JP2005164712A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus in which a wait time needed until an image formation is shortened and a power consumption for the image formation is reduced when receiving an instruction to perform the image formation during a stand-by state in a power-saving mode, . <P>SOLUTION: When the instruction to perform the image formation is received through an operation part (YES in S1, and YES in S2) during the power saving mode of a fixing part, a control part drives the fixing part in the power saving mode. At this time, the fixing part 45 is driven after decreasing the fixing speed of the fixing part 45 so that the fixing part 45 reaches temperatures necessary for a toner image to be fixed when recording paper is passed through the fixing part. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electrophotographic image forming apparatus, and more particularly to a technique for forming an image with a fixing unit in a power saving state.

Conventionally, in an electrophotographic image forming apparatus, if an image forming operation is not performed for a certain period of time, the fixing apparatus for fixing the toner image on the recording paper is lowered to a predetermined temperature. Some have a power-saving mode for waiting (Patent Document 1). In the power saving mode, when the image forming execution instruction is input by the operation of the operation unit by the user in the power saving mode, the temperature of the fixing device is increased until the temperature rises to a temperature necessary for fixing the toner image on the recording paper. After returning, image formation is executed.
JP 2003-131464 A

  In the image forming apparatus, for example, even when the number of users of the image forming apparatus is small and a single user prints a small number of sheets, the temperature of the fixing apparatus is raised to a predetermined fixing temperature to form an image. The device is returned from the power saving mode. However, since a considerable amount of time is required to return the fixing device to the predetermined fixing temperature, a waiting time is generated for the user before print output. In addition, a considerable amount of power is required to return the fixing device to a predetermined fixing temperature, but it is efficient to return from the power saving mode by consuming a large amount of power for printing a small number of sheets. bad.

  The present invention has been made to solve the above-described problem. When an image formation execution instruction is issued during standby in a power saving state, the waiting time until the start of image formation is shortened, and image formation is performed. An object of the present invention is to provide an image forming apparatus that consumes less power.

According to a first aspect of the present invention, there is provided a photosensitive member on which an electrostatic latent image is formed, a developing unit that supplies toner onto the surface of the photosensitive member, and the electrostatic latent image from the developing unit. A transfer means for transferring a toner image formed on the surface of the photoreceptor with the supplied toner onto the recording paper; a fixing means for thermally fixing the toner image transferred from the photoreceptor by the transfer means onto the recording paper; and an external operation An operation means for receiving an input of an image formation execution instruction by the image forming apparatus, and maintaining the fixing means in a power saving state in which a predetermined temperature is lowered from a predetermined thermal fixing temperature necessary for fixing the toner image on the recording paper under a predetermined condition. And an image forming apparatus including a control unit.
The control unit drives the fixing unit in the power saving state when the image forming execution instruction is received by the operation unit while the fixing unit is in the power saving state, and the recording paper is The fixing speed of the fixing unit is reduced so as to reach a temperature necessary for fixing the toner image when passing through the fixing unit.

  In this configuration, when the image forming execution instruction is received by the operation unit while the fixing unit is in the power saving state, the control unit is in the power saving state and fixes the toner image onto the recording paper. Even when the temperature is lower than the required heat fixing temperature, the fixing unit is driven in a power saving state while reducing the fixing speed to fix the toner image when the recording paper passes through the fixing unit. The required temperature is reached.

  The invention according to claim 2 is the image forming apparatus according to claim 1, wherein the control unit instructs the operation unit to perform image formation when the fixing unit is in the power saving state. Is received, the image forming speed by the image forming means of the photoconductor, the developing means and the transfer means is reduced in accordance with the reduction of the fixing speed of the fixing means.

  In this configuration, when the fixing unit is in the power saving state, when the image forming execution instruction is received by the operation unit and the control unit drives the fixing unit at a reduced fixing speed, the photosensitive member, the developing unit And the image forming speed of each image forming means of the transfer means by reducing the image forming speed of each image forming means of the transfer means in accordance with the reduction of the fixing speed of the fixing means. No difference in speed is caused between the fixing speed and the fixing speed.

The invention according to claim 3 is the image forming apparatus according to claim 1, wherein the control unit instructs the operation unit to perform image formation when the fixing unit is in the power saving state. Is received, without reducing the image formation speed by the image forming means of the photosensitive member, the developing means and the transfer means, only the fixing speed of the fixing means is reduced,
A recording paper conveyance path provided upstream of the fixing unit in the recording paper conveyance direction includes a fixing speed of the fixing unit and an image forming speed of each image forming unit of the photosensitive member, the developing unit, and the transfer unit. A recording paper retracting means for absorbing the deflection of the recording paper caused by the speed difference is formed.

  In this configuration, when the fixing unit is in the power saving state, when the image forming execution instruction is received by the operation unit and the control unit drives the fixing unit at a reduced fixing speed, the photosensitive member, the developing unit, and the The image forming speed of each image forming means of the transfer means is not reduced, only the fixing speed of the fixing means is reduced, the image forming speed of each image forming means of the photosensitive member, the developing means and the transferring means, and the fixing means The phenomenon caused by the speed difference from the fixing speed, that is, the recording paper bending that occurs when the leading edge of the recording paper reaches the fixing means, is recorded in the recording paper conveyance path on the upstream side of the fixing means in the recording paper conveyance direction. The paper is saved by means of paper shelter.

  According to a fourth aspect of the present invention, there is provided the image forming apparatus according to the third aspect, further comprising conveyance path switching means for switching whether the recording paper is guided to the recording paper retracting means or bypassed. It is what.

  In this configuration, the conveyance path switching means switches whether the recording paper is guided to the recording paper saving means or bypassed.

According to a fifth aspect of the present invention, in the image forming apparatus according to the fourth aspect, the transport path switching means guides the transport direction of the recording paper, and one end portion of the recording paper is retracting means. A guide member pivotally supported at the upstream end of the recording paper conveyance direction, and drive means for rotationally driving the guide member,
The recording paper transport path is provided with detection means for detecting the position of the recording paper in the recording paper transport path and sending a recording paper detection signal to the control means when the recording paper is detected,
When the image forming execution instruction is received by the operation unit, the control unit controls driving of the driving unit based on a recording sheet detection signal from the detection unit, and the fixing unit is in the power saving state. The guide member is rotated to a position for guiding the recording paper to the recording paper retracting means, and the recording paper is bypassed from the recording paper retracting means when the fixing means is not in the power saving state. The guide member is rotated.

  In this configuration, when the image forming execution instruction is received by the operation unit, the control unit drives and controls the drive unit based on the recording paper detection signal from the detection unit to rotate the guide member, and the fixing unit saves power. When in the state, the recording paper is guided to the recording paper saving means, and when the fixing means is not in the power saving state, the recording paper is bypassed from the recording paper saving means.

The invention according to claim 6 is the image forming apparatus according to claim 5, comprising timer means for measuring time,
When the control means receives the recording paper detection signal from the detection means while the fixing means is in the power saving state, the control means controls the drive means to bypass the recording paper from the recording paper retracting means. The guide member is rotated to a position to be moved, and a lapse of a required time from when the recording paper detection signal is received from the detection means to when the leading edge of the recording paper is conveyed to the fixing means by the timer means Is measured, the guide member is rotated to a position for guiding the recording paper to the recording paper retracting means.

  In this configuration, the position of the guide member is moved to a position corresponding to the position of the leading edge of the recording paper based on the elapsed time from when the control means receives the recording paper detection signal from the detecting means, which is measured by the timer means. It is supposed to let you.

  The invention according to claim 7 is the image forming apparatus according to any one of claims 1 to 6, wherein the control unit is configured to perform the operation when the fixing unit is in the power saving state. Only when an instruction for executing image formation less than a predetermined number of times as an image formation execution instruction is input to the operation means, driving of the fixing means with the fixing speed reduced is executed.

  In this configuration, when the fixing unit is in the power saving state, only when the control unit inputs an instruction for driving the fixing unit with a reduced fixing speed to execute the image formation less than a predetermined number of times. It is supposed to be executed.

  According to the first aspect of the present invention, if there is an image formation execution instruction when the fixing unit is in the power saving state, the fixing unit is driven in the power saving state, so that the toner image is fixed on the recording paper. Fixing means that can immediately start image formation without returning to the required predetermined heat fixing temperature, and reaches the temperature necessary for fixing the toner image when the recording paper passes through the fixing means. Therefore, the toner image can be sufficiently fixed on the recording paper even if the fixing unit is driven in the power saving state. As a result, even when there is an image formation execution instruction while the fixing unit is in a power saving state, good image formation can be performed with a small amount of power consumption, and the waiting time until the start of image formation is shortened. Can be made.

  According to the second aspect of the present invention, when there is an image formation execution instruction when the fixing unit is in the power saving state, the image forming speed of each of the image forming units of the photosensitive member, the developing unit, and the transfer unit is determined by the fixing unit. Since there is no difference in speed between the image forming speed of each image forming means of the photosensitive member, developing means and transfer means and the fixing speed of the fixing means, no special mechanism is provided. Without the provision of the image forming apparatus, it is possible to perform image formation without any trouble when driving the fixing unit with a reduced fixing speed.

  According to the third aspect of the present invention, if there is an image formation execution instruction when the fixing unit is in the power saving state, the image forming speed by the image forming units of the photosensitive member, the developing unit, and the transfer unit is not reduced, Since only the fixing speed of the fixing unit is reduced, it is not necessary to separately provide a drive source for the image forming unit and the fixing unit, or to separately provide a software configuration such as speed control for each unit. Further, since the image forming speed of each of the image forming units is sufficient for normal operation and when the fixing unit is in a power saving state, the print target data is corrected in accordance with the change in the image forming speed during image formation. It is not necessary to perform such processing, and it is difficult to cause problems in terms of image quality. Further, since the recording paper deflection caused by the difference in speed between the image forming speed of each image forming means and the fixing speed of the fixing means, which is generated upstream of the fixing means in the recording paper conveyance direction, is absorbed by the recording paper retracting means. The recording paper can be transported smoothly, and the influence of the speed difference on the image quality can be reduced.

  According to the fourth aspect of the present invention, it is possible to switch between guiding the recording sheet to the recording sheet retracting means and bypassing the recording sheet by the transport path switching means provided in the recording sheet retracting means.

  According to the fifth aspect of the present invention, when the image forming execution instruction is given to the operation unit, the guide member is rotated based on the recording sheet detection signal from the detection unit, and the fixing unit is in the power saving state. When the recording paper is guided to the recording paper saving means and the fixing means is not in the power saving state, the recording paper is bypassed from the recording paper saving means, so the speed difference between the image formation of the image forming means and the fixing speed of the fixing means The recording paper is guided to the recording paper retracting means only when the recording paper is bent on the upstream side in the recording paper conveyance direction of the fixing means, and the image formation of each of the image forming means and the fixing speed of the fixing means If the recording sheet is not bent at the upstream side of the fixing unit in the recording sheet conveyance direction, the recording sheet can be prevented from being guided to the recording sheet retracting unit. Thereby, it is possible to prevent the presence of the recording paper transporting unit from adversely affecting the leading end of the recording paper to the fixing unit.

  According to the sixth aspect of the invention, since the guide member is rotated according to the position of the leading end portion of the recording paper, the recording paper is retracted by the guide member until the leading end of the recording paper reaches the fixing means. By bypassing the recording paper, the recording paper can be smoothly conveyed to the fixing means without any trouble, and when the leading edge of the recording paper reaches the fixing means and the recording paper is bent, a guide is provided. The bent portion of the recording paper can be reliably guided to the recording paper retracting means by the member.

  According to the seventh aspect of the present invention, only when the operation unit inputs an instruction to execute image formation less than a predetermined number of times when the fixing unit is in the power saving state, the control unit controls the fixing speed. Since the reduced driving of the fixing unit is executed, it is possible to execute the driving of the fixing unit with a reduced fixing speed only under a certain condition.

(First embodiment)
Embodiments according to the present invention will be described below with reference to the drawings. FIG. 1 is a side view schematically showing an internal configuration of a multifunction peripheral as an example of an image forming apparatus according to an embodiment of the present disclosure. The multifunction device 1 has functions such as a copy function, a printer function, a scanner function, and a facsimile function. The multi-function device 1 includes a main body 2, a stack tray 3 disposed on the left side of the main body 2, a document reading unit 5 disposed on the top of the main body 2, and an upper side of the document reading unit 5. And a document feeding unit 6 disposed.

  An operation unit 47 is provided at the front part of the multifunction machine 1. The operation unit 47 displays a start key 471 for a user to input a print execution instruction, a ten key 472 for inputting the number of copies to be printed, operation guide information for various copying operations, and the like. A display unit 473 formed of a liquid crystal display or the like having a touch panel function, a reset key 474 for resetting setting contents set in the display unit 473, and a stop key for stopping a printing (image forming) operation being executed 475 and a function switching key 477 for switching between a copy function, a printer function, a scanner function, and a facsimile function.

  The document reading unit 5 includes a scanner unit 51 including a CCD (Charge Coupled Device) sensor and an exposure lamp, and a document table 52 and a document reading slit 53 made of a transparent member such as glass. The scanner unit 51 is configured to be movable by a drive unit (not shown). When reading a document placed on the document table 52, the scanner unit 51 is moved along the document surface at a position facing the document table 52, and the document image is scanned. The image data acquired while scanning is output to the control unit 100 (FIG. 2). Further, when reading a document fed by the document feeding unit 6, the document is moved to a position facing the document reading slit 53 and synchronized with the document feeding operation by the document feeding unit 6 via the document reading slit 53. The image of the original is acquired and the image data is output to the control unit 100.

  The document feeding unit 6 includes a document placing unit 61 for placing a document, a document discharge unit 62 for discharging a document whose image has been read, and a document placed on the document placing unit 61. A document transport mechanism 63 including a paper feed roller (not shown), a transport roller (not shown) and the like for feeding the paper one by one to a position facing the document reading slit 53 and discharging it to the document discharge section 62 is provided. The document conveyance mechanism 63 further includes a sheet reversing mechanism (not shown) that reverses the document and reversely conveys the document to a position facing the document reading slit 53, and scans both sides of the document through the document reading slit 53. 51 can be read.

  The document feeding unit 6 is provided so as to be rotatable with respect to the main body unit 2 so that the front side thereof can move upward. By moving the front side of the document feeder 6 upward to open the upper surface of the document table 52, the operator can place a read document, for example, a book in a spread state, on the upper surface of the document table 52. It has become.

  The main body 2 includes a plurality of paper feeding cassettes 461, a paper feeding roller 462 that feeds recording paper from the paper feeding cassette 461 one by one, and transports the recording paper to the recording unit 40. And a recording unit 40 that forms an image on the conveyed recording paper.

  The recording unit 40 outputs a laser beam or the like based on the image data acquired by the scanner unit 51 to expose the photosensitive drum (photosensitive member) 43, and forms a toner image on the photosensitive drum 43. A developing unit (developing unit) 44, a transfer unit (transfer unit) 41 for transferring the toner image on the photosensitive drum 43 to the recording paper, and the recording paper to which the toner image has been transferred are heated to form the toner image on the recording paper. A fixing unit (fixing unit) 45 for fixing, and conveyance rollers 463 and 464 that are provided in a sheet conveyance path in the recording unit 40 and convey the recording sheet to the stack tray 3 or the discharge tray 48 are provided.

  Note that a registration roller 466 is provided on the upstream side of the photosensitive drum 43 and the transfer unit 41 in the recording paper conveyance direction to take a timing for conveying the recording paper to the photosensitive drum 43 and the transfer unit 41 during image formation. . On the upstream side of the fixing unit 45 in the recording sheet conveying direction, a recording sheet retracting mechanism (for inserting a bent portion generated in the recording sheet when the leading end of the recording sheet reaches the nip portion of the fixing roller pair of the fixing unit 45 ( Recording paper saving means) 60 is provided.

  When forming images on both sides of the recording paper, the recording unit 40 forms an image on one side of the recording paper, and then the recording paper is nipped by the conveyance roller 463 on the discharge tray 48 side. . In this state, the conveyance roller 463 is reversed to switch back the recording paper, and the recording paper is sent to the paper conveyance path L and conveyed again to the upstream area of the recording unit 40, and an image is formed on the other surface by the recording unit 40. Thereafter, the recording paper is discharged to the stack tray 3 or the discharge tray 48.

  FIG. 2 is a functional block diagram showing a schematic configuration of the multifunction machine 1. The multifunction device 1 includes a control unit (operation means) 100 that controls operation of the entire apparatus. The control unit 100 includes a scanner unit 51 including an exposure lamp 511 and a CCD 512 that can read an original image, a paper transport unit 411, and an image forming unit (transfer unit 41, optical unit 42, photosensitive drum 43, and development unit). And a recording unit 40 including a fixing unit 45 and the like. The control unit 100 also includes an image memory 140 in which document data read by the scanner unit 51 is temporarily stored, and a large capacity HDD (storage device) having a storage capacity capable of storing a large amount of document data. 150 is connected.

  The image processing unit 160 converts an analog image signal output from the scanner unit 51 into a digital image when image reading is performed by the scanner unit 51, performs image processing for improving image quality, and then converts the image into a compressed image. This compressed image is written into the image memory 140. The control unit 100 stores the compressed image written in the image memory 140 in the HDD 150 as data constituting a file to be document managed. At the time of printout, the data read by the scanner unit 51 and the data (compressed image) read from the HDD 150 are written to the image memory 140, and the image processing unit 160 decompresses the compressed data, Image processing is performed according to the output state (separation such as laser exposure or LED exposure). For example, in the case of laser exposure, the laser signal (signal for controlling the laser beam emitted from the exposure apparatus) is analog. Modulate. The recording unit 40 (image forming unit 412) prints out based on the analog-modulated signal.

  Based on a program stored in an unillustrated ROM (or flash memory or the like), the control unit 100 sets the fixing temperature of the fixing unit 45 to the toner image recording paper when the image forming operation is not performed for a certain period of time. Is maintained in a power saving state in which the temperature is reduced by a predetermined temperature from the heat fixing temperature required for fixing. For example, when the peripheral surface temperature of the heat roller of the fixing roller pair of the fixing unit 45 is set to 180 ° C. during the normal image forming operation and the image forming operation is not performed for 10 minutes, the control unit 100 The heater in the heat roller is controlled so that the peripheral surface temperature of the heat roller is lowered by 90 ° C. from 180 ° C., and the peripheral surface temperature of the heat roller is maintained at 90 ° C. These are merely examples, and are not intended to limit the present invention to these numerical values.

  In addition, when the image forming execution instruction from the user is received by the operation unit 47 while the fixing unit 45 is in the power saving state, the control unit 100 drives the fixing unit 45 while remaining in the power saving state. When the recording paper passes through the fixing unit 45, the fixing speed of the fixing unit 45 (that is, the rotation speed of the pair of fixing rollers including the heat roller and the pressure roller) is reduced so that the temperature necessary for fixing the toner image is reached. Let me. For example, as described above, when the peripheral surface of the heat roller is lowered from 180 ° C. during normal image forming operation to 90 ° C. and the fixing unit 45 is in the power saving state, the control unit 100 drives the fixing roller pair as a drive source. Is controlled so that the rotational speed of the pair of fixing rollers is reduced to one half of that during the normal image forming operation.

  The control unit 100 also functions as a scanner controller 101, a facsimile controller 102, a printer controller 103, a copy controller 104, and a network controller 105 that control each function that can be executed by the multifunction device 1.

  The scanner controller 101 controls the operation of each unit necessary for the operation of the scanner unit. The facsimile controller 102 controls the operation of each unit necessary for the facsimile operation, and controls the facsimile communication unit 170 that adjusts data necessary for facsimile communication. The facsimile communication unit 170 is provided with an NCU (Network Control Unit) that controls connection of a telephone line with a destination facsimile that is a data transmission / reception partner. The copy controller 104 controls the operation of each unit necessary for the copy operation.

  The printer controller 103 performs operation control of each unit necessary for printer operation. The printer controller 103 includes a parallel I / F unit 181 that is connected to an external device by parallel transmission that transmits several bits at a time using a plurality of signal lines, and one bit at a time using a single signal line. A serial I / F unit 182 connected to an external device by serial transmission for sending data is connected.

  The network controller 105 controls data transmission / reception performed between the multifunction machine 1 and a computer on the network, as well as a site on the Internet. The network controller 105 transmits / receives data to / from the outside via the network I / F unit 210.

  The operation unit (operation means) 47 is used for inputting various instructions necessary for the operation of the multifunction machine 1 from an operator (user). The display unit 473 includes an LCD (liquid crystal display) or the like. The display unit 473 displays various operation messages necessary for the operation of the multi-function device 1 and various types of information on the registered document. And an operation key unit 476 including a numeric keypad for inputting the number of copies. Note that the display unit 473 preferably includes a touch panel function and has a configuration in which an operator can input a necessary instruction by touching the touch panel. When a document is registered in the multifunction device 1 or when a registered document is read out and printed out, an instruction from the operator is input from the operation unit 47.

  The control unit 100 is connected to a registration switch (detection means) 200 that detects that the recording paper has been supplied to the registration rollers 466 (FIG. 1). The registration switch 200 detects, for example, recording paper existing near the registration roller 466 by an optical sensor or the like, and the switch is turned on or off depending on the presence or absence of the recording paper (recording). On when paper is present). Based on the detection result by the registration switch 200, timing control of recording sheet conveyance to the photosensitive drum 43 and the transfer unit 41 by the registration roller 466 is performed.

  Further, a guide member driving unit 702 that forms part of a conveyance path switching mechanism (described later) and a timer (timer unit) 202 for measuring time are connected to the control unit 100. The guide member driving unit 702 is a mechanism that rotationally drives the guide member of the transport path switching mechanism, and the control unit 100 guides based on a recording paper detection signal (ON signal) sent from the registration switch 200. By controlling the timing of driving the member driving unit 702, it is switched whether to guide the recording paper to a recording paper retracting mechanism (described later) provided on the upstream side of the fixing unit 45 in the recording paper conveyance direction. ing. Details of drive control of the guide member drive unit 702 by the control unit 100 will be described later.

  Next, the recording paper retracting mechanism 60 and the transport path switching mechanism will be described. FIG. 3 is a diagram schematically showing the configuration around the recording unit 40 in the multifunction machine 1, FIG. 4 is a side view showing the transport path switching mechanism, and (a) is a state in which the recording paper is bypassed from the recording paper retracting mechanism 60. FIG. 6B is a diagram illustrating a state in which the recording sheet is guided to the recording sheet retracting mechanism 60.

  As shown in FIG. 3, the paper conveyance path L on the upstream side in the recording paper conveyance direction of the fixing unit 45 is formed in a concave shape, and this concave portion is the recording paper retracting mechanism 60. The recording paper retracting mechanism 60 conveys the recording paper by rotation of the fixing roller pair 450 of the fixing unit 45 when the fixing unit 45 is driven at a speed slower than the image forming speed by the image forming unit 412 (FIG. 2). Due to the speed difference between the speed (fixing speed) and the recording paper transport speed (image forming speed) due to the rotation of the photosensitive drum 43 of the image forming unit 412 and the transfer roller of the transfer unit 41, the fixing unit 45 is upstream in the recording paper transport direction. It absorbs the deflection of the recording paper generated on the side. When the recording paper is bent at the upstream side in the recording paper conveyance direction of the fixing unit 45 due to the speed difference, the bent portion of the recording paper enters the concave portion of the recording paper retracting mechanism 60, so that the recording paper is introduced into the fixing unit 45. In the vicinity of the opening 451, the recording paper does not cause a problem such as a paper jam.

  On the upstream side of the fixing unit 45 in the recording sheet conveyance direction, a conveyance path for switching whether the recording sheet conveyed through the sheet conveyance path L is guided into the recording sheet withdrawal mechanism 60 or bypassed by the recording sheet withdrawal mechanism 60. A switching mechanism (conveyance path switching means) 70 is provided. The transport path switching mechanism 70 includes a guide member 701 and a guide member drive unit (drive means) 702. The guide member 701 guides the transport direction of the recording paper transported along the paper transport path L, and the upstream end of the recording paper transport direction upstream of the recording paper retracting mechanism 60 in the recording paper transport direction. The end portion is pivotally supported. The guide member drive unit 702 is a drive source that rotationally drives the guide member 701, and includes, for example, a solenoid.

  In the present embodiment, the guide member 701 is formed in a substantially “<” shape and is rotatably provided at a fulcrum 7011 so that the recording paper on the paper conveyance path L is fed to the fixing roller pair 450 of the fixing unit 45. It has a guide part 7012 for guiding to the nip part, and a connecting part 7013 connected to the guide member driving part 702. When the recording paper is guided by the guide member 701 to the nip portion of the fixing roller pair 450 of the fixing portion 45, the guide portion 7012 is substantially parallel to the paper conveyance path L as shown in FIG. Thus, the guide member drive unit 702 rotates the guide member driving unit 702 to a position where it is connected to the sheet conveyance path L.

  Further, the leading edge of the recording paper reaches the nip portion of the fixing roller pair 450 of the fixing unit 45, and the recording paper produced by the speed difference between the rotation speed of the fixing roller pair 450 and the recording paper conveyance speed of the image forming unit 412. When guiding the deflection into the recording paper retracting mechanism 60, the guide member 7012 is driven to a position substantially parallel to the inclined portion 601 of the recording paper retracting mechanism 60 as shown by the broken lines in FIG. 4B and FIG. It is rotated by the part 702. With this configuration, the deflection of the recording paper is guided to the recording paper retracting mechanism 60. As described above, the guide member 701 can switch between guiding the leading edge of the recording sheet to the nip portion of the fixing roller pair 450 of the fixing unit 45 and guiding the bending of the recording sheet to the recording sheet retracting mechanism 60. Yes.

  Next, drive control of the transport path switching mechanism 70 during image formation by the multifunction machine 1 will be described. FIG. 5 is a flowchart showing the drive control processing of the transport path switching mechanism 70 during image formation by the multifunction device 1. In the above description, in the initial state, the guide member 701 of the transport path switching mechanism 70 is in a position for guiding the recording paper to the nip portion of the fixing roller pair 450 of the fixing portion 45 (state shown in FIG. 4A). ing.

  When the operation unit 47 receives an input of an image formation execution instruction from the user (YES in S1), the control unit 100 determines whether the fixing unit 45 is in a power saving state (S2). Here, when the fixing unit 45 is not in the power saving state (NO in S2), the control unit 100 performs normal image forming processing as usual (ie, the image forming speed of the image forming unit 412 and the fixing unit 45). An image forming process in which the fixing speed is set to a constant speed and the conveyance path switching mechanism 70 is not driven is executed (S15).

  When the fixing unit 45 is in the power saving state (YES in S2), the control unit 100 sets the predetermined number of image formation times (one image formation on one side of the recording paper and two times on both sides). It is determined whether it is less than (for example, 10 times) (S3). When the number of image formations is equal to or greater than the predetermined value (NO in S3), the control unit 100 raises the heat roller temperature of the fixing unit 45 to the predetermined temperature (about 180 ° C.) (S14). The fixing temperature at the time of normal image formation is returned from the low temperature state in the power saving state, and then the image forming process is executed (S15). Rather than fixing the toner image by driving the fixing unit 45 at a low speed while keeping the power-saving state at a low temperature, it is preferable to return the fixing unit 45 to the normal fixing temperature state. By setting the number of times required for completing the image formation to be short, the image formation based on the image formation execution instruction from the user can be completed in a short time.

  When the number of image formations is less than the predetermined value (YES in S3), the control unit 100 drives the image forming speed of the image forming unit 412 at the speed during the normal image forming operation (S4). The fixing speed, that is, the rotation speed of the fixing roller pair is driven at a speed reduced by a predetermined speed (S5). The speed reduced by the predetermined speed is, as described above, the case where the peripheral surface of the heat roller is lowered from 180 ° C. to 90 ° C. during the normal image forming operation and the fixing unit 45 is in the power saving state. The control unit 100 refers to a speed at which the rotation speed of the fixing roller pair is reduced to one-half that of a normal image forming operation (a specific speed in this case is, for example, 115 mm / sec).

  Subsequently, the control unit 100 drives the paper transport unit 411 (S6) to transport the recording paper to the image forming unit 412. At this time, when the recording paper transported through the paper transport path L reaches the registration switch 200 and the registration switch 200 is turned on (YES in S7), the control unit 100 starts time measurement by the timer 202. (S8). With the time measurement by the timer 202, the leading edge of the recording paper after the predetermined time t1 (that is, the leading edge of the recording paper on the paper conveyance path L reaches the registration switch 200 and the registration switch 200 is turned on). When the time required until the toner is conveyed to the nip portion of the fixing roller pair 450 has elapsed (YES in S9), the control unit 100 drives the guide member driving unit 702 (S10) to rotate the guide member 701. Then, the guide portion 7012 of the guide member 701 is moved to a position substantially parallel to the inclined portion 601 of the recording paper retracting mechanism 60.

  Further, when the timer 202 passes a predetermined time t2 (that is, a required time from when the registration switch 200 is turned on until the trailing edge of the recording paper is conveyed to the nip portion of the fixing roller pair 450) ( The control unit 100 drives the guide member driving unit 702 (S12), rotates the guide member 701, and moves the guide unit 7012 of the guide member 701 to a position substantially parallel to the sheet conveyance path L. Move. Thereafter, the control unit 100 determines whether or not the next image formation is performed (S13). When the next image formation is performed (YES in S13), the processing of S7 to S12 is repeated to perform image formation processing. When all the processes are completed, the process is terminated (NO in S13).

(Second Embodiment)
Next, a second embodiment of the multifunction machine 1 will be described. The basic configuration of the MFP 1 according to the second embodiment is the same as that shown in FIGS. However, the registration switch 200 and the timer 202 are not necessary. FIG. 6 is a diagram schematically illustrating the outline of the mechanism of the recording unit 40 in the multifunction machine 1 according to the second embodiment. In FIG. 6, the conveyance of the recording paper indicated by a solid line indicates a state in which the recording paper is bent when the fixing unit 45 is driven in the power saving state, and the conveyance of the recording paper indicated by a two-dot chain line is indicated by a fixing unit. The state of the recording paper in the case where the normal image forming operation is performed by returning 45 from the power saving state to the normal fixing temperature is shown.

  In the multi-function device 1 according to the first embodiment, the recording paper retracting mechanism 60 is provided with the transport path switching mechanism 70. However, the multi-function device 1 according to the second embodiment is upstream of the fixing unit 45 in the recording paper transport direction. Only the recording paper retracting mechanism 60 is provided on the side, and the transport path switching mechanism 70 is not provided. Since the multifunction machine 1 of the second embodiment is not provided with a mechanism for bypassing the recording paper leading end from the recording paper retracting mechanism 60, the leading end of the recording paper is recorded by the photosensitive drum 43, the transfer unit 41, and the like. The paper is retracted at a transport speed that does not enter the recess of the paper retracting mechanism 60. As shown in FIG. 6, the introduction unit 602 that guides the leading end portion of the recording sheet from the recording sheet retracting mechanism 60 to the nip portion of the fixing roller pair of the fixing unit 45 is the recording sheet retracting unit of the multifunction machine 1 according to the first embodiment. The angle with respect to the nip portion of the fixing roller pair 450 is formed to be gentler than that of the same portion of the mechanism 60, so that the recording paper conveyed through the paper conveyance path L can be easily guided to the nip portion of the fixing roller pair 450. ing.

  FIG. 7 is a flowchart showing processing at the time of image formation by the multi function device 1 according to the second embodiment. Note that the same processes as those of the multifunction machine 1 according to the first embodiment shown in FIG.

  The processing at the time of image formation by the multifunction device 1 according to the second embodiment will be described. Since the multifunction device 1 according to the second embodiment does not include the transport path switching mechanism 70, the operation unit 47 instructs the image formation execution instruction from the user. Is received (YES in S1) and the fixing unit 45 is in a power saving state (YES in S2), the control unit 100 determines whether the number of image formations is less than a predetermined value (for example, 10 times). Judgment (S3), whether the fixing unit 45 is driven in the power saving state to perform image formation (S4 and S5), or whether the fixing unit 45 is returned to the normal fixing temperature and then image formation is performed ( A process of selectively executing S14 and S15) is performed.

(Third embodiment)
Next, a third embodiment of the multifunction machine 1 will be described. The basic configuration of the MFP 1 according to the third embodiment is the same as that of the MFP 1 according to the second embodiment. FIG. 8 is a flowchart showing processing at the time of image formation by the multi function device 1 according to the third embodiment. Note that the same processes as those of the multifunction machine 1 according to the first embodiment shown in FIG.

  The multifunction device 1 according to the third embodiment does not include the recording paper retracting mechanism 60 and the conveyance path switching mechanism 70, and the image forming unit 412 forms an image in accordance with the low driving speed of the fixing unit 45 in the power saving state. Image formation is performed at a predetermined speed reduction. That is, when the number of times of image formation is less than a predetermined value (for example, 10 times) (YES in S3), the multi-function device 1 of the third embodiment records even if the fixing unit 45 is driven in the power saving state. When the paper passes through the nip portion of the fixing roller pair 450 of the fixing portion 45, the rotational speed of the fixing roller pair of the fixing portion 45 is reduced and driven so as to reach the temperature necessary for fixing the toner image. In accordance with the rotation speed of the fixing roller pair of the fixing unit 45, the recording paper conveyance speed by the photosensitive drum 43 and the transfer unit 41 of the image forming unit 412 is reduced (S5, S16).

  Accordingly, the recording paper does not bend even if the leading end of the recording paper reaches the nip portion of the fixing roller pair 450 of the fixing unit 45. Therefore, the recording paper retracting mechanism is provided in the paper conveyance path L upstream of the fixing unit 45 in the recording paper conveyance direction. 60 and the transport path switching mechanism 70 need not be provided.

  The present invention is not limited to the configuration of the above embodiment, and various modifications can be made. For example, in the above embodiment, the configuration and processing of the multifunction device 1 are illustrated in FIGS. 1 to 8. However, these configuration and processing are merely examples, and the configuration and processing of the multifunction device 1 according to the present invention are described above. It is not limited to.

  In the above-described embodiment, the image forming apparatus according to the present invention is described as the multifunction machine 1 having a printer function, a copy function, a fax function, and the like. However, the image forming apparatus according to the present invention has a printer function, The image forming apparatus may be provided with only a copy function or a fax function.

1 is a side view schematically showing an internal configuration of a multifunction peripheral as an example of an image forming apparatus according to an embodiment of the present disclosure. FIG. 2 is a functional block diagram illustrating a schematic configuration of a multifunction machine. FIG. 3 is a diagram schematically illustrating a configuration around a recording unit in a multifunction peripheral. 4A and 4B are side views illustrating a conveyance path switching mechanism, in which FIG. 4A is a diagram illustrating a state in which recording paper is bypassed from the recording paper retracting mechanism, and FIG. . 6 is a flowchart illustrating a drive control process of a conveyance path switching mechanism during image formation by a multifunction peripheral. It is a figure which shows typically the structure around the recording part in the multifunctional device which concerns on 2nd Embodiment. 10 is a flowchart illustrating processing at the time of image formation by the multifunction peripheral according to the second embodiment. 14 is a flowchart illustrating processing at the time of image formation by a multifunction peripheral according to a third embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Multifunctional device 41 Transfer part 42 Optical unit 43 Photosensitive drum 44 Developing part 45 Fixing part 450 Fixing roller pair 451 Recording paper inlet 47 Operation part 100 Control part 200 Registration switch 202 Timer 411 Paper conveyance part 412 Image formation part 461 Paper feed Cassette 466 Registration roller 60 Recording paper retracting mechanism 601 Inclined portion 602 Introduction portion 70 Transport path switching mechanism 701 Guide member 7011 Support point 7012 Guide portion 7013 Connecting portion 702 Guide member driving portion

Claims (7)

A photosensitive member on which an electrostatic latent image is formed, a developing unit that supplies toner onto the surface of the photosensitive member, and a toner that is supplied from the developing unit to the electrostatic latent image are formed on the surface of the photosensitive member. A transfer unit that transfers the toner image to the recording paper, a fixing unit that thermally fixes the toner image transferred from the photosensitive member by the transfer unit to the recording paper, and an operation unit that receives an input of an image formation execution instruction by an external operation; An image forming apparatus comprising: a control unit that maintains the fixing unit in a power saving state that is a predetermined temperature lower than a predetermined thermal fixing temperature necessary for fixing the toner image on the recording paper under a certain condition;
The control means drives the fixing means in the power saving state when the operation means accepts an image formation execution instruction while the fixing means is in the power saving state, and the recording paper is An image forming apparatus, wherein a fixing speed of the fixing unit is reduced so as to reach a temperature necessary for fixing the toner image when passing through the fixing unit.   When the image forming execution instruction is received by the operation unit while the fixing unit is in the power saving state, the control unit is configured to reduce the fixing speed of the fixing unit in accordance with the reduction of the fixing speed. 2. The image forming apparatus according to claim 1, wherein an image forming speed of each image forming unit of the transfer unit is reduced. When the image forming execution instruction is received by the operation unit while the fixing unit is in the power saving state, the control unit controls the image forming speed of each image forming unit of the photosensitive member, the developing unit, and the transfer unit. Without reducing, only the fixing speed of the fixing means is reduced,
A recording paper conveyance path provided upstream of the fixing unit in the recording paper conveyance direction includes a fixing speed of the fixing unit and an image forming speed of each image forming unit of the photosensitive member, the developing unit, and the transfer unit. The image forming apparatus according to claim 1, further comprising a recording paper retracting unit that absorbs the deflection of the recording paper caused by the speed difference.   The image forming apparatus according to claim 3, further comprising a conveyance path switching unit that switches between guiding the recording sheet to the recording sheet saving unit and bypassing the recording sheet. The conveyance path switching means guides the conveyance direction of the recording paper, and a guide member whose one end is pivotally supported by an end on the upstream side of the recording paper conveyance direction of the recording paper retracting means, Drive means for rotationally driving the guide member,
The recording paper transport path is provided with detection means for detecting the position of the recording paper in the recording paper transport path and sending a recording paper detection signal to the control means when the recording paper is detected,
When the image forming execution instruction is received by the operation unit, the control unit controls driving of the driving unit based on a recording sheet detection signal from the detection unit, and the fixing unit is in the power saving state. The guide member is rotated to a position for guiding the recording paper to the recording paper retracting means, and the recording paper is bypassed from the recording paper retracting means when the fixing means is not in the power saving state. The image forming apparatus according to claim 4, wherein the guide member is rotated. Timer means for measuring time,
When the control means receives the recording paper detection signal from the detection means while the fixing means is in the power saving state, the control means controls the drive means to bypass the recording paper from the recording paper retracting means. The guide member is rotated to a position to be moved, and a lapse of a required time from when the recording paper detection signal is received from the detection means to when the leading edge of the recording paper is conveyed to the fixing means by the timer means The image forming apparatus according to claim 5, wherein the guide member is rotated to a position where the recording sheet is guided to the recording sheet retracting unit when the recording sheet is measured.   The control means sets the fixing speed only when an instruction to execute image formation less than a predetermined number of times as the image formation execution instruction is input to the operation means while the fixing means is in the power saving state. The image forming apparatus according to claim 1, wherein the driving of the fixing unit reduced is executed.

Images