JP2001183954A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of specially isolating a device main body upper part in almost parallel from a device main body lower part and by which both-side printing is executed in the image forming device and attaining both-side printing. SOLUTION: The device main body upper part 32 is constituted so as to be openable in almost parallel from the device main body lower part 33, and has an image forming unit composed of plural drum sets and toner sets. The device main body lower part 33 has a carrying unit 53 and a both-side printing carrying unit 42. The both-side printing carrying unit 42 is attached by opening a cover 60, and is pulled out by opening a cover 40, so that jamming processing is easily performed. Also, when the device main body lower part 32 is opened from the device main body lower part 33, the carrying unit 53 is opened, so that an excellent maintenance performance is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an image forming apparatus capable of performing double-sided printing.

[0002]

2. Description of the Related Art FIG. 14 is a schematic perspective view of a conventional printer (image forming apparatus). In FIG. 1, a printer 1 includes a roof 2 which is an upper part of the apparatus main body and a lower part 3 of the apparatus main body. The roof 2 is provided with a paper discharge port 5 for discharging paper on its upper surface and a paper discharge tray 6 on which the discharged paper is stacked. A detachable paper cassette 8 is disposed from the front cover 7 and the lower part 3 of the apparatus main body, and an MPF tray (multi-paper feeder: general-purpose paper feed tray) 9 that can be stored in the lower part 3 of the apparatus main body is disposed on the right side thereof. An operation display unit 4 for inputting information to the printer 1 and displaying the status of the printer 1 is provided on the right side of the upper surface.

In the printer apparatus 1, when performing operations such as jam clearance and maintenance, the roof 2 is opened in the direction of arrow B around the rotation axis A. FIG. 15 shows a cross-sectional configuration when the above-described printer device 1 is opened, and also shows an internal structure thereof. As shown in FIG. 1, the printer 1 includes a detachable paper cassette 8,
Feed roll 1 that sequentially feeds the paper loaded and stored inside
2. A pair of standby rolls for temporarily stopping the fed sheet and sending the sheet to the image forming unit 11 at a predetermined timing.
3. A fixing device 14 for fixing the toner image onto the paper, a paper discharge roll pair 18 (a driving roll 18a and a driven roll 18b) for discharging the fixed paper out of the apparatus, and various settings and status display on the printer 1 The operation display unit 4 for performing the above-described operations
Is provided.

In the image forming unit 11, a charger 25 charges the peripheral surface of the photosensitive drum 23 to a uniform charge, and a print head 26 applies a charge to the peripheral surface of the photosensitive drum 23 based on print data. Exposure is selectively performed, a low potential portion is formed by the exposure, and an electrostatic latent image including the initial charging potential and the exposed low potential portion is recorded on the peripheral surface of the photosensitive drum 23. The developing device 27 transfers the toner inside to the low potential portion of the photoconductor drum 23 via the developing roll 27a, thereby developing (developing) the electrostatic latent image. The transfer unit 28 transfers the toner image on the photosensitive drum 23 to the paper surface of the conveyed sheet by an electric field of opposite polarity.

In the image forming unit 11, a photosensitive drum 23, a charger 25, a developing unit 27, a transfer unit 28, a cleaner 24, etc. are provided in a lower part 3 of the apparatus main body, and a print head 26 is provided in an upper part of the apparatus main body. Is provided on the roof 2.

The roof 2 is configured to be openable and closable in the direction of arrow B with the hinge portion 15 as a fulcrum relative to the lower portion 3 of the apparatus main body. At this time, the print head 26 and the driven roll 1 described above are used.
8 b is opened and closed integrally with the roof 2. The roof 2 indicated by a solid line in the figure indicates a closed state, and the roof 2 indicated by a dotted line indicates an opened state. The lock mechanism 16 for holding the roof 2 in the closed position includes a claw 17a provided on the lower part 3 of the apparatus main body and a claw 17 provided on the roof 2 side.
a and an engaging portion 17b which engages with the first member a.

On the other hand, most of the image forming unit 11
A cartridge C which is detachable from the lower part 3 of the apparatus main body is constituted, and comprises a first cartridge C1 in which the photosensitive drum 23 and the cleaner 24 are integrated, and a second cartridge C in which the developing device 7 and the like are integrated. The cartridges C1 and C2 can be detachably attached to a predetermined mounting portion of the lower portion 3 of the apparatus main body with the roof 2 opened. For example, the cartridges C1 and C2 can be detached from the cartridge C2. Maintenance such as maintenance and inspection work such as replacement of these cartridges and replenishment of consumables is performed due to wear and the like.

[0008]

The above-mentioned conventional printer (image forming apparatus) has the following problems. That is, color printers (color image forming apparatuses) are widely used today, and various methods of color printing are adopted. For example, there is a method in which a plurality of developing devices are arranged near the peripheral surface of one photosensitive drum and toner images are sequentially formed on the drum surface (method (a)). There is also a method using a drum-shaped intermediate transfer medium (method (b)), and a method in which a plurality of image forming units are arranged in a predetermined direction to directly form a toner image on a sheet (a so-called tandem method). ) Also exists.

Among them, the method (a) requires the use of a photosensitive drum having a large shape, and the printing speed is reduced. Further, in the method (b), since the intermediate transfer medium is used, the shape becomes large. Therefore, a tandem type color printer which has an excellent printing speed and has few problems in shape is promising. And in this type of printer device,
The image forming units of yellow (Y), magenta (M), cyan (C), and black (K) are used.

However, in the printer having the structure shown in FIG. 15, the image forming unit is provided in the lower portion 3 of the apparatus main body. Therefore, in the case of a tandem type color printer, the image forming units for yellow (Y), magenta (M), cyan (C), and black (K) are sequentially arranged in the lower portion 3 of the apparatus main body. For this reason, in maintenance, after the roof 2 is once opened, each image forming unit is taken out from above. For this reason,
Maintenance work is complicated.

In the conventional tandem type printer, the roof 2 is opened around the rotation axis A.
Since the roof 2 is opened with one of the fulcrums as a fulcrum,
Mechanical distortion and the like occurred, the position accuracy of each unit was poor, and the printing accuracy was not sufficient.

Further, in a tandem type color image forming apparatus, double-sided printing is often required, and the necessity of installing a transport unit for double-sided printing is great. In view of the above circumstances, the present invention provides an image forming apparatus in which the upper part of the apparatus main body can be separated substantially in parallel with the lower part of the apparatus main body and double-sided printing is possible.

[0013]

According to the first aspect of the present invention,
A sheet stacking unit disposed at a lower portion of the apparatus main body, for stacking sheets substantially horizontally, a sheet feeding unit for feeding out the sheets from the sheet stacking unit, and after conveying the sheet fed from the sheet feeding unit upward, A sheet conveying path formed in a hook shape so as to be conveyed substantially in parallel with the sheet surface on the sheet stacking means, and a sheet conveying path disposed above a substantially horizontal portion of the sheet conveying path, An image forming unit that forms a toner image on the paper, and a heat fixing unit that takes over the conveyance of the sheet on which the toner image is formed in the image forming unit, and conveys the toner image while fixing the toner image on the sheet with heat and pressure. A sheet carrying a fixed toner image conveyed by the heat fixing unit, and a sheet discharging and conveying unit for conveying the sheet to a sheet discharging unit, wherein the sheet discharging and conveying unit inherits the sheet Paper discharge conveyance path for guiding the paper to the paper discharge section, The paper is switched back from the road,
A return conveyance path that guides downward, and a predetermined double-sided printing conveyance unit that can be attached separately between the return conveyance path and a horizontal portion of the paper conveyance path and a paper supply unit. This can be achieved by providing an image forming apparatus having a space in advance.

The image forming section is composed of magenta (M), cyan (C), yellow (Y), and black (K) image forming units, and is arranged in a predetermined direction in the order, for example. Have been. The image forming unit includes, for example, a drum set including a charger, a print head, a photosensitive drum, and the like, and a toner set that stores a developing roll and toner. Both the drum set and the toner set are disposed on the upper body. ing.

The double-sided printing transport unit is mounted in a predetermined space provided in the apparatus main body, and this space is formed between the return transport path and the horizontal portion of the paper transport path and the paper feed section. Then, a conveyance unit for double-sided printing is mounted in this space to serve as a paper conveyance path for double-sided printing.

Further, the double-sided printing transport unit is provided with a plurality of rollers and the like inside, and the paper on which one side (front surface) of the paper has been subjected to the printing process by the image forming means is sent. The conveyance unit for double-sided printing sends the sheet to the image forming unit, and causes the sheet to perform the printing process again.
With this configuration, the printing process is performed on the other surface (back surface) of the same sheet, and double-sided printing can be performed.

According to a second aspect of the present invention, in the first aspect of the invention, the image forming apparatus divides an apparatus main body into an upper body and a lower body so as to be freely opened and closed, and arranges the image forming section in the upper body. And a predetermined space for attaching the double-sided printing transport unit to the lower body. When opening the upper body with respect to the lower body, the posture of the upper body with respect to the installation surface is closed. A configuration is provided that includes a body opening / closing mechanism for linking the two bodies so as to be retracted slightly to the rear of the apparatus and opened at a predetermined distance from the lower body while maintaining the posture substantially the same as the posture at the time.

With this configuration, the upper body can be opened with substantially the same posture as the lower body,
An image forming apparatus having a double-sided printing function that can easily perform maintenance processing and the like can be provided.

According to a third aspect of the present invention, in the second aspect of the present invention, the body opening / closing mechanism includes first and second arms each having one end as a pivot point in the front-rear direction of the upper body. A link member rotatably connected to the lower body at each of the other ends of the first and second arms, and the first and second arms and the link member are provided on both sides of the device. Configuration.

With this configuration, the upper body can be separated from the lower body substantially horizontally by using the link mechanism from both sides of the apparatus, and the upper body can be opened stably.

According to the fourth aspect of the present invention, there is provided the first aspect,
In the invention described in 2 or 3, the double-sided printing transport unit is configured to be detachably attached to the apparatus main body.

With this configuration, when double-sided printing is required, a double-sided printing transport unit can be mounted and used, and an optional image forming apparatus with increased convenience can be provided.

According to a fifth aspect of the present invention, in the first aspect,
In the invention described in 2, 3, or 4, the double-sided printing transport unit has a drawer, and the drawer is configured to be slidable in one direction with respect to the double-sided printing transport unit.

With this configuration, it is possible to easily cope with a paper jam in the transport unit for double-sided printing.

[0025]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an image forming apparatus according to the present embodiment, which is an example of a so-called tandem type printer. Further, the image forming apparatus of this embodiment is a printer apparatus for duplex printing. In the figure, a printer device 31 is connected to a host device such as a personal computer by a cable (not shown).

The printer 31 is composed of an upper part 32 of the apparatus and a lower part 33 of the apparatus. An operation panel 34 is provided on the upper part 32 of the apparatus, and a paper discharge section 35 for printing paper is also formed on the upper surface. I have. The operation panel 34 includes a key operation unit 34a in which a plurality of keys are arranged, and a liquid crystal display 34b that performs display based on display information output from a CPU (not shown). The print output created by the image forming unit described later is discharged to the paper discharge unit 35 by the rotation of the paper discharge roll 36, and is sequentially stacked on the paper discharge unit 35.

A transport unit for double-sided printing and a paper feed cassette, which will be described later, are provided in the lower portion 33 of the apparatus main body. In this configuration, the transfer unit for double-sided printing can be attached and detached. Further, a front cover 37 which can be opened and closed on the front surface of the apparatus main body 33 and a paper feed cassette 38 which is detachable from the apparatus main body lower part 33 are provided. For example, the front cover 37 is opened for jam clearance or maintenance.

On the right side of the lower part 33 of the apparatus main body, M
A mounting section 39 for a PF tray (multi-paper feeder: general-purpose paper feed tray) and a cover 40 are provided.
However, the MPF tray is not mounted on the mounting section 39 in FIG. The cover 40 is a cover for confirming a sheet transport path described later. In this example, the cover 40 is opened to perform maintenance such as a paper jam. The cover 40 is also opened when pulling out a drawer of a transport unit for double-sided printing described later.

FIG. 2 is an external view of the printer 31 showing a state in which the front cover 37 and the cover 40 are opened. Further, at the lowermost stage of the printer device 31 of this embodiment, the paper feed cassette 38 is housed as described above, and when replenishing the paper into the paper feed cassette 38, for example, by pulling the handle 38a forward, the paper feed cassette 38 Can be pulled out in the direction of the arrow.

FIG. 3 shows a printer 31 having the above appearance.
FIG. 2 is a cross-sectional view illustrating an internal configuration of the device. In FIG. 1, the printer device 31 includes an image forming unit 41, a conveyance unit 42 for double-sided printing, and a paper feeding unit 43. The four image forming units 44 to 47 are arranged side by side in the direction of the arrow as shown in the figure, and magenta (M), cyan (C), yellow from the right to the left in the drawing. (Y) and black (K). Also,
The magenta (M), cyan (C), and yellow (Y) image forming units 44 to 46 are configured to perform color printing by subtractive color mixing, and the black (K) image forming unit 47 is used for monochrome printing. I do.

Here, each of the above image forming units 44 to 4
Reference numeral 7 includes a drum set C1 and a toner set C2, and has the same configuration except for (color of) the developer stored in the developing container. Therefore, the configuration will be described using the image forming unit 46 for yellow (Y) as an example. The drum set C1 contains a photosensitive drum, a charger, a print head, and a cleaner, and the toner set C2 contains a developing roll and toner. The peripheral surface of the photoconductor drum 50 is made of, for example, an organic photoconductive material.
A charger 51a, a print head 51b, a developing roll 51c, a transfer unit 51d, and a cleaner 51e are sequentially arranged in the vicinity of the peripheral surface. The photoreceptor drum 50 rotates in the direction of the arrow, and first charges the peripheral surface of the photoreceptor drum 50 uniformly by applying a charge from the charger 51a. Then, an electrostatic latent image is formed on the peripheral surface of the photosensitive drum 50 by optical writing based on print information from the print head 51b,
A toner image is formed by the developing process of 1c. At this time, the toner image formed on the peripheral surface of the photosensitive drum 50 is
The yellow (Y) toner stored in the toner set C2 (development container). The toner image formed on the peripheral surface of the photosensitive drum 50 in this manner is
Reaches the position of the transfer device 51d with the rotation in the direction of the arrow,
The image is transferred onto a sheet that moves just below the photosensitive drum 50 in the direction of the arrow.

On the upper surface of the sheet, not only the yellow (Y) toner image but also the magenta (M) and cyan (C) toner images are transferred, and the printing of the color according to the subtractive color mixture is performed. Is performed.

The above-mentioned paper includes not only the paper carried out of the paper feed cassette 38 but also the paper supplied from the MPF tray 39 '.
a, and the respective toners are transferred along the above-described paths.

The fixing unit 56 includes a heat roll 56
a, 56b, a cleaning roll 56c, and the like. While the paper P is nipped and conveyed between the above-mentioned heat rolls 56a and 56b, for example, a toner image of a plurality of colors transferred to the paper is melted and heated on the paper P. Establish. The cleaning roll 56c has a function of applying oil to the heat roll 56a and removing toner remaining on the heat roll 56a.
The sheet on which the toner image is fixed by the fixing unit 56 is transported upward or leftward on the sheet via the switching plate 61.

The paper is transported by a paper feed cassette 38, a standby roll 52, a transport belt 53, a drive roll 54 and the like which constitute the above-mentioned paper feed section 43. The paper carried out of the cassette 38 is
The sheet is sent to the standby roller 52, and is further sent to the transfer belt 53 at a timing coincident with the toner image, and reaches each transfer section. Then, the toner image is transferred in each transfer section (51d), and the paper on which the toner image has been transferred moves on the transport belt 53 in the direction of the arrow according to the movement of the transport belt 53,
The heat fixing process is performed in the fixing unit 56.

On the other hand, the image forming section 41 and the sheet feeding section 43
Between the (sheet feed cassettes 38), a double-sided printing transport unit 42 is provided. FIG. 4 is a cross-sectional configuration diagram of the transport unit 42 for double-sided printing. In the figure, a paper transport path 48 is formed in the transport unit 42 for double-sided printing,
A plurality of transport rolls 48 a to 48
48e are provided. In addition, transport rolls 48d and 4d
A switch 49 is provided between 8e. In addition, the transport unit 42 for double-sided printing configured as described above is
By opening a lid 60 (see FIG. 3) provided on the left side surface of the device 1, it is configured to be detachable from the apparatus main body.

FIG. 5 is a schematic sectional view for explaining the structure of the drawer of the transport unit 42 for double-sided printing having the above-described structure. The drawer section 42 'is a transport unit 4 for double-sided printing.
By pulling a handle 42 ″, which is built in the guide unit 2 via a guide rail (not shown) and provided at the tip of the transport unit 42 for double-sided printing (drawer 42 ′), to the right in the drawing, as shown in FIG. Can be withdrawn.

The paper transport path 48 and the transport rolls 48b-
The paper transport path 48 and the transport rolls 48b to 48e are also pulled out in the same direction by pulling out the drawer 42 '. Therefore, when a sheet is jammed in the double-sided printing transport unit 42, the drawer 42 'can be pulled out and maintenance of the jammed sheet can be performed.

FIG. 6 is a cross-sectional view of the printer 31 showing a state in which the transport unit 42 for double-sided printing is not mounted, and also shows an opening and closing mechanism of the cover 40 described above. When the double-sided printing transport unit 42 is mounted on the apparatus main body, the support shaft 60 '
The lid 60 is opened in the direction of arrow C with the center at the center, and the conveyance unit 42 for double-sided printing is attached to the apparatus main body from the left side of the paper of FIG. On the other hand, the drawer 42 'is pulled out from the support shaft 40'.
, The cover 40 is opened in the direction of arrow D, and the above-mentioned handle 42 "is pulled out to the right in the drawing.

On the other hand, the printer 31 of this embodiment has an opening and closing mechanism for opening and closing the upper part 32 of the apparatus substantially horizontally with respect to the lower part 33 of the apparatus. FIG. 7 is an external perspective view of the printer device 31 for explaining the opening mechanism. As shown in the figure, the apparatus main body upper part 32 is opened while being kept substantially horizontal with respect to the apparatus main body lower part 33 by an opening / closing mechanism 64 provided in the printer device 31.

The opening / closing mechanism 64 has link frames 66, F on both sides thereof when viewed from the front of the printer device 31, respectively.
The configuration includes an arm 67, an R arm 68, a stay 69, an FR frame 65, and the like. The connection relationship between the members is determined by the link frame 6 provided in the upper part 32 of the apparatus main body.
6, one end of the F arm 67 and one end of the R arm 68 are rotatably supported.
7 is rotatably supported on an FR frame 65 provided in the lower portion 33 of the apparatus main body, and the other end of the R arm 68 is rotatable on a stay 69 fixed to the FR frame 65. It is configured to support. With such a configuration, the device main body upper portion 32 is opened substantially horizontally with respect to the device main body lower portion 33, and gradually moves backward and moves relative to the device main body lower portion 33 with the opening. The elongated hole 63 provided in the link frame 66 is used for sliding a support portion described later when the upper part 32 of the apparatus main body is opened.

In FIG. 7, for convenience of explanation, only the link mechanism on the right side of the printer device 31 when viewed from the front is numbered. In the following description, the member numbers of the left link mechanism of the printer device 31 will be denoted by a, and the member numbers of the right link mechanism will be denoted by b. Therefore, each member number of the link mechanism shown in FIG.
b, the R arm is indicated by 68b, the stay is indicated by 69b, and the FR frame is indicated by 65b.

FIGS. 8 and 9 are schematic diagrams of the opening and closing mechanism. FIG. 8 is a schematic diagram of the left and right opening and closing mechanism as viewed from the left side, and FIG. FIG. 2 shows a schematic view of the mechanism. FIG. 10 is a perspective view thereof. 8 to 10, the link frame 66 (66a, 66a,
66b), F arm 67 (67a, 67b), R arm 68 (68a, 68b), stay 69 (69a, 69)
b) and the FR frame 65 (65a, 65b) are main parts of the opening / closing mechanism. FIG. 10 does not show the link frames 66 (66a, 66b).

8 and 9, the F arm 67 (67a, 67b) and the R arm 68 shown by solid lines.
The positions (68a, 68b) indicate the opened position when the upper part 32 of the apparatus is opened, and the upper part 32 of the apparatus is kept substantially horizontal with respect to the lower part 33 of the apparatus. On the other hand, an F arm 67 (67a, 67b) and an R arm 68 shown by dotted lines
The position (68a, 68b) indicates a closed position when the upper part 32 of the apparatus is closed with respect to the lower part 33 of the apparatus.

Further, the supporting portions 71 (71a, 71b)
Is the F arm 67 (67a, 67b) and FR frame 6
5 (65a, 65b) is rotatably supported, and
(72a, 72b) is an R arm 68 (68a, 68).
b) and the stay 69 (69a, 69b) are rotatably supported. The support 77 (77a, 77b) is connected to the F-arm 67 (67a, 67b) and the link frame 66 (66).
a, 66b) are rotatably supported, and the support portions 78 (78
a, 78b) rotatably support the R arm 68 (68a, 68b) and the link frame 66 (66a, 66b).

Incidentally, as shown in FIG.
The FR frame 65a on the 6th side (the back side of the paper) is provided with four rectangular holes 81, which are provided to the extent that the strength as the opening / closing mechanism is maintained. Also, FR
The frame 65a has a function of using the holes 81 to open and close the upper portion 32 of the apparatus main body, as well as a function of radiating heat of the fixing unit 56 and suppressing a rise in temperature inside the apparatus.

FIG. 11 is a view for explaining a drive mechanism having the above-mentioned link structure. Note that the link mechanism is symmetrical as described above, and a drive mechanism having a link structure particularly corresponding to FIG. 8 will be described with reference to FIG. Therefore, in FIG. 11, the right side of the paper is the front of the printer device 31. As described above, the F arm 67a is rotatably provided on the support 71a, and the support 71a is fixed to the rotating gear 71a '. The R arm 68a is rotatably provided on a support portion 72a, and the support portion 72a is fixed to a rotating gear 72a '. Therefore, the F arm 67a and the rotating gear 71a 'rotate integrally, and the R arm 68a and the rotating gear 72a' also rotate integrally.

An intermediate pulley 73 is interposed between the rotary gears 71a 'and 72a', and a belt 74 is stretched between the rotary gears 71a 'and 72a' via the intermediate pulley 73. The intermediate pulley 73 applies a predetermined tension to the belt 74.

The rotating gear 72a 'is provided with a rotating body 75 having a built-in damper mechanism. This rotating body 75
Has an oil damper built therein, and has a function of suppressing a sudden drop due to gravity when lowering the upper part 32 of the apparatus main body and smoothly lowering the same. On the other hand, the upward lifting force when opening the apparatus main body upper part 32 is applied by the spring 76. One end of the spring 76 is attached to the housing 33 ′ of the lower part 33 of the apparatus main body, and is wound around the rotating gear 71 a ′ by a predetermined number of turns, and the tip (the other end) is formed on the housing 33 ′ (not shown). Is fixed in the hole. Therefore, the urging force of the spring 76 acts to rotate the rotary gear 71a 'in the direction of the arrow a', and serves as a lifting force for the upper portion 32 of the apparatus.

That is, when the rotary gear 71a 'rotates in the direction of the arrow a', the F-arm 67a rotates in the same direction, and at the same time, the belt 74 rotates in the direction of the arrow a. To the R arm 68a
Are rotated in the same direction. Accordingly, the link mechanism operates by the above driving, and the F arm 67a and the R arm 68a rotate according to the two-dot chain line shown in FIG.

The opening and closing process of the upper part 32 of the printer 31 of the present embodiment in the above configuration will be described below. Usually, the printer device 31 is used in the state shown in FIG. When the paper is insufficient, a paper supply instruction is displayed on the liquid crystal display 34b of the operation panel 34, and the paper supply to the paper supply cassette 38 is performed. On the other hand, if there is a paper jam, the position is displayed on the liquid crystal display 34b,
Opening is performed. In particular, when a paper jam occurs in the transport unit 42 for double-sided printing, the cover 40 is opened as described above, and the drawer 42 'is pulled out for maintenance.

On the other hand, when the paper jam is inside the printer 31 (when it is not at the position corresponding to the cover 40), when the drum set C1 or the toner set C2 is replaced, or when other maintenance is performed, Open the front cover 37. The front cover 37
Is open as shown in FIG.

Next, in this state, the upper part 32 of the apparatus main body is
Unlock to open. When the lock is released, the urging force of the spring 76 acts to rotate the F arm 67a in the direction of arrow a ', and at the same time, moves the belt 74 in the direction of arrow a.
In the same direction to rotate the R arm 68a in the same direction. Accordingly, the upper part 32 of the apparatus main body is moved upward by the above driving. FIG. 12 shows a state in which the link mechanism operates and the upper part 32 of the apparatus has slightly moved upward. In FIG. 1, only the main part of the link mechanism is shown, and the configuration of the MPF sheet cassette and cover 40 is omitted.

Thereafter, the apparatus main body upper part 32 further moves upward, and the apparatus main body upper part 32 is opened to a predetermined position. FIG.
3 is a view showing a state in which the upper part 32 of the apparatus main body is completely opened. Also, in this figure, only the main part of the link mechanism is shown, and the configurations of the MPF tray 39 'and the cover 40 are omitted. In this state, the apparatus main body upper part 32 is opened substantially horizontally with respect to the apparatus main body lower part 33, and maintains a predetermined interval. This interval takes into account, for example, the workability of the following maintenance processing.

On the other hand, as described above, the drum set C1
To close the apparatus main body upper part 32 after the replacement processing of the toner set C2 or the maintenance processing, the apparatus main body upper part 32 is pushed down. In this case, the apparatus can be closed without applying a strong force due to the weight of the upper part 32 of the apparatus main body. Further, an oil damper is provided on the rotating body 75 described above, so that the rotating body 75 can be closed smoothly against the urging force of the spring 76. In this case, the belt 74 is indicated by an arrow b.
, The rotating gear 71a 'rotates in the direction of the arrow b', and at the same time, the rotating gear 72a 'rotates in the direction of the arrow b ",
The apparatus main body upper part 32 is closed to the apparatus main body lower part 33.

Next, printing processing including double-sided printing processing will be described. First, the paper conveyed from the paper supply cassette 38 by the rotation of the paper supply roller 55 is conveyed to the standby roll 52 in the paper conveyance path, and is conveyed to the standby roll 52 at a timing coincident with the toner image.
Sent up. The paper sent on the conveyor belt 53 is magenta (M) by each of the image forming units 44 to 47.
Cyan (C), yellow (Y), and black (K) toners are transferred.

The paper to which the toner has been transferred in this manner is thermally fixed by the above-described fixing unit 56, and color printing based on subtractive color mixture is performed. For example, for example, magenta (M) toner and cyan (C) toner melt, a blue image is formed on a sheet, and yellow (Y) toner and magenta (M) toner melt to form a red image. .

The sheet on which color printing has been performed as described above is guided upward by, for example, a switching plate 61 set at a dotted line position, and is conveyed by a transport roll 62 to a discharge roll 36.
And the sheet is discharged to the sheet discharge unit 35 by the sheet discharge roll 36. In this case, the sheet is discharged in a so-called face-down state. On the other hand, when the switching plate 61 is set at the solid line position, the sheet is discharged to a sheet discharge tray (not shown) mounted on the left side of the sheet. In this case, the sheet is discharged in a so-called face-up state.

On the other hand, in the case of double-sided printing, the switching plate 61 is set at the dotted line position, the sheet is once guided upward, and when the rear end of the sheet reaches, for example, the transport roll 62, the transport of the sheet is stopped. Further, the sheet is transported in the reverse direction. With this control,
The sheet is conveyed downward on the left side of the switching plate 61 and is conveyed into the sheet conveying path 48 of the conveying unit 42 for double-sided printing. Thereafter, the paper on which the printing has been performed on the front side is carried by the transport rolls 48a to 48a.
The paper is conveyed rightward in the paper transport path 48 by 48c, and the switch 49 is turned on.

Thereafter, the sheet is further fed by a transport roll 48e or the like, and reaches a standby roll 52. Then, as described above, the sheet is fed onto the conveyor belt 53 at a timing coincident with the toner image formed on each photosensitive drum 50, and a new toner image is transferred onto the back surface of the sheet.

Thereafter, the paper on which the toner image has been transferred is subjected to heat fixing processing by the fixing unit 56, and color printing based on subtractive color mixture is performed as described above. Then, for example, it is guided upward by the switching plate 61 set at the dotted line position,
Alternatively, the sheet is guided to the left side of the paper by the switching plate 61 set at the solid line position, and is discharged to the paper discharge unit 35 or a paper discharge tray (not shown).

As described above, the printer 3 of the present embodiment
According to 1, a plurality of image forming units 44 to
A space is provided between the image forming unit 41 in which the image forming unit 47 is provided and the paper feeding unit 43 for mounting the double-sided printing transport unit 42, and the double-sided printing transport unit 42 is mounted in this space as needed, so that the efficiency is improved. Double-sided printing can be performed.

In the description of the present embodiment, the transport unit 42 for double-sided printing is detachably configured. However, the transport unit 42 for double-sided printing may be fixed to the printer 31.

[0064]

As described in detail above, according to the present invention, double-sided printing can be performed by using the double-sided printing transport unit, and an extremely convenient image forming apparatus can be obtained. .

Further, since the upper part of the apparatus main body can be opened substantially horizontally with respect to the lower part of the apparatus main body, it is possible to easily perform maintenance such as a paper jam occurring during the double-sided printing process. Furthermore, since the drawer portion can be easily pulled out from the double-sided printing transport unit, the maintainability in the event of a paper jam or the like is further improved.

[Brief description of the drawings]

FIG. 1 illustrates an image forming apparatus according to an embodiment, which is an example of a so-called tandem type color printer.

FIG. 2 is an external view of the printer showing a state where a front cover and the like are opened.

FIG. 3 is a cross-sectional view illustrating an internal configuration of the printer device.

FIG. 4 is a sectional view of a single-sided printing transport unit.

FIG. 5 is a schematic cross-sectional view illustrating a configuration of a drawer provided in a transport unit for double-sided printing.

FIG. 6 is a cross-sectional view illustrating an internal configuration of a printer device to which a conveyance unit for duplex printing is not mounted.

FIG. 7 is a perspective view of the image forming apparatus illustrating a link mechanism.

FIG. 8 is a diagram illustrating a left link mechanism.

FIG. 9 is a diagram illustrating a right link mechanism.

FIG. 10 is a perspective view of a link mechanism.

FIG. 11 is a diagram illustrating a drive configuration of a link mechanism.

FIG. 12 is a perspective view showing a state where the printer device is slightly raised.

FIG. 13 is a perspective view showing a state in which the printer device is completely opened.

FIG. 14 is an overall configuration diagram of a conventional printer device.

FIG. 15 is an internal configuration diagram of a conventional printer device.

[Explanation of symbols]

31 Printer 32 Upper part 33 Lower part 34 Operation panel 34a Key operation part 34b Liquid crystal display 35 Paper discharge part 36 Paper discharge roll 37 Front cover 38 Paper feed cassette 39 MPF tray 40 Cover 41 Image forming part 42 Double-sided printing transport Unit 42 'drawer 42 "handle 43 paper feeder 44-47 image forming unit 48 paper transport path 48a-48e transport roll 49 switch 50 photoconductor drum 51a charger 51b printhead 51c developing roll 51d transfer unit 51e cleaner 52 standby roll 53 Conveying belt 54 Drive roll 55 Feed roller 56 Fixing unit 56a, 56b Heat roll 56c Cleaning roll 60 Lid 61 Switching plate 62 Transport roll 65 (65a, 65b) FR frame 66 ( 6a, 66b) Link frame 67 (67a, 67b) F arm 68 (68a, 68b) R arm 69 (69a, 69b) Stay 71 (71a, 71b), 72 (72a, 72b) Support 71a ', 71b', 72a ', 72b' Rotating gear 73 Intermediate pulley 74 Belt 75 Rotating body 76 Spring 77, 78 Support 81 Opening

Continued on the front page (72) Shizui Saikawa 2-229 Sakuragaoka, Higashiyamato-shi, Tokyo Inside the Casio Computer Co., Ltd. Tokyo Office (72) Koichi Toshiyuki 2-229 Sakuragaoka, Higashiyamato-shi, Tokyo Casio Computer Co., Ltd. Tokyo In-house F-term (reference) 2C061 AP04 AQ06 AR03 AS02 BB10 BB30 BB35 CD03 CD05 CD08 CD12 2H028 BA09 BA12 BA16 2H071 AA02 BA03 BA13 BA14 DA23 EA18 3F100 AA02 BA14 CA12 CA13 DA01 EA06

Claims (5)

[Claims] A sheet stacking means disposed at a lower portion of the apparatus main body for stacking sheets substantially horizontally; a sheet feeding means for feeding sheets from the sheet stacking means; and a sheet fed from the sheet feeding means facing upward. After being conveyed, the paper conveyance path formed in a hook shape so as to be conveyed substantially parallel to the sheet surface on the paper stacking means, and disposed above a substantially horizontal portion of the paper conveyance path, An image forming unit for forming a toner image on a sheet to be conveyed, and the image forming unit taking over the conveyance of the sheet on which the toner image is formed, and conveying the toner image while fixing the toner image on the sheet by heat and pressure An image forming apparatus, comprising: a heat fixing unit that performs fixing and a sheet carrying a fixed toner image conveyed by the heat fixing unit; and a sheet discharging conveying unit that conveys the sheet to a sheet discharging unit. , Paper discharge transport that inherits the paper and guides it to the paper discharge section And a return conveyance path for switching back the sheet from the paper discharge conveyance path and guiding the sheet downward, and a separate body is provided between the return conveyance path and the horizontal portion of the paper conveyance path and the paper supply section. An image forming apparatus, which is provided with a predetermined space in which the transfer unit for double-sided printing provided in (1) can be attached. 2. The image forming apparatus according to claim 1, wherein the apparatus main body is divided into an upper body and a lower body so as to be freely opened and closed, the image forming section is provided in the upper body, and the transfer unit for double-sided printing is provided in the lower body. When opening the upper body with respect to the lower body, the attitude of the upper body with respect to the installation surface, while maintaining the attitude of the upper body with respect to the installation surface is substantially the same as the attitude at the time of closing, the rear part of the device 2. The image forming apparatus according to claim 1, further comprising a body opening / closing mechanism for linking the two bodies with each other so as to open slightly apart from the lower body at a predetermined interval. 3. The body opening and closing mechanism includes first and second arms each having one end as a pivot point in the front-rear direction of the upper body, and the other end of each of the first and second arms. 3. The image forming apparatus according to claim 2, further comprising a link member rotatably connected to the lower body, wherein the first and second arms and the link member are provided on both sides of the apparatus. 4. The image forming apparatus according to claim 1, wherein the double-sided printing transport unit is detachably attached to the predetermined space of the apparatus main body. 5. The double-sided printing transport unit has a drawer portion, and the drawer portion is configured to be slidable in one direction with respect to the double-sided printing transport unit. 5. The image forming apparatus according to claim 2, 3, or 4.