JP2011057408A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming device capable of surely holding an ejected sheet in a hanging-down state, without rubbing ink on the sheet. <P>SOLUTION: Paper 5 of forming an ink image by an image recording means 100 is carried by a paper ejecting carrying part 6 as a sheet ejecting holding means. The paper ejecting carrying part 6 has a branch guide member 70 of a belt carrying system for electrostatically attracting the paper. The paper 5 is carried in the horizontal direction and is ejected so that its tip part hangs down outside a left side surface of an image forming device body 1, and carrying by the paper ejecting carrying part 6 is stopped in the timing of detecting the paper rear end by an unillustrated sensor arranged in the vicinity of the branch guide member 70. The paper 5 is attracted and held in its rear end part to and by the branch guide member 70, and a user extracts and takes out the paper 5 in this state. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile machine, a plotter, and a printing machine, and a multifunction machine having at least one of them, and more specifically, holds a sheet trailing edge so that the sheet leading edge is suspended. The present invention relates to an image forming apparatus having a so-called catch-type paper discharge function.

In this type of image forming apparatus, generally, an image-formed sheet is discharged to a discharge tray provided in a state of protruding outward from the side surface of the apparatus main body.
However, the bulkiness due to the protrusion of the paper discharge tray increases the size of the image forming apparatus due to the increase in the width in the paper discharge conveyance direction, and hinders the freedom of installation layout.
In order to cope with this problem, conventionally, an image forming apparatus including a so-called catch-type paper discharge device has been proposed. In this case, the sheet is discharged so that the front end of the sheet is hung outside the side surface of the apparatus without providing a discharge tray, and the trailing end of the sheet is held so that it can be pulled out.
According to this method, since the paper discharge tray is unnecessary, the above problem can be solved.
Japanese Patent Application Laid-Open No. H10-228667 describes a configuration in which the ink application surface side (image forming side) of the sheet is a spur roller and the other surface is a roller, and the sheet is discharged outside the apparatus while being sandwiched.
Patent Document 2 describes a configuration in which the rear end portion of a sheet is sandwiched and held by a pair of discharge rollers.

As in the configuration described in Patent Document 1, if a catch-type paper discharge device is configured with a pair of conveying rollers using a spur on one side, the holding force is weak and the sheet cannot be held, and the sheet may fall off. there were.
In the method described in Patent Document 2, since the sheet is sandwiched and held by a pair of discharge rollers, in the case where it takes time to dry the ink applied to the sheet, the roller contacts the image and drags, rubs, etc. There is a possibility that an abnormal image will be generated.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus that can reliably hold a discharged sheet in a suspended state without rubbing ink on the sheet. .

  In order to achieve the above object, according to the first aspect of the present invention, the image recording means for recording an image by ejecting ink onto the sheet and the sheet after the image recording are in a state where the leading end of the sheet hangs down in the discharge direction. And a sheet discharge holding unit that discharges and holds the rear end of the sheet. The sheet discharge holding unit sucks and holds the sheet surface opposite to the surface recorded by the image recording unit. It is characterized by having a body.

According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the suction holder includes an endless suction belt, a support member that rotatably supports the suction belt, and a suction function on the suction belt. It is characterized by having an adsorption source for imparting.
According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect of the present invention, the image forming apparatus includes an image recording unit outlet sensor that detects that a sheet has passed through the image recording unit, and the image recording unit outlet sensor is off. Then, the discharge operation of the sheet discharge holding means is stopped.

According to a fourth aspect of the present invention, in the image forming apparatus according to any one of the first to third aspects, a protective guide member that covers or protects the upper portion of the sheet hanging is provided at the discharge port for discharging in the horizontal direction. It is characterized by that.
According to a fifth aspect of the present invention, in the image forming apparatus according to the fourth aspect, the protective guide member is provided so as to be rotatable in the vertical direction.
According to a sixth aspect of the present invention, in the image forming apparatus according to the fourth or fifth aspect, the protective guide member is provided with a spur that rotates when a leading end of a sheet hits.

According to the present invention, only the surface opposite to the sheet surface on which the ink is applied is sucked and held, so that the image quality can be prevented from being deteriorated due to rubbing of the ink on the sheet and held. Can be reliably maintained.
When discharging a long sheet longer than a predetermined length, it is possible to prevent the danger that the leading edge of the sheet contacts the ground by changing the position of the trailing edge of the sheet.
Even when ejecting thick paper, stacking can be performed without changing the paper by changing the rear end position of the paper.
By providing the protective guide member, it is possible to prevent dust and dirt from adhering to the paper and becoming dirty. Further, although there is a risk that the sheet is bent or a jam occurs under the installation conditions of the apparatus, it can be prevented by providing a protective guide member.
The protective guide member is provided so as to be rotatable, and when not used, the installation area can be reduced by closing the protective guide member. Moreover, it is possible to prevent dust and dust from entering the apparatus by covering the discharge port with the protective guide member.
By providing a spur on the protective guide member, it is possible to prevent the occurrence of abnormal images such as rubbing and to smoothly guide the sheet. Even if the printed paper contacts the spur, there is no occurrence of an abnormal image such as dragging or rubbing because the tip of the spur has an acute angle.

1 is a schematic configuration diagram of an image forming apparatus according to a first embodiment of the present invention. FIG. 6 is a schematic perspective view of a paper discharge unit including a branch guide member. It is a figure which shows the drive structure of the paper discharge unit containing a branch guide member. It is a perspective view of a branch guide member. It is a perspective view from another viewpoint, such as a branch guide member. It is a detailed perspective view of a branch guide member etc. It is a figure which shows the structure which controls the upper limit and lower limit in rotation of a branch guide member. It is a control block diagram. FIG. 10 is a diagram illustrating a discharge operation in a horizontal discharge mode. 6 is a flowchart of a control operation in a horizontal paper discharge mode. It is a figure which shows operation | movement of the branch guide member in normal paper discharge mode. It is a figure which shows operation | movement of the branch guide member in double-sided paper discharge mode. FIG. 6 is a schematic configuration diagram of an image forming apparatus according to a second embodiment and a diagram illustrating a discharge state of a long sheet. It is a figure which shows the discharge state of a cardboard. It is a flowchart of paper type mode setting. 6 is a flowchart of a control operation in a horizontal plain paper discharge mode. 6 is a flowchart of a control operation in a horizontal special paper discharge mode. It is a figure which shows the principal part of the image forming apparatus which concerns on 3rd Embodiment. It is a figure which shows the optimal state of the approach angle of the sheet | seat with respect to a spur.

Embodiments of the present invention will be described below with reference to the drawings.
First, a first embodiment will be described with reference to FIGS. Based on FIG. 1, an outline of a configuration of an inkjet printing apparatus as an image forming apparatus according to the present embodiment will be described. An image forming unit 2 for forming an image, a sub-scanning conveying unit 3 and the like are provided inside the apparatus main body 1. A paper feeding unit 4 is provided on the bottom side of the apparatus main body 1 so that the paper 5 as a sheet is separated and fed one by one. A duplex unit 50 is provided further below the sheet feeding unit 4.
While the paper 5 is intermittently conveyed at a position facing the image forming unit 2 by the sub-scanning conveying unit 3, the image forming unit 2 discharges droplets onto the paper 5 to form a required image.
In the normal paper discharge mode, after the image is formed, the paper 5 is discharged onto a paper discharge tray 7 as an in-body paper discharge tray formed on the upper surface of the apparatus main body 1 through a paper discharge conveyance unit 6 as a sheet discharge holding unit. Make paper. The image forming unit 2 and the sub-scanning conveying unit 3 are unitized to form an image recording unit 100, which is detachably attached to the apparatus main body 1.

  As an input system for image data (print data) formed by the image forming unit 2, an image reading unit (scanner unit) 11 for reading an image is provided above the apparatus main body 1 and above the paper discharge tray 7. In the image reading unit 11, the scanning optical system 15 including the illumination light source 13 and the mirror 14 and the scanning optical system 18 including the mirrors 16 and 17 move to move the image of the document placed on the contact glass 12. The scanned original image is read as an image signal by an image reading element (CCD) 20 disposed behind the lens 19, and the read image signal is digitized and subjected to image processing. Can be printed. A pressure plate 10 is provided on the contact glass 12 for pressing the document.

The image forming unit 2 includes a carriage 23 and a recording head 24 including a droplet discharge head that discharges black (K), cyan (C), magenta (M), and yellow (Y) inks. A shuttle type is used in which the carriage 23 is moved in the main scanning direction and droplets are ejected from the recording head 24 while the paper 5 is fed in the paper conveyance direction (sub-scanning direction) by the sub-scanning conveyance unit 3.
A sub tank 25 is mounted on the carriage 23 in order to supply a recording liquid of a required color to each recording head 24. Reference numeral 26 denotes an ink cartridge containing the inks of the respective colors. The ink cartridge 26 is detachable from the apparatus main body 1 and replenishes and supplies ink (recording liquid) from each color ink cartridge 26 to each color sub-tank 25 via a tube (not shown).

  As the recording head 24, a piezoelectric plate is used as pressure generating means (actuator means) for pressurizing ink in the ink flow path (pressure generating chamber), and the vibration plate forming the wall surface of the ink flow path is deformed to change the ink flow path. A so-called piezo type that discharges ink droplets by changing the internal volume, or a so-called thermal that discharges ink droplets with pressure by heating the ink in the ink flow path using a heating resistor to generate bubbles The volume of the ink flow path is changed by deforming the vibration plate by the electrostatic force generated between the vibration plate and the electrode. For example, an electrostatic type that discharges ink droplets can be used.

The sub-scanning conveyance unit 3 includes a conveyance roller 32 that is a driving roller and a tension roller for conveying the paper 5 fed from below by facing the image forming unit 2 while changing the conveyance direction by approximately 90 degrees. An endless conveyance belt 31 that is bridged between the driven rollers 33, a charging roller 34 that is a charging means to which an AC bias voltage that is an alternating voltage is applied to charge the surface of the conveyance belt 31, and a conveyance belt A platen guide member 35 that guides the sheet 31 in a region facing the image forming unit 2, a first pressure roller (inlet pressure roller) 36 that presses the sheet 5 toward the conveyance belt 31 at a position facing the conveyance roller 32, and A second pressure roller (front end) that presses the sheet 5 toward the conveying belt 31 at a position facing the platen guide member 35 between the conveying roller 32 and the recording head 24 as image forming means. A pressure roller) 37, and a separation claw 39 for separating the sheet 5 on which an image is formed by the image forming section 2 from the conveying belt 31.
The conveyance belt 31 is configured to circulate in the paper conveyance direction (sub-scanning direction) when the conveyance roller 32 is rotated from the sub-scanning motor 131 via the timing belt 132 and the timing roller 133.

The paper feeding unit 4 is detachable from the apparatus main body 1 and separates the paper 5 in the paper feeding cassette 41 one by one from the paper feeding cassette 41 which is a storing means for stacking and storing a large number of papers 5. A sheet feeding roller 42 and a friction pad 43 for feeding out and a registration roller pair 44 for registering the sheet 5 to be fed are provided.
The paper feed unit 4 includes a manual tray 46 for stacking and storing a large number of sheets 5 and a manual feed roller 47 for feeding the sheets 5 one by one from the manual tray 46. Members for feeding the paper 5 to the sub-scanning conveyance unit 3 such as the paper feed roller 42, the registration roller pair 44, and the manual feed roller 47 are rotationally driven by a driving means (not shown) via an electromagnetic clutch (not shown).

The paper discharge conveyance unit 6 includes a pair of conveyance rollers 61 and 62 for conveying the paper 5 on which image formation has been performed, and a pair of conveyance rollers 63 and a pair of paper discharge rollers 65 for sending the paper 5 to the paper discharge tray 7. In addition, a reverse discharge path 66 is provided for transporting the transported paper 5 by reversing (here, making a U-turn).
In the transport roller pairs 61, 62, 63, the lower roller is a normal cylindrical or cylindrical roller, and the upper roller is a spur (a roller-like member having a large number of acute-angle protrusions on the peripheral surface). A sheet is pressed against a roller to obtain a conveying force. The spur is just going around.
As described above, the paper discharge tray 7 faces the space formed between the image forming portion and the image reading device 11 and performs in-cylinder paper discharge.
A paper discharge sensor (hereinafter also referred to as “paper discharge SW”) 74 is provided in the vicinity of the upstream side of the paper discharge roller pair 65. The paper discharge sensor 74 is omitted as appropriate in other drawings.

As will be described later, a branch guide member 70 as a suction holding member having a suction belt is integrally provided in the paper discharge transport unit 6. In the normal paper discharge mode in which paper is discharged to the paper discharge tray 7, as shown in FIG. 11, the branch guide member 70 is rotated upward with the upstream side in the paper transport direction as a fulcrum.
In the horizontal paper discharge mode in which paper is discharged so that the leading end side of the paper 5 hangs out of the left side surface of the apparatus main body 1 in the drawing, the branch guide member 70 is set to a substantially horizontal position as shown in FIG.
In the double-sided mode, as shown in FIG. 12, the branch guide member 70 is rotated downward. The paper is guided to the duplex unit 50 and an image is formed on the back surface (second surface), and then discharged so as to hang down in the paper discharge tray 7 or in the horizontal paper discharge mode as described above.
In the duplex unit 50, duplex transport roller pairs 53a, 53b, 53c, 53d, and 53e are arranged along the sheet transport direction on the downstream side of the duplex entrance roller pair 51, and these rollers are driven by a duplex motor (not shown). The
The sheet 5 on which an image is formed on one side is guided downward by the branch guide member 70, and is conveyed from the pair of duplex entrance rollers 51 to the first duplex standby unit 53 via the duplex conveyance path 52.
A pair of reversing rollers 55a and 55b are arranged in the second double-sided standby unit 55, and the paper 5 conveyed from the first double-sided standby unit 53 side is switched back. Thereafter, the branching claw 54 is switched and conveyed to at least the duplex exit roller pair 56 by the reverse drive of the duplex motor.

The paper discharge conveyance unit 6 will be described in detail with reference to FIGS. FIG. 2 is a perspective view of the paper discharge conveyance unit 6 as viewed from the back side of the apparatus, and FIG. 3 is a schematic explanatory view of FIG.
A conveyance roller shaft 164 is rotatably supported between the side plates 161 and 162 of the paper discharge conveyance unit 6. In FIG. 2, reference numeral 163 denotes a paper discharge guide member.
The side plate 161 is provided with a paper discharge motor 165. The rotation of the paper discharge motor 165 is transferred to the conveying roller pair 61 via the pulley 166, the timing belt 167 and the integral pulleys 168A and 168B, and further from the roller 168B to the timing belt. 169 and the pulley 170 to the conveying roller pair 62, and further from the pulley 170 to the conveying roller pair 63 via the timing belt 171 and the pulley 172, and further from the pulley 172 to the pulleys 173, 174, 175 and 176, the conveying roller shaft. A driving force transmission mechanism is provided that transmits to the driving roller 65 </ b> A of the paper discharge roller pair 65 via a pulley 177 and a timing belt 178 fixed to 164.
In FIG. 3, reference numeral 182 denotes a branch sensor (hereinafter also referred to as “branch SW”) provided in the vicinity of the upstream side of the branch guide member 70 in the sheet conveyance direction, and reference numeral 181 denotes a sensor that detects opening and closing of the paper discharge guide member 163. Is shown. The paper discharge guide member 163 can be opened and closed for jam processing in the normal paper discharge mode.

The branch guide member 70 and the like will be described in detail with reference to FIGS.
The branch guide member 70 includes a conveyance roller shaft 164, a roller 75 fixed to the conveyance roller shaft 164, a pair of brackets 76 and 77 that are rotatably provided on the conveyance roller shaft 164, and the brackets 76 and 77. The tension roller 78 rotatably supported on the end side, the suction belt 80 wound around the roller 75 and the tension roller 78, and the shaft roller insertion holes of the tension rollers 78 of the brackets 76 and 77 are arranged. And a pressurizing member (spring) 81 that urges toward the downstream side in the sheet conveying direction.
A charging roller 82 is provided as a suction source for charging the suction belt 80 and imparting a suction function (electrostatic suction force) below the upstream side of the branch guide member 70 in the sheet conveyance direction. The charging roller 82 is supported between the side plates 161 and 162. The suction belt 80 is charged by pressing the charging roller 82 against the suction belt 80 and applying an AC bias voltage which is an alternating voltage.
On the downstream side of the branch guide member 70 in the sheet conveyance direction, a separation claw 83 for separating the sheet adsorbed by the adsorption belt 80 is pressed against the adsorption belt 80 and provided. The separation claw 83 is supported between the side plates 161 and 162.

A platen gear 84 with a torque limiter is integrally fixed (press-fitted) to the bracket 76, and the platen gear 84 is fixed to a motor gear 86 fixed to a rotating shaft of a DC motor 85 as a rotational drive source fixed to the side plate 162. Meshing.
The platen gear 84, the DC motor 85, and the motor gear 86 constitute a rotating means for rotating the branch guide member 70.
The brackets 76 and 77 are rotatable with respect to the conveying roller shaft 164. However, when the DC motor 85 is not rotated, the branch guide member 70 is prevented from rotating due to its own weight due to the engagement of the platen gear 84 and the motor gear 86. The
The rotation of the discharge motor 165 rotates the timing belt 178 and the pulley 177, and the rotation of the transport roller shaft 164 rotates the suction belt 80 in the sheet transport direction. That is, in the present embodiment, the guide member driving means for rotating the suction belt 80 is configured to serve also as the paper discharge motor 165 that is the drive source of the paper discharge conveyance unit 6.
With the above configuration, the branch guide member 70 can be rotated in the vertical direction by the rotation of the DC motor 85 independently of the rotation of the suction belt 80.

As shown in FIG. 6, a paper presence / absence detection sensor (hereinafter also referred to as “paper presence / absence SW”) 92 is installed in a recess 83 a formed by cutting out the central portion of the separation claw 83.
A photo sensor 90 is provided at a position facing the free end side of the bracket 76 so as to detect the horizontal paper discharge mode (standby position or home position) of the branch guide member 70.
As shown in FIG. 7, a detection convex portion 76 a for detection by the photosensor 90 is formed at the free end of the bracket 76. The position where the detection convex portion 76a is detected by the photosensor 90 is the standby position.
The upward rotation of the branch guide member 70 is restricted by the stopper A, and the downward rotation is restricted by the stopper B. When the bracket of the branch guide member 70 comes into contact with the stoppers A and B, the platen gear 84 with a torque limiter idles.
The photo sensor 90 and the stoppers A and B are supported via one or both of the side plates 161 and 162.

As shown in FIG. 8, control such as rotation of the branch guide member 70 is performed by a control unit 88 serving as a conveyance control unit. The control means 88 is a microcomputer having a CPU, ROM, RAM, I / O interface and the like.
Next, the basic operation of the branch guide member 70 will be described. The paper discharge motor 165 is rotated in accordance with the timing at which the image forming unit 2 forms an image, and the suction belt 80 is also rotated simultaneously. It is to be noted that charging is performed in synchronization with the rotation of the suction belt 80 and the suction becomes possible. The timing for charging is not particularly required, and charging is performed in synchronization with the rotation of the suction belt.
When the sheet is on the suction belt 80, the branch SW 182 is turned on, the control unit 88 recognizes that there is a sheet, and controls so that the next sheet is not conveyed.
Further, when the paper presence / absence SW 92 is in an on state (a state where the paper is discharged and the trailing edge of the paper is held by the branch guide member), the control unit 88 recognizes that there is a paper and the next paper is not conveyed. To control.

The basic operation of the horizontal paper discharge mode will be described below.
As shown in FIG. 9, the sheet on which the image has been formed is transported substantially horizontally while being sucked by the suction belt 80 of the branch guide member 70 that is held substantially horizontally, and is discharged on the discharge guide member 163. It is discharged through the mouth 163a (omitted in other figures).
The control operation is shown in FIG. The control unit 88 determines whether or not the duplex mode is selected, and sets the paper discharge mode if the duplex mode is not set. In the discharge mode setting, it is determined whether the horizontal discharge mode or the normal discharge mode.
In the present embodiment, in the horizontal paper discharge mode, the paper is conveyed by the suction belt 80 and the branch SW 182 is turned off. At the same time, the paper discharge motor 165 is turned off, and the paper discharge is completed.
When the paper discharge mode is not set to the horizontal paper discharge mode, the normal paper discharge mode is set.

As shown in FIG. 9, a protective guide member 200 having a curved shape is provided outside the paper discharge outlet 163a so as to cover the upper part of the hanging paper 5. The protective guide member 200 is disposed so that the paper does not come into contact with plain paper (regular paper) (the front end of the paper hangs down due to its own weight), and prevents dust, dust, and the like from adhering to the discharge port portion.
The width of the protective guide member 200 in the horizontal direction is set as short as possible from the viewpoint of the advantage of downsizing the conventional discharge tray installation method.
If paper with strong elasticity such as thick paper is mistakenly conveyed and discharged, there is a concern that the paper may hit the wall at the end of the discharge port 163a and cause jamming. However, the protective guide member 200 forcibly pushes the paper downward. By doing so, it is possible to avoid obstacles such as jams.

The specific operation in the horizontal paper discharge mode will be described below with reference to FIGS.
The sheet 5 on which an image is recorded (applied with ink) by the image forming unit 2 is transported by the transport roller pairs 61, 62, 63 and reaches the branch guide member 70. The sheet is adsorbed by the branch guide member 70 and discharged in a state where the leading end portion hangs down from the apparatus. When the branch SW 182 is turned off, the paper discharge motor 165 is stopped, and the rear end of the sheet is held while being attracted by the branch guide member 70. The user manually pulls out the discharged paper and takes out the output paper.
In the horizontal paper discharge mode, only one sheet is stacked (held), and the branch guide member 70 has a function of transporting the paper to another paper discharge port, so that the paper remains in the branch guide member 70. The next printing operation is not started in this state.
As the control, when the paper presence / absence SW 92 is in an ON state (a state where the paper is ejected and the trailing edge of the paper is held by the branch guide member), the control means 88 recognizes that there is a paper, and the next printing operation is It is controlled so that it cannot start.

Since the suction method in this embodiment uses the electrostatic suction method, the paper once sucked on the suction belt 80 does not come off the suction belt 80 unless the user removes the paper. Also, the paper is safe because a high resistance prevents a current or the like from flowing even if the user touches the paper.
Further, since the sheet is adsorbed and the conveying roller or the like is not pressed against the image surface, there is no occurrence of an abnormal image such as rubbing or dragging. In the case of double-sided printing, there is no problem because the already dried surface is held by suction.

Next, a second embodiment will be described based on FIGS. The same parts as those in the above embodiment are denoted by the same reference numerals, and unless otherwise specified, the description of the configuration and the function already described is omitted and only the main part will be described (the same applies to other embodiments below).
If long paper is discharged horizontally as special paper, the leading edge of the long paper may reach the ground and get dirty, scratched, etc. In this embodiment, the paper is stored in the device as much as possible. The object is to solve the above problems.
As shown in FIG. 13, in the vicinity of the exit of the image recording unit 100, a print unit exit SW 201 is provided as an image recording unit exit sensor.

As an operation, when the print unit exit SW 201 disposed downstream of the image forming unit 2 is turned off due to the passage of the rear end of the sheet, the sheet discharge motor 165 is stopped to hold the sheet. The long paper 5S1 is held in a state where its leading end does not reach the ground (floor surface) and hangs down.
In this case, the sheet 5S1 is held by the suction holding force of the branch guide member 70. The output paper is manually pulled out and taken out by the user in the same manner as described above. As described above, the conveying roller pair 61, 62, 63 is a spur roller pair, and no clamping pressure is applied unlike a normal conveying roller pair, so that the sheet can be easily pulled out even when the paper discharge motor 165 is stopped. .
As shown in FIG. 14, when the thick paper 5S2 is discharged horizontally as special paper, the paper discharge motor 165 is stopped and the paper is held when the print unit exit SW 201 is turned off due to the passage of the rear edge of the paper, as described above. To do. The user pulls out the paper by hand. In FIG. 14, the distance between the transport roller pair 61 and the print unit exit SW 201 is reduced.
FIG. 15 is a flowchart of basic operations for determining whether or not special paper is used in the horizontal paper discharge mode, FIG. 16 is a flowchart of operations when the paper is not special paper, and FIG. 17 is a flowchart of operations when special paper is used. Yes.

A third embodiment will be described with reference to FIGS. 18 and 19.
As shown in FIG. 18, the protection guide member 202 according to the present embodiment has a hinge portion 203 fixed to the outer surface of the paper discharge guide member 163, and one end portion supported by the hinge portion 203 and can be rotated in the vertical direction. It is comprised from the guide member main body 204 provided in this.
Two spurs 205 are rotatably supported on the guide member main body 204. The guide member main body 204 is rotated by a biasing force of a biasing member (not shown) and stops at a predetermined upper position (rotating position shown in FIG. 18). The guide member 163 can be locked. In the locked state, the paper discharge outlet 163a is closed by the guide member main body 204.
When discharging the paper in the horizontal direction, the apparatus is operated with the guide member main body 204 unlocked and opened.

The paper is guided to be pushed downward by a spur 205 attached rotatably to the guide member main body 204. Since the spur 205 is in point contact with the paper, abnormal images (dragging and rubbing) are prevented. A spur 205 (a roller-like member having a large number of acute-angle protrusions on the peripheral surface) pushes the paper transport direction downward. Since this spur 205 does not have an opposing conveyance roller, it has only a simple guide function. When the paper comes into contact with the spur 205, the tip of the spur 205 hits the paper, but since the contact is only a point, rubbing due to point contact is not visible and does not cause a problem as an abnormal image.
Here, the positional relationship between the approach direction of the discharged sheet and the spur 205 is such that the perpendicular line 207 passing through the center of the spur 205 and the spur 205 with respect to the inclined surface 206 of the guide member main body 204 as shown in FIG. It is preferable that the sheet enters in the vicinity of the intersection 208 with the outer periphery and from the intersection 208 toward the downstream side in the sheet discharge direction.
By doing so, the spur 205 is easily rotated in the sheet discharge direction when the front end of the sheet hits the spur 205, so that damage to the front end of the sheet can be reduced.

As described above, according to the present invention, since it is not necessary to provide a paper discharge tray which has been conventionally required for discharging in the horizontal direction, the installation space size of the apparatus can be reduced. Further, by using the in-cylinder sheet discharge which is the original purpose, the left side of the apparatus (the downstream side in the sheet discharge direction in the case of horizontal sheet discharge) can be installed as close to (as close to) the wall as possible. .
In each of the above embodiments, the configuration in which the sheet is adsorbed to the adsorption belt 80 by the electrostatic adsorption force is exemplified, but the configuration may be adopted in which the sheet is adsorbed by negative air pressure.
Further, by adopting a configuration in which the sheet is adsorbed by the branch guide member 70, there is an advantage that the discharge roller can be made unnecessary and the width direction of the apparatus can be reduced in size.
A configuration may be adopted in which a paper discharge roller is provided without the branch guide member 70 and is sucked by the paper discharge roller. In this case, the transfer path is changed by a branch claw.
In addition, a suction discharge roller may be provided downstream of the branch guide member 70. In this case, even if the trailing edge of the sheet is adsorbed by the sheet discharge roller, the next sheet can be discharged to the sheet discharge tray 7 by the branch guide member 70, so that the image recording operation can be continued.
Further, although the branch guide member 70 is constituted by a belt, it may be constituted by a roller.

DESCRIPTION OF SYMBOLS 5 Sheet as sheet 6 Sheet discharge holding means 70 Branch guide member as suction holding body 75 Roller as support member 78 Tension roller as support member 80 Adsorption belt 82 Charging roller as suction source 100 Image recording means 200 Protection guide member 201 Image recording means exit sensor 205 Spur

Japanese Patent Laid-Open No. 08-073102 Japanese Patent No. 4245498

Claims (6)

Image recording means for recording an image by discharging ink onto a sheet;
In an image forming apparatus comprising: a sheet discharge holding unit that discharges a sheet after image recording to a state in which a sheet leading end in the discharging direction hangs down and holds the sheet trailing end.
The image forming apparatus according to claim 1, wherein the sheet discharge holding unit includes a suction holding body that sucks a sheet surface opposite to the surface recorded by the image recording unit. The image forming apparatus according to claim 1, wherein
The image forming apparatus is characterized in that the suction holding body includes an endless suction belt, a support member that rotatably supports the suction belt, and a suction source that imparts a suction function to the suction belt. apparatus. The image forming apparatus according to claim 1 or 2,
An image forming apparatus having an image recording means exit sensor for detecting that a sheet has passed through the image recording means, and stopping the discharge operation of the sheet discharge holding means after the image recording means exit sensor is turned off. . The image forming apparatus according to any one of claims 1 to 3,
An image forming apparatus, comprising: a protective guide member that covers or protects an upper portion of a sheet depending on a discharge port when discharging in a horizontal direction. The image forming apparatus according to claim 4.
An image forming apparatus, wherein the protective guide member is provided so as to be rotatable in a vertical direction. The image forming apparatus according to claim 4 or 5,
An image forming apparatus, wherein the protective guide member is provided with a spur that rotates when the leading edge of the sheet comes into contact therewith.

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