JP7131340B2 - image forming device - Google Patents

Description

The present invention relates to an image forming apparatus, and is suitable for application to, for example, an electrophotographic image forming apparatus (so-called printer).

Conventionally, as an image forming apparatus, for example, while a sheet is conveyed along a predetermined conveying path by a conveying section, a toner image is formed by an image forming section using toner as a developer, transferred onto the sheet, and is transferred to the sheet by a fixing section. It is widely used to form an image (that is, print processing) by applying heat or pressure to the paper to fix the toner image.

Among these, in the conveying section, by appropriately rotating a roller arranged to abut on the conveying path or appropriately running a belt stretched around a plurality of pulleys arranged along the conveying path, Paper can be advanced along the transport path. For this reason, the image forming apparatus is provided with a drive transmission unit (also called a drive system), which transmits driving force from a transport motor as a driving force source to the transport unit through a drive train composed of a combination of a plurality of gears and the like. (See, for example, Patent Document 1).

Japanese Patent Application Laid-Open No. 2000-267544 (Fig. 1 etc.)

By the way, in the drive train described above, for example, a cylindrical shaft made of a metal material is fixed to a housing or the like, and a shaft hole drilled in the center part of a disk-shaped gear made of a resin material is attached to the shaft. By inserting the gear, the gear can be rotatably supported with a simple structure.

However, in this drive train, the inner peripheral surface of the shaft hole is worn as the gear rotates for a long period of time, and the hole diameter is enlarged. As a result, the gears in the drive train rattle against the shaft, causing vibration and noise, and furthermore, there is a risk that the teeth of other gears will not mesh properly, making it impossible to transmit driving force. was there.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above points, and intends to propose an image forming apparatus capable of excellently transmitting a driving force with a simple structure.

In order to solve such a problem, the image forming apparatus of the present invention has an image forming section which has a rotating image carrier and forms a developer image on the circumferential surface of the photosensitive drum using a developer, and a rotating transfer section. A transport unit having a driving body for transporting a medium and transferring a developer image to the medium, and a fixing driving body for rotation, and fixing by applying heat and pressure to the medium onto which the developer image has been transferred. a waste developer conveying unit for conveying waste developer generated in the image forming unit, a drive transmission device for transmitting driving force, an image forming unit, a conveying unit, a fixing unit, and A control unit for controlling the drive transmission device is provided, and the drive transmission device includes a first drive source that generates a drive force, a first drive train that transmits the drive force from the first drive source, and a drive train that transmits the drive force to the first drive train. a first transmission member that is provided and rotates integrally with the first rotation shaft about a first rotation shaft along the first direction; a second drive source that generates a drive force; and a drive force from the second drive source and a second transmission member provided in the second drive train and supported by the first rotation shaft so as to be rotatable independently of the first rotation shaft, the first transmission member transmits the driving force to be supplied to the conveying body of the waste developer conveying portion, and the first drive train of the drive transmission device transmits the driving force to the fixing driving member provided in the fixing portion, and the drive transmission device The second driving train transmits the driving force to the transfer driving body provided in the conveying section .

According to the present invention, when the second transmission member inserted through the first rotation shaft rotates in the same direction as the first rotation shaft, compared to the case where the second transmission member is inserted through the fixed rotation shaft. , the frictional force generated between the first rotating shaft and the second transmission member can be reduced. Accordingly, in the present invention, wear of the second transmission member is suppressed, the second transmission member can be stably rotated without eccentricity, and the driving force from the second drive source can be smoothly transmitted by the second transmission member. . Furthermore, in the present invention, the first transmission member can transmit the driving force to the conveying body of the waste developer conveying section, so that the configuration can be simplified. In addition to this, in the present invention, since driving forces are transmitted from mutually different driving trains to the fixing driving body of the fixing section and the transfer driving body of the conveying section, the medium is conveyed by the conveying section independently of the operation of the fixing section. It can be performed.

According to the present invention, it is possible to realize an image forming apparatus capable of excellently transmitting a driving force with a simple configuration.

1 is a schematic diagram showing the configuration of an image forming apparatus; FIG. 4 is a schematic perspective view showing the configuration of a drive transmission section; FIG. 4 is a schematic perspective view showing the configuration of a drive transmission section; FIG. 4 is a schematic front view showing the configuration of a drive transmission unit; FIG. 4 is a schematic perspective view showing rotation of gears in a fixing drive transmission section; FIG. FIG. 4 is a schematic perspective view showing rotation of gears in a belt drive transmission section; 4 is a timing chart showing operation timings in a drive transmission unit;

EMBODIMENT OF THE INVENTION Hereinafter, the form (it is mentioned as embodiment below) for implementing invention is demonstrated using drawing.

[1. Configuration of Image Forming Apparatus]
As shown in the left side view of FIG. 1, the image forming apparatus 1 is a color electrophotographic printer, and prints a desired color image on a sheet of paper P. As shown in FIG. In this image forming apparatus 1, various parts are arranged inside a housing 2 formed in a substantially box shape. Incidentally, the image forming apparatus 1 does not have an image scanner function for reading documents, a communication function using a telephone line, or the like, and is a single-function SFP (Single Function Printer) having only a printer function.

In the following description, the right end portion in FIG. 1 is defined as the front of the image forming apparatus 1, and the up-down direction, left-right direction, and front-rear direction are defined when viewed facing the front. In the following description, the direction of clockwise rotation when viewed from the left direction is defined as the direction of arrow R1, and the direction of rotation in the opposite direction is defined as the direction of arrow R2.

The image forming apparatus 1 is configured to be entirely controlled by a control section 3 provided within a housing 2 . The control unit 3 is mainly composed of a CPU (Central Processing Unit) (not shown), and reads and executes a predetermined program from a ROM (Read Only Memory), a flash memory, etc. (not shown) to perform various processes related to printing. I do. The control unit 3 also has a storage unit such as a RAM (random access memory), a hard disk drive, a flash memory, etc., and stores various information in this storage unit. Further, the control unit 3 is connected to a host device such as a computer device (not shown), and when receiving a print instruction or print data from the host device, it starts print processing.

On the front side of the upper surface of the housing 2 is a display device such as a liquid crystal panel. An operation unit 5, which is a combination of a plurality of operation buttons such as buttons, receives an operation instruction from the user and notifies the control unit 3 of the operation instruction.

At the bottom of the housing 2, a paper feed cassette 10 is provided for storing paper P, which is a leaf-shaped recording medium. The paper feed cassette 10 is formed, for example, in the shape of a hollow rectangular parallelepiped, and has an open upper surface. Incidentally, the paper P is a so-called cut paper that is cut into A4 size, for example.

A paper feeding unit 11 is provided in the front upper part of the paper feeding cassette 10 . The paper feeding unit 11 is composed of a plurality of rollers and the like. When a driving force is transmitted from a paper feed drive unit, which will be described later, the paper feed unit 11 rotates the rollers appropriately, so that only the uppermost sheet of the paper P stored in the paper feed cassette 10 is rotated. is separated from other sheets P and fed out obliquely forward and upward.

A lower transport section 12 that transports the paper P is provided on the front side or upper side of the paper feed section 11 . The lower transport section 12 is composed of a transport guide that guides the paper P, a transport roller pair that transmits a driving force to the paper P, and the like. The lower conveying portion 12 advances the paper P delivered from the paper feeding portion 11 along the conveying path W such that it advances forward and upward and then folds back obliquely upward, and delivers it to the middle conveying portion 13 on the rear side. .

A conveyor belt 16 made of an endless belt is stretched around pulleys 14 and 15 arranged on the front side and the rear side, respectively, in the intermediate conveying section 13 . The upper portion of the conveying belt 16 forms a conveying path W along an oblique direction connecting the lower front side and the upper rear side. When a driving force is supplied from a belt driving unit, which will be described later, the intermediate conveying unit 13 rotates the rear pulley 15 (hereinafter also referred to as a transfer driving member) in the direction of arrow R2, thereby moving the upper portion of the conveying belt 16. Make it run backwards. As a result, when the sheet P is sent out from the lower conveying section 12, the middle conveying section 13 can place it on the upper portion of the conveying belt 16 and convey it along the conveying path W in the rear obliquely upward direction.

Four image drum (ID) units 17K, 17Y, 17M, and 17C (hereinafter collectively referred to as image drum units 17) are arranged in an oblique direction from the lower front side to the upper rear side on the upper side of the middle transport section 13. ) are placed. Each image drum unit 17 corresponds to each color of black (K), yellow (Y), magenta (M), and cyan (C), but has the same configuration except for the corresponding colors.

The image drum unit 17 as an image forming section includes an LED head in which a large number of LEDs (Light Emitting Diodes) are arranged along the left-right direction, and a photosensitive drum whose peripheral surface can be charged and whose charging state changes according to irradiation of light. It has a body drum PD and a plurality of rollers. Among them, the photosensitive drum PD and each roller are rotated in a predetermined rotation direction by a driving force transmitted from an image drum driving section, which will be described later.

A toner conveying section 18 is arranged above the image drum unit 17 . Further, four toner cartridges 19 are arranged in the horizontal direction in about two-thirds of the area on the front side of the upper side of the toner conveying portion 18 . Each toner cartridge 19 contains the same black (K), yellow (Y), magenta (M) and cyan (C) toners as the corresponding colors of the image drum units 17 .

The toner conveying portion 18 is mainly composed of a tubular member, and connects the toner cartridges 19 and the image drum units 17 of corresponding colors, respectively. The toner conveying section 18 conveys toner from the toner cartridge 19 to the image drum unit 17 under the control of the control section 3 .

Under the control of the controller 3, the image drum unit 17 causes the LED head to emit light with an irradiation pattern corresponding to the image to be formed, forms a charged image on the circumferential surface of the photosensitive drum PD, and attaches toner to the image. forming a toner image; For convenience of explanation, the toner is hereinafter also referred to as the developer, the photosensitive drum PD is also referred to as the image carrier, and the toner image is also referred to as the developer image. Further, the image drum unit 17 transfers the toner image onto the paper P conveyed along the conveying path W by the conveying belt 16 .

By the way, in the image drum unit 17, if toner remains on the surface of the photosensitive drum without being transferred onto the paper P, the toner is scraped off from the surface of the photosensitive drum by the cleaning blade CB. The toner scraped off at this time is called waste toner or waste developer.

Inside the housing 2, a waste toner conveying unit 20 for conveying waste toner and a waste toner cartridge 21 for storing waste toner are provided. The waste toner cartridge 21 has an elongated rectangular parallelepiped shape extending in the front-rear direction, and a space for containing waste toner is formed therein. Incidentally, the waste toner cartridge 21 is located on the right side of the paper feed cassette 10 and is detachably attached to the housing 2 . The waste toner conveying portion 20 is composed of a tubular portion arranged to connect each image drum unit 17 and the waste toner cartridge 21, a spiral conveying body arranged inside the tubular portion, and the like. ing.

A waste toner conveying unit 20 as a waste developer conveying unit rotates a spiral conveying body in a predetermined direction in a pipe portion when a driving force is transmitted from a fixing driving unit, which will be described later, to remove waste toner from the pipe portion. It is sequentially conveyed from the image drum unit 17 to the waste toner cartridge 21 and stored in the waste toner cartridge 21 .

Incidentally, in the image forming apparatus 1, the waste generated in the image drum unit 17 is reduced because the toner is powder and the waste toner conveying unit 20 has a structure in which the waste toner is conveyed by rotating a spiral conveying body. It takes a relatively long time to finish conveying the toner to the waste toner cartridge 21 .

A fixing section 22 is arranged behind the middle conveying section 13 and the image drum unit 17 . In the fixing section 22, a heating section 23 and a pressure section 24 are arranged below and above the transport path W, respectively. The heating unit 23 has an elongated heater, a plurality of rollers, and the like arranged in the left-right direction, and a cylindrical heating belt is arranged so as to surround the circumference thereof. The pressure unit 24 has a cylindrical pressure roller with a central axis extending in the left-right direction, and rotatably supports the pressure roller and biases the heating unit 23 . The fixing section 22 is also provided with a plurality of temperature sensors for detecting temperatures of heaters, heating belts, and the like. Each temperature sensor detects the temperature and notifies the controller 3 of the detected temperature. For convenience of explanation, the rollers of the heating section 23 and the pressure rollers of the pressure section 24 are collectively referred to as a fixing driving body.

The fixing unit 22 heats the heating unit 23 with a heater, and receives a driving force from a fixing driving unit (to be described later) to drive each fixing driving unit, so that the heating belt rotates in the direction of arrow R1. , and the pressure roller is rotated in the direction of arrow R2. As a result, when the sheet of paper P onto which the toner image has been transferred is conveyed from the intermediate conveying unit 13 along the conveying path W, the fixing unit 22 applies heat and pressure to the sheet of paper P to fix the toner image. The paper P is continuously transported along the transport path W rearward and obliquely upward.

Paper sensors 25 and 26 are provided on the front side and rear side of the heating section 23 and the pressure section 24 in the fixing section 22, respectively. The paper sensors 25 and 26 detect the presence or absence of the paper P on the transport path W, and notify the controller 3 of the obtained detection results.

For convenience of explanation, hereinafter, of the conveying path W, the linear portion along the upper portion of the conveying belt 16 and the fixing section 22, that is, the portion inclined so as to rise as it advances in the rearward direction will be referred to as a middle inclined portion. It is also called a transport path WS. The medium-inclined transport path WS has an inclination angle of about 10 degrees with respect to the horizontal direction.

An upper conveying section 27 is arranged behind or above the fixing section 22 . The upper transport section 27, like the lower transport section 12, is composed of a transport guide for guiding the paper P, a pair of transport rollers for transmitting driving force to the paper P, and the like. The upper conveying section 27 advances the sheet P delivered from the fixing section 22 along a conveying path W such that it is advanced obliquely upward rearward and then folded back obliquely upward forward, is discharged from the discharge port 28, and is transported to the front side. It is placed on the placing tray 29 . The loading tray 29 is formed on the upper surface of the housing 2, and the vicinity of the discharge port 28 is scooped downward, and is inclined so as to gradually rise as it advances forward.

Thus, the image forming apparatus 1 conveys the sheet P along the conveying path W by the intermediate conveying section 13 and the like while rotating rollers and the like provided in each section as appropriate, and forms a toner image on the sheet by the image drum unit 17 . After the image is transferred to P, the image is fixed on the paper P by the fixing unit 22, thereby performing the printing process.

[2. Configuration of Drive Transmission Unit]
By the way, as schematically shown in FIGS. 2, 3 and 4, a drive transmission section 30 is incorporated inside the housing 2 of the image forming apparatus 1 . The drive transmission unit 30 has plate-like left side plates 31 and right side plates 32 arranged on the left and right sides of the transport path W formed by the intermediate transport unit 13 and the like, respectively. The left side plate 31 and the right side plate 32 are formed in the shape of a plate that is thin in the left-right direction as a whole, and each plate-like metal material is appropriately processed by cutting, bending, or the like.

Various parts such as motors, gears, and support shafts for supporting the gears are appropriately attached to the left side plate 31 and the right side plate 32, thereby forming the paper feed drive transmission section 40, the belt drive transmission section 50, and the like. An image drum drive transmission section 60 and a fixing drive transmission section 70 are formed respectively.

The paper feed drive transmission unit 40 (FIG. 3) is mainly arranged on the lower front side of the right side plate 32. A motor 41 is attached to the right side plate 32, and a gear 42 is attached to the output shaft of the motor 41. is installed. In addition, a plurality of gears 43, 44, 45, etc. are rotatably supported by a plurality of support shafts (not shown) erected leftward from the right side plate 32 in the paper feed drive transmission unit 40. It is

The gears 42 and the like are disc-shaped with their central axes extending in the left-right direction, and are gears having teeth formed on the outer peripheral portion thereof. Further, in the paper feeding drive transmission section 40, the position and radius of each gear are appropriately selected, and the gears 42, 43, 44 and 45 are connected in order so as to mesh with each other. In addition, in FIG. 2 and the like, for the convenience of drawing, each gear is simplified and represented as a simple disk shape.

With such a configuration, when the paper feeding drive transmission section 40 rotates the motor 41 to generate driving force under the control of the control section 3, the driving force is sequentially transmitted by the gears 42, 43, 44 and 45, etc., and eventually Each roller and the like of the paper feeding unit 11 (FIG. 1) are rotated.

The image drum drive transmission section 60 (FIG. 3) is arranged on the right side of each image drum unit 17 (FIG. 1), that is, near the center of the right side plate 32 . The image drum drive transmission unit 60 is provided with a motor, a plurality of gears, etc. (none of which are shown). The image drum drive transmission section 60 rotates a motor (not shown) under the control of the control section 3 to generate drive force, and transmits the drive force appropriately through gears or the like. The body drum, various rollers, etc. are rotated appropriately.

The fixing drive transmission unit 70 (FIG. 2) is mainly arranged near the center on the rear side of the right side plate 32. A fixing motor 71 as a first drive source is attached to the right side plate 32, A gear 72 is attached to the output shaft of the fixing motor 71 . A plurality of gears 73 , 74 and 75 are rotatably supported by a plurality of support shafts (not shown) erected rightward from the right side plate 32 in the fixing drive transmission section 70 . ing. The gear 72 or the like has a disc shape with a central axis along the left-right direction, or a shape in which a plurality of discs with different radii are stacked, and each disc has teeth formed on the outer peripheral portion thereof. there is Further, in the fixing drive transmission section 70, the position and radius of each gear are appropriately selected, and the gears 72, 73, 74 and 75 are connected in order so as to mesh with each other.

With such a configuration, when the fixing drive transmission section 70 rotates the fixing motor 71 to generate a driving force under the control of the control section 3, the driving force is sequentially transmitted by the gears 72, 73, 74 and 75 and the like. Each roller of the fixing section 22 (FIG. 1) is rotated.

In addition, the fixing drive transmission section 70 is provided with gears 81 , 82 and 83 , a shaft 84 and a gear 85 . The gears 81, 82, 83, and 85 are disc-shaped gears with their central axes extending in the left-right direction, similarly to the gears 72 and the like, and are gears having teeth formed on their outer peripheral portions. The gears 81 and 82 are rotatably supported by a plurality of support shafts (not shown) erected rightward from the right side plate 32 .

The shaft 84 as the first rotating shaft is formed in an elongated columnar shape, that is, in a rod shape, with the center axis along the left-right direction. For convenience of explanation, the horizontal direction is hereinafter also referred to as the main scanning direction or the first direction. The shaft 84 is rotatably supported by bearings 31B and 32B attached to the left side plate 31 and the right side plate 32, respectively, and is inserted through an insertion hole (not shown) formed in the right side plate 32. ing.

The gears 83 and 85 are attached while being inserted through the shaft 84 and rotate integrally with the shaft 84 . Among these, the gear 83 as a first transmission member is positioned on the right side of the right side plate 32 and meshes with the gear 82 . A gear 85 as a third transmission member is located on the right side of the left side plate 31, and the spiral conveying body drive section 35 (FIGS. 2 and 4) interlocks with the spiral conveying body of the waste toner conveying section 20 (FIG. 1). ) gears. For convenience of explanation, hereinafter, a plurality of gears provided in the fixing drive transmission section 70, that is, the gears 72 and the like and the gears 81 and the like are collectively referred to as a fixing gear train 70G or a first drive train.

With such a configuration, the fixing drive transmission section 70 rotates the fixing motor 71 in the direction of arrow R2 under the control of the control section 3 as shown in FIG. and 83 in sequence. At this time, gear 81 rotates in the direction of arrow R1, gear 82 rotates in the direction of arrow R2, and gear 83 rotates in the direction of arrow R1. Accordingly, the shaft 84 and the gear 85 (FIG. 2) rotate together with the gear 83 in the direction of the arrow R1. For convenience of explanation, the direction of arrow R1 is hereinafter also referred to as a predetermined rotation direction or a first rotation direction.

In other words, the shaft 84 transmits the driving force from the right side to the left side of the intermediate conveying section 13 and the like (FIG. 4). At this time, in the gear 83 (FIG. 5), at the point where it meshes with the gear 82, a force acts in the direction indicated by the arrow F83 along the tangential line of the circumference approximating both, that is, in the rear oblique downward direction. . Further, the gear 85 (FIG. 2) tries to apply a force backward and obliquely downward to the gear of the helical conveying body driving portion 35 at the point where it meshes with the gear of the helical conveying body driving portion 35. As a result, a force acts in the direction indicated by the arrow F85, that is, in the diagonally forward and upward direction.

Subsequently, the fixing drive transmission section 70 transmits the driving force from the gear 85 to the spiral conveying body driving section 35 (FIGS. 2 and 4), thereby causing the waste toner conveying section 20 (FIG. 1) to move from the spiral conveying body driving section 35 to the waste toner conveying section 20 (FIG. 1). ) is rotated by transmitting a driving force to the spiral conveying body, and the waste toner is conveyed toward the waste toner cartridge 21 in the pipe portion of the waste toner conveying portion 20 .

On the other hand, the belt drive transmission unit 50 (FIG. 3) is arranged on the left side of the right side plate 32, on the lower side or near the center of the rear side. , and a gear 52 is attached to the output shaft of the belt motor 51 .

A plurality of gears 53, 54 and 55 are rotatably supported by a plurality of support shafts (not shown) erected leftward from the right side plate 32 of the belt drive transmission portion 50. ing. The gear 52 or the like has a disc shape with a central axis along the left-right direction, or a shape in which a plurality of discs with different radii are stacked, and each disc has teeth formed on the outer peripheral portion thereof. there is Further, in the belt drive transmission unit 50, the position and radius of each gear are appropriately selected, and the gears 52, 53, 54 and 55 are connected in order so as to mesh with each other.

Further, the belt drive transmission portion 50 is provided with a gear 56 . A gear 56 as a second transmission member is a disc-shaped gear having a central axis extending in the left-right direction, and is a gear having teeth formed on an outer peripheral portion thereof, and meshes with the gear 55 . Further, the gear 56 has an axial hole penetrating in the left-right direction through the central portion thereof, and the shaft 84 of the fixing drive transmission section 70 is inserted through this axial hole so that the gear 56 can move freely with respect to the shaft 84, that is, the shaft 84 can move freely. can be rotated independently of In other words, the gear 56 is independently and rotatably supported by the shaft 84 . Further, the gear 56 meshes with a gear 57 attached to the pulley 15 of the intermediate transfer section 13 (FIG. 4). For convenience of explanation, hereinafter, the plurality of gears provided in the belt drive transmission section 50, that is, the gears 52 and the like are collectively referred to as a belt gear train 50G or a second drive train. Incidentally, the shaft 84 is provided with suppressing members (not shown) in the vicinity of the left and right sides of the gear 56, respectively, to suppress displacement of the gear 56 in the left-right direction.

With such a configuration, the belt drive transmission unit 50 rotates the belt motor 51 in the direction of arrow R1 based on the control of the control unit 3 to generate driving force, as shown in FIG. , 54, 55 and 56 in sequence. At this time, gear 52 rotates in the direction of arrow R1, gear 53 rotates in the direction of arrow R2, gear 54 rotates in the direction of arrow R1, gear 55 rotates in the direction of arrow R2, and gear 56 rotates in the direction of arrow R2. As a result, the gear 56 is subjected to a force acting in the direction indicated by the arrow F56 along the tangential line of the circumference of the gear 55, ie, in the rear obliquely downward direction, at the point where the gear 56 meshes with the gear 55.

Further, the belt drive transmission unit 50 transmits the driving force from the gear 56 to the gear 57 (FIG. 4), thereby rotating the gear 57 integrally with the pulley 15 in the direction of arrow R2 (FIG. 1). As a result, the belt drive transmission section 50 causes the conveyor belt 16 of the intermediate conveyor section 13 to run so that the upper portion thereof advances rearward and upward.

[3. Operation of drive transmission unit in printing process]
Next, operations of the fixing drive transmission section 70 and the belt drive transmission section 50 when the image forming apparatus 1 performs print processing will be described. Here, it is assumed that the image forming apparatus 1 transitions to the sleep mode because the state in which no print processing is performed continues for a predetermined time after the power of the image forming apparatus 1 is turned on. In this sleep mode, the image forming apparatus 1 operates only a part of the control unit 3, etc., and stops the operations of the paper feeding unit 11, the middle conveying unit 13, the image drum unit 17, the fixing unit 22, etc., thereby reducing power consumption. reducing power.

As shown in FIGS. 7A and 7B, the control unit 3 of the image forming apparatus 1 controls the belt motor 51 of the belt drive transmission unit 50 and the fixing motor of the fixing drive transmission unit 70 at time T0 in the sleep mode. 71 are stopped. Incidentally, in FIGS. 7A and 7B, the operating (that is, rotating) state of the belt motor 51 and the fixing motor 71 is high level, and the stopped state is low level. are shown as waveforms S51 and S71.

When the control unit 3 receives a print instruction, print data, and the like from a host device such as a computer device (not shown) at a time T1, it performs a so-called warming-up process by operating the fixing motor 71 while keeping the belt motor 51 stopped. Start. That is, in the image forming apparatus 1, the shaft 84 of the fixing drive transmission section 70 rotates while the gear 56 of the belt drive transmission section 50 is stopped.

At this time, the control section 3 also starts heating by the heater of the fixing section 22 . As a result, in the fixing section 22, the temperature of the heating section 23, which was lowered in the sleep mode, is raised to the temperature necessary for the fixing process. In the fixing section 22, the temperature of the heating belt is made uniform in the circumferential direction by causing the heating belt to run as the fixing motor 71 operates. At this time, the fixing drive transmission section 70 also transmits the driving force to the waste toner conveying section 20 (FIG. 1), so that the waste toner conveying section 20 starts rotating the spiral conveying body.

Eventually, at time T2, when the temperature sensor provided in the fixing section 22 detects that the heating belt or the like has reached a predetermined temperature, the control section 3 ends the warming-up process, starts the printing process, and continues to operate the fixing motor. The belt motor 51 is operated while the belt 71 is operated. That is, in the image forming apparatus 1, both the shaft 84 of the fixing drive transmission section 70 and the gear 56 of the belt drive transmission section 50 are rotated. As a result, the driving force is transmitted from the gear 56 to the gear 57 in the intermediate conveying portion 13 to rotate the pulley 15 (FIGS. 1 and 4), thereby causing the conveying belt 16 to run. At this time, the control section 3 also operates the sheet feeding drive transmission section 40 and the image drum drive transmission section 60 (FIG. 2).

In the image forming apparatus 1 (FIG. 1), in this printing process, the paper P is fed out from the paper feeding cassette 10, and the paper P is sequentially conveyed by the lower conveying portion 12 and the middle conveying portion 13, and each image drum unit 17 releases the toner. Images are generated and transferred onto the paper P in sequence. Subsequently, in the image forming apparatus 1 , the toner image is fixed on the sheet P by the fixing section 22 , and the sheet P is conveyed by the upper conveying section 27 and discharged from the discharge port 28 .

At this time, the control unit 3 monitors the detection result of the paper P obtained from the paper sensor 26 (FIG. 1) of the fixing unit 22, and the timing of transferring the last printed paper P from the fixing unit 22 to the upper transport unit 27 That is, time T3 (FIG. 7), which is the timing when the paper sensor 26 stops detecting the paper P, is detected. Further, the control unit 3 stops the belt motor 51 at time T4 after a predetermined first time DT1 has elapsed from this time T3. As a result, in the image forming apparatus 1, the shaft 84 of the fixing drive transmission section 70 rotates again while the gear 56 of the belt drive transmission section 50 is stopped.

The first time DT1 is set in advance as the time required to transport the paper P in the upper transport section 27 based on the transport speed of the paper P in the image forming apparatus 1 and the length of the transport path W in the upper transport section 27. It is For this reason, the control unit 3 causes the belt motor to start at time T4 when the paper sensor 26 detects the end of the paper P and the paper P is completely discharged from the discharge port 28 after the first time DT1 has passed. 51 can be stopped to stop the conveyor belt 16 . At this time, the control section 3 also stops the image drum drive transmission section 60 (FIG. 2).

On the other hand, the control section 3 continues the operation of the fixing motor 71 at this time. Accordingly, in the image forming apparatus 1, the waste toner generated in each image drum unit 17 is continuously transported to the waste toner cartridge 21 by the waste toner transport section 20 (FIG. 1).

After that, the control section 3 stops the fixing motor 71 at time T5 when a predetermined second time DT2 has passed from time T3. As a result, in the image forming apparatus 1, the shaft 84 of the fixing drive transmission section 70 rotates again while the gear 56 of the belt drive transmission section 50 is stopped.

The second time DT2 is set in advance based on the time required for conveying waste toner generated in the image drum unit 17 to the waste toner cartridge 21 . Also, the second time DT2 is longer than the first time DT1. Therefore, the control section 3 completes the generation of the toner image in the image drum unit 17, and after the waste toner conveying section 20 finishes conveying almost all the generated waste toner to the waste toner cartridge 21, the waste toner conveying section 20 can be stopped.

[4. effects, etc.]
In the above configuration, the image forming apparatus 1 according to the present embodiment has a shaft 84 (FIGS. 2 and 3) that rotates integrally with the gears 83 and 85 of the fixing drive transmission section 70 in the drive transmission section 30. The gear 56 of the drive transmission portion 50 was inserted.

When the image forming apparatus 1 performs print processing, the drive transmission section 30 rotates the shaft 84 in the direction of arrow R1 integrally with the gears 83 and 85 of the fixing drive transmission section 70, and rotates the gear 56 of the belt drive transmission section 50. is rotated in the same direction as the arrow R1 (FIGS. 5 and 6). At this time, in the drive transmission unit 30, the gear 56 is passed through the shaft 84 and both are rotated in the same direction of the arrow R1. Can slow down.

As a result, in the drive transmission unit 30, the friction generated between the gear 56 and the shaft 84 can be reduced compared to the case where the gear 56 is inserted through a fixed support shaft, and the wear of the gear 56 can be suppressed. can. As a result, in the drive transmission unit 30, the possibility of eccentricity of the gear 56 due to wear can be greatly reduced, so that the gear 56 normally meshes with other gears 57, etc., that is, without generating noise, vibration, or the like. A state in which the driving force can be smoothly transmitted can be favorably maintained.

Especially in the image forming apparatus 1, when performing print processing, the fixing motor 71 is operated before the belt motor 51 at the start of warm-up processing, and after the belt motor 51 is stopped after the end of the printing processing, the fixing motor 71 is operated. is stopped (Fig. 7). Therefore, in the drive transmission unit 30, when the gear 56 to which the driving force is transmitted from the belt motor 51 is rotated, the shaft 84 to which the driving force is transmitted from the fixing motor 71 can be kept rotating.

As a result, in the image forming apparatus 1, when the gear 56 (FIGS. 3 and 6) rotates, that is, when the driving force is transmitted between the gear 56 and the gears 55 and 57, the gear 56 and the shaft 56 rotate. When a certain amount of force acts on 84, the rotational speed difference between them can be kept relatively small, and the generated friction can also be kept small.

In other words, in the image forming apparatus 1 (FIG. 1), when the printing process is performed, the fixing section 22 starts operating from the warm-up stage, and the waste toner conveying section 20 operates even after the printing process is completed. On the other hand, the transport belt 16 is run only when the paper P is transported along the transport path W. Therefore, in the drive transmission unit 30, by inserting the gear 56 to which the driving force is transmitted from the belt motor 51 into the shaft 84 to which the driving force is transmitted from the fixing motor 71, the shaft 84 is rotated when the gear 56 is rotated. is always rotating.

In the image forming apparatus 1 (FIG. 1), the paper P is transported along the transport path W only in one direction from the paper feed cassette 10 to the discharge port 28, and the paper P is transported in the opposite direction. nothing to do Therefore, in the image forming apparatus 1, the traveling direction of the conveying belt 16 and the rotating directions of the heating belt and the pressure roller in the fixing section 22 are always constant. In addition, since the waste toner conveying section 20 conveys the waste toner generated in the image drum unit 17 to the waste toner cartridge 21, the spiral conveying body is not reversely rotated. Therefore, in the drive transmission unit 30, the rotation directions of the gear 56 and the shaft 84 can always be rotated in the same direction of the arrow R1 (FIGS. 5 and 6), and the difference in rotation speed can be kept relatively small.

From another point of view, in the drive transmission section 30, since the shaft 84 of the fixing drive transmission section 70 is inserted through the gear 56 of the belt drive transmission section 50 (FIG. 3, etc.), interference with the gear 56 is avoided. Therefore, it is not necessary to arrange the shaft 84 above or below the gear 56, so that it can be arranged in an extremely narrow space. Further, in the drive transmission unit 30, there is no need to add a gear for transmitting the driving force to the shaft 84, which is required when the shaft 84 is arranged at a position avoiding the gear 56, for example. Furthermore, in the drive transmission section 30, there is no need to separately provide a support shaft for rotatably supporting the gear 56 in the belt drive transmission section 50. FIG. As a result, in the image forming apparatus 1, the configuration can be simplified by minimizing the parts such as gears and support shafts constituting the drive transmission section 30 without increasing the size of the housing 2 uselessly. can.

According to the above configuration, in the drive transmission section 30 of the image forming apparatus 1, the shaft 84 that rotates integrally with the gears 83 and 85 of the fixing drive transmission section 70 is inserted into the gear 56 of the belt drive transmission section 50. rice field. When the image forming apparatus 1 performs print processing, the drive transmission section 30 rotates the shaft 84 of the fixing drive transmission section 70 and the gear 56 of the belt drive transmission section 50 in the same direction of the arrow R1. Compared to the case where the shaft is inserted, the difference in rotational speed between the gear 56 and the shaft 84 can be reduced, and wear of the gear 56 can be suppressed. As a result, in the drive transmission unit 30, the possibility of the gear 56 becoming eccentric due to wear can be greatly reduced, and the gear 56 can be properly meshed with the other gears 57, etc., and a state in which the drive force can be smoothly transmitted can be maintained satisfactorily. can.

[5. Other embodiments]
In the above-described embodiment, the shaft 84 that rotates together with the gears 83 and 85 in the fixing drive transmission section 70 is passed through the gear 56 of the belt drive transmission section 50 (FIG. 2, etc.). However, the present invention is not limited to this. For example, the gear 56 may be inserted through a shaft (not shown) that rotates integrally with a predetermined gear in the image drum drive transmission section 60, or the gear of the paper feed drive transmission section 40 (not shown) may be inserted. (not shown) may be inserted through the shaft 84, and various gears may be inserted through various shafts.

Especially in the image forming apparatus 1 (FIG. 1), from the viewpoint of protecting the surface of the photosensitive drum provided in the image drum unit 17, the fixing drive transmission section 70 and the belt drive transmission section 50 operate at the same timing. The period during which the photosensitive drum is rotated and the period during which the conveying belt 16 is run are aligned. For this reason, in the drive transmission section 30, the gear of the belt drive transmission section 50 is inserted through the shaft that rotates as the fixing drive transmission section 70 is driven, or the shaft that rotates as the belt drive transmission section 50 is driven. By inserting the gears of the drive transmission portion 70, the rotation timings of the shaft and the gears can be aligned.

In the above-described embodiment, in the drive transmission section 30 (FIG. 2, etc.), the shaft 84 that transmits the driving force from the right side to the left side of the conveyance path W formed by the middle conveyance section 13, etc., that is, the conveyance path A case has been described in which the gear 56 is inserted through the shaft 84 having the gear 83 attached to the right side of W and the gear 85 attached to the left side. However, the present invention is not limited to this. Gear 56 may pass through various shafts mounted thereon for rotation therewith.

Furthermore, in the embodiment described above, the case where the shaft 84 is made of a metal material and the gear 56 is made of a resin material has been described. However, the present invention is not limited to this, and the shaft 84 and the gear 56 may be made of various materials, for example, made of a resin material.

Furthermore, in the above-described embodiment, in the printing process, by rotating the belt motor 51 while the fixing motor 71 is always rotating, the gear 56 is rotated while the shaft 84 is always rotating. (Fig. 7). However, the present invention is not limited to this, and the gear 56 may be rotated even when the shaft 84 is stopped, for example. Furthermore, the shaft 84 may temporarily rotate in the opposite direction to the gear 56 as well. However, in this case, it is desirable to minimize the time during which the shaft 84 rotates in the opposite direction, or to keep the rotation speed as low as possible.

Furthermore, in the above-described embodiment, a case has been described in which the present invention is applied to the image forming apparatus 1 which is a single-function printer (that is, SFP). However, the present invention is not limited to this. / Printer). The present invention may also be applied to various devices having an electrophotographic printing function, such as facsimile machines and copiers.

Furthermore, the invention is not limited to the embodiments described above and other embodiments. That is, the scope of the present invention also extends to embodiments obtained by arbitrarily combining part or all of the above-described embodiment and other embodiments described above, and to embodiments in which a part is extracted. be.

Furthermore, in the embodiment described above, the fixing motor 71 as the first drive source, the fixing gear train 70G as the first drive train, the shaft 84 as the first rotation shaft, and the gear 83 as the first transmission member and the belt motor 51 as the second drive source, the belt gear train 50G as the second drive train, and the gear 56 as the second transmission member constitute the drive transmission section 30 as the drive transmission device. . However, the present invention is not limited to this, and includes a first drive source, a first drive train, a first rotating shaft, a first transmission member, a second drive source, and a second drive train having various configurations. , and the second transmission member may constitute a drive transmission device.

INDUSTRIAL APPLICABILITY The present invention can be used, for example, in a fixing section of an image forming apparatus having an electrophotographic printing function.

Reference Signs List 1 image forming apparatus 3 control section 13 intermediate conveying section 14, 15 pulley 16 conveying belt 17 image drum unit 19 toner cartridge 20 waste toner Conveying section 21 Waste toner cartridge 22 Fixing section 30 Drive transmission section 31 Left side plate 32 Right side plate 35 Spiral conveying body driving section 40 Supply Paper drive transmission unit 50 Belt drive transmission unit 50G Belt gear train 51 Belt motor 52, 53, 54, 55, 56, 57, 72, 73, 74, 81, 82, 83, 85 Gears 60 Image drum drive transmission section 70 Fixing drive transmission section 70 G Fixing gear train 71 Fixing motor 84 Shaft P Paper W Conveying path.

Claims (7)

an image forming unit having a rotating image carrier and using a developer to form a developer image on a peripheral surface of the image carrier;
a transport unit having a rotating transfer drive for transporting a medium and transferring the developer image to the medium;
a fixing unit that has a rotating fixing driving body and applies heat and pressure to fix the medium onto which the developer image has been transferred;
a waste developer conveying unit having a rotating conveying body for conveying waste developer generated in the image forming unit;
a drive transmission device for transmitting a driving force;
a control unit that controls the image forming unit, the conveying unit, the fixing unit, and the drive transmission device;
The drive transmission device is
a first driving source that generates a driving force;
a first drive train that transmits driving force from the first drive source;
a first transmission member provided in the first drive train and rotating integrally with the first rotation shaft along the first direction around the first rotation shaft;
a second driving source that generates a driving force;
a second drive train that transmits driving force from the second drive source;
a second transmission member provided in the second drive train and rotatably supported by the first rotation shaft independently of the first rotation shaft;
the first transmission member transmits a driving force to be supplied to the conveying body of the waste developer conveying portion;
The first drive train of the drive transmission device transmits driving force to the fixing driving body provided in the fixing section,
The second drive train of the drive transmission device transmits a driving force to the transfer driving body provided in the conveying section.
An image forming apparatus characterized by: The first transmission member and the first rotating shaft rotate in a predetermined rotation direction when a driving force is transmitted from the first driving source through the first driving train,
The image forming apparatus according to claim 1, wherein the second transmission member rotates in the rotation direction when driving force is transmitted from the second drive source via the second drive train. 2. The image forming apparatus according to claim 1, further comprising a third transmission member attached to said first rotation shaft and rotating integrally with said first rotation shaft and said first transmission member. 4. The image forming apparatus according to claim 3, wherein the third transmission member is attached to a side of the first rotating shaft opposite to the first transmission member across the conveying section. In a state in which both the first drive source and the second drive source of the drive transmission device are stopped, the control unit starts the operation of the first drive source, and then operates the second drive source. 2. The image forming apparatus according to claim 1, wherein an operation is started. In a state in which both the first drive source and the second drive source of the drive transmission device are operating, the control unit stops the operation of the second drive source, and then stops the operation of the first drive source. The image forming apparatus according to claim 1, wherein the operation is stopped. The image forming apparatus according to claim 1, wherein the control section operates the second drive source while operating the first drive source of the drive transmission device.

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