JP7230473B2 - image forming device - Google Patents

Description

The present invention relates to an inkjet image forming apparatus.

The inkjet printer described in Patent Document 1 includes a medium suction device having a medium suction portion that suctions a medium, an inkjet head that faces a part of the medium suction portion with the medium sandwiched therebetween, and a winding that wraps around the medium suction portion. and an endless conveyor belt. The conveying belt is formed in a mesh shape by weaving members. A suction panel included in the medium suction portion is formed with a plurality of suction holes. A negative pressure generator included in the medium suction device sucks the medium on the conveying belt through the suction holes and the mesh.

JP 2016-163984 A

In the above-described inkjet printer, it is not clear whether the suction holes of the medium suction portion are larger or smaller than the mesh opening (mesh opening diameter) of the conveying belt. However, since the conveyor belt is woven, it is presumed that the opening of the conveyor belt is smaller than the opening area of the suction holes. In such a case, the suction force generated by the negative pressure generator directly acts on the medium through the large suction holes and the small mesh of the conveyor belt, so the suction force (air flow rate related to suction) on the conveyor belt is more than necessary. can grow to As a result, not only the medium is sucked onto the conveying belt, but also the ink droplets ejected from the inkjet head may be sucked. As a result, the landing position of the ink droplets on the medium shifts (landing deviation occurs), so there is a problem that the image is disturbed.

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides an image forming apparatus capable of properly attracting a medium onto a belt and suppressing displacement of ink droplets due to a suction force.

In order to achieve the above object, the image forming apparatus of the present invention comprises a conveying plate having a plurality of first suction holes formed thereon, and a belt having a plurality of second suction holes formed therein and sliding on one surface of the conveying plate. a suction unit for sucking the medium on the belt through the first suction hole and the second suction hole; a droplet discharge head for discharging droplets toward the medium, wherein the first suction holes are formed to have a smaller opening area than the second suction holes.

In this case, it is preferable that the second suction holes are formed in such a size that two or more of the first suction holes can be visually observed from one of the second suction holes.

In this case, the conveying plate includes a plate body in which a plurality of fitting grooves are formed, and a plurality of opening members in which the plurality of first suction holes are formed and which are mounted in the plurality of fitting grooves. It is preferable to be

In this case, the opening member includes an opening surface portion in which the plurality of first suction holes are formed and which forms the same plane as the upper surface of the plate main body when mounted in the fitting groove; It is preferable to include a pair of fixed pieces which are formed in an extended state and are hooked on the lower surface of the plate body when fitted in the fitting groove.

ADVANTAGE OF THE INVENTION According to this invention, a medium can be made to adsorb|suck properly on a belt, and the landing deviation of a droplet by suction force can be suppressed.

1 is a schematic diagram (front view) showing the internal structure of a printer according to an embodiment of the present invention; FIG. 1 is a schematic diagram (front view) showing an inkjet head and a suction transport unit of a printer according to one embodiment of the present invention; FIG. FIG. 2 is a plan view showing a suction transport unit (excluding transport belts and the like) according to one embodiment of the present invention; FIG. 4 is a plan view showing an enlarged part of the suction transport unit according to one embodiment of the present invention; FIG. 4 is a perspective view showing an opening member of the suction transport unit according to one embodiment of the present invention; FIG. 5 is a sectional view taken along line VI-VI in FIG. 4;

Embodiments of the present invention will be described below with reference to the accompanying drawings. In the drawings, "Fr" indicates "front", "Rr" indicates "rear", "L" indicates "left", "R" indicates "right", and "U" indicates " "Upper" and "D" indicate "Lower". Further, the "conveying direction" refers to the direction in which the sheet S is conveyed, and the terms "upstream" and "downstream" and similar terms refer to the concept of "upstream" and "downstream" of the conveying direction and similar concepts. .

[Printer overview]
An overall configuration of a printer 1 as an ink jet image forming apparatus will be described with reference to FIGS. 1 to 4. FIG. FIG. 1 is a schematic diagram (front view) showing the internal structure of the printer 1. As shown in FIG. FIG. 2 is a schematic diagram (front view) showing the inkjet head 50 and the suction transport unit 20. As shown in FIG. FIG. 3 is a plan view showing the suction transport unit 20 (excluding the transport belt 24 and the like). FIG. 4 is a plan view showing an enlarged part of the suction transport unit 20. As shown in FIG.

As shown in FIG. 1, the printer 1 includes a device main body 2 having a substantially rectangular parallelepiped appearance. A paper feed cassette 3 for containing paper sheets S (medium) is detachably provided at the bottom of the apparatus main body 2 . A discharge tray 4 is provided on the upper left side of the apparatus main body 2 .

Further, the printer 1 includes a paper feeding device 10 , a conveying device 11 , a recording device 12 , a maintenance device 13 , and a control device 14 inside the device body 2 . The paper feeding device 10 is provided on the upstream side of the transport path 5 extending from the paper feeding cassette 3 . The conveying device 11 and the recording device 12 are provided substantially in the center of the device body 2 . The maintenance device 13 is provided between the conveying device 11 and the discharge tray 4 . The control device 14 centrally controls the operation of the printer 1 based on a pre-stored program or the like.

The transport path 5 includes a supply path 5A formed in a substantially U shape between the paper feed cassette 3 and the transport device 11, a discharge path 5B formed between the transport device 11 and the paper discharge tray 4, contains. A registration roller pair 16 that temporarily blocks the sheet S and aligns the leading edge position is provided on the downstream side of the supply path 5A. A plurality of transport roller pairs 17 and 18 that rotate and transport the sheet S while nipping it are provided at appropriate positions in the supply path 5A and the discharge path 5B.

<Conveyor>
As shown in FIG. 1 , the transport device 11 includes a suction transport unit 20 , a discharge unit 30 and an elevating unit 40 . The suction transport unit 20 is provided below the recording device 12 . The discharge unit 30 is provided on the left side of the suction transport unit 20 . The lift unit 40 is provided below the suction transport unit 20 .

<Adsorption transfer unit>
As shown in FIGS. 1 to 3 , the suction transport unit 20 includes a transport frame 21 , a drive mechanism 22 , a transport plate 23 , a transport belt 24 and a suction section 25 .

(conveyor frame)
The conveying frame 21 is formed in a frame shape by bridging a construction frame (not shown) between a pair of main frames 21A (see FIG. 3) spaced apart in the front-rear direction. The transport frame 21 is movably supported by a lifting unit 40 (see FIG. 1).

(drive mechanism)
As shown in FIGS. 2 and 3, the drive mechanism 22 includes a drive roller 22A, a driven roller 22B, and three tension rollers 22C. These rollers 22A, 22B, 22C are rotatably supported by a pair of main frames 21A. The drive roller 22A is arranged on the upper left side of the transport frame 21 and connected to the transport motor M via a gear train (not shown). The driven roller 22B is arranged on the lower right side of the transport frame 21 . The three tension rollers 22C are arranged below the drive roller 22A and above and to the left of the driven roller 22B.

(Conveyor plate)
As shown in FIG. 3, the conveying plate 23 is made of, for example, a synthetic resin material and is formed in a substantially rectangular flat plate shape when viewed from above. The carrier plate 23 is arranged between the pair of main frames 21A and fixed to the pair of main frames 21A. The transport plate 23 is arranged to face the lower portion of the inkjet head 50 included in the recording device 12 (see FIG. 2). A plurality of first suction holes 26 are formed in the conveying plate 23 (see FIG. 4). The first suction hole 26 is a circular hole penetrating the conveying plate 23 in the thickness direction. Details of the conveying plate 23 and the first suction holes 26 will be described later.

(conveyor belt)
As shown in FIG. 2, the conveying belt 24 (belt) is formed in an endless shape (annular shape) from a synthetic resin material, for example. The transport belt 24 is wound around the transport plate 23 and a plurality of rollers 22A, 22B, 22C. The upper surface of the conveying belt 24 constitutes a substantially horizontal conveying surface 24A with which the sheet S is in close contact. The transport belt 24 slides on the upper surface (one surface) of the transport plate 23 by operating the transport motor M to rotate the drive roller 22A (see the arrow in FIG. 1). A plurality of second suction holes 27 are formed in the conveying belt 24 (see FIG. 4). The second suction hole 27 is a circular hole penetrating the conveying belt 24 in the thickness direction.

(Suction part)
As shown in FIG. 2 , the suction unit 25 is provided at a position below the transport plate 23 and surrounded by the transport belt 24 . The suction unit 25 includes four blower fans 28 that create a negative pressure in the space below the carrier plate 23 (see FIG. 3). The suction unit 25 (blower fan 28 ) sucks the sheet S on the conveying belt 24 (conveying surface 24</b>A) through the first suction holes 26 and the second suction holes 27 . The sheet S is conveyed together with the conveying belt 24 while being attracted to the conveying surface 24</b>A of the conveying belt 24 .

<Ejection unit>
As shown in FIG. 1, the discharge unit 30 includes a discharge drive roller 30A, a discharge driven roller 30B, and a discharge transport belt 31 wound around these rollers 30A and 30B. The discharge drive roller 30A is connected to the transport motor M via a gear train (not shown). The discharge transport belt 31 runs in the direction of the arrow in FIG. 1 by operating the transport motor M to rotate the discharge driving roller 30A. A drying device 32 for drying the ink on the sheet S is provided above the discharge conveying belt 31 .

<lifting unit>
Although a detailed description of the structure is omitted, the lift unit 40 has a function of lifting and lowering the adsorption transport unit 20 between the recording position and the retracted position. The recording position is a position for forming an image on the sheet S by bringing the suction transport unit 20 closer to the inkjet head 50 . The retracted position is a position at which the suction transport unit 20 is separated from the inkjet head 50 so that a maintenance operation (described later) can be performed.

<Recording device>
As shown in FIGS. 1 and 2, the recording device 12 includes a plurality of inkjet heads 50 (droplet ejection heads). A plurality of inkjet heads 50 are provided so as to correspond to inks of four colors (yellow, magenta, cyan, and black). Four color inks are stored in four ink tanks 51 . The four ink tanks 51 are arranged on the upper part of the apparatus body 2 . An ink tank 51 storing ink of a corresponding color is connected to the inkjet head 50 .

The inkjet head 50 is arranged to face the transport plate 23 with the transport belt 24 interposed therebetween. The inkjet head 50 has a nozzle surface 50A facing the conveying belt 24 (conveying surface 24A) across a predetermined gap (see FIG. 2). The nozzle surface 50A is provided parallel to the transport surface 24A. A plurality of ejection nozzles (not shown) for ejecting ink droplets onto the sheet S on the transport surface 24A are formed on the nozzle surface 50A. The inkjet head 50 is arranged so as to be able to eject ink droplets over a range wider than the width of the sheet S (the length in the front-rear direction).

<Maintenance device>
As shown in FIG. 1 , maintenance device 13 includes cap unit 55 , wipe unit 56 , and slide unit 57 .

The cap unit 55 includes a plurality of caps 55</b>A that adhere to the nozzle surfaces 50</b>A of the plurality of inkjet heads 50 . The plurality of caps 55A has a function of preventing drying of the ink in the ejection nozzles and preventing clogging of the ejection nozzles. The wipe unit 56 includes a plurality of wipers 56A that move while contacting the nozzle surfaces 50A of the plurality of inkjet heads 50. As shown in FIG. The wiper 56A has a function of wiping off ink or the like adhering to the nozzle surface 50A and cleaning the nozzle surface 50A. The slide unit 57 includes a cap carriage on which the cap unit 55 is mounted and a wipe carriage on which the wipe unit 56 is mounted (both not shown). The slide unit 57 has the function of moving the cap unit 55 or the wipe unit 56 directly below the inkjet head 50 .

[Printing]
Here, the operation of the printer 1 will be described with reference to FIG. 1 and the like. The control device 14 executes image forming processing (printing operation) as follows. It is assumed that the suction transport unit 20 is arranged at the recording position.

The paper feeding device 10 separates the sheets S in the paper feeding cassette 3 one by one and feeds them to the supply path 5A. The sheet S is temporarily blocked by the registration roller pair 16 through the supply path 5A. After correcting the skew of the sheet S, the registration roller pair 16 feeds the sheet S toward the suction conveyance unit 20 (conveyance surface 24A) in synchronization with the ink ejection operation. The suction unit 25 (blower fan 28) generates a negative pressure to apply a suction force to the sheet S on the conveying surface 24A. The conveying belt 24 conveys the sheet S attracted to the conveying surface 24A in the direction of the arrow in FIG. The inkjet head 50 ejects ink droplets (liquid droplets) toward the sheet S conveyed while being attracted to the conveying belt 24 . As a result, an ink image is formed on the sheet S that is conveyed while being attracted to the conveying surface 24A.

The sheet S on which an image has been formed is sent from the conveying belt 24 to the discharge conveying belt 31 . The drying device 32 dries the ink on the sheet S passing through the discharge conveying belt 31 . Then, the sheet S is discharged from the discharge conveying belt 31 to the discharge tray 4 through the discharge path 5B.

[Maintenance operation]
Next, maintenance operations for the inkjet head 50 will be described. Specifically, a capping operation for attaching the cap 55A to the inkjet head 50 and a wiping operation for wiping off ink adhering to the nozzle surface 50A will be described. A maintenance operation (capping operation, wiping operation) is started automatically (or based on a user's instruction) by the control device 14 while the printing operation is stopped.

First, the capping operation will be explained. The lift unit 40 lowers the suction transport unit 20 from the recording position to the retracted position. The slide unit 57 moves the cap carriage directly below the inkjet head 50 . After that, the lift unit 40 raises the suction transport unit 20 to push up the cap unit 55 mounted on the cap carriage. The cap 55A of the cap unit 55 is in close contact with the nozzle surface 50A of the inkjet head 50 to seal the ejection nozzles. Note that the cap carriage is returned to its original position.

As described above, the ink in the ejection nozzle is moistened, and clogging of the ejection nozzle can be prevented. When the capping operation is finished, the inside of the cap 55A is opened to the atmosphere by an air communication mechanism (not shown), and then the reverse procedure of the above-described capping operation is performed.

The wiping operation is performed in the same procedure as the capping operation described above. That is, after the lift unit 40 lowers the suction transport unit 20 to the retracted position, the slide unit 57 moves the wipe carriage directly below the inkjet head 50 . After that, the lift unit 40 raises the suction transport unit 20 to push up the wipe unit 56 mounted on the wipe carriage, and brings the tip of the wiper 56A into close contact with the nozzle surface 50A. The wiping unit 56 moves the tip of the wiper 56A while contacting the nozzle surface 50A to wipe off the ink adhering to the nozzle surface 50A. When ending the wiping operation, the reverse procedure of the above-described wiping operation is performed.

By the way, in the printing operation, the suction force exerted by the suction unit 25 on the transport surface 24A acts not only on the sheet S but also on the ink droplets ejected from the inkjet head 50 (ejection nozzle). If a large suction force acts on the ink droplets ejected from the ejection nozzles, the landing positions of the ink droplets on the sheet S may be shifted and the image may be disturbed. Conversely, if the suction force is too weak, the sheet S cannot be attracted to the conveying surface 24A, and the sheet S may wrinkle or slip on the conveying belt 24. FIG. Even in this case, the landing position of the ink droplet is shifted, which causes the image to be disturbed. Therefore, the printer 1 according to the present embodiment has a configuration capable of properly sucking the sheet S onto the conveying belt 24 and suppressing displacement of the ink droplets due to the suction force.

[Details of transport plate]
First, the details of the carrier plate 23 will be described with reference to FIGS. 3 to 6. FIG. FIG. 5 is a perspective view showing the opening member 65 of the suction transport unit 20. As shown in FIG. 6 is a sectional view taken along line VI-VI of FIG. 4. FIG.

As described above, the transfer plate 23 is made of synthetic resin, and is manufactured by injecting thermoplastic synthetic resin into a mold. The molten resin filled in the mold shrinks in volume when it is cooled and solidified (molding shrinkage). If the conveying plate 23 were formed as a single member, it would be difficult to form the plurality of first suction holes 26 and the like with high accuracy because of the large dimensional change (tolerance) due to molding shrinkage. Therefore, the conveying plate 23 has a structure in which a separate component having the first suction holes 26 is attached to the plate main body 60 .

As shown in FIGS. 3 and 4, the conveying plate 23 includes a plate body 60 and a plurality of opening members 65. As shown in FIGS. Note that FIG. 3 illustrates a state in which the conveying belt 24 and the opening member 65 are removed. 4, only the plate body 60, a state in which the opening member 65 is attached to the plate body 60, and a state in which the conveying belt 24 is attached are shown in one sheet of drawing.

<Board body>
As shown in FIG. 3 , the plate body 60 is a substantially rectangular flat plate that forms the outer shape of the transfer plate 23 . A plurality of fitting grooves 61 are formed in the plate body 60 . The fitting groove 61 is a rectangular depression that is elongated in the transport direction and has rounded corners. The plurality of fitting grooves 61 are arranged in a row at approximately equal intervals in the transport direction (horizontal direction). In addition, the plurality of fitting grooves 61 arranged in a row (row of fitting grooves 61) are arranged at predetermined intervals in the front-rear direction. Rows of fitting grooves 61 adjacent in the front-rear direction are shifted in the transport direction. That is, the plurality of fitting grooves 61 are generally arranged in a zigzag pattern.

As shown in FIGS. 4 and 6, two through holes 62 are formed in the bottom surface of the fitting groove 61 . The through hole 62 is a circular hole, and has an opening area (diameter) larger than that of the second suction hole 27 of the conveyor belt 24 . The number of through holes 62 to be formed is not limited to two, and may be one or more. Moreover, the shape of the through-hole 62 is not limited to a circular shape, and may be formed in a polygonal shape (not shown).

<Opening member>
As shown in FIGS. 4 and 5, the opening member 65 is formed in a rectangular shape with rounded corners corresponding to the fitting groove 61 when viewed from above. The plurality of opening members 65 are components that are mounted (fitted) in the plurality of fitting grooves 61 . The opening member 65 includes an opening surface portion 66 and a pair of fixing pieces 67 .

As shown in FIG. 5, the opening surface portion 66 is a rectangular flat plate with rounded corners. A plurality of first suction holes 26 are formed in the opening surface portion 66 . The pair of fixed pieces 67 are formed to extend downward from both end portions of the opening surface portion 66 in the transport direction. At the lower ends of the pair of fixed pieces 67, claw portions 67A protrude outward in the conveying direction (directions away from each other). An outer surface of the claw portion 67A is formed with an inclined surface extending outward in the conveying direction from the bottom to the top.

When the opening member 65 is inserted into the fitting groove 61, the pair of claws 67A (the inclined surfaces thereof) come into contact with the edges of the fitting groove 61 (the opening surface portion 66), and the pair of fixing pieces 67 approach each other. bend. When the pair of claw portions 67A climbs over the opening surface portion 66, the pair of fixing pieces 67 return to their original positions due to their own elasticity. As shown in FIG. 6 , when the opening member 65 is mounted in the fitting groove 61 , the opening surface portion 66 forms substantially the same plane as the upper surface of the plate body 60 . Also, in this state, the pair of claw portions 67A (the pair of fixing pieces 67) are hooked on the lower surface of the plate body 60. As shown in FIG. As a result, the opening member 65 is attached to the fitting groove 61 .

[First Suction Hole, Second Suction Hole]
As shown in FIG. 4 , the plurality of first suction holes 26 are arranged in a zigzag pattern on the opening surface portion 66 of the opening member 65 . Also, the first suction hole 26 is formed in a tapered shape, the diameter of which decreases from the lower surface of the opening surface portion 66 toward the upper surface thereof. The plurality of second suction holes 27 are arranged in a zigzag pattern on the conveyor belt 24 . In addition, although the plurality of first suction holes 26 and the plurality of second suction holes 27 are arranged in a zigzag pattern, they may be arranged in a grid pattern, for example (not shown).

As shown in FIGS. 4 and 6 , the first suction holes 26 are formed to have a smaller opening area than the second suction holes 27 . Specifically, the second suction holes 27 are formed in such a size that two first suction holes 26 can be seen from one second suction hole 27 . More specifically, the diameter of the second suction hole 27 is set to approximately 2 to 2.5 times the diameter of the first suction hole 26 .

Note that "two first suction holes 26 can be visually observed from one second suction hole 27" means that a part or all of the two first suction holes 26 can be visually observed from one second suction hole 27. It means that you can Moreover, it does not necessarily require that part or all of the two first suction holes 26 be visible from all the second suction holes 27 . That is, the sizes of the first and second suction holes 26 and 27 should be set so that at least two portions of the first suction holes 26 are within the range of one second suction hole 27. . Also, the sizes of the first and second suction holes 26 and 27 may be set so that two or more first suction holes 26 can be visually observed from one second suction hole 27 (not shown). figure). Also, the number, arrangement, size, etc. of the first and second suction holes 26 and 27 can be freely adjusted. Also, the shape of the first and second suction holes 26 and 27 is not limited to circular, but may be polygonal (not shown).

In the printer 1 according to the present embodiment described above, the first suction holes 26 opened in the transport plate 23 are formed smaller than the second suction holes 27 opened in the transport belt 24 . According to this configuration, since the suction force dispersed through the plurality of first suction holes 26 acts on the sheet S on the belt through the second suction holes 27, the first suction holes 26 are larger than the second suction holes 27. An unnecessary increase in the suction force acting on the conveying belt 24 can be suppressed as compared with the case. Therefore, the ink droplets ejected from the inkjet head 50 (ejection nozzles) are not sucked into the first and second suction holes 26 and 27, and the impact position of the ink droplets on the sheet S is suppressed from shifting. . As a result, the sheet S can be properly sucked onto the conveying belt 24, and the landing deviation of the ink droplets due to the suction force can be suppressed. In addition, it is possible to suppress the disturbance of the image due to the impact deviation of the ink droplets.

Further, according to the printer 1 according to the present embodiment, by dividing the fitting groove 61 and the opening member 65 into a plurality of parts, the fitting groove 61 and the opening member 65 can be miniaturized. Shrinkage (molding shrinkage) during molding (the plate body 60 and the opening member 65) can be reduced. As a result, dimensional tolerance due to molding shrinkage can be reduced. Further, since the opening member 65 is formed of a member different from the plate main body 60, the arrangement of the fitting groove 61 and the opening member 65 can be freely set according to the size of the sheet S and the like. Further, if various kinds of opening members 65 with different sizes and numbers of the first suction holes 26 are prepared, the suction force acting on the sheet S can be freely changed only by exchanging the opening member 65.例文帳に追加As a result, the suction force can be adjusted at a low cost compared to the case where all the conveying plates 23 are replaced.

Further, according to the printer 1 of the present embodiment, by hooking the fixing piece 67 on the lower edge of the fitting groove 61 , the opening member 65 can be held in a state of being attached to the fitting groove 61 . Further, the opening member 65 can be easily removed from the fitting groove 61 by releasing the hooking of the fixing piece 67 . That is, the opening member 65 can be easily replaced.

In the printer 1 according to the present embodiment, the plate body 60 and the opening member 65 are separately formed in consideration of the fact that the transport plate 23 is made of synthetic resin, but the present invention is not limited to this. . For example, when molding shrinkage is very small (when using a synthetic resin with a small shrinkage rate, when the conveying plate 23 is small, etc.), the conveying plate 23 may be integrally formed. Further, the conveying plate 23 is not limited to being made of synthetic resin, and may be made of, for example, metal or a porous body (such as pumice stone) having a large number of air holes.

In the printer 1 according to the present embodiment, the inkjet head 50 is used as an example of a droplet ejection head, but the invention is not limited to this. For example, the droplet ejection head may eject liquid resin or the like. Further, the medium is not limited to paper, and may be made of resin, glass, or the like.

It should be noted that the description of the above embodiment shows one aspect of the image forming apparatus according to the present invention, and the technical scope of the present invention is not limited to the above embodiment.

1 Printer (image forming device)
23 Conveying plate 24 Conveying belt (belt)
25 suction part 26 first suction hole 27 second suction hole 50 inkjet head (droplet discharge head)
60 Plate body 61 Fitting groove 65 Opening member 66 Opening surface portion 67 Fixed piece S Sheet (medium)

Claims (3)

a conveying plate having a plurality of first suction holes;
a belt formed with a plurality of second suction holes and sliding on one surface of the conveying plate;
a suction unit that sucks the medium on the belt through the first suction hole and the second suction hole;
a droplet ejection head arranged opposite to the transport plate with the belt interposed therebetween, and ejecting droplets toward the medium transported while being adsorbed on the belt;
The carrier plate is
a plate body having a plurality of fitting grooves with through holes formed in the bottom surface;
a plurality of opening members formed with the plurality of first suction holes and mounted in the plurality of fitting grooves,
The image forming apparatus, wherein the first suction holes are formed to have a smaller opening area than the second suction holes. 2. An image forming apparatus according to claim 1, wherein said second suction holes are formed to have a size such that two or more of said first suction holes can be visually observed from one said second suction hole. Device. The opening member
an opening surface portion in which the plurality of first suction holes are formed and which forms the same plane as the upper surface of the plate body when mounted in the fitting groove;
3. A pair of fixing pieces extending downward from the opening surface portion and hooked to the lower surface of the plate body when mounted in the fitting groove. The image forming apparatus according to .

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