JP7279604B2 - image forming device - Google Patents

Description

The present invention relates to an image forming apparatus.

2. Description of the Related Art Some image forming apparatuses are equipped with a blower that blows air to the image forming unit in order to suppress the temperature rise in the image forming unit (for example, Japanese Patent Application Laid-Open No. 2002-200011).

Further, an image forming apparatus has been proposed which is provided with an air intake/exhaust device for blowing air to the exposure section and the fixing section, and which is configured to be able to adjust the air blowing volume of each (for example, Japanese Patent Application Laid-Open No. 2002-200002).

JP 2007-122044 A (see, for example, paragraphs 0021 to 0022) JP 2012-150313 A (see, for example, paragraphs 0064 to 0073)

However, there is a demand for more efficient cooling of the image forming unit.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus capable of cooling an image forming unit more efficiently.

An image forming apparatus of the present invention includes an image forming unit that forms an image, a blower that blows air toward the image forming unit , a switching unit that switches between an image forming state and a non-image forming state of the image forming unit , a blowing amount changing section for changing a blowing amount of air blown from the blowing section toward the image forming unit in mechanical conjunction with switching between an image forming state and a non-image forming state of the image forming unit by the switching section. . The switching unit switches the image forming unit to an image forming state by connecting driving force transmission to the image forming unit, and switches the image forming unit to a non-image forming state by interrupting driving force transmission to the image forming unit. It has a ring mechanism. The coupling mechanism has a movable portion movable between a first position and a second position, and the movable portion connects driving force transmission to the image forming unit by moving to the first position. and cuts off the transmission of the driving force to the image forming unit by moving to the second position .
The image forming apparatus of the present invention further includes an image forming unit that forms an image, a blowing unit that blows air toward the image forming unit, and a switching unit that switches between an image forming state and a non-image forming state of the image forming unit. and a blowing amount changing unit that changes the blowing amount of air blown from the blowing unit toward the image forming unit in mechanical conjunction with the switching of the image forming unit between the image forming state and the non-image forming state by the switching unit. have The image forming unit has a developer carrier that carries a developer, an image carrier that carries an image, and a driving force receiving section connected to the developer carrier or the image carrier. The switching portion has an engaging portion that engages with the driving force receiving portion, and the blowing amount changing portion has an opening/closing door that contacts the engaging portion to open or at least partially close the blowing port of the blowing portion. .

According to the present invention, the amount of air blown to the image forming unit is changed in mechanical interlocking with the switching of the image forming unit between the image forming state and the non-image forming state by the switching section. can be cooled more efficiently.

1 is a perspective view showing an image forming apparatus according to a first embodiment; FIG. 2 is a diagram showing the internal configuration of the image forming apparatus according to the first embodiment; FIG. FIG. 2 is a diagram showing the arrangement of process units and toner cartridges according to the first embodiment; FIG. 2A is a diagram showing the positional relationship between the process unit, the toner cartridge, and the toner duct according to the first embodiment; FIG. 3B is a diagram showing the conveying spiral inside the toner duct; 2 is a perspective view showing a state in which the top cover and front cover of the image forming apparatus according to the first embodiment are opened; FIG. 3 is a perspective view showing the process unit of the first embodiment; FIG. 2 is a perspective view showing a housing and a process unit according to the first embodiment; FIG. FIG. 2 is a perspective view showing part of a driving force transmission section to a process unit according to the first embodiment; FIG. 2 is a perspective view showing part of a driving force transmission section to a process unit according to the first embodiment; It is a perspective view showing a side plate and an air duct of a 1st embodiment. FIG. 3 is a view of the side plate and the air duct of the first embodiment viewed from the process unit side; 3 is a view of the driving force transmission section of the first embodiment as viewed from the process unit side; FIG. 4A and 4B are top views showing operations of the first slider and the second slider of the first embodiment; FIG. 7A to 7C are schematic diagrams showing operations of the first slider and the second slider of the first embodiment; FIG. FIG. 2 is a view of the housing side portion of the first embodiment viewed from the process unit side; 3 is a view of the driving force transmission section of the first embodiment as viewed from the process unit side; FIG. FIG. 2 is a view of the housing side portion of the first embodiment viewed from the process unit side; 2 is a block diagram showing a control system of the image forming apparatus according to the first embodiment; FIG. FIG. 10 is a view of a fan duct, an opening/closing door, and a developing roller coupling according to a second embodiment, viewed from the process unit side; It is the figure which looked at the fan duct and the opening-and-closing door of 2nd Embodiment from the process unit side. It is the figure which looked at the opening-and-closing door of 2nd Embodiment from the process unit side. It is the perspective view (A) and (B) which shows the opening-and-closing door of 2nd Embodiment. It is a top view which shows the opening-and-closing door of 2nd Embodiment. FIG. 10 is a bottom view showing a fan duct, an opening/closing door, and a developing roller coupling according to a second embodiment; FIG. 10 is a front view showing an air duct, an opening/closing door, and a developing roller coupling according to a second embodiment; It is a perspective view which shows the air duct of 2nd Embodiment. FIG. 10 is a view of a fan duct, an opening/closing door, and a developing roller coupling according to a second embodiment, viewed from the process unit side; FIG. 10 is a bottom view showing a fan duct, an opening/closing door, and a developing roller coupling according to a second embodiment; It is a perspective view which shows the air duct of 2nd Embodiment. It is a schematic diagram (A) and (B) for demonstrating the lift-up mechanism of 3rd Embodiment. It is a perspective view which shows the lift-up mechanism of 3rd Embodiment, and its periphery. It is a perspective view which shows the lift-up slider of 3rd Embodiment, and its periphery. FIG. 11 is a perspective view showing a side plate of a process unit according to a third embodiment; FIG. Figure 34 is a cross-sectional view along line 34-34 in Figure 33; Figure 35 is a cross-sectional view along line 35-35 in Figure 34; It is a perspective view which shows the lift-up mechanism of 3rd Embodiment, and its periphery. FIG. 11 is a block diagram showing a control system of an image forming apparatus according to a third embodiment; FIG. It is a perspective view which shows the lift-up mechanism of the modification of 3rd Embodiment, and its periphery.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that the present invention is not limited by this embodiment.

First embodiment.
<Configuration of Image Forming Apparatus>
FIG. 1 is a perspective view showing the appearance of an image forming apparatus 1 according to the first embodiment. FIG. 2 is a diagram showing the internal configuration of the image forming apparatus 1. As shown in FIG. The image forming apparatus 1 is a printer that forms a color image using electrophotography.

As shown in FIG. 2, the image forming apparatus 1 includes a medium supply unit 110 that supplies a medium P such as printing paper, an image forming unit 100 that forms a toner image (developer image), and an image forming unit 100 that forms an image. A transfer unit 120 for transferring the toner image onto the medium P, a fixing device 130 for fixing the toner image on the medium P, a medium discharge unit 140 for discharging the medium P, and a housing 101 for housing them.

The medium supply unit 110 includes a paper feed tray 111 containing the medium P, a pickup roller 112 arranged to contact the medium P contained in the paper feed tray 111, and a pickup roller 112 arranged adjacent to the pickup roller 112. It has a feed roller 113 and a retard roller 114 arranged to face the feed roller 113 .

The paper feed tray 111 accommodates media P such as printing paper in a stacked state. The pickup roller 112 rotates in contact with the medium P on the paper feed tray 111 and feeds out the medium P from the paper feed tray 111 . The feed roller 113 feeds the medium P fed out by the pickup roller 112 to the transport path. The retard roller 114 rotates in a direction opposite to the feeding direction by the feed roller 113, and applies conveyance resistance to the medium P to prevent double feeding.

The medium supply unit 110 also has a transport roller 115 and a transport roller 118 along the medium P transport path. The conveying roller 115 is composed of a registration roller 116 and a pinch roller 117 that abuts against it. skew is corrected and conveyed. The transport rollers 118 transport the medium P from the transport rollers 115 to the image forming section 100 .

The image forming section 100 has four process units 10K, 10C, 10M, and 10Y as image forming units that form black, cyan, magenta, and yellow toner images. Print heads 13K, 13C, 13M, and 13Y as exposure devices are arranged so as to face respective photosensitive drums 11 (described later) of process units 10K, 10C, 10M, and 10Y.

The process units 10K, 10C, 10M, and 10Y are arranged in this order along the transport direction of the medium P (here, from right to left in the drawing). The process units 10K, 10C, 10M, and 10Y are referred to as "process units 10" when there is no particular need to distinguish them. Also, the print heads 13K, 13C, 13M, and 13Y are referred to as "print heads 13" when there is no particular need to distinguish between them.

The process unit 10 includes a photosensitive drum 11 as an image carrier that carries a toner image, a charging roller 12 as a charging member, a developing roller 14 as a developer carrier, a supply roller 15 as a supply member, It has a developing blade 16 as a developer regulating member and a unit frame 30 that accommodates them.

The photoreceptor drum 11 is a cylindrical member having a photosensitive layer (charge generation layer and charge transport layer) provided on the surface of a conductive substrate, and is rotated clockwise in the drawing by a drive motor 17 (FIG. 18).

The charging roller 12 is arranged to contact the surface of the photoreceptor drum 11 and rotates following the rotation of the photoreceptor drum 11 . A charging voltage is applied to the charging roller 12 by a charging voltage power supply 202 (FIG. 18) to uniformly charge the surface of the photosensitive drum 11 . An electrostatic latent image is formed on the uniformly charged surface of the photosensitive drum 11 by light irradiation from the print head 13 .

The developing roller 14 is arranged to contact the surface of the photoreceptor drum 11 and rotates in a direction opposite to that of the photoreceptor drum 11 (counterclockwise in the drawing). The developing roller 14 is applied with a developing voltage by a developing voltage power supply 203 (FIG. 18), attaches toner to the electrostatic latent image formed on the surface of the photosensitive drum 11, and forms a toner image.

The supply roller 15 is arranged to contact or face the surface of the developing roller 14 and rotates in the same direction as the developing roller 14 . The supply roller 15 is supplied with a supply voltage from a supply voltage source 204 (FIG. 18) and supplies toner to the developing roller 14 .

The developing blade 16 is a metal blade elongated in the axial direction of the developing roller 14 and arranged to be pressed against the surface of the developing roller 14 . The developing blade 16 regulates the thickness of the toner layer formed on the surface of the developing roller 14 .

In the process unit 10, the portion including the developing roller 14, the supply roller 15 and the developing blade 16, that is, the portion contributing to the development of the electrostatic latent image constitutes a developing unit.

Above the process units 10K, 10C, 10M and 10Y, toner cartridges 20K, 20C, 20M and 20Y are provided as developer storage units for supplying toner to the process units 10K, 10C, 10M and 10Y. The toner cartridges 20K, 20C, 20M and 20Y are detachably attached to a top cover 102 which will be described later.

The toner cartridges 20K, 20C, 20M and 20Y contain black, cyan, magenta and yellow toners, respectively. The toner cartridges 20K, 20C, 20M, and 20Y are referred to as "toner cartridges 20" when there is no particular need to distinguish between them.

The print head 13 has, for example, a light-emitting element array in which light-emitting elements such as LEDs (light-emitting diodes) are arranged, and a lens array that converges light emitted from the light-emitting elements onto the surface of the photosensitive drum 11 . The print head 13 is driven by the head controller 206 (FIG. 18) to expose the surface of the photosensitive drum 11 to form an electrostatic latent image.

The transfer unit 120 includes an endless transfer belt 122 as a transfer body, a drive roller 123 and an idle roller 124 around which the transfer belt 122 is stretched, and process units 10K, 10C, 10M and 10Y through the transfer belt 122. A transfer roller 121 is provided so as to face each photosensitive drum 11 .

The transfer belt 122 runs while attracting and holding the medium P on its surface by electrostatic force. The drive roller 123 is rotated by a belt motor 125 (FIG. 18) to cause the transfer belt 122 to run. The idle roller 124 applies tension to the transfer belt 122 . A transfer voltage is applied to the transfer roller 121 by a transfer voltage power supply 205 (FIG. 18), and the toner image on each photosensitive drum 11 is transferred onto the medium P. As shown in FIG.

The fixing device 130 is arranged downstream of the image forming section 100 in the direction in which the medium P is conveyed. The fixing device 130 has, for example, a fixing roller 131 and a pressure roller 132 pressed against the fixing roller 131 . The fixing roller 131 incorporates a heater 133 (FIG. 18) as a heat source and is rotated by a fixing motor 135 (FIG. 18). The fixing roller 131 and pressure roller 132 apply heat and pressure to the toner image transferred to the medium P to fix the toner image onto the medium P. FIG.

The medium discharge section 140 is arranged downstream of the fixing device 130 in the transport direction of the medium P, and includes discharge rollers 141 and 142 which are two pairs of rollers. The discharge rollers 141 and 142 convey the medium P sent out from the fixing device 130 along the discharge conveying path and discharge it to the outside of the image forming apparatus 1 . A stacker unit 143 for stacking media discharged by the discharge rollers 141 and 142 is provided in the upper part of the image forming apparatus 1 .

The image forming apparatus 1 is provided with a re-conveying mechanism 150 that reverses the medium P having the toner image fixed on its surface and conveys it to the above-described conveying rollers 115 for double-sided printing. A switching guide 136 that guides the medium P fed from the fixing device 130 to the medium discharge section 140 or the re-conveying mechanism 150 is provided on the downstream side of the fixing device 130 .

The re-conveying mechanism 150 includes conveying rollers 151 and 153 and a switching guide 152 that temporarily feed the medium P into the evacuation path R3 and switch the front and back sides, and conveying rollers 154, 155, and 156 that convey the medium P along the return conveying path R4. have. The return transport path R4 joins the upstream side of the transport rollers 118 in the transport path R1. A pinch roller 157 that contacts the registration roller 116 from the opposite side to the pinch roller 117 is provided near the exit of the return transport path R4.

The medium P conveyed along the return conveying path R4 by the conveying rollers 154, 155, and 156 is conveyed to the upstream side of the conveying roller 118 on the conveying path R1 by the roller pair consisting of the registration roller 116 and the pinch roller 157. FIG. Note that if the image forming apparatus 1 does not have a double-sided printing function, the re-conveying mechanism 150 is unnecessary.

The image forming apparatus 1 also has an openable and closable top cover 102 attached to the top of the housing 101 and an openable and closable front cover 103 attached to the front of the housing 101 . The top cover 102 is provided with an operation unit 104 (FIG. 1) such as an operation panel. Further, the toner cartridges 20K, 20C, 20M and 20Y described above are attached to the top cover 102 .

In FIG. 2, the direction of the rotation axis of the photosensitive drum 11 is the X direction. The X direction is the width direction of the medium P. The axial direction of each roller of each unit described above is parallel to the X direction. The depth direction of the image forming apparatus 1 (horizontal direction in FIG. 2) orthogonal to the X direction is defined as the Y direction. The XY plane is the horizontal plane here. Also, the direction perpendicular to the XY plane, here the vertical direction, is defined as the Z direction. As for the Y direction, the front cover 103 side is the -Y direction, and the opposite side is the +Y direction.

In FIG. 2, the process units 10K, 10C, 10M, and 10Y are arranged in a direction inclined with respect to the Y direction. Hereinafter, the arrangement direction of the process units 10K, 10C, 10M, and 10Y will be referred to as the unit arrangement direction (generally the Y direction). Note that the unit arrangement direction does not necessarily have to be a direction inclined with respect to the Y direction, and may be parallel to the Y direction.

<Toner Conveyance from Toner Cartridge to Process Unit>
FIG. 3 is a schematic diagram showing the positional relationship between the process units 10K, 10C, 10M and 10Y and the toner cartridges 20K, 20C, 20M and 20Y.

The process units 10K, 10C, 10M, and 10Y all have a long shape in the X direction, and are arranged in a line in the unit arrangement direction (approximately the Y direction). On the other hand, the toner cartridges 20K, 20C, 20M, and 20Y all have long shapes in the unit arrangement direction and are arranged in the X direction.

Toner ducts 22K, 22C, 22M and 22Y, which are toner transport paths, are provided between the toner cartridges 20K, 20C, 20M and 20Y and the process units 10K, 10C, 10M and 10Y, respectively.

The toner ducts 22K, 22C, 22M, and 22Y include connecting portions 21K, 21C, 21M, and 21Y connected to the toner cartridges 20K, 20C, 20M, and 20Y, and connecting portions connected to the process units 10K, 10C, 10M, and 10Y. 23K, 23C, 23M and 23Y.

In this example, the connecting portions 21K, 21C, 21M, and 21Y are arranged at the same position in the Y direction. Also, the connecting portions 23K, 23C, 23M, and 23Y are arranged at the same X-direction position. However, it is not limited to such arrangement.

The toner supply unit 2 is composed of the toner cartridges 20K, 20C, 20M, 20Y and the toner ducts 22K, 22C, 22M, 22Y. The toner supply unit 2 is attached to the top cover 102 .

The toner ducts 22K, 22C, 22M, and 22Y are referred to as "toner ducts 22" when there is no particular need to distinguish them. The connecting portions 21K, 21C, 21M, and 21Y are referred to as "connecting portions 21" when there is no particular need to distinguish between them. The connection portions 23K, 23C, 23M, and 23Y are referred to as "connection portions 23" when there is no particular need to distinguish between them.

FIG. 4A is a diagram showing the positional relationship in the YZ plane between the toner supply unit 2 and the process units 10K, 10C, 10M and 10Y. Although one toner duct 22 is shown in FIG. 4A, actually four toner ducts 22K, 22C, 22M, and 22Y are provided as shown in FIG. .

The toner stored in the toner cartridge 20 is dropped and supplied from the connecting portion 21 into the toner duct 22 . Inside each toner duct 22, a conveying spiral 25 (FIG. 4B) is provided as a conveying member for conveying toner. The conveying spiral 25 conveys the toner along the toner duct 22 from the connecting portion 21 to the connecting portion 23 . The toner conveyed through the toner duct 22 to the connection portion 23 is dropped and supplied to the process unit 10 .

FIG. 4B is a diagram showing the conveying spiral 25 inside the toner duct 22. As shown in FIG. The conveying spiral 25 is arranged over substantially the entire longitudinal direction of the toner duct 22 and rotates around the longitudinal axis of rotation of the toner duct 22 . The conveying spiral 25 is driven by a toner supply motor 26 . A toner supply motor 26 is provided for each conveying spiral 25 here. However, the driving force of the common toner supply motor 26 may be transmitted to the individual conveying spirals 25 via clutches.

FIG. 5 shows a state in which the top cover 102 and the front cover 103 of the image forming apparatus 1 are opened. The top cover 102 is swingably supported by an X-direction swing axis C1 provided in the housing 101 . The swing axis C1 is provided at the +Y-direction end and the +Z-direction end of the housing 101 . By rocking the top cover 102 about the rocking axis C1, the top cover 102 can be opened as indicated by arrow A in FIG.

The front cover 103 is swingably supported by an X-direction swing axis C2 provided in the housing 101 . The swing axis C2 is provided at the end of the housing 101 in the -Y direction and the end in the -Z direction. By rocking the front cover 103 about the rocking axis C2, the top cover 102 can be opened as indicated by an arrow B in FIG.

As described above, toner supply unit 2 (that is, toner cartridges 20K, 20C, 20M, 20Y and toner ducts 22K, 22C, 22M, 22Y) is supported by top cover 102 . Therefore, when the top cover 102 is opened, the toner supply unit 2 also swings in the direction indicated by the arrow A.

Also, the process units 10K, 10C, 10M, and 10Y are attached to a basket frame 107 that swings integrally with the top cover 102 . Each process unit 10 has a rotating member such as a photosensitive drum 11, and a driving force is transmitted from the housing 101 side.

Therefore, the front cover 103 is opened before the top cover 102 is opened, mechanically interlocking with the opening operation of the front cover 103, and the transmission of driving force to each process unit 10 is cut off. Driving force transmission to each process unit 10 will be described later.

Since the process units 10K, 10C, 10M, and 10Y are opened together with the top cover 102, the upper portion of the transfer unit 120 can be accessed from the outside, and the jammed medium P can be easily removed. Note that the toner cartridge 20 can be replaced while the front cover 103 is open.

FIG. 6 is a perspective view showing the process unit 10. FIG. The process unit 10 has a unit frame 30 elongated in the X direction and side frames 31 and 32 formed at both ends in the X direction. Unit frame 30 accommodates photosensitive drum 11 , charging roller 12 , developing roller 14 , supply roller 15 and developing blade 16 . A toner receiving port 30 a for receiving toner from the toner duct 22 is formed in the upper portion of the unit frame 30 .

The process unit 10 includes a developing roller coupling portion 33 as a driving force receiving portion (first driving force receiving portion) for receiving the driving force for rotating the developing roller 14 , and a driving force for rotating the photosensitive drum 11 . and a photoreceptor drum coupling portion 34 as a driving force receiving portion (second driving force receiving portion) that receives the driving force.

The developing roller coupling portion 33 is fixed to the shaft of the developing roller 14 . The photoreceptor drum coupling portion 34 is fixed to the shaft of the photoreceptor drum 11 . The side frame 31 is formed with openings 31a and 31b for exposing the developing roller coupling portion 33 and the photosensitive drum coupling portion 34, respectively.

Further, the side frame 31 is provided with an opening 35 for introducing air (that is, cooling air) blown from an air blowing port 53 to be described later into the process unit 10 .

In the process unit 10, the contact portion between the developing roller 14 and the developing blade 16 generates a relatively large amount of heat. It is desirable that the position is opposite to the contact portion of the X direction. However, it is not limited to this position.

FIG. 7 is a perspective view showing the process units 10K, 10C, 10M and 10Y and the housing side portion 105 of the housing 101. FIG. A driving force transmission unit 6 ( FIG. 12 ) that transmits a driving force to each process unit 10 is provided on a +X direction side portion (housing side portion) 105 of the housing 101 and covered with an inner cover 106 .

FIG. 8 is a perspective view showing part of the driving force transmission section 6. As shown in FIG. In FIG. 8, the inner cover 106 shown in FIG. 7 is omitted. The driving force transmission portion 6 is engaged with the developing roller coupling 41 as an engaging portion (first engaging portion) that engages with the developing roller coupling portion 33 of the process unit 10 and the photosensitive drum coupling portion 34 . and a photosensitive drum coupling 42 as an engaging portion (second engaging portion). These couplings 41 and 42 are attached to the housing 101 so as to be rotatable around the rotation axis in the X direction.

The developing roller coupling 41 has an Oldham coupling mechanism inside, and is configured so that even if there is a slight misalignment with the developing roller coupling portion 33, the misalignment can be absorbed and the driving force can be transmitted. ing. Similarly, the photoreceptor drum coupling 42 has an Oldham coupling mechanism inside, and is configured so as to absorb axial misalignment with the photoreceptor drum coupling portion 34 and transmit the driving force.

The developing roller coupling 41 has an engaging shaft portion 411 that engages with the developing roller coupling portion 33 at the end in the -X direction. A gear 412 is attached to a shaft 413, which is a rotating shaft of the developing roller coupling 41, to which the driving force from the drive motor 17 (FIG. 9) is transmitted.

The photoreceptor drum coupling 42 has an engaging shaft portion 421 that engages with the photoreceptor drum coupling portion 34 at the end in the -X direction. A gear 422 to which driving force from the driving motor 17 is transmitted is attached to a shaft 423 which is a rotating shaft of the photoreceptor drum coupling 42 .

FIG. 9 is a perspective view showing part of the driving force transmission section 6. As shown in FIG. The developing roller couplings 41 corresponding to the process units 10K, 10C, 10M and 10Y are referred to as developing roller couplings 41K, 41C, 41M and 41Y. Similarly, the photoreceptor drum couplings 42 corresponding to the process units 10K, 10C, 10M and 10Y are referred to as photoreceptor drum couplings 42K, 42C, 42M and 42Y.

The driving force of the drive motor 17 is transmitted to the gears 412 of the developing roller couplings 41K, 41C, 41M and 41Y and the photoreceptor drum couplings 42K, 42C, 42M and 42Y through the transmission mechanism 18 having a gear train. It is transmitted to each gear 422 .

FIG. 10 is a perspective view showing the side plate 55 arranged on the housing side portion 105 and the air duct 50 attached thereto. FIG. 11 is a view of the side plate 55 viewed from the process unit 10 side. As shown in FIG. 10, the side plate 55 is formed by bending a plate-like member.

A motor support portion 55 a to which the blower fan 56 is attached is formed at the upper end portion (the end portion in the +Z direction) of the side plate 55 . The blower fan 56 is attached to the +X side (the side opposite to the process unit 10) of the motor support portion 55a.

A blower duct 50 as a blower is attached to the side plate 55 adjacent to the +Y side of the motor support portion 55a. The blower duct 50 constitutes a blower path for blowing the cooling air sent from the blower fan 56 to each process unit 10 . The air duct 50 has a main duct 51 extending in the unit arrangement direction (approximately the Y direction) and forming a main part of the air duct, and four branch ducts 52 branching from the main duct 51 .

The four branch ducts 52 extend substantially in the -Z direction from the main duct 51 and face the side frames 31 (FIG. 6) of the process units 10K, 10C, 10M and 10Y. At the tip of each branch duct 52, an air blowing port 53 for sending out cooling air toward the process unit 10 is formed. The blower port 53 is formed at a position facing the opening 35 (FIG. 6) described above.

At the tip of the branch duct 52, an inclined wall 54 is formed so that the cooling air flowing from the main duct 51 in the -Z direction is sent out from the air blowing port 53 in the -X direction.

The side plate 55 also has a plurality of fixing portions 55b for fixing a cover member 80 (FIG. 15), which will be described later, and four holes through which the shafts 413 (FIG. 8) of the developing roller couplings 41 of the process units 10 pass. and a portion 55c (FIG. 11).

FIG. 12 is a view of the driving force transmission section 6 as seen from the process unit 10 side. The driving force transmission unit 6 includes a first slider 60 for moving the developing roller coupling 41K and the photosensitive drum coupling 42K in the X direction, the developing roller couplings 41C, 41M, 41Y, and the photosensitive drum coupling It has a second slider 70 as a blowing amount changing section (movable section) for moving 42C, 42M and 42Y in the X direction.

Both the first slider 60 and the second slider 70 are long in the unit arrangement direction (approximately the Y direction) and move straight in the unit arrangement direction. The first slider 60 and the second slider 70 constitute a switching mechanism for switching the transmission path of the driving force in the driving force transmission section 6 . Let the positions of the first slider 60 and the second slider 70 shown in FIG. 12 be reference positions (first positions).

As shown in FIG. 12, the first slider 60 has an opening 61 through which the engaging shaft 411 of the developing roller coupling 41K passes, and an opening through which the engaging shaft 421 of the photosensitive drum coupling 42K passes. a portion 62; Both the openings 61 and 62 have a shape elongated in the longitudinal direction of the first slider 60 .

When the first slider 60 is at the reference position, the engaging shaft portion 411 of the developing roller coupling 41K is positioned at the -Y direction end of the opening 61, and the engaging shaft portion 421 of the photosensitive drum coupling 42K is positioned at the end of the opening 62 in the -Y direction.

A lever connecting portion 64 connected to the swing lever 108 provided on the housing 101 is formed at the end of the first slider 60 in the -Y direction.

The second slider 70 has an opening 71 through which the engaging shafts 411 of the developing roller couplings 41C, 41M, and 41Y pass, and the engaging shafts 421 of the photosensitive drum couplings 42C, 42M, and 42Y. and an opening 72 for passage therethrough. Both the openings 71 and 72 have a shape elongated in the longitudinal direction of the second slider 70 .

When the second slider 70 is at the reference position, the engaging shafts 411 of the developing roller couplings 41C, 41M and 41Y are positioned at the ends of the opening 71 in the -Y direction, and the photoreceptor drum couplings 42C and 42M are aligned. , 42Y are positioned at the ends of the openings 72 in the -Y direction.

FIG. 13A is a top view showing a state in which both the first slider 60 and the second slider 70 of the driving force transmission section 6 are at the reference position (first position). The first slider 60 has a concave portion 60a, an inclined portion 60b, and a convex portion 60c as contact portions that contact the developing roller coupling 41K. The concave portion 60a, the inclined portion 60b, and the convex portion 60c are arranged in this order in the +Y direction. The convex portion 60c protrudes in the +X direction with respect to the concave portion 60a, and the inclined portion 60b extends so as to connect the concave portion 60a and the convex portion 60c.

The developing roller coupling 41K is urged in the -X direction by an urging member 63 (FIG. 14A) such as a spring, and the first slider 60 moves toward any one of the concave portion 60a, the inclined portion 60b and the convex portion 60c. abutting.

In FIG. 13A, the developing roller coupling 41K is in contact with the recess 60a. That is, the developing roller coupling 41K is located at the end of its movement range in the -X direction (that is, the position closest to the process unit 10).

FIG. 13B is a top view showing a state in which the first slider 60 and the second slider 70 of the driving force transmission section 6 are moved in the -Y direction. When the first slider 60 moves in the -Y direction, the developing roller coupling 41K contacts the convex portion 60c from the concave portion 60a via the inclined portion 60b. As a result, the developing roller coupling 41K moves in the +X direction (that is, the direction away from the process unit 10).

Returning to FIG. 13A, the second slider 70 has a concave portion 70a, an inclined portion 70b, and a convex portion 70c as contact portions that contact the developing roller couplings 41C, 41M, and 41Y, respectively. The concave portion 70a, the inclined portion 70b, and the convex portion 70c are arranged in this order in the +Y direction. The convex portion 70c is positioned in the +X direction with respect to the concave portion 70a. The inclined portion 70b extends so as to connect the concave portion 70a and the convex portion 70c.

Each of the developing roller couplings 41C, 41M, and 41Y is biased in the -X direction by a biasing member 73 (FIG. 14A) such as a spring, and the concave portion 70a, inclined portion 70b, and It is in contact with any one of the protrusions 70c.

In FIG. 13A, the developing roller couplings 41C, 41M, and 41Y are all in contact with the recess 60a. That is, the developing roller couplings 41C, 41M, and 41Y are located at the ends in the -X direction of their movement ranges (that is, the positions closest to the process unit 10).

As shown in FIG. 13B, when the second slider 70 moves in the -Y direction, the developing roller couplings 41C, 41M, and 41Y all come into contact with the convex portion 70c via the inclined portion 70b from the concave portion 70a. . As a result, the developing roller couplings 41C, 41M, and 41Y all move in the +X direction (that is, the direction away from the process unit 10).

The positions of the first slider 60 and the second slider 70 shown in FIG. 13B are referred to as blocking positions (second positions).

14A to 14C are schematic diagrams for explaining the operations of the first slider 60 and the second slider 70. FIG.

FIG. 14A shows a state in which both the first slider 60 and the second slider 70 are at the reference position.

FIG. 14B shows a state in which both the first slider 60 and the second slider 70 are moved from the reference position in the -Y direction to the blocking position.

FIG. 14C shows a state in which the first slider 60 is at the reference position and the second slider 70 is moved from the reference position in the -Y direction to the blocking position.

A contact portion 66 is formed at the +Y direction end portion of the first slider 60 . A contact portion 76 is formed at the end of the second slider 70 in the -Y direction. The contact portion 66 of the first slider 60 and the contact portion 76 of the second slider 70 are configured to contact each other.

In the state shown in FIG. 14A, both the first slider 60 and the second slider 70 are at the reference position (first position). Therefore, the developing roller coupling 41K is positioned in the recessed portion 60a of the first slider 60, and the developing roller couplings 41C, 41M, and 41Y are positioned in the recessed portion 70a of the second slider .

Therefore, the developing roller coupling 41K is engaged with the developing roller coupling portion 33 of the process unit 10K. Further, the developing roller couplings 41C, 41M and 41Y are engaged with the developing roller coupling portions 33 of the process units 10C, 10M and 10Y. That is, the driving force is transmitted to all the developing rollers 14 of the process units 10K, 10C, 10M and 10Y.

In the state shown in FIG. 14B, both the first slider 60 and the second slider 70 have moved in the -Y direction from the reference position and reached the blocking position (second position). The operation of the sliders 60 and 70 is performed by opening the front cover 103 by the user.

That is, when the user opens the front cover 103 (FIG. 5), the rocking lever 108 connected to the front cover 103 rotates, and the action of the lever connecting portion 64 (FIG. 12) moves the first slider 60 in the -Y direction. move to Then, due to the contact of the contact portions 66, 76, the second slider 70 follows the first slider 60 and moves in the -Y direction.

As a result, the developing roller coupling 41K moves through the inclined portion 60b of the first slider 60 to the convex portion 60c, and the developing roller couplings 41C, 41M, and 41Y move through the inclined portion 70b of the second slider 70 to the convex portion. Go to 70c.

Therefore, the developing roller coupling 41K is separated from the developing roller coupling portion 33 of the process unit 10K. Further, the developing roller couplings 41C, 41M and 41Y are separated from the developing roller coupling portions 33 of the process units 10C, 10M and 10Y. That is, transmission of driving force to all the developing rollers 14 of the process units 10K, 10C, 10M and 10Y is cut off.

In the state shown in FIG. 14C, while the first slider 60 remains at the reference position, the second slider 70 moves from the reference position in the -Y direction and reaches the blocking position. The movement of the second slider 70 is performed by the switching motor 48 shown in FIG.

A rack gear portion 75 ( FIG. 12 ) is provided at the +Y direction end of the second slider 70 , and a gear 49 rotated by a switching motor 48 is engaged with the rack gear portion 75 . The second slider 70 is linearly moved in the unit arrangement direction (approximately the Y direction) due to the engagement between the rack gear portion 75 and the gear 49 . On the other hand, the first slider 60 does not move.

As a result, the developing roller couplings 41C, 41M, and 41Y move to the convex portion 70c via the inclined portion 70b of the second slider 70 while the developing roller coupling 41K remains positioned in the concave portion 60a of the first slider 60. FIG.

Therefore, the developing roller coupling 41K is engaged with the developing roller coupling portion 33 of the process unit 10K, and the developing roller couplings 41C, 41M, 41Y are connected to the developing roller coupling portions 33 of the process units 10C, 10M, 10Y. Separate. That is, the driving force is transmitted to the developing roller 14 of the process unit 10K, but the driving force transmission to the developing rollers 14 of the process units 10C, 10M and 10Y is cut off.

Although the movements of the developing roller couplings 41K, 41C, 41M and 41Y have been described here, the movement of the photosensitive drum couplings 42K, 42K and 41Y is performed by the movement of the sliders 60 and 70 shown in FIGS. 42C, 42M and 42Y also move in the same manner as the developing roller couplings 41K, 41C, 41M and 41Y.

Therefore, in the state shown in FIG. 14A, the driving force is transmitted to all the developing rollers 14 and photosensitive drums 11 of the process units 10K, 10C, 10M and 10Y. In other words, all of the process units 10K, 10C, 10M, and 10Y are in the image forming state (first state). Color printing is performed in this state.

Further, in the state shown in FIG. 14B, transmission of driving force to all the developing rollers 14 and photosensitive drums 11 of the process units 10K, 10C, 10M and 10Y is cut off. In other words, all of the process units 10K, 10C, 10M, and 10Y are in the non-image forming state (second state). In this state, the top cover 102 is opened and closed.

In the state shown in FIG. 14C, the driving force is transmitted to the developing roller 14 and the photosensitive drum 11 of the process unit 10K, and the driving force is applied to the developing roller 14 and the photosensitive drum 11 of the process units 10C, 10M, and 10Y. Driving force transmission is interrupted. In other words, the process unit 10K is in the image forming state and the process units 10C, 10M and 10Y are in the non-image forming state.

In this state, monochrome printing is performed by the process unit 10K. Therefore, during monochrome printing, the developing rollers 14 and photosensitive drums 11 of the process units 10C, 10M, and 10Y that are not used for printing can be stopped.

Since the driving force transmission section 6 can switch between the image forming state and the non-image forming state of the process units 10K, 10C, 10M, and 10Y, it is also called a switching section (or state changing section).

FIG. 15 is a diagram of the housing side portion 105 of the housing 101 viewed from the process unit 10 side. The developing roller couplings 41K, 41C, 41M and 41Y, the photosensitive drum couplings 42K, 42C, 42M and 42Y, the first slider 60 and the second slider 70 shown in FIG. there is The cover member 80 is fixed to the fixing portion 55b (FIG. 10) of the side plate 55. As shown in FIG.

The cover member 80 includes holes 81 through which the engaging shafts 411 of the developing roller couplings 41K, 41C, 41M, and 41Y are inserted, and the engaging shafts of the photosensitive drum couplings 42K, 42C, 42M, and 42Y. It has a hole portion 82 through which the portion 421 is inserted and an opening portion 83 through which the cooling air from the blower port 53 passes.

FIG. 16 is a view of the driving force transmission section 6 when the first slider 60 and the second slider 70 are in the state shown in FIG. 14C (that is, during monochrome printing) as viewed from the process unit 10 side. .

When the second slider 70 is at the blocking position shown in FIG. 14C, the engaging shafts 411 of the developing roller couplings 41C, 41M, and 41Y are positioned at the ends of the openings 71 in the +Y direction. . The engagement shafts 421 of the photoreceptor drum couplings 42C, 42M, and 42Y are positioned at the ends of the openings 72 in the +Y direction.

Furthermore, when the second slider 70 is at the blocking position shown in FIG. 14C, among the four air blowing ports 53 of the air blowing duct 50, the three air blowing ports 53 corresponding to the process units 10C, 10M, and 10Y are in the second position. 2 slider 70 (so hidden behind the second slider 70 in FIG. 16). A portion of the second slider 70 that closes the three blower ports 53 is called a closing portion. On the other hand, the blower port 53 corresponding to the black process unit 10K is not closed by the first slider 60 but is open.

FIG. 17 is a diagram of the housing side portion 105 viewed from the process unit 10 side during monochrome printing. When viewed from the process unit 10 side, of the four openings 83 of the cover member 80, the blower port 53 corresponding to the black process unit 10K is exposed from the opening 83, but the other process units 10C, 10M, The three blower ports 53 corresponding to 10Y are hidden.

Because of this configuration, during monochrome printing, the cooling air sent through the air blowing duct 50 as the air blowing part is intensively blown from one air blowing port 53 to the black process unit 10K.

That is, the cooling air is not blown to the process units 10C, 10M, and 10Y in which the photosensitive drum 11 and the developing roller 14 do not rotate (that is, in a non-image forming state), and the photosensitive drum 11 and the developing roller 14 rotate ( That is, the cooling air is intensively blown to the process unit 10K (which is in the image forming state). Therefore, the cooling air can be efficiently blown to the process unit 10K, and the process unit 10K can be efficiently cooled.

<Control System of Image Forming Apparatus>
Next, a control system of the image forming apparatus 1 will be described. FIG. 18 is a block diagram showing the control system of the image forming apparatus 1. As shown in FIG. The image forming apparatus 1 has a control device 200 , an I/F (interface) control section 221 , a reception memory 222 , an image data editing memory 223 , an operation section 104 and a sensor group 225 .

The image forming apparatus 1 also includes a power control unit 201, a head control unit 206, a drive control unit 207, a belt drive control unit 208, a fixing control unit 209, a fixing drive control unit 210, and a paper feeding control unit. and a part 211 .

The control device 200 has a microprocessor, a ROM (Read Only Memory), a RAM (Random Access Memory), an input/output port, a timer, and the like. The control device 200 receives print data and control commands from a host device via the I/F control section 221 and controls the operation of the image forming device 1 .

The reception memory 222 temporarily stores print data input from a host device via the I/F control unit 221 . The image data editing memory 223 receives the print data stored in the reception memory 222 and records image data formed by editing the print data, that is, image data.

The operation unit 104 includes a display unit (e.g., an LED) for displaying the state of the image forming apparatus 1, a switch for inputting an instruction by an operator, and the like. The sensor group 225 includes various sensors for monitoring the operating state of the image forming apparatus 1, such as a toner remaining amount sensor for detecting the toner remaining amount in the process unit 10, and a toner remaining amount sensor for detecting the toner remaining amount in the toner cartridge 20. A medium position sensor for detecting the transport position of the medium P is included.

The power control unit 201 includes a charging voltage power source 202 that applies a charging voltage to the charging roller 12, a development voltage power source 203 that applies a development voltage to the developing roller 14, a supply voltage power source 204 that applies a supply voltage to the supply roller 15, and a transfer voltage power source 204. A transfer voltage power supply 205 that applies a transfer voltage to the roller 121 is controlled. The head control unit 206 sends the image data recorded in the image data editing memory 223 to the print head 13 and controls the light emission of the print head 13 .

The drive control unit 207 controls the drive motor 17 that rotates the developing roller 14 and the photosensitive drum 11 of each process unit 10 . The charging roller 12 rotates following the rotation of the photosensitive drum 11 , and the supply roller 15 rotates due to rotation transmission from the developing roller 14 or the photosensitive drum 11 . A belt drive control unit 208 controls a belt motor 125 for driving the transfer belt 122 .

The fixing control unit 209 has a temperature control circuit and supplies current to the heater 133 based on the output signal of the thermistor 134 of the fixing device 130 . Fixing drive control section 210 controls fixing motor 135 that rotates fixing roller 131 ( FIG. 1 ) of fixing device 130 . Note that the discharge rollers 141 and 142 are rotated by rotation transmission from the fixing motor 135 .

The paper feed transport control unit 211 controls a paper feed motor 212 that rotates the pickup roller 112 and the feed roller 113 and a transport motor 213 that rotates the transport rollers 115 and 118 .

The control device 200 also controls the toner supply motor 26 that drives the conveying spiral 25 in order to supply toner from the toner cartridge 20 to each process unit 10 .

The controller 200 also controls a switching motor 48 that switches connection and disconnection of driving force transmission to the process units 10C, 10M, and 10Y, and a blower fan 56 that blows cooling air through the blower duct 50 .

<Operation of Image Forming Apparatus>
Next, a printing operation (image forming operation) by the image forming apparatus 1 will be described with reference to FIGS. 2 and 18. FIG. When the control device 200 of the image forming apparatus 1 receives a print command and print data from the host device via the I/F control unit 221, the print operation is started.

During color printing, the printing operation is performed with both the first slider 60 and the second slider 70 positioned at the reference positions (FIGS. 12 and 13). Therefore, the developing roller couplings 41K, 41C, 41M and 41Y and the photosensitive drum cups are installed in all the developing roller coupling portions 33 and the photosensitive drum coupling portions 34 (FIG. 6) of the process units 10K, 10C, 10M and 10Y. Rings 42K, 42C, 42M and 42Y (Fig. 9) are engaged. As a result, the driving force is transmitted to all the developing rollers 14 and photosensitive drums 11 of the process units 10K, 10C, 10M and 10Y. In other words, the process units 10K, 10C, 10M, and 10Y are all in the image forming state.

Further, since both the first slider 60 and the second slider 70 are at the reference position, all the blower ports 53 (FIG. 10) of the blower duct 50 are open. Therefore, the cooling air sent from the blower fan 56 via the blower duct 50 is sent from the four blower ports 53 to all of the process units 10K, 10C, 10M, and 10Y.

At the start of printing, the control device 200 starts supplying the medium P by the medium supply unit 110 . Specifically, the paper feed transport control unit 211 drives the paper feed motor 212 to rotate the pickup roller 112 and the feed roller 113 . The pickup roller 112 feeds the medium P accommodated in the paper feed tray 111, and the feed roller 113 feeds the fed medium P to the transport path. Further, the transport rollers 115 and 118 are rotated by the transport motor 213 to transport the medium P sent to the transport path to the image forming section 100 .

Further, the control device 200 drives the belt motor 125 by the belt drive control section 208 to rotate the drive roller 123 and cause the transfer belt 122 to run. The transfer belt 122 attracts and holds the medium P and conveys it. The medium P passes through the process units 10K, 10C, 10M and 10Y in this order.

Then, the control device 200 applies a charging voltage, a developing voltage, and a supply voltage to the charging roller 12, the developing roller 14, and the supply roller 15 of each process unit 10 by the power supply control section 201, respectively.

The control device 200 also causes the drive control section 207 to rotate the drive motors 17 corresponding to the respective process units 10 to rotate the developing rollers 14 and the photosensitive drums 11 . Along with these rotations, the charging roller 12 and the supply roller 15 also rotate. The charging roller 12 uniformly charges the surface of the photosensitive drum 11 .

The control device 200 further controls light emission of the print head 13 by the head control unit 206 based on the image data of each color. The print head 13 exposes the surface of the photosensitive drum 11 to form an electrostatic latent image.

In each process unit 10 , the supply roller 15 supplies toner to the developing roller 14 , and the developing blade 16 forms a toner layer on the surface of the developing roller 14 . The electrostatic latent image formed on the surface of the photosensitive drum 11 is developed with the toner on the surface of the developing roller 14 to form a toner image. The toner image formed on the surface of the photosensitive drum 11 is transferred onto the medium P on the transfer belt 122 by a transfer voltage applied from the power control unit 201 to the transfer roller 121 .

In this manner, the toner images of each color formed by each of the process units 10K, 10C, 10M, and 10Y are sequentially transferred onto the medium P and superimposed. The medium P onto which the toner image of each color has been transferred is further conveyed by the transfer belt 122 and reaches the fixing device 130 .

In the fixing device 130 , a fixing roller 131 is heated to a fixing temperature by a heater 133 and rotated by a fixing motor 135 . The medium P transported to the fixing device 130 is heated and pressed between the fixing roller 131 and the pressure roller 132, and the toner image is fixed on the medium P. FIG.

The medium P on which the toner image is fixed is conveyed along the discharge conveying path by the discharge rollers 141 and 142 of the medium discharge section 140 and discharged to the outside of the image forming apparatus 1 . The ejected medium P is stacked on the stacker section 143 . Thus, the printing operation on the medium P is completed.

On the other hand, during monochrome printing, the control device 200 drives the switching motor 48 to move the second slider 70 to the blocking position shown in FIG. 14(C). Therefore, the developing roller couplings 41C, 41M, 41Y and the photosensitive drum couplings 42C, 42M, 42Y are engaged with the developing roller coupling portions 33 and the photosensitive drum coupling portions 34 of the process units 10C, 10M, 10Y. do not.

Therefore, the driving force is transmitted to the developing roller 14 and the photosensitive drum 11 of the process unit 10K, and the driving force is not transmitted to the developing roller 14 and the photosensitive drum 11 of the process units 10C, 10M and 10Y. In other words, the process unit 10K is in the image forming state, while the process units 10C, 10M and 10Y are in the non-image forming state.

Also, since the first slider 60 and the second slider 70 are at the positions shown in FIG. 14(C), the blower port 53 corresponding to the process unit 10K is opened as shown in FIG. 53 is closed by the second slider 70 . Therefore, the cooling air from the air duct 50 is intensively blown to the process unit 10K.

In this state, the control device 200 applies the charging voltage, the developing voltage, and the supply voltage to the charging roller 12, the developing roller 14, and the supply roller 15 of the process unit 10K by the power supply control section 201, respectively.

The control device 200 also causes the drive control unit 207 to rotate the drive motor 17 of the process unit 10K to rotate the developing roller 14 and the photosensitive drum 11 . Along with these rotations, the charging roller 12 and the supply roller 15 also rotate. The charging roller 12 uniformly charges the surface of the photosensitive drum 11 .

Further, the control device 200 causes the head controller 206 to control light emission of the print head 13 corresponding to the process unit 10K based on the black image data. The print head 13 exposes the surface of the photosensitive drum 11 to form an electrostatic latent image.

The electrostatic latent image formed on the surface of the photosensitive drum 11 is developed with the toner on the surface of the developing roller 14 to form a toner image. Then, the image is transferred onto the medium P on the transfer belt 122 by a transfer voltage applied from the power control unit 201 to the transfer roller 121 .

A black toner image is transferred to the medium P in this manner. Thereafter, fixing of the toner image and ejection of the medium P are performed in the same manner as in color printing.

<Action>
Next, the operation of this embodiment will be described. In the process unit 10, the photosensitive drum 11, the charging roller 12, the developing roller 14, and the supply roller 15 rotate while being in contact with each other, thereby generating heat. In particular, the developing blade 16 is pressed against the surface of the developing roller 14, and heat is generated by friction. If the surface temperature of the photoreceptor drum 11 rises due to this heat, it leads to deterioration of image quality.

By blowing air into each process unit 10 from the blower fan 56 through the blower port 53, the inside of the process unit 10 can be cooled. As a result, an increase in the surface temperature of the photoreceptor drum 11 can be suppressed, and image quality can be improved.

The image forming apparatus 1 generally performs monochrome printing more frequently than color printing. For this reason, some models have a black toner cartridge with a larger capacity than other toner cartridges, or have a faster printing speed during monochrome printing than during color printing.

Therefore, the temperature of the black process unit 10K rises more easily than the other process units 10C, 10M, and 10Y, and the improvement of the cooling efficiency of the black process unit 10K is a problem.

In the image forming apparatus 1 of the first embodiment, during monochrome printing, the blower port 53 corresponding to the process unit 10K is opened, and the blower ports 53 corresponding to the process units 10C, 10M, and 10Y are closed. Therefore, the cooling air sent by the blower fan 56 is intensively blown to the process unit 10K, improving the cooling efficiency of the process unit 10K.

In addition, since the cooling efficiency of the process unit 10K is improved, there is no need to lower the printing speed for the purpose of suppressing the temperature rise, so the time required for printing can be shortened.

Further, during monochrome printing, the driving force for rotating the developing roller 14 and the photosensitive drum 11 is not transmitted to the process units 10C, 10M and 10Y. Therefore, no heat is generated in the process units 10C, 10M, and 10Y, and the temperature does not rise due to no cooling air blowing.

In addition, since the blower port 53 is opened and closed mechanically in conjunction with the switching of the driving force transmission to the process units 10C, 10M, and 10Y (that is, by the movement of the second slider 70), it is possible to perform monochrome printing with a simple configuration. It is possible to implement the operation of intensively blowing the cooling air to the black process unit 10K.

In particular, since the blower port 53 is opened and closed by the second slider 70 that switches the driving force transmission to the process units 10C, 10M, and 10Y, there is no need to provide an independent mechanism or an independent shutter for opening and closing the blower port 53. The configuration of the image forming apparatus 1 can be simplified, and the manufacturing cost can be reduced.

When the user opens the front cover 103, the first slider 60 and the second slider 70 move to the blocking position shown in FIG. 14B as described above. The air blowing port 53 corresponding to each of the process units 10C, 10M, and 10Y is closed by the second slider 70 . Therefore, foreign matter is prevented from entering the fan duct 50 .

<Effect of Embodiment>
As described above, the image forming apparatus 1 according to the first embodiment includes the blower duct 50 (air blower) for blowing air toward the process units 10C, 10M, and 10Y, and the drive unit for the process units 10C, 10M, and 10Y. The second slider 70 changes the amount of air blown from the air duct 50 in mechanical interlock with switching of force transmission (that is, switching between the image forming state and the non-image forming state of the process units 10C, 10M, and 10Y). air volume changer).

Therefore, in the operation mode (monochrome printing) in which the process units 10C, 10M, and 10Y are not used, air is blown intensively to the process unit 10K, and the process unit 10K can be efficiently cooled.

In particular, the blower port 53 is open when driving force transmission to the process units 10C, 10M, and 10Y is connected, and is closed when the driving force transmission is interrupted. Therefore, air can be blown only when heat is generated in the process units 10C, 10M, and 10Y, and the cooling efficiency can be improved.

In addition, since the second slider 70 (movable portion) that switches the transmission of driving force to the process units 10C, 10M, and 10Y opens and closes the blower port 53, an independent mechanism or an independent shutter for opening and closing the blower port 53 is provided. Therefore, the configuration of the image forming apparatus 1 can be simplified, and the manufacturing cost can be reduced.

Each of the process units 10C, 10M, and 10Y has a developing roller coupling portion 33 and a photoreceptor drum coupling portion 34, and couplings 41 and 42 are engaged with these coupling portions 33 and 34, whereby the process unit 10C is , 10M and 10Y. The second slider 70 moves the couplings 41 and 42 toward and away from the joints 33 and 34, and opens and closes the blower port 53 at that time. Therefore, it is possible to open and close the blower port 53 with a simpler configuration.

Also, by efficiently blowing air to the black process unit 10K, which is frequently used, the temperature rise of the process unit 10K can be suppressed, and the image quality can be improved.

Second embodiment.
Next, a second embodiment of the invention will be described. In the above-described first embodiment, the second slider 70 opens and closes the blower ports 53 corresponding to the process units 10C, 10M, and 10Y. On the other hand, in the second embodiment, the opening/closing door 90 opens and closes the blower port 53 .

A configuration for switching driving force transmission to the process units 10K, 10C, 10M, and 10Y is substantially the same as the configuration described in the first embodiment. However, the opening 71 (FIG. 12) of the second slider 70 is longer than that of the first embodiment, so that the air outlet 53 is not closed even when the second slider 70 is in the position shown in FIG. It is configured.

FIG. 19 is a view of the fan duct 50, the opening/closing door 90, and the developing roller coupling 41 as viewed from the process unit 10 side. FIG. 20 is a view of the air duct 50 and the opening/closing door 90 viewed from the process unit 10 side.

The opening/closing door 90 shown in FIGS. 19 and 20 is provided for all of the air blowing ports 53 corresponding to the process units 10K, 10C, 10M, and 10Y, and operates in conjunction with the developing roller coupling 41 . 19 and 20 and FIGS. 21 to 29 described later, for the sake of simplicity, the extending direction of the fan duct 50 (the unit arrangement direction described in the first embodiment) will be described as the Y direction.

The opening/closing door 90 is arranged in the +X direction (that is, the side opposite to the process unit 10) with respect to the developing roller coupling 41. As shown in FIG. 19 and 20, the developing roller coupling 41 is in the engaged position where it engages the developing roller coupling portion 33 (FIG. 6). The configuration of the developing roller coupling 41 is as described in the first embodiment.

As shown in FIG. 20 , an opening/closing door 90 for opening and closing the air blowing port 53 is provided at the air blowing port 53 at the tip of the branch duct 52 . The opening/closing door 90 has a rotation shaft 91 whose axial direction is the Z direction. The rotating shaft 91 is arranged in the −Y direction with respect to the air blowing port 53 and supported by a supporting portion provided in the branch duct 52 .

FIG. 21 is a diagram of the opening/closing door 90 viewed from the process unit 10 side. 22A and 22B are perspective views showing the opening/closing door 90. FIG. FIG. 23 is a top view showing the opening/closing door 90. FIG. The opening/closing door 90 includes a rotating shaft 91 , a first wall portion 92 extending radially outwardly from the rotating shaft 91 , and positioned at approximately 90 degrees with respect to the first wall portion 92 with respect to the rotating shaft 91 . and a second wall portion 95 formed in the .

The first wall portion 92 is a wall portion that closes the blower port 53 . An inclined portion 93 inclined with respect to the Z direction (that is, the axial direction of the rotation shaft 91) is formed on the surface of the first wall portion 92. As shown in FIG. The inclined portion 93 closes the opening 52 c ( FIG. 26 ) of the inclined wall 54 of the branch duct 52 while the first wall portion 92 opens the blower port 53 . The inclined portion 93 directs the cooling air flowing in the branch duct 52 in the −Z direction (indicated by the arrow W in FIG. 19) toward the +X direction, that is, toward the process unit 10 side.

The second wall portion 95 of the opening/closing door 90 closes the −Y direction end portion 52b of the branch duct 52 in a state where the first wall portion 92 closes the air blowing port 53 (FIG. 29). An inclined portion 94 inclined with respect to the Z direction is formed between the first wall portion 92 and the second wall portion 95 . The inclined portion 94 closes the opening 52 c ( FIG. 29 ) of the inclined wall 54 of the branch duct 52 while the first wall portion 92 closes the air outlet 53 .

FIG. 24 is a bottom view showing the air duct 50, the opening/closing door 90, and the developing roller coupling 41. FIG. FIG. 25 is a view of the fan duct 50, the opening/closing door 90, and the couplings 41 and 42 viewed from the +Y side. FIG. 26 is a perspective view showing air duct 50 and opening/closing door 90. As shown in FIG.

24 to 26, the shaft 413 (FIG. 8) of the developing roller coupling 41 and the shaft 423 (FIG. 8) of the photosensitive drum coupling 42 are omitted. The developing roller coupling 41 is in an engagement position where it engages with the developing roller coupling portion 33 (FIG. 6).

As shown in FIG. 24 , an arm portion 95 a that abuts on the developing roller coupling 41 is formed at the tip of the second wall portion 95 of the opening/closing door 90 . A torsion spring 98 is provided as a biasing member to bias the opening/closing door 90 . The center of the torsion spring 98 is wound around the rotating shaft 91 .

One end of the torsion spring 98 abuts on a projection 58 (FIG. 19) protruding from the lower surface of the branch duct 52, and the other end abuts on the lower end of the second wall portion 95 of the open/close door 90. It abuts on pin 96 . The open/close door 90 is urged by a torsion spring 98 so that the arm portion 95 a contacts the +X side end face of the developing roller coupling 41 .

The branch duct 52 of the fan duct 50 has a wall portion 52a (FIG. 26) at the end in the +Y direction and a fan port 53 at the end in the -X direction. As shown in FIG. 26, the above-described opening 52c is formed in the inclined wall 54 of the branch duct 52 in order to allow the opening/closing door 90 to rotate. The opening 52c is closed by the inclined portion 93 of the opening/closing door 90 described above.

As shown in FIGS. 19 to 20 and FIGS. 24 to 26, when the developing roller coupling 41 is at the engaging position, the developing roller coupling 41 does not bias the arm portion 95a of the opening/closing door 90. . In this state, the first wall portion 92 of the opening/closing door 90 does not block the blower port 53 . That is, the blower port 53 is open.

Therefore, the cooling air sent from the blower fan 56 ( FIG. 10 ) through the blower duct 50 passes through the branch duct 52 and is blown from the blower port 53 to the process unit 10 .

27 and 28 are diagrams showing a state in which the developing roller coupling 41 is separated from the developing roller coupling portion 33 (FIG. 6) in the +X direction. 27 is a view of the fan duct 50, the opening/closing door 90, and the developing roller coupling 41 as viewed from the process unit 10 side, and FIG. 28 shows the fan duct 50, the opening/closing door 90, and the developing roller coupling 41. FIG. It is a bottom view.

When the developing roller coupling 41 separates from the developing roller coupling portion 33 ( FIG. 6 ) in the +X direction, the developing roller coupling 41 abuts against the arm portion 95 a of the open/close door 90 , and the open/close door 90 moves toward the rotation shaft 91 . rotates around the center. As a result, the first wall portion 92 of the opening/closing door 90 closes the blower port 53 .

Therefore, the cooling air sent from the blower fan 56 ( FIG. 10 ) through the blower duct 50 is not blown from the blower port 53 to the process unit 10 .

The −Y direction end 52b (FIG. 28) of the branch duct 52 is blocked by the second wall 95 of the opening/closing door 90, and the opening 52c of the inclined wall 54 is closed by the inclined portion 94 of the opening/closing door 90. blocked. Therefore, the cooling air from the air duct 50 is prevented from flowing out to the surroundings.

During color printing, the couplings 41 and 42 are engaged with all the developing roller coupling portions 33 and photosensitive drum coupling portions 34 (FIG. 6) of the process units 10K, 10C, 10M and 10Y, as in the first embodiment. do. Therefore, the blower ports 53 corresponding to the process units 10K, 10C, 10M, and 10Y are all opened by the opening/closing door 90, and cooling air is blown to all of the process units 10K, 10C, 10M, and 10Y.

On the other hand, during monochrome printing, as in the first embodiment, the couplings 41 and 42 are engaged with the developing roller coupling portion 33 and the photosensitive drum coupling portion 34 (FIG. 6) of the process unit 10K, and the process unit 10C. , 10M and 10Y, the couplings 41 and 42 are not engaged with the developing roller coupling portion 33 and the photosensitive drum coupling portion 34 (FIG. 6).

Therefore, the blower port 53 corresponding to the process unit 10K is opened by the openable door 90, and the blower port 53 corresponding to each of the process units 10C, 10M, and 10Y is closed by the openable door 90. FIG. Therefore, the cooling air is intensively blown to the process unit 10K.

As described above, in the second embodiment, the opening/closing door 90 opens and closes the air blowing port 53 in conjunction with the developing roller coupling 41. Therefore, as in the first embodiment, the process unit 10K is operated during monochrome printing. Cooling air can be blown intensively. Thereby, the process unit 10K can be efficiently cooled and the image quality can be improved.

Further, since the opening/closing door 90 opens and closes the air blowing port 53 by contacting the developing roller coupling 41, there is no need to provide an independent mechanism for opening and closing the air blowing port 53, and the configuration of the image forming apparatus 1 can be reduced. simplification and manufacturing costs can be reduced.

Here, the opening/closing door 90 abuts on the developing roller coupling 41 to open and close the blower port 53 . 53 may be opened and closed.

Third embodiment.
In each of the above-described embodiments, a configuration has been described in which the blower port 53 is opened and closed mechanically in conjunction with switching of driving force transmission to the process units 10C, 10M, and 10Y. However, other configurations may be adopted as long as the airflow rate is changed in mechanical interlock with switching between the image forming state and the non-image forming state of the process units 10C, 10M, and 10Y.

In the third embodiment, the blower port 53 is mechanically interlocked with a lift-up mechanism (spacing mechanism) 300 that moves the process units 10C, 10M, and 10Y toward and away from the transfer unit 120. Open and close. The lift-up mechanism 300 is also called a switching section (or state changing section).

30A and 30B are schematic diagrams for explaining the lift-up mechanism 300. FIG. As shown in FIG. 30A, the image forming section 100 has process units 10K, 10C, 10M and 10Y. During color printing, each photoreceptor drum 11 of the process units 10K, 10C, 10M, and 10Y is in contact with the transfer belt 122 of the transfer unit 120. FIG.

The state in which the photosensitive drums 11 of the process units 10C, 10M, and 10Y are in contact with the transfer belt 122 of the transfer unit 120 is referred to as an image forming state (first state) of the process units 10C, 10M, and 10Y. .

On the other hand, during monochrome printing, as shown in FIG.

The state in which the photosensitive drums 11 of the process units 10C, 10M, and 10Y are separated from the transfer belt 122 of the transfer unit 120 in this way is defined as the non-image forming state (second state) of the process units 10C, 10M, and 10Y.

In the third embodiment, the opening and closing of the air blowing port 53 is performed in conjunction with switching between the image forming state and the non-image forming state of the process units 10C, 10M, and 10Y by the lift-up mechanism 300. FIG.

FIG. 31 is a perspective view showing the lift-up mechanism 300 and its surroundings. The lift-up mechanism 300 has a lift-up slider 301 as a movable body movable in the unit arrangement direction (substantially Y direction) described in the first embodiment. The lift-up slider 301 is arranged on the -X side (process unit 10 side) of the cover member 80 described with reference to FIG.

The lift-up slider 301 includes a side plate portion 302 arranged in contact with the cover member 80, and three elevating portions 310 provided on the -X side of the side plate portion 302 for elevating the process units 10C, 10M, and 10Y. and

Each elevator 310 has a bottom portion 311 , an inclined portion 312 and a top portion 313 . The top portion 313 protrudes in the +Z direction with respect to the bottom portion 311 , and the inclined portion 312 extends so as to connect the bottom portion 311 and the top portion 313 . The bottom portion 311, the inclined portion 312, and the top portion 313 are arranged in a line in this order in the +Y direction.

Each lifting part 310 abuts on the abutting surface 38 provided on the lower surface of the side frame 31 (FIG. 6) of the process units 10C, 10M, and 10Y. The contact surface 38 is, for example, an arc-shaped curved surface, but is not limited to this.

When the lift-up slider 301 is at the reference position (first position) shown in FIG. 31, the contact surfaces 38 of the process units 10C, 10M and 10Y face the bottom 311. As shown in FIG. In this state, the process units 10C, 10M, and 10Y are at positions (that is, transfer positions) where the respective photosensitive drums 11 are in contact with the transfer belt 122 as shown in FIG. 30(A).

On the other hand, when the lift-up slider 301 moves in the -Y direction and reaches a lift-up position (second position: FIG. 36), which will be described later, the contact surfaces 38 of the process units 10C, 10M, and 10Y reach the top portion 313. It abuts and is pushed up in the +Z direction. As a result, as shown in FIG. 30B, the process units 10C, 10M, and 10Y reach positions where the respective photoreceptor drums 11 are separated from the transfer belt 122 in the +Z direction (that is, separated positions).

The side plate portion 302 of the lift-up slider 301 has three openings 304 through which the photosensitive drum couplings 42C, 42M, and 42Y corresponding to the process units 10C, 10M, and 10Y pass. The opening 304 is an elongated hole elongated in the unit arrangement direction (approximately the Y direction).

A closing portion (lid portion) 303 is formed on the upper side (+Z side) of the side plate portion 302 of the lift-up slider 301 to close the three air blowing ports 53 corresponding to the process units 10C, 10M, and 10Y.

When the lift-up slider 301 is at the reference position (FIG. 31), none of the three closing portions 303 are positioned to overlap the blower port 53, and the blower port 53 is open. On the other hand, when the lift-up slider 301 moves in the -Y direction and reaches the lift-up position (FIG. 36), the three closing portions 303 close the blower ports 53 respectively.

FIG. 32 is a diagram showing the lift-up slider 301 and its surroundings with the support plate 160, which will be described later, removed. The lift-up slider 301 has a rack gear 305 as a drive transmission section on the lower surface (surface in the -Z direction) of the lifting section 301 .

A pinion 306 is provided at a position where it meshes with the rack gear portion 305 . The pinion 306 is connected to an elevation motor 320, which is a drive source, via a gear train 307 (including a reduction gear, an idle gear, etc.). The driving force of the lifting motor 320 is transmitted to the rack gear 305 via the gear train 307 and the pinion 306, and the lift-up slider 301 moves straight in the unit arrangement direction (approximately Y direction).

Returning to FIG. 31, a support plate 160 parallel to the cover member 80 is arranged on the −X side (process unit 10 side) of the lift-up slider 301 . Lift-up slider 301 is held between cover member 80 and support plate 160 .

The support plate 160 has four grooves 161 that engage with the positioning portions 36 ( FIG. 6 ) provided on the side frame 31 of each process unit 10 . The groove portion 161 extends substantially in the Z direction and has an open top end (an end portion in the +Z direction).

The cover member 80 has four grooves 85 that engage with the positioning portions 37 ( FIG. 6 ) provided on the side frame 31 of each process unit 10 . The groove portion 85 extends substantially in the Z direction and has an open top end (an end portion in the +Z direction).

33 is a perspective view showing the side frame 31. FIG. FIG. 34 is a cross-sectional view taken along line 34-34 shown in FIG. FIG. 35 is a cross-sectional view taken along line 35-35 shown in FIG.

As shown in FIG. 33, a positioning portion 36 is attached to the lower end (the end in the −Z direction) of the side frame 31 . The positioning portion 36 has a small-diameter shaft portion 36a inside the side frame 31 in the X direction. The shaft portion 36a of the positioning portion 36 engages with the groove portion 161 of the support plate 160, as shown in FIGS.

A positioning portion 37 is attached to the upper end of the side frame 31 (the end in the +Z direction). The positioning portion 37 is a substantially cylindrical portion that protrudes from the side frame 31 in the +X direction. The positioning portion 37 engages with the groove portion 85 of the cover member 80 as shown in FIGS. 34 and 35 .

By engaging the positioning portions 36 and 37 of the side frame 31 with the groove portion 161 of the support plate 160 and the groove portion 85 of the cover member 80 respectively, the postures of the process units 10C, 10M and 10Y are maintained during the lift-up operation. .

Note that, as shown in FIG. 31, the support plate 160 has recesses 162 higher in height (that is, positions in the Z direction) than the bottoms 311 at positions respectively corresponding to the three bottoms 311 of the lift-up slider 301 at the reference position. have When the contact surfaces 38 (FIG. 33) of the process units 10C, 10M, and 10Y face the bottom portion 311 of the lift-up slider 301, the contact surfaces 38 are held in contact with the recess 162 of the support plate 160. be.

FIG. 36 is a perspective view showing a state in which the lift-up slider 301 has moved in the -Y direction from the reference position (FIG. 31) and reached the lift-up position. In FIG. 36, the top portion 313 of the lift-up slider 301 contacts the contact surfaces 38 (FIG. 6) of the process units 10C, 10M, and 10Y to bias them in the +Z direction.

As a result, the process units 10C, 10M and 10Y are lifted in the +Z direction, and the photosensitive drums 11 of the process units 10C, 10M and 10Y are separated from the transfer belt 122 as shown in FIG. 30(B).

Also, when the lift-up slider 301 moves in the -Y direction, the closing portion 303 of the lift-up slider 301 closes the blower ports 53 corresponding to the process units 10C, 10M, and 10Y. Since the blower port 53 corresponding to the process unit 10K is open, the air flowing through the blower duct 50 is intensively blown to the process unit 10K.

The configuration for switching the driving force transmission to the process units 10K, 10C, 10M, and 10Y is substantially the same as the configuration described in the first embodiment. Since the first slider 60 and the second slider 70 (FIG. 12) are arranged in the +X direction of the cover member 80 in the same way as in the first embodiment, the cover member 80 in FIGS. hidden.

Further, as described in the second embodiment, the opening 71 (FIG. 12) of the second slider 70 is longer than that in the first embodiment, and the second slider 70 extends in the unit arrangement direction (approximately the Y direction). ) so that the second slider 70 does not close the blower port 53 .

FIG. 37 is a block diagram showing the control system of the image forming apparatus according to the third embodiment. As shown in FIG. 37, in the control system of the image forming apparatus according to the third embodiment, the control system (FIG. 18) of the image forming apparatus 1 according to the first embodiment includes a lift-up slider 301 (lift-up mechanism 300) is added with an elevating motor (spacing mechanism motor) 320 for driving.

When performing monochrome printing, the control device 200 drives the switching motor 48 to cut off the transmission of driving force to the process units 10C, 10M, and 10Y, and then drives the lift motor 320 to turn on the process units 10C and 10M. , 10Y from the transfer position to the separation position. Other configurations of the third embodiment are as described in the first embodiment.

The operation of the image forming apparatus according to the third embodiment is as follows. During color printing, the lift-up slider 301 is at the reference position (FIG. 31). When the lift-up slider 301 is at the reference position, the bottom portion 311 of the lift-up slider 301 faces the contact surfaces 38 (FIG. 6) of the process units 10C, 10M and 10Y.

Therefore, the process units 10K, 10C, 10M, and 10Y are positioned at the transfer position (that is, the position where the photosensitive drum 11 contacts the transfer belt 122). In other words, all of the process units 10K, 10C, 10M, and 10Y are in the image forming state.

Also, at this time, the three closing portions 303 of the lift-up slider 301 are not positioned to close the blower port 53 . Therefore, cooling air is blown to the process units 10K, 10C, 10M, and 10Y from the four air blowing ports 53 of the air blowing duct 50 .

Both the first slider 60 and the second slider 70 are at the positions shown in FIG. 12, and all the developing rollers 14 and the photosensitive drums of the process units 10K, 10C, 10M and 10Y are positioned as described in the first embodiment. A driving force is transmitted to the body drum 11 . In this state, the medium P is supplied from the medium supply unit 110 (FIG. 2), and a color image is formed as described in the first embodiment.

On the other hand, during monochrome printing, the control device 200 drives the switching motor 48 to move the second slider 70 to the blocking position shown in FIG. 14(C). As a result, the developing roller couplings 41C, 41M, 41Y and the photosensitive drum couplings 42C, 42M, 42C, 42M, 42C, 42M, 42C, 42M, 42C, 42M, 42C, 42M, 42C, 42M, 42C, 42M, 41Y from the developing roller coupling portions 33 and the photosensitive drum coupling portions 34 (FIG. 6) of the process units 10C, 10M, 10Y. 42Y is separated.

Next, the controller 200 drives the lift motor 320 to move the lift-up slider 301 from the reference position (FIG. 31) to the lift-up position (FIG. 36). As a result, the top portion 313 of the lift-up slider 301 comes into contact with the contact surface 38 (FIG. 6) of the process units 10C, 10M and 10Y, lifting the process units 10C, 10M and 10Y in the +Z direction.

Therefore, the process units 10C, 10M, and 10Y are positioned at the separated position (that is, the position where the photosensitive drum 11 is separated from the transfer belt 122), and only the process unit 10K is positioned at the transfer position. In other words, the process units 10C, 10M, and 10Y are switched from the image forming state to the non-image forming state.

Also, at this time, the three closing portions 303 of the lift-up slider 301 close the blower port 53 as shown in FIG. Therefore, the blower ports 53 corresponding to the process units 10C, 10M, and 10Y are closed, and only the blower port 53 corresponding to the process unit 10K is opened. Therefore, the cooling air from the air duct 50 is intensively blown to the process unit 10K. In this state, the medium P is supplied from the medium supply unit 110 (FIG. 2), and a monochrome image is formed as described in the first embodiment.

As described above, in the third embodiment, the air blowing ports 53 of the process units 10C, 10M, and 10Y are opened and closed in conjunction with the elevation of the process units 10C, 10M, and 10Y by the lift-up mechanism 300. FIG. Therefore, when the process units 10C, 10M, and 10Y are not used (during monochrome printing), these air blowing ports 53 can be closed to intensively blow cooling air to the process unit 10K. Thereby, the process unit 10K can be efficiently cooled and the image quality can be improved.

In addition, since the air blowing ports 53 of the process units 10C, 10M, and 10Y are opened and closed by the movement of the lift-up slider 301, these air blowing ports 53 can be opened and closed according to the state changes of the process units 10C, 10M, and 10Y with a simple configuration. can be opened and closed.

In addition, since the lift-up slider 301 has the closing portion 303 for opening and closing the blower ports 53 of the process units 10C, 10M, and 10Y, there is no need to provide independent shutters, and the number of parts can be reduced.

In addition, by moving the process units 10C, 10M, and 10Y to the separated positions by the lift-up mechanism 300 during monochrome printing, unnecessary sliding of parts such as the photosensitive drums 11 and the transfer belt 122 is eliminated, and friction between them is suppressed. can do.

Modification.
Next, a modification of the third embodiment will be described. FIG. 38 is a perspective view showing lift-up slider 301 and its surroundings in a modification of the third embodiment. The lift-up slider 301 of the modified example has holes 308 through which cooling air passes in three closing parts 303 corresponding to the air blowing ports 53 of the process units 10C, 10M, and 10Y.

The hole portion 308 is a portion through which the cooling air passes when the closing portion 303 closes the air blowing port 53 . Although the shape of the hole 308 is circular in FIG. 38, other shapes are possible.

In the modified image forming apparatus, during monochrome printing, the lift-up slider 301 moves in the -Y direction from the reference position shown in FIG. 38 and reaches the lift-up position shown in FIG. As a result, each closing portion 303 of the lift-up slider 301 substantially closes each of the air blowing ports 53 of the process units 10C, 10M, and 10Y.

However, since the closing portion 303 has the hole portion 308, the air blowing ports 53 of the process units 10C, 10M, and 10Y are not completely closed. In other words, each blower port 53 of the process units 10C, 10M, and 10Y is partially closed. That is, during monochrome printing, a small amount of cooling air is blown to the process units 10C, 10M, and 10Y through the air blowing port 53 and the hole 308. FIG.

During monochrome printing, the amount of air blown to the process units 10C, 10M, and 10Y is smaller than during color printing. Therefore, while the cooling air is intensively blown to the process unit 10K, a small amount of cooling air is also blown to the process units 10C, 10M, and 10Y.

During monochrome printing, the photosensitive drums 11 and developing rollers 14 of the process units 10C, 10M, and 10Y do not rotate, but the heat generated during color printing may remain. By blowing a small amount of cooling air to the process units 10C, 10M, and 10Y, the cooling effect can be enhanced.

The configuration of the image forming apparatus of the modified example is the same as that of the image forming apparatus of the third embodiment except that the closed portion 303 of the lift-up slider 301 is formed with the hole portion 308 .

Also, the operation of the image forming apparatus of the modified example is the same as that of the image forming apparatus of the third embodiment, except that a small amount of cooling air is blown to the process units 10C, 10M, and 10Y during monochrome printing.

As described above, according to this modification, by reducing the amount of air blown to the process units 10C, 10M, and 10Y during monochrome printing, the process unit 10K can be efficiently cooled, and the process units 10C, 10M, and 10Y can be cooled efficiently. can also be cooled by a small amount of cooling air.

Although the hole 308 is provided in the closing portion 303 of the lift-up slider 301 here, any structure may be used as long as the amount of air blown to the process units 10C, 10M, and 10Y is reduced during monochrome printing. For example, the closing portion 303 of the lift-up slider 301 may be configured to partially (for example, half) close the blower port 53 during monochrome printing.

Also, the configuration for reducing the amount of air blown to the process units 10C, 10M, and 10Y during monochrome printing may be applied to the image forming apparatuses of the first and second embodiments described above. In this case, for example, the second slider 70 shown in FIG. 12 may be provided with a hole similar to the hole 308 of the modified example. Further, a hole portion similar to the hole portion 308 of the modified example may be provided in the first wall portion 92 of the opening/closing door 90 shown in FIG. 22(A).

In the above-described first to third embodiments, the configuration of opening and closing the blowing port 53 of the blowing duct 50 (or changing the opening area) is adopted. Any configuration may be used as long as it changes the amount of cooling air blown to the process units 10C, 10M, and 10Y.

Further, in the first to third embodiments described above, the blower port 53, which is a part of the blower duct 50, is opened and closed, but the blower port provided separately from the blower duct 50 may be opened and closed. For example, the opening 83 of the cover member 80 (FIG. 15) through which the cooling air passes may be opened and closed. That is, it is sufficient to open and close an air blowing port provided in a blowing passage for sending cooling air toward the process unit 10 .

Although the embodiments and modifications of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications and alterations are possible.

INDUSTRIAL APPLICABILITY The present invention can be used in image forming apparatuses (for example, copiers, facsimiles, printers, multi-function machines, etc.) that form images on media using electrophotography.

1 image forming apparatus 2 toner supply unit 6 driving force transmission unit 10, 10K, 10C, 10M, 10Y process unit 11 photoreceptor drum (image carrier) 12 charging roller (charging member) 13, 13K, 13C, 13M, 13Y print head (exposure device) 14 development roller (developer carrier) 15 supply roller (supply member) 16 development blade (developer regulation member) 18 transmission mechanism 20, 20K, 20C, 20M, 20Y toner cartridge (developer container) 22, 22K, 22C, 22M, 22Y toner duct 30 unit frame 30a toner receiving port 31 side frame 31a, 31b opening 32 side frame 33 developing roller coupling portion 34 photosensitive drum coupling portion 35 opening 36 positioning portion 37 positioning portion 38 contact surface 41, 41K, 41C, 41M, 41Y developing roller coupling 42, 42K, 42C, 42M, 42Y Coupling for photoreceptor drum 48 Switching motor 50 Air duct (air blower) 51 Main duct (air duct) 52 Branch duct 53 Air outlet 54 Inclined wall 55 Side plate 56 Air fan 58 Convex Section 60 First Slider 61, 62 Opening 63 Biasing Member 70 Second Slider (Movable Part) 71, 72 Opening 73 Biasing Member 80 Cover Member 81, 82 Hole 83 Opening Part 90 Open/close door 91 Rotating shaft 92 First wall 93, 94 Inclined part 95 Second wall 95a Arm 98 Torsion spring (biasing member) 100 Image forming part 101 Housing , 102 top cover, 103 front cover, 105 housing side portion, 106 inner cover, 107 basket frame, 108 swing lever, 110 medium supply section, 120 transfer unit, 122 transfer belt (transfer body), 130 fixing device, 140 medium Discharge part 160 Support plate 161 Groove part 162 Retreat part 200 Control device 300 Lift-up mechanism 301 Lift-up slider (moving body) 302 Side plate part 303 Closing part 308 Hole part 310 Lifting part 320 Lifting motor, 411, 421 engagement shaft, 412, 422 gear, 423 shaft.

Claims (14)

an image forming unit that forms an image;
a blower that blows air toward the image forming unit;
a switching unit for switching between an image forming state and a non-image forming state of the image forming unit;
A blowing amount change that mechanically changes a blowing amount of air blown from the blowing section toward the image forming unit in conjunction with switching between an image forming state and a non-image forming state of the image forming unit by the switching section. Department and
has
The switching unit is
A cup that brings the image forming unit into an image forming state by connecting driving force transmission to the image forming unit and brings the image forming unit into a non-image forming state by interrupting driving force transmission to the image forming unit. having a ring mechanism,
the coupling mechanism has a movable portion movable between a first position and a second position;
The movable portion connects driving force transmission to the image forming unit by moving to the first position, and cuts off driving force transmission to the image forming unit by moving to the second position.
An image forming apparatus characterized by: The air volume changing unit is
when the image forming unit is in the image forming state, opening the blower port of the blower unit;
2. The image forming apparatus according to claim 1, wherein at least a portion of said blower port is closed when said image forming unit is in a non-image forming state. 3. The image forming apparatus according to claim 2, wherein the air blow amount changing section closes all of the air blow ports when the image forming unit is in a non-image forming state. 4. The movable part according to any one of claims 1 to 3, wherein the movable part has a closing part that faces the blower port of the blower part when the movable part is in the second position. Image forming device. The image forming unit has a developer carrier that carries a developer, an image carrier that carries an image, and a driving force receiving portion connected to the developer carrier or the image carrier,
The coupling mechanism has an engaging portion that engages with the driving force receiving portion,
5. The movable portion according to claim 1, wherein the movable portion engages the engaging portion with the driving force receiving portion and moves the engaging portion so as to escape from the driving force receiving portion. The image forming apparatus according to any one of items 1 to 1 . The image forming apparatus according to any one of claims 1 to 5 , wherein the movable portion is a slider that moves straight. an image forming unit that forms an image;
a blower that blows air toward the image forming unit;
a switching unit for switching between an image forming state and a non-image forming state of the image forming unit;
A blowing amount change that mechanically changes a blowing amount of air blown from the blowing section toward the image forming unit in conjunction with switching between an image forming state and a non-image forming state of the image forming unit by the switching section. Department and
has
The image forming unit has a developer carrier that carries a developer, an image carrier that carries an image, and a driving force receiving portion connected to the developer carrier or the image carrier,
The switching portion has an engaging portion that engages with the driving force receiving portion,
The image forming apparatus according to claim 1, wherein the air volume changer has an opening/closing door that abuts against the engaging portion to open or at least partially close an air blowing port of the air blowing portion. 8. The image forming apparatus according to claim 7 , wherein the opening/closing door abuts against the engaging portion when the engaging portion engages with the driving force receiving portion to close the blower port. 9. The image forming apparatus according to claim 7 , further comprising a biasing member that biases the opening/closing door in a direction to open the air outlet. The image forming apparatus according to any one of Claims 7 to 9 , wherein the opening/closing door rotates around a predetermined rotation axis. 11. The image forming apparatus according to any one of claims 1 to 10 , wherein the air blowing section blows the air blown along the air blowing path toward the image forming unit. The image forming apparatus according to any one of claims 1 to 11 , wherein the blower section is a blower duct. comprising a plurality of image forming units including an image forming unit for forming a black image;
13. The air blow amount changing unit reduces the amount of air blown from the air blow unit to an image forming unit that forms an image other than a black image during monochrome printing. The image forming apparatus according to . the air blower includes a plurality of air blowing ports corresponding to the plurality of image forming units;
At the time of monochrome printing, the air blow amount changing section opens at least a part of the air blow openings corresponding to the image forming units that form images other than black while keeping the air blow openings corresponding to the image forming units that form black images open. 14. The image forming apparatus according to claim 13 , wherein the image forming apparatus is closed.

Images