It is preferable to adjust according to the temperature detected by the exit part.

For example, when the temperature of the fixing unit is high, it is desirable to improve the cooling power of the cooling unit early. Conversely, when the temperature of the fixing unit is low, it is desirable to improve the cooling power of the cooling unit later. According to the above configuration, since the cooling control unit adjusts the timing of increasing the cooling power in accordance with the temperature of the fixing unit, more efficient temperature control can be performed.

[0092] Further, the cooling control unit adjusts the amount of the predetermined recording paper according to the temperature detected by the temperature detection unit when the reception unit receives the image forming command. It is preferable to do.

According to the above configuration, the cooling control unit adjusts the “predetermined amount of recording paper” described above according to the temperature of the fixing unit at the time when the printing mode is started. Therefore, in the printing mode, it is possible to accurately cut in half the amount of recording paper on which the fixing unit is overheated when printing is performed.

[0094] The cooling control unit may adjust the amount of the predetermined recording paper according to the time of the standby mode.

[0095] For example, when the standby mode time is long, it is considered that the temperature of the fixing unit is sufficiently lowered, so it is desirable to improve the cooling power later. On the contrary, when the standby mode time is short, it is considered that the temperature of the fixing portion that has risen during the previous image formation is not sufficiently lowered, so it is desirable to improve the cooling power as soon as possible. According to the above configuration, since the cooling control unit adjusts the timing for improving the cooling power in accordance with the time of the standby mode, more efficient temperature control can be performed.

[0096] In addition, the cooling control unit may adjust the amount of the predetermined recording sheet according to the type of the recording sheet.

The amount of heat taken from the fixing unit by the recording paper varies depending on the type of the recording paper. According to the above configuration, the cooling control unit adjusts the timing for improving the cooling power in accordance with the type of recording paper, thereby enabling more efficient temperature control. Where Examples of the type of recording paper include the size of the recording paper, the weight of the recording paper, and the material of the recording paper. The cooling control unit may adjust the timing in consideration of all of these, or may adjust the timing in consideration of only one part, such as one or two.

Further, the image forming apparatus is provided in the image forming apparatus and detects an abnormality that occurs after the temperature is detected from the sheet feeding tray by the temperature detecting unit that detects the temperature and the sheet feeding and conveying unit. An abnormality detection unit that detects the abnormality in the image forming mode when the abnormality is detected by the abnormality detection unit, and is higher than a predetermined temperature by the temperature detection unit. When is detected, it is preferable to improve the cooling power of the cooling unit more than before detection.

[0099] According to the configuration described above, it is possible to prevent the apparatus from becoming overheated when an abnormality is detected. Here, the cooling control unit improves the cooling power of the cooling unit only when a temperature higher than the predetermined temperature is detected, so that it is possible to prevent the inside of the apparatus from being cooled more than necessary. Can do.

[0100] The image forming apparatus further includes a temperature detection unit that is provided in the image forming apparatus and detects a temperature, and the cooling control unit is detected by the temperature detection unit in the standby mode. It is preferable to stop the operation of the cooling unit based on the measured temperature.

[0101] According to the above configuration, when the inside of the apparatus is overheated after the end of the image forming mode or the like, the cooling power of the cooling unit is maintained as it is, and when the temperature is below or below a predetermined temperature. The operation of the cooling unit is stopped. As described above, it is possible to prevent the apparatus from being overheated in the standby mode.

[0102] Further, when the cooling control unit shifts from the image forming mode to the standby mode, the cooling unit may stop the operation of the cooling unit after a predetermined time has elapsed since the end of the image forming mode. .

[0103] According to the above configuration, the operation of the cooling unit is stopped after a predetermined time from the end of the image forming mode. Therefore, it is possible to prevent the inside of the apparatus from being overheated in the standby mode. [0104] It should be noted that the specific embodiments or examples made in the section of the best mode for carrying out the invention are merely to clarify the technical contents of the present invention. The present invention is not limited to specific examples and should not be construed in a narrow sense. Various modifications can be made within the spirit of the present invention and the scope of the following claims.

Industrial applicability

According to the present invention, an image forming apparatus capable of efficiently performing temperature control of the fixing unit can be realized. Therefore, it can be suitably applied to a general laser printer or the like.

Claims

The scope of the claims

[1] A receiving unit that receives an image formation command, a paper feeding unit that draws and conveys recording paper from a paper feeding tray, a fixing unit that fixes developer on the recording paper, and a heating unit that heats the fixing unit; A cooling unit that cools the fixing unit, and a cooling control unit that controls the operation of the cooling unit, and the feeding is completed by the sheet feeding and conveying unit in response to the reception of the image forming command by the receiving unit. There are two modes: an image forming mode in which the developer is transferred to the recording paper, and the developer is fixed on the recording paper by the fixing unit heated by the heating unit, and a standby mode in which an image forming command is received. An image forming apparatus having

A recording paper detection unit for detecting that the recording paper is being pulled in by the paper feeding and conveying unit;

The cooling control unit stops the operation of the cooling unit in the standby mode, and in the image forming mode, the cooling power of the cooling unit is detected more than before detection in response to detection by the recording paper detection unit. An image forming apparatus characterized by being improved.

[2] The image forming apparatus according to claim 1,

The image forming apparatus, wherein the recording paper detection unit is provided adjacent to the fixing unit and detects that the leading edge of the recording paper is conveyed to the fixing unit.

[3] The image forming apparatus according to claim 1,

The cooling control unit has been detected by the recording sheet detection unit so as to improve the cooling power of the cooling unit during the period from when the recording sheet reaches the fixing unit to when the passage is completed. An image forming apparatus characterized in that the cooling power of a cooling unit is improved after a predetermined time has elapsed from a point in time.

[4] The image forming apparatus according to claim 3,

A temperature detection unit provided in the image forming apparatus for detecting the temperature of the fixing unit;

The image forming apparatus, wherein the cooling control unit adjusts the predetermined time according to a temperature detected by the temperature detection unit.

[5] The image forming apparatus according to claim 4, The cooling control unit adjusts the predetermined time according to a temperature detected by the temperature detection unit when an image forming command is received by the receiving unit. apparatus.

[6] The image forming apparatus according to claim 3,

The cooling control unit adjusts the predetermined time according to the time of the standby mode.

[7] The image forming apparatus according to claim 3,

The image forming apparatus, wherein the cooling control unit adjusts the predetermined time according to a type of the recording paper.

[8] The image forming apparatus according to claim 1,

A recording paper counting unit that counts the amount of recording paper that has been continuously imaged; and wherein the cooling control unit counts the amount of recording paper counted by the recording paper counting unit in the image forming mode. The image forming apparatus characterized in that when the amount of recording paper is a predetermined amount of recording paper, the cooling power of the cooling unit is improved as compared with that before detection in accordance with detection by the recording paper detection unit.

[9] The image forming apparatus according to claim 8,

The image forming apparatus further includes a temperature detection unit that detects a temperature, and the cooling control unit adjusts the amount of the predetermined recording sheet according to the temperature detected by the temperature detection unit. An image forming apparatus.

[10] The image forming apparatus according to claim 9,

The cooling control unit adjusts the amount of the predetermined recording sheet in accordance with the temperature detected by the temperature detection unit when the image forming instruction is received by the reception unit. An image forming apparatus.

[11] The image forming apparatus according to claim 8,

The image forming apparatus, wherein the cooling control unit adjusts an amount of the predetermined recording sheet according to a time of the standby mode.

[12] The image forming apparatus according to claim 8,

The cooling control unit adjusts the amount of the predetermined recording sheet according to the type of the recording sheet. An image forming apparatus.

[13] The image forming apparatus according to claim 1,

A temperature detector provided in the image forming apparatus for detecting temperature;

An anomaly detection unit for detecting an anomaly that has occurred after the paper feeding / conveying unit pulls in from the paper feed tray;

When the cooling control unit detects an abnormality in the image forming mode by the abnormality detection unit and a temperature higher than a predetermined temperature is detected by the temperature detection unit, the cooling unit The cooling power is improved compared to before detection.

, Image forming apparatus.

[14] The image forming apparatus according to claim 1,

The image forming apparatus further includes a temperature detection unit that detects a temperature, and the cooling control unit stops the operation of the cooling unit based on the temperature detected by the temperature detection unit in the standby mode. An image forming apparatus characterized in that

[15] The image forming apparatus according to claim 1,

The cooling control unit stops the operation of the cooling unit after a predetermined time has elapsed from the end of the image forming mode when the image forming mode is shifted to the standby mode. Forming equipment.

16. A cooling control program for operating the image forming apparatus according to claim 1, wherein the cooling control program causes a computer to function as the cooling control unit.

[17] A computer-readable recording medium on which the program according to claim 16 is recorded.