JPH06155840A - Image forming apparatus - Google Patents

Abstract

PURPOSE:To reduce the entire height by branching and arranging a retracting conveying passage for guiding a record sheet at the time of retracting the sheet below an introducing conveying passage for guiding the sheet to holding means in an image forming apparatus such as a copying machine, etc. CONSTITUTION:A record sheet P of a record sheet cassette 18 is picked up one by one from an uppermost sheet by a pickup roller 32, and sent to a conveying roller pair 44 through an introducing conveying passage 34. The roller pair 44 are further guide the record sheet P with a stationary guide member 52a, a movable guide member 52b, and feed it to a platen roller 48 to form an image. A retracting conveying passage 56 is connected from below in a branched state to a midway of a rear half of the passage 34 and extended obliquely downward. It is formed with a front half 56a terminated at an upper part in a space for forming a lower housing 14 and further a rear half 56b horizontally extended toward a front face of a hosing 12 to guide a retracting record sheet (p).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus configured to print or draw on the surface of a recording sheet to be conveyed and discharge the sheet.

[0002]

2. Description of the Related Art Conventionally, as one of recording (image forming) systems in image forming apparatuses such as copying machines, printers, and facsimiles, a recording head movable in the width direction of a recording sheet,
Alternatively, by providing a recording head in which recording elements are arranged over the entire width direction of the recording paper, and moving the recording paper in the moving direction of the recording head, or in the direction orthogonal to the arrangement direction of the recording elements, There is one that forms an image over the entire area of the recording paper. That is, the main scanning is performed by the recording head, and the sub-scanning is performed by moving the recording paper.

As a moving / conveying structure of a recording sheet in a conventional image forming apparatus for performing sub-scanning by moving the recording sheet as described above, a holding means (clamper) capable of holding the leading end of the recording sheet.
Is also movable along the scanning direction of the recording paper, and by moving the recording paper while holding the leading end of the recording paper with this clamper, the recording paper is moved (conveyed). According to this configuration, it is possible to accurately manage the movement of the recording paper. Therefore, it is particularly suitable for a color image forming apparatus such as a color printer that needs to form an image a plurality of times on the same recording paper.

[0004]

In the conventional color image forming apparatus constructed as described above, it is necessary to form an image a plurality of times on the same recording paper as described above. The recording paper on which the image has already been formed must be retracted to the image forming start position. here,
If the conveyance distance between the recording paper cassette accommodating the recording paper and the image forming start position is set to be longer than the length of one recording paper along the conveying direction, the retreating recording paper is moved in the conveying path at the time of conveyance. It is possible to guide you.

However, in such a case, the above-mentioned conveying distance must be set long, and it cannot be adopted from the viewpoint of downsizing of the apparatus. For this reason, it is necessary to employ a structure in which the backward conveyance path is provided in a state where the recording paper introduction conveyance path from the recording paper cassette to the image forming position is branched.

Here, if a structure is provided above the recording paper cassette in a state where it is branched from the introduction conveyance path, in other words, in a state where it is branched above the introduction conveyance path, the backward conveyance path is adopted. A dedicated installation space for arranging the passages is required, which increases the overall height of the device.
As a result, the size of the entire apparatus is increased, which is not preferable. On the other hand, a conveyance path switching member for guiding the introduction conveyance path to the backward conveyance path is required, which causes an increase in the number of parts, which is also not preferable from this viewpoint. Further, the degree of bending of the portion attached to the backward conveying path becomes tight, which may cause the recording sheet to have a curl when the recording sheet moves backward. From this viewpoint, improvement has been demanded.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide an image forming apparatus capable of keeping the overall height low. Another object of the present invention is to provide an image forming apparatus capable of retracting the recording paper without requiring a separate member for switching the conveyance path while achieving downsizing of the apparatus. . Another object of the present invention is to provide an image forming apparatus capable of suppressing curling of the recording paper as much as possible.

[0008]

In order to solve the above problems and achieve the object, the image forming apparatus according to the present invention is held by a movable recording paper holding means according to the first aspect of the invention. In the image forming apparatus that performs the image forming operation by scanningly moving the recording paper between the platen roller and the recording head arranged close to the platen roller by the movement of the recording paper holding means, the recording paper is recorded. It is characterized in that a backward conveying path is provided below the introduction conveying path for guiding to the paper holding means so as to guide the recording paper when the recording paper moves backward.

The image forming apparatus according to the present invention is
According to the second aspect of the present invention, the housing, the recording paper holding means movably provided while holding the recording paper, the platen roller, and the recording head provided so as to be capable of coming into contact with and separating from the platen roller. And an introduction conveyance path for guiding the recording paper to the recording paper holding means, and a backward conveyance path that is arranged under the introduction conveyance path so as to branch and guides the recording paper when the recording paper retreats. It is characterized by doing.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A configuration of an embodiment of an image forming apparatus according to the present invention is applied to a color printer as follows.
It will be described in detail with reference to the accompanying drawings. As shown in Figure 1,
The color printer 10 is a so-called full-color image forming apparatus, and is a plurality of times (magenta, cyan, yellow, black) on the same recording paper P based on image information separated into three colors of red, blue and green. The color image is formed on the recording paper P by sequentially performing image formation four times).

The color printer 10 is provided with a housing 12 which defines the outer surface thereof.
A lower housing portion 14 for accommodating a control unit (not shown) including a control board and an upper housing for accommodating a printer mechanism portion, which is arranged directly above the lower housing portion 14 and connected to the lower housing portion 14. And a section 16. On the front surface (left side surface in the figure) of the lower housing portion 14,
Although not shown, a slot for inserting and removing the control board and the like, and a lower cover for opening the slot so as to be openable are attached.

On the other hand, the upper housing portion 16 is arranged so as to surround the periphery of the printer mechanism portion, the upper and lower surfaces are open, and the housing body 16 communicates with the lower housing portion 14.
a. On the lower side of the front surface (left side surface in the drawing) of the housing body 16a, a cassette insertion port 16b into which a recording paper cassette 18 containing a large number of recording papers P is inserted.
Is formed on the upper side of the cassette insertion port 16b, and the first recording sheet P for ejecting the printed recording sheet P in the face-up state (that is, the state where the print surface faces upward) is formed.
The sheet discharge port 16c is formed.

Here, although not shown, a cassette cover for opening the cassette insertion opening 16b is attached to the front surface of the housing body 16a. That is, in this embodiment, the recording paper cassette 1
8 is a state in which the color printer 10 is mounted,
When the cassette 12 is completely inserted into the housing 12 and a cassette cover (not shown) is closed, the cassette 12 is completely hidden inside the housing 12. Further, a paper discharge port cover 16d for closing the paper discharge port 16b so as to be opened is attached. The discharge port cover 16d is rotatably supported on the front surface of the housing body 16a with its lower portion as a rotation fulcrum, and its configuration and operation will be described later in detail.

On the other hand, an opening 16e is formed on the upper surface of the housing body 16a so as to open the housing body 16a substantially entirely. The upper cover member 16f has its rear end in a state where the opening 16e is openably closed. Spindle 2 at (right end in the figure)
It is pivotally supported by the housing main body 16a through 0. That is, in this embodiment, the housing 12 is of a so-called clamshell type with its upper surface opened.

Here, the upper cover member 16f has an upper surface on which a paper receiving tray is inclined so that the depth from the upper surface is gradually increased toward the front (that is, toward the left in the drawing). A recess 16g is formed. That is, the discharge tray is defined from the portion of the upper cover member 16f where the recess 16g is formed. In addition, this recess 16g
A second paper ejection port 16h for ejecting the printed recording paper P in a face-down state (that is, a state where the printing surface faces downward) is formed on the front standing surface of the.

A thermal transfer head 2 to be described later is provided on the lower surface of the rear end portion (right end portion in the drawing) of the upper cover member 16f.
The mounting stay 24 to which 2 is mounted is integrally mounted in a lowered state. In other words, in this embodiment, as will be described later in detail, the printer mechanism section is accompanied by an upward pulling operation of the upper cover member 16f (a rotating operation around the support shaft 20 in the clockwise direction in the drawing). Is opened over substantially the entire surface, and in particular, the thermal transfer head 22
Ribbon cassette 2 to be described later is lifted upward while being separated from the other components of the printer mechanism.
A space is provided above 6 to allow a space for taking it in and out along the vertical direction.

At the lower part of the front end (the left end in the figure) in the above-mentioned upper housing part 16, the recording paper cassette 18 inserted through the above-mentioned cassette insertion port 16b is detachably attached. A sheet feeding unit 28 is provided.
Further, the recording paper P stored in the recording paper cassette 18 is introduced into the upper housing 16 one by one from the paper feeding unit 28,
After reversing the introduced recording paper P upward, the thermal transfer head 2
A paper transport mechanism 30 is provided for discharging the recording paper P, on which the color image is formed, which will be described later, via the housing 2 from the housing 12.

The sheet conveying mechanism 30 is in rolling contact with one front end of the upper side of the recording sheet P stored in the recording sheet cassette 18 mounted in the sheet feeding section 28, and the uppermost recording sheet P is rotated as the recording sheet P is rotated. Is provided with a pickup roller 32 for picking up to the right in the figure. In addition, this paper transport mechanism 3
Reference numeral 0 denotes an introduction conveyance path 34 for reversing the recording paper P picked up by the pickup roller 32 to the thermal transfer head 22, and a recording paper P provided via a clamper 36, which is arranged continuously to the introduction conveyance path 34. A clamper transport path 38 for transporting P, and a paper discharge transport path 40 that is arranged continuously to the clamper transport path 38 and discharges the recording paper P on which a color image has been formed to the outside of the housing 12.

Here, the recording paper P picked up from the recording paper cassette 18 is sandwiched at the base end portion of the above-described introduction conveyance path 34, and the recording paper P is conveyed toward the thermal transfer head 22 through the introduction conveyance path 34. A pair of introducing rollers 42 are provided. On the downstream side of the introduction roller pair 42 in the conveyance direction of the recording paper P, a conveyance roller for nipping the recording paper P reaching here and conveying the recording paper P toward the thermal transfer head 22 through the introduction conveyance path 34. A pair 44 is provided. The front half portion from the base end portion of the introduction conveyance path 34 to the portion where the conveyance roller pair 44 is provided is set to be substantially horizontal, and a pair of fixed guides are arranged so as to sandwich it vertically. Member 4
6a, 46b.

On the other hand, at the terminal end of the introduction transport path 34, the platen roller 48 around which the recording paper P reaching this point is partially wound, and the side surface of the platen roller 48 is rolled and contacted.
A pinch roller 50 for contacting the recording paper P with pressure is provided. The platen roller 48 is arranged above the position where the pickup roller 32 is arranged. Therefore, the latter half of the introduction conveyance path 34 from the conveyance roller pair 46a, 46b to the platen roller 48 has a recording paper. It is formed so as to exhibit a substantially semicircular arc so that P is inverted upward. The latter half of the introduction conveyance path 34 is fixed guide member 52a arranged so as to sandwich the latter.
And the movable guide member 52b. Here, the movable guide member 52b is pivotally supported around the support shaft 54, and the pinch roller 50 described above is pivotally supported at the upper end of the movable guide member 52b.

The above-mentioned thermal transfer head 22 can be brought into contact with the platen roller 48 on its upper side, and a transfer portion is defined between the two. That is, by heating the ink ribbon R via the thermal transfer head 22 in a state in which the ink ribbon R and the recording paper P housed in the ribbon cassette 26 are overlapped with each other, the sublimation dye of the ink ribbon R is removed. It is adapted to be transferred onto the recording paper P.

Here, the backward conveying path 56 is connected from below to the middle part of the latter half of the introducing conveying path 34 described above. The backward conveyance path 56 is smoothly connected to the middle part of the latter half of the introduction conveyance path 34 (that is, connected in a direction tangential to the above-described arc), extends obliquely downward, and is described above. A front half portion 56a that terminates at an upper portion in the space defined by the lower housing portion 14, and a rear half portion that extends from the end of the front half portion 56a toward the front surface of the housing 12 (to the left in the drawing) substantially horizontally. And 56b.

As described above, by providing the backward transport path 56, the recording paper P picked up from the recording paper cassette 18 is transported through the introduction transport path 34 until its rear end reaches the above-mentioned transfer portion, On the other hand, the recording paper P, which retreats along the introduction conveyance path 34 with the returning operation described later, is naturally introduced at its rear end into the first half of the retreat conveyance path 56 based on the strength of its own waist, and as a result, recording The entire sheet of paper P can be moved backward in the backward conveyance path 56 without returning to the paper feed unit 28.

In this embodiment, as described above, the backward conveying path 56 is arranged so as to be connected to the introducing conveying path 34 from below, that is, below the introducing conveying path 34, and , So as to extend into the lower housing portion 14. As a result, the disposition height of the upper housing 16 can be kept low by disposing such a backward conveying path 56, and the size of the color printer 10 as a whole can be kept low.

On the other hand, the above-mentioned clamper conveyance path 38 extends above the recording paper cassette 18 accommodated in the paper feed section 28 along the substantially horizontal direction toward the front of the upper housing section 16. It is arranged. Specifically, the clamper conveyance path 38 is shown in FIG. 1 in a state where the clamper 36 movably guided and supported by a pair of guide shafts 58 arranged parallel to each other in a horizontal plane clamps the recording paper P. As shown in FIG. 3, the sheet is conveyed / returned by moving between a print start position facing the platen roller 48 and a print end position facing the base end portion of the discharge conveyance path 40 as shown in FIG. It is defined by the recording paper P conveyance path.
The configuration of the clamper 36 will be described later.

Further, the above-described paper discharge / conveyance path 40 is formed straight from the clamper conveyance path 38 in a straight line, and the printed recording paper P is kept as it is (that is, in a face-up state) and the housing 12 is provided. Printed recording paper P, which is formed so as to draw an arc upward from the first paper discharge conveying path 40A for discharging outside and the clamper conveying path 38
And a second conveyance path portion 40B to be disposed outside the housing 12 in an inverted posture (that is, in a face-down state). Here, at the base end portion of the paper discharge conveyance path 40, the printed recording paper P sent from the clamper conveyance path 38 is transferred to the first paper discharge conveyance path unit 4
A gate member 60 is provided for selecting whether to send the sheet to the 0A or the second sheet discharge conveyance path section 40B.

The gate member 60 is provided on the clamper conveyance path 38 in accordance with the opening / closing operation of the sheet discharge port cover 16d described above.
The printed recording paper P from the first paper discharge conveyance path section 40.
A first position for leading to A, and a second sheet discharge conveyance path portion 40B
It is pivotally supported around the support shaft 60a so as to be swingable with respect to the second position for guiding to. Here, the end of the above-described first paper discharge transport path 40A faces the above-described first paper discharge port 16c, and the end of the second paper transport path 40B ends at the above-mentioned second discharge. It faces the paper mouth 16h.

Therefore, as will be described in detail later, as shown in FIG. 3, the paper discharge port cover 16d is opened, and the first paper discharge port 1 is opened.
By opening 6c, the gate member 60 is brought to the first position, and as a result, the printed recording paper P from the clamper conveyance path 38 is conveyed straight as it is, and the first paper discharge is performed. It will be discharged to the outside of the housing 12 through the port 16c. On the other hand, as shown in FIG. 1, the discharge port cover 16d is closed and the first discharge port 16c is closed, so that the gate member 60 is brought to the second position.
As a result, the printed recording paper P from the clamper conveyance path 38 is forced by the gate member 60 located at the second position so as to pass through the second paper ejection conveyance path portion 40B, and this second paper ejection conveyance is performed. It is discharged from the passage 40B to the outside of the housing 12 through the second discharge port 16h.

Specifically, the second paper discharge transport path 40B is
It is defined between the inner peripheral guide member 62a that defines the inner peripheral surface thereof, the outer peripheral guide member 62b that defines the outer peripheral surface thereof, and the upper surface of the gate member 60 at the second position. On the other hand, the first paper discharge conveyance path portion 40A is defined between the tapered lower surface formed on the lower end of the outer peripheral guide member 62b and the upper surface of the gate member 60 at the first position. There is.

On the other hand, in the first paper discharging and conveying path 40A, the first paper discharging and conveying path 40A is sandwiched between the gate member 60 and the first paper discharging port 16c. In addition, a first paper discharge roller pair 64 is provided in a state of rolling contact with the outside. In addition, in the second paper discharge conveyance path 40B, the second paper discharge path 16B is positioned between the respective end portions of the inner peripheral guide member 62a and the outer peripheral guide member 62b and the second paper discharge port 16h. The roller pair 66 is provided in a state of rolling contact with each other with the second sheet discharge conveyance path 40B interposed therebetween.

In this way, by constructing the paper discharge transport path 40, when the user of the color printer 10 prints an image over a plurality of pages on the recording paper P, the print surface is in a discharged state. When it is desired to immediately check what is printed by facing upward, or when it is desired to prevent the printed recording paper P from being curled, as shown in FIG. Simply by opening the first discharge port 16c, the printed recording paper P is face-up from the first discharge port 16c via the first discharge transport path section 40A. The sheets are sequentially discharged onto the discharge port cover 16d.

On the other hand, when the user wants to print an image over a plurality of pages on the recording paper P, and wants to stack the recording paper P in the print order even if the print surface faces downward in the discharged state. As shown in Figure 1,
By simply closing the discharge port cover 16d and closing the second discharge port 16c, the printed recording paper P is discharged from the second discharge port 16h via the second discharge transport path section 40B. In the face-down state, the sheets are sequentially discharged into the recess 16g of the upper cover member 16f that functions as a sheet discharge tray.

In this way, in this embodiment, the printed matter is printed by simply opening or closing the paper discharge port cover 16d provided on the front surface of the housing 12 according to the intention of the user. Whether the recording paper P is discharged straight in a face-up state or face-down in a state of being turned upside down.
It will be possible to select, and the operability will be greatly improved.

Next, referring to FIGS. 4 and 5, a connecting mechanism 68 for connecting the discharge port cover 16d and the gate member 60.
The configuration and operation of will be described.

As shown in FIG. 4, the discharge port cover 16d is
The housing main body 1 is provided with a support shaft 70 that pivotally supports the support shaft 70.
It is provided in 6a. Here, the connecting mechanism 68 includes a locking piece 72 integrally attached to the inner surface of the paper discharge port cover 16d. The locking piece 72 is planted in a substantially upright state on the inner surface of the paper discharge port cover 16d.
A first locking roller 74 is attached to the tip of the locking piece 72. With one end (the left end in the figure) engaged with the first locking roller 74 from above, the swing lever 7
Reference numeral 6 is swingably supported around a support shaft 78 extending along a horizontal axis orthogonal to the paper discharge direction of the recording paper P in the first paper discharge conveyance path portion 40A. Here, this support shaft 78
Is fixed to a substantially central portion of the swing lever 76 in the longitudinal direction.

The other end of the swing lever 76 (in the figure,
The second locking roller 80 is attached to the right end). On the other hand, the above-described gate member 60 is provided with an engaging piece 82 integrally attached to the gate member 60 and extending substantially forward. Here, this gate member 60
The angular position of the engaging piece 82 is defined in a state where the tip of the engaging piece 82 is in contact with the second locking roller 80 from below. Then, this engaging piece 82 is always the second locking roller 8
In order to maintain the state of abutting on 0 from below, a coil spring 84 for biasing the engaging piece 82 to rotate around the support shaft 60a is connected at the lower end. The upper end of the coil spring 84 is connected to the side surface of the housing body 16a via a locking pin 86.

Since the connecting mechanism 68 is configured as described above, as shown in FIG. 4, when the paper discharge port cover 16d closes the first paper discharge port 16b, the locking piece 72 is It is in a state of extending rearward along the substantially horizontal direction.
In this extended state, the engaging piece 82 is urged to rotate around the support shaft 60a in the clockwise direction by the urging force of the coil spring 84, and as a result, the tip end of the oscillating lever 7 engages.
6 is rotated around the support shaft 78 in the counterclockwise direction. The swing lever 76 thus biased to rotate in the counterclockwise direction is regulated in its rotation position in a state where one end of the swing lever 76 is in contact with the first locking roller 74 from above. It will be a matter.

As described above, in the state where the discharge port cover 16d closes the first discharge port 16b in this way, the discharge port cover 16d is connected to the discharge port cover 16d through the connection mechanism 68. Gate member 60 is defined to assume the second position.

From the state shown in FIG. 4, the discharge port cover 1
When 6d is rotated so as to open the first sheet discharge port 16c, in other words, it is rotated around the support shaft 70 in a counterclockwise direction and is brought into a substantially horizontal state. As shown in, the locking piece 72 is rotated from a substantially horizontal state to a substantially vertical state. Based on this rotation operation, the rocking lever 76 whose one end engages with the locking piece 72 is rocked around the support shaft 78 in the clockwise direction. In response to this swing drive, the engaging piece 82 with which the second locking roller 80 provided at the other end of the swing lever 76 engages is moved downward against the biasing force of the coil spring 84. It will be forced down. As a result, the gate member 60 to which the engaging piece 82 is integrally attached is rotationally driven around the support shaft 60a in the counterclockwise direction, and is thus rotated to the first position described above. Will be

On the other hand, from the state shown in FIG.
When 6d is rotated so as to close the first paper discharge port 16c, in other words, when it is rotated around the support shaft 70 in the clockwise direction, as shown again in FIG. The piece 72 rotates from a substantially vertical state to a substantially horizontal state. Based on this rotation operation, the rocking lever 76 whose one end engages with the locking piece 72 is rocked around the support shaft 78 in the counterclockwise direction by the biasing force of the coil spring 84. In response to this swinging drive, the engagement piece 82 moves the coil spring 84.
It will be pushed down forcibly against the urging force of. As a result, the gate member 60, to which the engaging piece 82 is integrally attached, is rotationally driven in the counterclockwise direction around the support shaft 60a, and thus returns to the above-described first position. Will be done.

As shown in FIG. 1 again, the movable guide member 52
An operation arm 88 is disposed on the right side of FIG. 1b in a state of being separated by a predetermined distance. The operation arm 88 is rotatably supported around a support shaft 90 that is set parallel to the support shaft 54 that supports the movable guide member 52b (that is, extends along the width direction of the color printer 10). Has been done. The operation arm 88 has a predetermined width in the width direction of the color printer 10, and roller-shaped cam followers 88A are provided at the upper ends of both side ends in the width direction.
Is rotatably provided. In addition, this operation arm 8
A cam shaft 92 extending along the width direction of the color printer 10 is disposed substantially above the printer 8. Then, at a position of the cam shaft 92 corresponding to the cam follower 88A,
The roller pressing cams 94 are fixed. A head operating cam 96, which will be described later, is also provided on the cam shaft 92.

On the other hand, the lower end of the movable guide member 52b and the lower end of the operating arm 88 are connected to each other by a spring 98. Due to the elastic return force of the spring 98, the movable guide member 52b is oscillated and urged counterclockwise in FIG. 1 and the operation arm 88 clockwise. Further, as will be described in detail later, the operation arm 88 swings around the support shaft 90 in accordance with the rolling contact position between the roller pressure contact cam 94 and the cam follower 88A, and the spring 98 moves in response to this swing. The swinging urging force on the guide member 52b changes. That is, according to the rotation of the cam shaft 92, the pressure contact force of the pinch roller 50 axially supported on the upper end of the movable guide member 52b against the platen roller 48 is changed.

That is, the swing of the operation arm 88 is restricted by the cam follower 88A contacting the outer peripheral cam surface of the roller pressure contact cam 94. On the other hand, the swing of the movable guide member 52b is restricted by the pinch roller 22 at the upper end of the movable guide member 52b contacting the platen roller 34 laterally in the horizontal direction. The operation arm 88 swings with the displacement of the outer peripheral cam surface with which the cam follower 88A abuts due to the rotation of the cam shaft 92 (rotation of the roller pressing cam 94), and the amount of deformation of the spring 98 changes due to this swing. As a result, the pressure contact force of the pinch roller 22 to the platen roller 34 changes.

On the upper side of the platen roller 34, the recording paper P
A thermal transfer head 22 is provided which is configured to swingably support a thermal head array 100 in the width direction of a head frame 102. This thermal transfer head 22 is
The head frame 102 is swingably supported on the above-described mounting stay 24 by a pivot shaft 104 at substantially the center in the left-right direction in FIG. Here, the thermal head array 1
00 is swingably supported around the pivot shaft 104.

As already described above, the mounting stay 24 is integrally attached to the upper cover member 16f pivotally supported from the housing body 16a so as to be swingable around the support shaft 20. . Also, this pivot 104
Although not shown in the figure, two spiral springs are wound and mounted, and the first spiral spring is interposed between the pivot shaft 104 and the head frame 102, and by the urging force thereof, The head frame 102 is rockingly biased clockwise in FIG. The second spiral spring is interposed between the pivot shaft 104 and the thermal head array 100, and the urging force of the second spiral spring urges the thermal head array 100 to oscillate counterclockwise in FIG. ing. In other words, the thermal head array 100 and the head frame 102 are rotationally biased in the directions away from each other by the biasing force of the second spiral spring.

The pivot 10 of the head frame 102
4, the end portions on the opposite side of the thermal head array 100 (that is, the end portions facing the cam shaft 92) are positioned at both ends in the width direction and correspond to the head operation cams 96. Thus, the cam follower 102a is attached. The swing of the thermal transfer head 22 causes the cam follower 1 to move.
02a is regulated by abutting on the outer peripheral cam surface of the head operation cam 96 fixed to the corresponding position of the cam shaft 92 described above. As a result, the thermal transfer head 22 is oscillated while following the displacement of the outer peripheral cam surface from the center of rotation due to the rotation of the head operation cam 96 (that is, the rotation of the cam shaft 92). .

The outer peripheral cam surface of the head operating cam 96 is formed in three steps with different radii within a predetermined angular range, and the cam followers 102a come into contact with the cam surfaces of the respective outer diameters, whereby the thermal transfer head 22 is formed. Has three different swing angles.

That is, when the cam follower 102a is in contact with the largest diameter cam surface, the thermal head array 10 is
0 is the transfer action position which faces the upper side of the platen roller 34 and is brought into pressure contact with a predetermined pressing force. Cam follower 102
When a is in contact with the second-stage middle-diameter cam surface, the thermal head array 100 is positioned slightly above the platen roller 34, and a space is provided between the outer periphery of the platen roller 34 and the thermal head array 100. The sheet feeding position is provided.
When the cam follower 102a corresponds to the smallest diameter cam surface, the cam follower 102a is separated from the head operating cam 96. As a result, the restraining force for restraining the position of the thermal transfer head 22 disappears. Therefore, the thermal transfer head 22 swings clockwise in FIG. 1 by the urging force of the first spiral spring (not shown), and the head frame 102 When the upper surface of the thermal head array 100 comes into contact with a part of the upper cover member 16f, the thermal head array 100 comes to a retracted position where it is largely separated from the platen roller 34.

On the other hand, the above-mentioned ribbon cassette 26 is detachably mounted in the housing body 16a so as to be located between the thermal transfer head 22 and the platen roller 48. This ribbon cassette 26 will be described in detail later.
Indicates a state in which the upper cover member 16f is rotated upward (that is, a state in which the upper cover member 16f is rotated in the clockwise direction around the support shaft 20).
In, the housing main body 16a is set so as to be taken in and out substantially vertically through the upper opening 16e of the housing body 16a.

The ribbon cassette 26 includes a delivery-side ink ribbon reel 106 in which an untransferred ink ribbon R is wound and housed, a take-up side ink ribbon reel 108 in which the transferred ink ribbon R is wound and housed, and both. And a connecting plate 110 for connecting to each other. On the other hand, in the housing body 16a, the delivery side ink ribbon reel 10 is positioned below the thermal transfer head 22.
6, the first receiving member 112 having a recess for receiving 6 is disposed, and the first receiving member 1 with the platen roller 34 interposed therebetween.
12, the take-up side ink ribbon reel 108
A second receiving member 114 having a recess for receiving is arranged.

The sending side ink ribbon reel 106, the winding side ink ribbon reel 108 and the connecting plate 110 are
It is integrally formed as an ink ribbon cassette. The ink ribbon R wound around the delivery-side ink ribbon reel 106 is configured such that ribbons of respective colors to be transferred are sequentially connected for each page (one sheet) of recording paper.

At the time of image formation in which the thermal transfer head 22 is at the transfer operation position, the ink ribbon R is sandwiched between the platen roller 48 and the thermal head array 100 (recording paper P in a state of overlapping with the recording paper P). P is on the platen roller 48 side, and the ink ribbon R is on the side of the thermal head array 100) and is synchronized with the movement of the recording paper P from the delivery side ink ribbon reel 106 to the take-up side ink ribbon. It will be wound up on the reel 108.

Platen roller 48 and thermal transfer head 22
On the left side in FIG. 1 of FIG.
Are supported by the housing body 16a and are horizontally arranged in the front-rear direction (left-right direction in FIG. 1). The guide shafts 58 are provided on the left and right sides of the color printer 10 in the width direction. As described above, the clamper 36 is slidably supported on the guide shafts 58 along the guide shafts 58.

Although not described in detail, the above-mentioned clamper 36 is provided on the upper side of the lower roller 116a having a rubber layer having a predetermined thickness formed on the surface thereof, and is provided on the upper side of the metallic upper roller 1 having a smooth surface.
18b is provided with a support roller pair 116 arranged in pressure contact. The lower roller 116a is connected to a gear (not shown in FIG. 1) when the clamper 36 is located at the sheet feeding position and the sheet discharging position.
The gears 6a and 6a mesh with drive gears (not shown in FIG. 1), respectively, and are rotationally driven counterclockwise in FIG. 1 by a rotary drive force transmitted through the drive gears. That is, when the clamper 36 is located at the paper feeding position and the paper discharging position, the lower roller 118a can be rotationally driven.

Next, the drive system in each of the above components will be schematically described. First, various rollers provided to convey the recording paper P, that is, the pickup roller 3
2, the introduction roller pair 42, the conveyance roller pair 44, the platen roller 48, the support roller pair 116 of the clamper 36, the first paper discharge roller pair 64, and the second paper discharge roller pair 66 are inside parts of the color printer 10. Is directly connected to a conveyance roller drive motor (not shown) provided in the above or via a clutch (not shown), and is rotationally driven by the conveyance roller drive motor. The transport roller drive motor can be rotationally driven in both forward and reverse directions.

Further, the above-mentioned cam shaft 92 is linked to a cam shaft drive motor (not shown), and is rotationally driven by this cam shaft drive motor. The roller pressure contact cam 96 and the operation head cam 96 are rotationally driven in synchronization with each other by the rotational drive of the cam shaft drive motor.

The take-up side ink ribbon reel 108 is linked to an ink ribbon take-up drive motor (not shown),
The ink ribbon take-up drive motor is rotationally driven. By rotating the take-up side ink ribbon reel 108 by the ink ribbon take-up drive motor, the take-up side ink ribbon reel 108 takes up the ink ribbon 54 wound around the delivery side ink ribbon reel 106.

Further, the above-mentioned clamper 36 is stretched between pulleys (not shown) located at both ends of the guide shaft 58, and a movable drive belt (not shown) arranged so as to have a track parallel to the guide shaft 58. Are coupled in place. This moving drive belt is driven to rotate by a clamper moving drive motor (not shown), and the clamper 36 is moved to the left and right in FIG. 1 along the guide shaft 58 by the movement of the moving drive belt. As a result, the clamper 36 moves the paper feed position defined by the position adjacent to the platen roller 48 and the thermal transfer head 22 as shown in FIG. 1 and the paper discharge conveyance path 4 as shown in FIG.
They can be positioned at the paper discharge position facing the 0 entrance portion, respectively.

The transport roller drive motor, the cam shaft drive motor, the ink ribbon take-up drive motor, the clamper movement drive motor, and the clutch (not shown) are configured to be driven and controlled by a controller (not shown). Has been done.

Color printer 10 constructed as described above
Is controlled and driven by a control device (not shown), and operates as described below to perform predetermined image formation (color printing operation).

First, as shown in FIG. 6, the thermal transfer head 22
From the standby state (retracted position) in which the thermal head array 100 of FIG.
The head operation cam 96 is rotated by the clockwise rotation in FIG.
7 and the roller pressing cam 94 are simultaneously rotated to move the thermal transfer head 22 to the thermal head array 100 as shown in FIG.
Is a paper feeding position slightly separated from the transfer operation position. Then, by driving the pickup roller 32,
The recording paper P accommodated in the recording paper P cassette 18 is taken out from the paper feed unit 28 and introduced into the paper transport mechanism 30. Then, the recording paper P is conveyed toward the clamper 36 via the introduction conveyance path 34 by the rotational driving of the introduction roller pair 42 and the conveyance roller pair 31. At this time, the clamper 36 is in the sheet feeding position.

The picked-up recording paper P is conveyed with its leading end guided by the arcuate guide surface of the movable guide member 52b, and is caught between the platen roller 48 and the pinch roller 22. After that, by rotation of the platen roller 48 which is driven to rotate counterclockwise in the drawing, the platen roller 48 is further conveyed toward the clamper 36 and guided by the thermal transfer head 22 to form the support roller pair 118 of the clamper 36 at the sheet feeding position. Toward the press contact portion of the upper and lower rollers 118a and 118b. When the leading end of the recording paper P reaches the pressure contact portion of the upper and lower rollers 118a and 118b of the support roller pair 118 of the clamper 36, the lower roller 118a is rotationally driven counterclockwise in the drawing, and the recording paper is interposed between the support roller pair 118. Bite P,
The rotational drive of the lower roller 118a is stopped when the predetermined amount of bite is reached. As a result, the leading end of the recording paper P is sandwiched and held by the support roller pair 118 of the clamper 36.

Thereafter, as the head operation cam 96 rotates, first, as shown in FIG. 8, the thermal head array 100 of the thermal transfer head 22 comes into contact with the outer peripheral surface of the platen roller 48 from above and is brought to the transfer operation position. After that, the head operation cam 96 further rotates, and resists the biasing force of the second spiral spring described above, and the head frame 1
02 is further rotated counterclockwise. In this way, as shown in FIG. 9, the head frame 102 comes close to the thermal head array 100. As a result, the thermal head array 100 is mounted on the platen roller 48.
It comes into contact with a predetermined pressure contact force.

From this state, as shown in FIG. 2, the clamper 36 is driven to the left from the paper feeding position, and the recording paper P is driven to move through the transfer portion. In synchronization with the movement of the recording paper P, the ink ribbon R is moved to the take-up side ink ribbon reel 1
08, and the first thermal magenta image formation (transfer) on the recording paper P by the thermal head array 100.
Is performed.

Since this embodiment is applied to a color image forming apparatus, this transfer process is performed in the magenta,
It is performed four times for cyan, yellow, and black. That is,
After the first magenta transfer process is completed, the clamper 3
6 is returned to the paper feeding position as shown in FIG. 1 from the state of the paper discharging position shown in FIG. 2, and is in the standby state for the next cyan transfer operation. After that, the clamper 36 is moved to the left side again (the recording sheet P is therefore moved and driven), and the cyan transfer process is performed. Thereafter, this process is repeated a predetermined number of times, and yellow and black are performed. Will be continuously executed.

Incidentally, when the recording paper P during the transfer operation is returned to the paper feeding position, the platen roller 48 is operated by the clamper 3 described above.
6 is rotationally driven in the opposite direction (clockwise direction in the figure) to that when the recording paper P is held (during paper feeding). When the clamper 36 returns to the paper feeding position, the trailing edge of the recording paper P does not return to the introduction transportation path 34 but returns to the backward transportation path 56 based on the strength of the waist of the recording paper P.
Will be run backwards (pull back).

In this way, the clamper 36 is operated after the transfer process of the predetermined number of times is completed (transfer of all colors is completed).
Is at the paper discharge position, where the lower roller 1 of the clamper 36 is
18a is rotated counterclockwise so that the support roller pair 118
The recording paper P held by is conveyed to the paper discharge side.

The recording paper P sent out (discharged) from the clamper 36 is, as already described above, the discharge port cover 16
When d is opened, by the first paper discharge roller pair 64 via the first paper discharge transport path portion 40A defined by the upper surface of the gate member 60 brought to the first position. The sheet is carried out (discharged) from the first paper discharge port 16c to the outside of the housing 12, and is discharged onto the paper discharge port cover 16d.

On the other hand, when the paper discharge port cover 16d is closed, the gate member 60 is brought to the second position.
Due to this, the first paper discharge conveyance path portion 40A is closed, and the recording paper P sent out (discharged) from the clamper 36 is moved along the inclined upper surface of the gate member 60 to the second paper discharge conveyance path portion. Forced to carry 40B. As a result, the recording paper P is turned up by being conveyed through the second paper discharge conveyance path portion 40B, and the second paper discharge roller pair 66 moves the recording paper P out of the housing 12 from the second paper discharge port 16h. It is carried out (discharged) and discharged into the recess 16g of the upper cover member 16f that functions as a discharge tray.

On the other hand, when the recording paper P is jammed during conveyance, or when the ink ribbon R in the delivery-side ink ribbon reel 106 of the ribbon cassette 26 runs out, when the ribbon cassette 26 is taken out, or When mounting the new ribbon cassette 26, first, as shown in FIG. 10, the latch mechanism (not shown) is released and the upper cover member 16f is rotated around the support shaft 20 in the clockwise direction. By the rotation of the upper cover member 16f, the opening 1 formed on the upper surface of the upper housing portion 16
6e will be opened over almost the entire surface. Further, the thermal transfer head 22 which is pivotally supported by the mounting stay 24 integrally mounted on the upper cover member 16f and is in the retracted position,
With the rotation of the upper cover member 16f, the upper cover member 1
In a state where the relative positional relationship with 6f is not changed, it is lifted up as shown in FIG. As a result, the upper space of the ribbon cassette 26 is opened over the entire surface.

In this way, in this embodiment, the ribbon cassette 26 is moved in the substantially vertical direction both when the used ribbon cassette 26 is taken out and when the unused ribbon cassette 26 is mounted. It can be moved along with, and the workability of the attaching / detaching operation is dramatically improved.

On the other hand, after the ribbon cassette 26 is taken out upward in this way, as shown in FIG. 11, the upper portion of the platen roller 48 is substantially opened, and as a result, the jammed recording paper P Can be easily removed.

The opening operation of the upper cover member 16f is not limited to being performed in the state where the thermal transfer head 22 is in the retracted position as described above, and in some cases, the thermal transfer head 22 feeds paper. The opening operation of the upper cover member 16f may be executed in the position or the transfer action position.

Even in such a case, as will be described below, the thermal transfer head 22 is lifted upward as the upper cover member 16f rotates. That is, when the thermal transfer head 22 is at the sheet feeding position or the transfer action position, the cam follower 102a attached to the head frame 102 contacts the outer peripheral surface of the operation head cam 96 and its position is restricted. Become. When the thermal transfer head 22 is lifted upward in accordance with the rotation of the upper cover member 16f from such a state, the cam follower 102a is separated from the outer peripheral surface of the operation head cam 96 according to the lifting operation.

For this reason, the force that restrains the cam follower 102a is released, and as a result, the restraining force that restrains the position of the thermal transfer head 22 disappears. Therefore, the thermal transfer head 22 does not have the first helical spring (not shown). By the urging force of the head frame 102, the head frame 102 abuts against the upper surface of the upper cover member 16f, so that the thermal head array 100 is largely separated from the platen roller 34 and the upper cover member 16f. On the other hand, the relative positional relationship is similar to that of the retracted position described above.

In this way, whether the thermal transfer head 22 is at the retracted position, the paper feeding position, or the transfer operation position, it is satisfactorily and surely moved upward as the upper cover member 16f is opened. Will be lifted.

Needless to say, the present invention is not limited to the configuration of the above-described embodiment, but can be variously modified without departing from the scope of the present invention.

For example, in the above-described embodiment, the recording head 22 is described as being attached to the attaching stay 24 integrally attached to the upper cover member 16f, but the present invention has such a configuration. Without being limited thereto, the point is that the recording paper head 22 is further moved from the standby position to the platen roller 4 in accordance with the rotating operation of the upper cover member 16f.
It may be interlockingly connected so as to move in a direction away from the side of the ribbon cassette 8, in other words, to a position where it does not interfere with the upward removal of the ribbon cassette 26.

Further, in the above-described embodiment, the recording paper P to be discharged passes through the first discharge conveyance path 40A or the second discharge according to the opening / closing operation of the discharge port cover 16d. Although it has been described that the setting is made as to whether or not the sheet passes through the paper transport path 40B, the present invention is not limited to such a configuration.
For example, a discharge mode switching button is separately provided, and the opening / closing operation of the discharge port cover 16d and the switching operation of the discharge path of the recording paper P are executed according to the switching operation of the discharge mode switching button. It may be configured. In short, it suffices that the opening / closing operation of the discharge port cover 16d and the switching operation of the discharge path of the recording paper P are performed in a mutually linked state.

Further, in the above-described embodiment, the recording paper P running backward in the introduction transport path 34 is explained as being brought to the backward transport path 56 based on the strength of the waist of the user.
The present invention is not limited to such a configuration, and for example, a recording paper path restricting member made of a Mylar film or the like is provided in the introduction conveyance path 34, and the recording paper path restricting member Introduce the conveying path 34 to the platen roller 48
When the recording sheet P is conveyed in the forward direction toward, the recording sheet P is retracted in the reverse direction of the introduction conveyance path 34, the recording sheet P is moved to the backward conveyance path 56. You may attach so that a conveyance direction may be regulated so that it may enter.

[0081]

As described in detail above, in the image forming apparatus according to the present invention, according to the first aspect of the invention, the recording paper held by the movable recording paper holding means is stored in the recording paper holding means. In the image forming apparatus that performs the image forming operation by moving the platen roller and the recording head arranged in proximity to the platen roller by the movement, an introduction conveyance path for guiding the recording sheet to the recording sheet holding means. It is characterized in that it is provided with a backward conveying path that branches downward and guides the recording sheet when the recording sheet moves backward.

The image forming apparatus according to the present invention is
According to the second aspect of the present invention, the housing, the recording paper holding means movably provided while holding the recording paper, the platen roller, and the recording head provided so as to be capable of coming into contact with and separating from the platen roller. And an introduction conveyance path for guiding the recording paper to the recording paper holding means, and a backward conveyance path that is arranged under the introduction conveyance path so as to branch and guides the recording paper when the recording paper retreats. It is characterized by doing.

Therefore, according to the present invention, it is possible to provide an image forming apparatus capable of keeping the overall height low. Further, according to the present invention, it is possible to provide an image forming apparatus capable of retreating the recording paper without requiring a separate member for switching the conveyance path while reducing the size of the apparatus. Further, according to the present invention, it is possible to provide an image forming apparatus capable of suppressing the curl of the recording paper as much as possible.

[Brief description of drawings]

FIG. 1 is a side sectional view showing a schematic configuration of a color printer to which a configuration of an embodiment of an image forming apparatus according to the present invention is applied.

FIG. 2 is a side sectional view showing the color printer shown in FIG. 1 in a state where a clamper is at a sheet discharge position.

FIG. 3 is a side sectional view showing the color printer shown in FIG. 1 in a state in which a paper discharge port cover is opened.

FIG. 4 is a side sectional view showing a paper discharge structure of the color printer shown in FIG. 1 in a state in which a paper discharge port cover is closed.

5 is a side cross-sectional view showing a paper discharge structure of the color printer shown in FIG. 4 with a paper discharge port cover opened.

6 is a side sectional view showing the structure around the platen roller of the color printer shown in FIG. 1 with the thermal transfer head in the retracted position.

7 is a side sectional view showing a structure around a platen roller of the color printer shown in FIG. 6 in a state where a thermal transfer head is at a sheet feeding position.

8 is a side sectional view showing a structure around a platen roller of the color printer shown in FIG. 6 in a state where a thermal transfer head is in a transfer operation position and a thermal head array is in light contact with a platen roller.

9 is a side sectional view showing the structure around the platen roller of the color printer shown in FIG. 6 in a state where the thermal transfer head is in a transfer operation position and the thermal head array is in strong contact with the platen roller.

FIG. 10 is a side sectional view showing the color printer shown in FIG. 1 with an upper cover member opened.

11 is a side sectional view showing the color printer shown in FIG. 10 with a ribbon cassette taken out upward.

[Explanation of symbols]

 P Recording paper R Ink ribbon 10 Color printer 12 Housing 14 Lower housing part 16 Upper housing part 16a Housing body 16b Cassette insertion port 16c First paper discharge port 16d Paper discharge port cover 16e Opening 16f Upper cover member 16g Paper receiving recess Location 16h Second discharge port 18 Recording paper cassette 20 Spindle 22 Thermal transfer head 24 Mounting stay 26 Ribbon cassette 28 Paper feed unit 30 Paper transport mechanism 32 Pickup roller 34 Introduction transport path 36 Clamper 38 Clamper transport path 40 Discharge transport path 40A 1st discharge conveyance path part 40B 2nd discharge conveyance path part 42 Introducing roller pair 44 Conveying roller pair 46a; 46b Fixed guide member 48 Platen roller 50 Pinch roller 52a Fixed guide member 52b Movable guide member 54 Spindle 56 Backward transport path 6a The first half of the backward conveyance path 56b The second half of the backward conveyance path 58 Guide shaft 60 Gate member 60a Support shaft 62a Inner circumference guide member 62b Outer circumference guide member 64 First paper discharge roller pair 66 Second paper discharge roller pair 68 Connection Mechanism 70 Spindle 72 Locking piece 74 First locking roller 76 Swing lever 78 Spindle 80 Second locking roller 82 Engaging piece 84 Coil spring 86 Locking pin 88 Operating arm 88a Cam follower 90 Spindle 92 Cam Shaft 94 Roller pressure contact cam 96 Operation head cam 98 Spring 100 Thermal head array 102 Head frame 102a Cam follower 104 Pivot shaft 106 Sending side ink ribbon reel 108 Winding side ink ribbon reel 110 Connecting plate 112 First receiving member 114 Second receiving Member 116 Support roller pair 116a Lower roller 116b Upper roller.

Claims (4)

[Claims] 1. An image is obtained by moving a recording paper held by a movable recording paper holding means between a platen roller and a recording head arranged close to the platen roller by the movement of the recording paper holding means. In an image forming apparatus that performs a forming operation, a retraction conveyance path that branches the recording sheet below an introduction conveyance path that guides it to the recording sheet holding unit and guides it when the recording sheet retreats is provided. A characteristic image forming apparatus. 2. A housing, a recording paper holding means movably provided while holding the recording paper, a platen roller, a recording head provided so as to be able to come into contact with and separate from the platen roller, and the recording. It is characterized in that it is provided with an introduction conveyance path for guiding the paper to the recording sheet holding means, and a backward conveyance path which is arranged under the introduction conveyance path so as to be branched and which guides the recording sheet when it retreats. Image forming apparatus. 3. A lower part of the housing is provided with a disposition space in which a control means for controlling an image forming operation is disposed, and the retreat conveyance path extends to the disposition space. The image forming apparatus according to claim 2. 4. The introduction transport path includes an arc-shaped transport path portion, and the backward transport path is connected in a state of being substantially in contact with the arc-shaped portion of the introduction transport path. Alternatively, the image forming apparatus described in 2.