JP2001122492A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of preventing a recording medium from being attracted to discharge sheet guide member without using a brush for static elimination. SOLUTION: A long platen 42 is installed in a plotter 40, while an discharge sheet guide member 44 in cylindrical shape is installed under the platen forefront about the sheet discharging direction. The guide member 44 has a shaft 46 stretching perpendicular to the sheet discharging direction (Arrow C) in which the image part 16a of the recoding medium is discharged and a cylinder 48 rotating round the shaft 46. The shaft 46 and cylinder 48 are coupled together by a coupling plate 47 to build a single piece structure, and the shaft 46 also rotate together with the cylinder 48. The ends of the shaft 46 are fixed to legs 52 through bearings 50.

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 for forming an image on a recording medium conveyed in a predetermined direction, and more particularly to an image forming apparatus suitable for an ink jet system for forming an image by discharging ink.

[0002]

2. Description of the Related Art As one of output devices of a computer or a workstation, an electrophotographic image forming apparatus for forming an image on a recording medium using a developer, and an ink jet for forming an image by discharging ink onto the recording medium. 2. Description of the Related Art A conventional image forming apparatus is known.

An example of such an image forming apparatus, for example, an ink jet type image forming apparatus will be described with reference to FIG.

FIG. 11 is a schematic view showing an example of a conventional ink jet type image forming apparatus.

[0005] The ink jet type image forming apparatus 10 comprises:
A print head 12 is provided with a plurality of ink discharge ports for discharging ink, and a carriage 14 on which the print head is mounted and reciprocates in a scanning direction (a direction perpendicular to the plane of FIG. 11). The inkjet image forming apparatus 10 includes a drive roller that intermittently conveys a recording medium such as a roll paper 16 in an arrow A direction (a recording paper conveyance direction, which is referred to as a sub-scanning direction) orthogonal to the above scanning direction. 18 and a paper transport roller 20 are also provided. Further, the inkjet type image forming apparatus 10 is provided with a platen 22 on which a recording medium is placed, and a paper discharge guide plate 24 for guiding the recording medium to the outside.

When an image is formed on the roll paper 16, the roll paper 16 being transported by the drive roller 18 and the paper transport roller 20 is temporarily stopped, and the carriage 14 is reciprocated in the above-described predetermined direction. The print head 1 is provided on a portion of the paper 16 which is located in the image forming area 26 where an image is formed.
According to the control of 2, ink is ejected from an ink ejection port (not shown) to form (print) an image for one band, and thereafter,
The roll paper 16 is transported by a predetermined length, and the image forming area 26 is conveyed.
The operation of forming an image for the next band on the newly located surface is repeated.

When the portion of the roll paper 16 located in the image forming area 26 absorbs ink, this portion may rise. In addition, a portion located in the image forming area 26 may rise due to wrinkles or curl of the roll paper 16. Such a rise changes the distance between the print head 12 and the roll paper, so that the image quality deteriorates. Therefore, a plurality of air suction holes 22a are formed in the platen 22, and air is sucked from the air suction holes 22a by the suction fan 28 disposed below the air suction holes 22a, thereby the roll paper 16 is placed on the platen 2.
2 to prevent its lifting.

The image forming area 2 of the roll paper 16
The portion on which the image is formed at 6 (hereinafter, referred to as an image portion) is guided by the paper discharge guide plate 24 and discharged. At this time, the image portion and the paper discharge guide plate 24 may rub against each other to generate static electricity. When such static electricity is generated, the image portion of the roll paper 16 is electrostatically attracted to the paper discharge guide plate 24 and the roll paper 16 is not smoothly transported. For this reason, even if the roll paper 16 is sucked through the air suction holes 22a, a portion of the roll paper 16 located in the image forming area 26 may float or wrinkles may be generated in this portion. As a result, the quality of the formed image deteriorates, and further, the roll paper 16
May collide with the print head 12 and damage the print head 12.

When an image is formed on a small-sized cut sheet instead of the roll sheet 16 as described above, the cut sheet on which the image has been formed remains electrostatically attracted to the sheet discharge guide plate 24. Sometimes. In this case, the cut sheet that has been conveyed next may overlap with the preceding cut sheet, disturbing the image of the cut sheet, or causing a paper jam (jam).

Referring to FIGS. 12 and 13, an ink-jet type image forming apparatus in which measures for preventing the above-mentioned trouble caused by static electricity have been taken will be described.

FIG. 12 is a perspective view showing a conventional ink jet type image forming apparatus in which a countermeasure against static electricity is taken. FIG. 13 is a schematic diagram showing an internal configuration of the ink jet type image forming apparatus shown in FIG. In these drawings, the same components as those shown in FIG. 11 are denoted by the same reference numerals.

The feature of the ink jet type image forming apparatus 30 is that a boundary between the platen 22 and the paper discharge guide plate 24 is
The point is that a static elimination brush 32 for eliminating static electricity is arranged.
By arranging the static elimination brush 32 in this way,
Static electricity generated between the image portion and the paper discharge guide plate 24 is eliminated. As a result, the trouble caused by the static electricity as described above is eliminated.

[0013]

However, the static elimination brush 3
2 is installed, so it costs much. Further, since the charge removing brush 32 is worn, its life is limited. Further, the hairs of the charge removing brush 32 may come off and scatter around, and may adhere to the recording medium or the print head 12.
When the hair of the discharging brush 32 adheres to the print head 12,
There is a possibility that ink ejection may be defective.

In addition, the ink jet type image forming apparatus 3
0 includes a cleaning blade for cleaning the ink ejection ports of the print head 12, and the like.
If the bristles of the charge removing brush 32 adhere to the cleaning blade or the like, the ink discharge ports may not be sufficiently cleaned. Furthermore, depending on the temperature and humidity of the environment in which the inkjet type image forming apparatus 30 is used, the static elimination brush 32 may not be able to sufficiently eliminate static electricity, and the recording medium may be attracted to the paper discharge guide member 24.

In order to solve the above problems, it is necessary to take measures to prevent the hairs of the charge removing brush 32 from falling off and to prevent the fallen hairs from scattering. However, even if such a preventive measure is taken, it is not possible to completely prevent the hair from falling off or scattering, and there may be a case where defective ink ejection or adsorption of the recording medium occurs.

SUMMARY OF THE INVENTION In view of the above circumstances, it is an object of the present invention to provide an image forming apparatus which prevents a recording medium from being attracted to a paper ejection guide member without using a charge removing brush.

[0017]

According to an aspect of the present invention, there is provided an image forming apparatus comprising: a platen for placing a recording medium on an image forming area where an image is formed; In an image forming apparatus for forming an image in a portion located in an image forming area, (1) guiding an image portion of a recording medium on which an image is formed in the image forming area to the outside, wherein the image portion is guided And a paper discharge guide member that rotates about an axis extending in a cross direction that intersects the direction.

Here, (2) the paper discharge guide member may be a cylindrical member extending in the cross direction.

(3) The paper discharge guide member may be composed of a plurality of disc-shaped individual paper discharge guide members coaxially arranged in the cross direction.

(4) Each of the plurality of individual paper discharge guide members may rotate independently of each other.

Further, the above-mentioned image forming apparatus includes:
(5) The paper ejection guide member that rotates the paper ejection guide member may be provided with a non-contact drive source.

(6) The drive source may be a suction fan that discharges the sucked air and rotates the paper discharge guide member.

Still further, (7) the suction fan may be one for sucking air so that the recording medium is adsorbed on the platen.

Further, the above image forming apparatus is
(8) There may be provided a blocking means for blocking the air for rotating the paper discharge guide member at a predetermined timing.

Further, the above-mentioned image forming apparatus includes:
(9) A stop member for stopping the rotation of the paper discharge guide member at a predetermined timing may be provided.

Further, the above-mentioned image forming apparatus is provided with (1)
0) A drive source connected to the paper discharge guide member and configured to rotate the paper discharge guide member may be provided.

(11) The drive source may reciprocate a print head which ejects ink onto a recording medium in the main scanning direction while reciprocating in a predetermined main scanning direction.

Furthermore, (12) the paper discharge guide member may be one in which cylindrical irregularities extending in the circumferential direction are formed on the outer peripheral surface.

(13) The paper discharge guide member may be formed such that a groove extending in parallel with the central axis is formed on the outer peripheral surface.

(14) The paper ejection guide member may have a large number of irregularities formed on the surface thereof.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an image forming apparatus according to the present invention will be described below with reference to the drawings.

A first embodiment of the image forming apparatus will be described with reference to FIGS.

FIG. 1 is a schematic diagram showing a color plotter (hereinafter referred to as a plotter) which is an example of an image forming apparatus using an ink jet system. FIG. 2A is a perspective view showing a paper ejection guide member of the plotter of FIG. 1, and FIG. 2B is a side view showing the paper ejection guide member. In these figures, FIG.
Components that are the same as those shown in FIG. 1 are given the same reference numerals.

The features of the plotter 40 are that a platen 42 longer than the platen 22 is incorporated in the plotter 40 in place of the platen 22 (see FIG. 1), and that a cylindrical The point is that the paper ejection guide member 44 is incorporated in the plotter 40.

The paper discharge guide member 44 is an example of a direction perpendicular to the paper discharge direction (the direction of arrow C) in which the image portion 16a of the recording medium is discharged (an example of an intersecting direction in the present invention). A shaft 46 extending in the same direction) and a cylinder 48 rotating about the shaft 46 as a central axis. Shaft 46 and cylinder 48
As shown in FIG. 2 (b), are integrally connected by a connecting plate 47, and the shaft 46 rotates together with the cylinder 48. Both ends of the shaft 46 are fixed to the legs 52 via bearings 50.

The platen 42 is a conventional platen 2
It is longer than 2 and extends in the paper discharge direction. The leading end of the platen 42 in the sheet discharging direction is located above the cylinder 48 so as to cover the cylinder 48. Therefore, as shown in FIG. 1, the image portion 16a conveyed on the platen 42
Is guided so as to fall from the leading end in the sheet discharging direction. The dropped image portion 16a is guided outside by the cylinder 48 while contacting the outer peripheral surface of the side of the cylinder 48.

Incidentally, the shaft 46 and the cylinder 48 are not connected to a drive source for rotating them. The force for rotating the shaft 46 and the cylinder 48 is a contact force when the image portion 16a of the recording medium contacts the outer peripheral surface of the cylinder 48. Since this contact force is usually a very weak force, the paper discharge guide member 44 is configured so that the cylinder 48 rotates even with this weak force.

In order to adopt such a configuration, the bearing 50 is configured such that when a slight load (for example, about several g) acts on the cylinder 48, the cylinder 48 rotates together with the shaft 46 in the direction of arrow D. I have. The circularity of the cylinder 48 is high, and the cylinder 48 has a good balance in the diameter direction.

Since the paper discharge guide member 44 is configured as described above, the image portion 16a conveyed on the platen 42 falls from the leading end of the platen 42 in the paper discharge direction as shown in FIG. When the cylinder 48 contacts the outer peripheral surface of the side of the cylinder 48, the cylinder 48 rotates by the contact force to guide the image portion 16a downward. The image portion 16a guided downward in this manner and cut by the cutter (not shown) naturally falls under its own weight. Therefore, the image portion 16a is
8 is not rubbed. Therefore, the cylinder 48 and the image portion 1
No static electricity is generated between the image portion 16a and the cylindrical portion 48a.
As a result, the problem caused by the suction is eliminated, and the quality of the image formed on the image portion 16a does not deteriorate.
Further, since the image portion 16a does not rub the cylinder 48, the durability of the cylinder 48 is excellent.

Even if the cut image portion 16a sticks to the cylinder 48 and remains, the leading end of the next cut image portion 16a replaces the remaining preceding image portion 16a. As a result, the preceding image portion 16a falls under its own weight. The cylinder 48
Has a large roughness, so that static electricity is hardly generated.

With reference to FIG. 3, another example of the paper ejection guide member 44 will be described.

FIG. 3A is a perspective view showing another example of the paper ejection guide member, and FIG. 3B is a side view showing the paper ejection guide member. In this figure, the same components as those in FIG. 2 are denoted by the same reference numerals.

The paper discharge guide member 60 is characterized by a plurality of disc-shaped individual paper discharge guide members 62 instead of the cylinder 48 shown in FIG.
It is in the point which arranged. The plurality of individual paper discharge guide members 62 are coaxially arranged on one shaft 64, and rotate independently of each other with the shaft 64 as a rotation center axis. Individual paper ejection guide member 62
Are rotatably connected to a shaft 64 by connection arms 66, respectively. It should be noted that a plurality of individual paper discharge guide members 62
Since they have the same shape, when they are made of resin, one small mold may be used.

The size of the recording medium guided by the discharge guide member 60 may change. In this case, the number of individual paper discharge guide members 62 with which the recording medium comes into contact changes according to the size. Therefore, when an image is formed on a small-sized recording medium, only a small number of individual paper discharge guide members 62 corresponding to the small size rotate independently. For this reason,
Only the individual discharge guide members 62 corresponding to the size of the recording medium rotate independently, and the individual discharge guide members 62 not corresponding to this size (the individual discharge guide members not contacting the recording medium) do not rotate. Therefore, the rotation resistance is smaller than when all the individual paper discharge guide members 62 rotate, and the individual paper discharge guide members 62 are easily rotated. As a result, generation of static electricity is further suppressed.

With reference to FIG. 4, another example of the paper discharge guide member 44 will be described.

FIG. 4A is a perspective view showing still another example of the paper ejection guide member, and FIG. 4B is a side view showing the paper ejection guide member. In this figure, the same components as those in FIG. 2 are denoted by the same reference numerals.

The paper discharge guide member 70 is characterized in that, instead of the cylinder 48 shown in FIG. 2, a cylindrical member 72 having circumferentially extending ribs 72a formed on the outer peripheral surface at predetermined intervals is used. By the rib 72a, irregularities are formed on the outer peripheral surface of the cylindrical member 72.

The recording medium guided by the paper ejection guide member 70 is guided while being in contact with the cylindrical member 72 having the unevenness formed on the outer peripheral surface. Therefore, the contact area when the recording medium comes into contact with the outer peripheral surface is smaller than when there is no unevenness on the outer peripheral surface. As a result, the generation of static electricity due to the recording medium rubbing the outer peripheral surface of the cylindrical member 72 is more reliably prevented. The interval between the ribs 72a adjacent to each other and the number of the ribs 72a are selected so that the contact force when the recording medium comes into contact with the ribs 72a is such that the cylindrical member 72 is rotated. In addition, when the recording medium comes into contact with the ribs 72a, static electricity may be generated to some extent. In consideration of such a point, the separation property when the recording medium is separated from the cylindrical member 72 is improved. Next, the interval and the number of the ribs 72a are selected.

With reference to FIG. 5, another example of the paper discharge guide member 44 will be described.

FIG. 5A is a perspective view showing still another example of the paper ejection guide member, and FIG. 5B is a side view showing the paper ejection guide member. In this figure, the same components as those in FIG. 2 are denoted by the same reference numerals.

The discharge guide member 80 is characterized by a plurality of grooves 8 extending in the longitudinal direction of the shaft 46 instead of the cylinder 48 shown in FIG.
2a is that the cylindrical member 82 having the formed 2a is used. By the plurality of grooves 82a, irregularities are formed on the outer peripheral surface of the cylindrical member 82.

The recording medium guided by the paper ejection guide member 80 is guided while contacting a cylindrical member 82 having a plurality of grooves 82a (irregularities) formed on the outer peripheral surface. Therefore, the contact area when the recording medium comes into contact with the outer peripheral surface is smaller than when there is no unevenness on the outer peripheral surface. As a result, the generation of static electricity due to the recording medium rubbing the outer peripheral surface of the cylindrical member 82 is more reliably prevented. The plurality of grooves 82a
Are selected such that the contact force when the recording medium comes into contact with the cylindrical member 82 is such that the cylindrical member 82 rotates. The recording medium is a cylindrical member 8.
In some cases, a small amount of static electricity may be generated when the recording medium comes into contact with the recording medium 2.
Select the interval of a and its number.

The above-described paper discharge guide members 44, 60, 70,
According to 80, for example, the roll paper 16 cut so as to have a size of A4 size (210 mm in length) or more is not electrostatically attracted to the cylinder 48, the individual discharge guide member 62, and the cylindrical members 72 and 82. Paper can be discharged smoothly.

By the way, in an image forming apparatus such as a plotter, the leading end of the recording medium may be curved instead of straight, or the leading end of the recording medium may be curled due to humidity. The roll paper 16 may be cut so that the length in the transport direction is shorter than the length of the A4 size paper. In such a case, the leading end of the recording medium cannot reach a position where the cylinder 48, the individual discharge guide member 62, and the cylindrical members 72 and 82 can be rotated. If the cylinder 48 does not rotate, the recording medium is not discharged. A paper ejection guide member in which the cylinder 48 and the like are forcibly rotated even when the cylinder 48 and the like are not rotated by the recording medium will be described with reference to FIG.

FIG. 6 is a schematic diagram showing a schematic configuration of a plotter in which a cylinder is forcibly rotated. In this figure, the same components as those shown in FIG. 1 are denoted by the same reference numerals.

The plotter 90 is provided with a platen 92 on which the roll paper 16 is placed. Below the platen 92, a suction fan 94 for adsorbing a portion of the roll paper 16 located in the image forming area to the platen 92 is arranged. A number of air suction holes 92a are formed in the platen 92, and when the suction fan 94 is rotated, air is sucked from the air suction holes 92a. For this reason, even if the roll paper 16 has a portion that is raised due to curl, cockling, or wrinkles, the roll paper 16 adheres to the platen.

Further, below the leading end of the platen 92 in the sheet discharging direction, a sheet discharging guide member 100 for guiding an image portion to the outside is arranged. The basic configuration of the paper ejection guide member 100 is the same as the paper ejection guide member 44 shown in FIGS.
The paper discharge guide member 100 is characterized in that wind receiving members 102 for receiving wind are fixed to both ends (or one end) of the shaft 46 in the longitudinal direction. The air receiving member 102 includes a disk 104 fixed to the shaft 46 and a plurality of (eight in this case) air receiving plates 106 formed radially on the disk 104.

The above-described suction fan 94 and the paper discharge guide member 1
During the period 00, the air (wind) sucked and discharged by the suction fan 94 hits the wind receiving plate 106, and the cylinder 48 moves in the direction indicated by the arrow C.
An air path that rotates in the direction is formed. Therefore,
When the suction fan 94 is rotating, the cylinder 48 is forcibly rotated in the direction of arrow C, and the recording medium in contact with the cylinder 48 is discharged with this rotation.

In the configuration shown in FIG. 6, the cylinder 48 always rotates while the suction fan 94 is being driven. However, for example, the cylinder 48 may be rotated only when the roll paper 16 is cut and discharged. This configuration will be described with reference to FIGS.

FIG. 7 is a schematic diagram showing a state in which the rotation of the cylinder is stopped by the stop arm, and FIG. 8 is a schematic diagram showing a state in which the cylinder can be rotated by releasing the stop arm. In these drawings, the same components as those shown in FIG. 6 are denoted by the same reference numerals.

At one end of the shaft 46 in the longitudinal direction, a wind receiving member 10
2 is fixed. Immediately above this wind receiving member 102,
A stop arm 110 (an example of a stop member according to the present invention) that stops the rotation of the cylinder 48 at a predetermined timing is provided. The stop arm 110 has a “U” shape, and selectively rotates around a shaft 112 in the directions of arrows D and E. Lower end 110 of stop arm 110
One end of the coil spring 114 is fixed to a, and the other end is fixed to the wall of the main body. Stop arm 11
0 is urged by a coil spring 114 so as to rotate in the direction of arrow D about the shaft 112.

A projection 116 for stopping the stop arm 110 so that the stop arm 110 does not rotate too much
12 is formed above. The stop arm 110 is rotated in the direction of arrow D by the coil spring 114 to
When the stop arm 110 is stopped in a state where the stop arm 110 abuts, the lower end 110 a of the stop arm 110 is in contact with one of the plurality of wind receiving plates 106 of the wind receiving member 102. For this reason, even if it receives the wind from the suction fan 94 (see FIG. 6), the cylinder 48 cannot rotate and remains stopped.

When an image is being formed on a recording medium, the carriage 14 scans the area L1. When the carriage 14 is located within the range of the area L1, the carriage 14 is not in contact with the stop arm 110 at all, the stop arm 110 is in contact with the wind receiving plate 106, and the cylinder 48 remains stopped. is there.

On the other hand, when the image forming operation is completed and the recording medium is cut, the blade 118a protrudes from the cutting device 118 and moves the carriage 14 to the position shown in FIG. 8 while cutting the recording medium. In this case, the carriage 14 is located in the region L2, and the carriage 14 is
14 at the top end of the stop arm 110
10b is pushed in the direction of arrow E. Thereby, the stop arm 1
10 rotates around the shaft 112 in the direction of arrow E, and the lower end portion 110a of the stop arm 110 separates from (separates from) the wind receiving plate 106. As a result, the cylinder 48 starts rotating, and the cut recording medium is discharged with this rotation. In addition,
After cutting the recording medium with the blade 118a, the carriage 14
Exits from the area L2. As a result, the state returns to the state shown in FIG.

In the above example, the cylinder 48 is stopped by bringing the stop arm 110 into contact with the wind receiving plate 106. However, the suction fan 94 (see FIG. 6) is stopped so that the cylinder 48 stops at the same timing as described above. ) May be incorporated with a blocking member (not shown) for blocking the wind from the above. In this case, it is preferable that the blocking member be configured to interlock with the movement of the carriage 14. Note that, instead of the cylinder 48, the individual paper discharge guide member 62
(See FIG. 3) or cylindrical members 72 and 82 (see FIGS. 4 and 5). Bearings 5 are provided at both ends of the shaft 46.
Since 0 is fitted, the rotation resistance of the shaft 46 is small.

Another example of the paper ejection guide member will be described with reference to FIGS. 9 and 10.

FIG. 9 is a perspective view showing another example of the paper ejection guide member, and FIG. 10 is a side view showing the paper ejection guide member of FIG. In these drawings, the same components as those shown in FIG. 1 are denoted by the same reference numerals.

The paper discharge guide member 120 is an example of a direction orthogonal to the paper discharge direction (the direction of arrow C) in which the image portion 16a of the recording medium is discharged (the direction of the cross in the present invention). (In the same direction) and a cylinder 48 that rotates about the axis 122. The shaft 122 is slightly longer than the shaft 46 (see FIGS. 1 and 2).
Has one end protruding from the cylinder 48. A belt pulley 124 is fixed to the protruding portion as described later. The shaft 122 and the cylinder 48 are
As in the case of 8, the connecting plate 47 (see FIG. 2) is connected to form an integral unit, and the shaft 122 rotates together with the cylinder 48.

A belt pulley 124 is fixed to a portion of the shaft 122 protruding from the cylinder 48. At a position away from the belt pulley 124, a pulley 126 having a built-in one-way clutch (not shown) is provided with a side plate (not shown). (Not shown). Belt pulley 124 and pulley 1
An endless belt 128 is stretched around 26. The shaft 130 is fitted in a one-way clutch built in the pulley 126. The shaft 130 is parallel to the shaft 122 and is rotatably fixed to two side plates (not shown). When the shaft 122 rotates in the direction of arrow C, the endless belt 12 is rotated.
A one-way clutch is fitted to the shaft 130 so that the shaft 8 and the shaft 130 also rotate in the direction of arrow C. Also, the shaft 12
2 rotates in the direction opposite to the direction of arrow C and pulley 12
Numeral 6 indicates that the shaft 130 does not rotate and does not rotate.

A substantially straight arm 132 is fixed to the end of the shaft 130. One end of a tension coil spring 134 is fixed to the lower end of the arm 132. The other end of the extension coil spring 134 is fixed to a side plate (not shown). Accordingly, the arm 132 is urged to rotate about the shaft 130 in a direction opposite to the direction of arrow C. As described above, the cylinder 4
Drive source (arm 132 or endless belt 12
8 etc.) are connected. Note that arm 1
At a position where 32 is slightly inclined from the vertical direction, a stopper (not shown) for stopping the rotation of the arm 132 is formed.

The cam 14a is formed on the carriage 14 to contact the upper end of the arm 132. As shown in FIG. 9, when the recording medium is cut by the cutter 118a (see FIG. 8) and the carriage 14 reaches outside the image forming area,
The cam 14a pushes the upper end of the arm 132 in the direction of arrow F. Thereby, the shaft 130, the endless belt 128, and the shaft 1
24 rotates in the direction of arrow C and the cylinder 48 also rotates in the direction of arrow C, and the cut recording medium is discharged with this rotation. Instead of the cylinder 48, the individual paper discharge guide member 62 (see FIG. 3) and the cylindrical members 72 and 82 (see FIGS. 4 and 5).
Reference) may be used.

[0072]

As described above, in the image forming apparatus of the present invention, even when the paper ejection guide member contacts the image portion when the paper ejection guide member guides the image portion, the paper ejection guide member rotates. Therefore, the image portion does not rub the paper discharge guide member. Therefore, no static electricity is generated between the paper ejection guide member and the image portion, and the image portion is prevented from being attracted to the paper ejection guide member due to the static electricity. As a result, the problem caused by the suction is eliminated, and the quality of the image formed in the image portion does not deteriorate. Further, since the image portion does not rub against the paper discharge guide member, the durability of the paper discharge guide member is excellent. Therefore, it is possible to prevent the image portion from being electrostatically attracted without using the charge removing brush.

Here, when the paper discharge guide member is a cylindrical member extending in the cross direction, a paper discharge guide member having a simple configuration can be formed.

When the paper discharge guide member is composed of a plurality of disc-shaped individual paper discharge guide members coaxially arranged in the cross direction, a paper discharge guide member having a simple configuration can be formed. When this individual guide member is made of, for example, resin, the size of the mold is reduced, so that it can be manufactured at low cost.

Further, the plurality of individual paper discharge guide members are
If they rotate independently of each other,
When the size of the recording medium changes, the number of individual discharge guide members with which the recording medium contacts changes according to this size,
Therefore, when forming an image on a small-sized recording medium,
Only the individual discharge guide members corresponding to this small size rotate independently. For this reason, only the individual discharge guide member corresponding to the size of the recording medium rotates independently, and the individual discharge guide member not corresponding to this size (the discharge guide member that does not contact the recording medium) does not rotate. Thus, the rotation resistance is smaller than when all the individual paper ejection guide members rotate, and the paper ejection guide members are easily rotated. As a result, generation of static electricity is further suppressed.

In addition, when the paper discharge guide member is provided with a non-contact drive source, the paper discharge guide member is rotated by the drive source. Even if an image is formed on any type of recording medium, the paper ejection guide member can reliably guide this recording medium while rotating. Further, since the paper discharge guide member and the drive source are not in contact with each other, wear and friction due to the contact do not occur. Accordingly, it is possible to prevent troubles caused by the wear and friction.

Further, when the driving source is a suction fan for discharging the sucked air and rotating the paper discharge guide member, a low cost driving source can be obtained.

Further, in the case where the suction fan sucks air so that the recording medium is adsorbed on the platen, one suction fan has a function of adsorbing the recording medium on the platen and a sheet discharge guide member. Since it also has a function of rotating, the cost is reduced.

Further, when a shut-off means for shutting off the air for rotating the paper discharge guide member at a predetermined timing is provided, the paper discharge guide member can be rotated at a required timing, so that a user-friendly image forming apparatus can be formed. A device is obtained.

Further, when a stop member for stopping the rotation of the discharge guide member at a predetermined timing is provided,
Since the rotation of the paper ejection guide member can be stopped at a timing as required, an easy-to-use image forming apparatus can be obtained.

Further, in the case where a drive source connected to the discharge guide member and rotating the discharge guide member is provided, the discharge guide member is rotated by the drive source connected to the discharge guide member. Therefore, regardless of the size and type of recording medium on which an image is formed, the discharge guide member can more reliably guide the recording medium while rotating reliably.

Further, in the case where the drive source reciprocates a print head which ejects ink to a recording medium in the main scanning direction while reciprocating in a predetermined main scanning direction, one drive source may be used. Since both the function of reciprocating the print head and the function of driving the paper ejection guide member are provided, the cost is reduced.

Further, in the case where the above-mentioned paper discharge guide member is formed on the outer peripheral surface thereof with irregularities extending in the cylindrical circumferential direction, the area of the recording medium in contact with the paper discharge guide member is as follows:
There is no unevenness and it is smaller than when it is flat. For this reason, generation of static electricity is more reliably prevented.

Further, when the paper discharge guide member has a groove formed on the outer peripheral surface extending parallel to the central axis, the area where the recording medium contacts the paper discharge guide member has no groove. It is smaller than that of a plane. For this reason, generation of static electricity is more reliably prevented.

Further, when the paper ejection guide member has a large number of irregularities formed on the surface thereof, the area of the recording medium in contact with the paper ejection guide member is smaller than when the recording medium has no irregularities and is flat. Also decreases. For this reason, generation of static electricity is more reliably prevented.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a plotter that is an example of an image forming apparatus using an inkjet method.

2A is a perspective view illustrating a paper ejection guide member of the plotter of FIG. 1, and FIG. 2B is a side view illustrating the paper ejection guide member.

FIG. 3A is a perspective view illustrating another example of the paper ejection guide member, and FIG. 3B is a side view illustrating the paper ejection guide member.

FIG. 4A is a perspective view illustrating still another example of the paper ejection guide member, and FIG. 4B is a side view illustrating the paper ejection guide member.

FIG. 5A is a perspective view illustrating still another example of the paper ejection guide member, and FIG. 5B is a side view illustrating the paper ejection guide member.

FIG. 6 is a schematic diagram showing a schematic configuration of a plotter in which a cylinder is forcibly rotated.

FIG. 7 is a schematic diagram showing a state in which rotation of the cylinder is stopped by a stop arm.

FIG. 8 is a schematic diagram showing a state in which the cylinder can be rotated by releasing the stop arm.

FIG. 9 is a perspective view illustrating another example of the paper ejection guide member.

FIG. 10 is a side view showing the paper ejection guide member of FIG. 9;

FIG. 11 is a schematic view illustrating an example of a conventional inkjet type image forming apparatus.

FIG. 12 is a perspective view showing a conventional inkjet type image forming apparatus in which a countermeasure against static electricity is taken.

13 is a schematic diagram illustrating an internal configuration of the inkjet type image forming apparatus of FIG.

[Explanation of symbols]

 40, 90 Plotter 44, 60, 70, 80 Discharge guide member 48 Cylinder 62 Individual discharge guide member 72, 82 Cylindrical member 94 Suction fan 124 Belt pulley 126 Pulley 128 Endless belt

Continued on front page F-term (reference) 2C056 EA20 FA02 FA10 HA28 HA31 HA32 2C059 BB07 BB13 BB21 BB22 2C060 AA09 BA01 BB05 BB14 BC04 BC14 BC23 3F049 EA24 FC01 LA07 LB03 3F101 FA01 FB00 FE01 FE11 LA01 LB03

Claims (14)

[Claims] 1. An image forming apparatus comprising: a platen for placing a recording medium on an image forming area on which an image is formed, wherein the image forming apparatus forms an image on a portion of the recording medium located in the image forming area. A guide member that guides an image portion on which an image is formed in the image forming area to the outside, and that rotates around an axis extending in a cross direction that intersects the guide direction in which the image portion is guided. An image forming apparatus characterized in that: 2. The image forming apparatus according to claim 1, wherein the discharge guide member has a cylindrical shape extending in the cross direction. 3. The image forming apparatus according to claim 1, wherein the discharge guide member includes a plurality of disc-shaped individual discharge guide members coaxially arranged in the cross direction. 4. The image forming apparatus according to claim 3, wherein each of the plurality of individual paper ejection guide members rotates independently of each other. 5. The paper discharge guide member according to claim 1, further comprising a non-contact drive source for rotating the paper discharge guide member. Image forming device. 6. The recording sheet image forming apparatus according to claim 5, wherein the driving source is a suction fan that discharges the sucked air to rotate the discharge guide member. 7. The image forming apparatus according to claim 6, wherein the suction fan sucks air so that a recording medium is attracted to the platen. 8. The image forming apparatus according to claim 6, further comprising a blocking unit configured to block, at a predetermined timing, air for rotating the sheet discharge guide member. 9. The image forming apparatus according to claim 6, further comprising a stop member for stopping the rotation of the discharge guide member at a predetermined timing. 10. The image according to claim 1, further comprising a drive source connected to the paper ejection guide member for rotating the paper ejection guide member. Forming equipment. 11. The apparatus according to claim 10, wherein said drive source reciprocates a print head which ejects ink onto a recording medium in said main scanning direction while reciprocating in a predetermined main scanning direction. The image forming apparatus as described in the above. 12. The paper discharge guide member according to claim 2, wherein a cylindrical concave and convex extending in a circumferential direction is formed on an outer peripheral surface. The image forming apparatus as described in the above. 13. The paper ejection guide member according to claim 2, wherein a groove extending parallel to a central axis of the paper ejection guide member is formed on an outer peripheral surface. Image forming apparatus. 14. The image forming apparatus according to claim 1, wherein the discharge guide member has a plurality of irregularities formed on a surface thereof.