JP5953945B2 - Print medium conveying apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a print medium transport apparatus that transports paper and the like, and an image forming apparatus.

  2. Description of the Related Art Conventionally, in an image forming apparatus or the like, paper such as a document or recording paper is sequentially transported from a paper tray to a paper discharge unit by a print medium transport device. The print medium conveyance device includes a conveyance path composed of a plurality of guide portions and a plurality of rollers that are driven to rotate, and the sheet is conveyed in the conveyance path.

  When the printing operation is started, toner images formed on the four types of image carriers of yellow, magenta, cyan, and black are transferred to the intermediate transfer belt. On the other hand, the sheets fed one by one from the sheet tray are transported along the transport path to the secondary transfer device, and the toner image on the intermediate transfer belt is transferred onto the sheet. Then, after the toner image is fixed on the sheet in the fixing unit, the sheet is discharged from the printing medium conveying apparatus to the outside of the apparatus.

  At this time, a skew correction device for correcting a state of being bent obliquely during the conveyance of the sheet is provided in the conveyance path. The skew correction device aligns the position of the leading edge by abutting the leading edge of the sheet against the guide unit, and corrects the position so that the sheet is parallel to the secondary transfer apparatus. Specifically, the leading edge of the paper is abutted against the guide portion by feeding the paper excessively between the skew correction roller and the conveying roller located upstream thereof. In order to align the sheets in this way, a space is required in which a portion of the fed sheets can escape from the conveyance path to form a slack, and for that purpose, a sufficient distance and space must be provided between the rollers. In addition, it is necessary to secure a longer interval between thicker and thicker sheets.

  However, in recent years, there has been an increasing need for image forming apparatuses such as printers to support various types of paper, and it is required to print thick paper with high rigidity, paper with short length such as postcards, etc. in one unit. It is getting to be.

  When slack is formed between the rollers as in the skew correction device, if the rollers are arranged at a short interval, the thick paper with high rigidity will be stiff, and the transport roller will feed extra paper. Will not be able to. In such a case, for example, as shown in Patent Document 1, a mechanism for separating the pair of rollers in the vertical direction is provided, and the sheet is conveyed by another conveying roller provided on the upstream side thereof. By doing so, the sheet is not in contact with the separated rollers, and a slack is formed at a long roller pitch between the upstream roller and the skew correction roller. However, the separation operation that can be normally performed in a short time is about several millimeters, so that the separation distance is insufficient to secure a space for forming a sufficient slack, which is an obstacle to sheet feeding. There was a problem that it would end up.

  The present invention has been made in view of the above, and provides a printing medium conveyance device capable of ensuring a space that can sufficiently feed out different length sheets for direction correction when conveying a printing medium. It is to provide.

In order to solve the above-described problems and achieve the object, the printing medium conveyance device of the present invention is in contact with a conveyance path serving as a path through which the printing medium is conveyed and a front portion in the conveyance direction of the printing medium. A contact portion for stopping conveyance of the print medium, a holding portion for holding the front portion of the print medium in contact with the contact portion, and conveying the print medium so as to abut against the contact portion. A first conveyance unit that forms a slack in the print medium between the held unit and the holding unit; the first conveyance unit is provided closer to the holding unit in the conveyance direction than the first conveyance unit; transported to abut against the said between said holding part holding the print medium, a second conveying unit, and a removable portion detachable to form slack in the printing medium, the second transport unit Are the upper surface side of the print medium, and A roller portion provided on each side of the surface, and a guide portion that guides the print medium from both sides independently of the conveyance path, and the detachable portion includes the roller portion of the second conveyance portion and the roller portion The guide part can be removed .

  The print medium transport apparatus according to the present invention can secure a space in which sheets of different lengths can be sufficiently sent out to correct the direction when transporting the print medium.

FIG. 1 is a side view of the image forming apparatus according to the embodiment. FIG. 2 is a side view of the print medium conveying apparatus according to the embodiment. FIG. 3 is a side view of the print medium transport apparatus with the second transport unit of the embodiment attached and detached. FIG. 4 is a side view of the print medium transport apparatus with the second transport unit according to the embodiment attached and detached. FIG. 5 is a side view of the print medium transport apparatus with the second transport unit of the embodiment attached and detached.

  FIG. 1 is a side view of an image forming apparatus provided with a print medium conveying apparatus according to an embodiment of the present invention. As shown in FIG. 1, the image forming apparatus 100 includes a paper feeding device 200, a print medium transport device 300, a skew feeding correction device 400, an image carrier 500, a secondary transfer device 600, and a fixing device 700.

  The image carrier 500 is an image carrier 500Y, 500M, 500C, 500Bk of four colors of yellow, magenta, cyan, and black. Further, the image forming apparatus 100 includes an intermediate transfer belt 501. The toner images formed by the image carriers 500Y, 500M, 500C, and 500Bk are transferred to the intermediate transfer belt 501.

  The paper feeding device 200 feeds paper from the paper feeding trays 201 a and 201 b to the printing medium transport device 300. Sheets S are stacked on the sheet feed trays 201a and 201b. The paper S fed from the paper feeding device 200 is transported to the print medium transport device 300. The print medium conveyance device 300 includes a conveyance path 301 and a conveyance roller pair 302. The conveyance path 301 is configured by a guide plate, and the sheet S is conveyed along the conveyance path 301. The conveyance path 301 is configured to sandwich the paper S from both the upper surface and the lower surface of the paper S. A plurality of conveyance roller pairs 302 are provided in the conveyance path 301, rotate by being driven with a rotation shaft as a fulcrum, and convey the sheet S sandwiched between the rollers.

  FIG. 2 is a side view showing details of the skew feeding correction device 400. As illustrated in FIG. 2, the print medium conveyance device 300 includes a first conveyance unit 303, a second conveyance unit 304, and a skew correction device 400. The skew correction device 400 includes a first transport unit 303, a second transport unit 304, a contact unit 401, and a holding unit 402.

  The first transport unit 303 and the second transport unit 304 transport the paper S in order to align the paper S. The 1st conveyance part 303 is comprised by the roller parts 303a and 303b. The roller portions 303 a and 303 b protrude into the conveyance path 301 from holes formed in the guide plate that constitutes the conveyance path 301. The second transport unit 304 includes roller units 304a and 304b and guide units 305a and 305b. The guide portions 305 a and 305 b guide the paper S from both sides and control the transport direction of the paper S, as with the guide plates that constitute the transport path 301, but are not continuous with the guide plates of the transport path 301. It has an independent configuration. Further, holes are formed in the guide portions 305a and 305b, and the roller portions 304a and 304b protrude into the conveyance path 301 from the holes.

  In addition, the printing medium conveyance device 300 is provided with an attachment / detachment mechanism 306 that can attach / detach the second conveyance unit 304. The attachment / detachment mechanism 306 can form a space by not providing a guide plate in a portion of the transport path 301 where the second transport unit 304 is mounted, and the second transport unit 304 can be fitted into this space. The second transport unit 304 is fixed to the print medium transport apparatus 300 by fastening means such as screws (not shown). Therefore, the second transport unit 304 can be manually attached and detached.

  The first transport unit 303 and the second transport unit 304 are driven by a common drive transmission unit 307. The drive transmission unit 307 is in contact with the respective rollers of the first transport unit 303 and the second transport unit 304 so that the rotational force is transmitted. By sharing the drive unit in this way, it is not necessary to newly provide a drive unit or a control unit, and the cost of the apparatus can be reduced. The rotation in the first transport unit 303 may be transmitted to the second transport unit 304 via the drive transmission unit 307 without rotating the drive transmission unit 307 itself.

  The contact unit 401 contacts the front side portion in the transport direction of the sheet S, and aligns the leading end of the sheet S in parallel with the contact unit 401. In the present embodiment, the contact portion 401 is configured in such a shape that the guide plate is bent and protrudes into the conveyance path 301. The first transport unit 303 or the second transport unit 304 transports the paper S by a predetermined distance after the paper S comes into contact with the contact unit 401 and temporarily stops the transport of the paper S. Then, in synchronization with the image drawn on the intermediate transfer belt 501 being conveyed to a predetermined position, the first conveyance unit 303 or the second conveyance unit 304 resumes conveyance of the sheet S, and at that time, contact The sheet 401 is conveyed by retracting the unit 401 downward. Note that the contact portion can also be realized as a so-called nip abutting method that abuts against a contact point of the sheet S in the holding unit 402 described later. In this case, the contact portion 401 and the holding portion 402 are shared by one member.

  The holding unit 402 is a roller pair that holds the front side of the sheet S in the transport direction. When the first transport unit 303 or the second transport unit 304 transports the sheet S so as to abut against the contact unit 401, the skew feeding correction device 400 is configured to hold the holding unit 402 and the first transport unit 303 or the first transport unit 303. The slant is corrected by forming a slack on the paper S with the second transport unit 304. In FIG. 2, since the second transport unit 304 is provided, the slack of the paper S is formed at a distance L2 between the holding unit 402 and the second transport unit 304. The sheets S thus aligned are further conveyed to the secondary transfer device 600. Then, the secondary transfer device 600 transfers the toner image formed on the intermediate transfer belt 501 onto the paper S. Next, the fixing device 700 fixes the toner image transferred to the paper S, and the paper S is discharged from the image forming apparatus 100.

  FIG. 3 is a side view showing a state where the second transport unit 304 is detached from the print medium transport apparatus 300. In FIG. 3, after removing the second transport unit 304, the guide unit 308, which is a separate member, is mounted so as to cover the space formed in the attachment / detachment mechanism 306. In addition, although the guide part 308 is formed substantially parallel to the conveyance path 301, as shown in FIG. 4, the guide part 308a may have a shape protruding to the side where the slack is formed. With such a configuration, it is possible to easily form a sag starting from the guide portion 308a.

  In FIG. 3, since the second transport unit 304 does not exist, the slack of the sheet S is formed at a distance L <b> 1 between the first transport unit 303 and the holding unit 402. Since the distance L1 is longer than L2 shown in FIG. 2, a slack can be formed even with a longer size of the paper S compared to the state where the second transport unit 304 is present.

  FIG. 5 is a side view showing another method of attaching and detaching the second transport unit. As shown in FIG. 5, in the print medium transport apparatus 3000, the second transport unit 1304 includes roller units 1304a and 1304b and guide units 1305a and 1305b. The guide portion 1305 b is configured integrally with a guide plate that forms the conveyance path 301, and the roller portion 1304 b and the guide portion 1305 b cannot be removed from the attachment / detachment portion 1306. On the other hand, the roller portion 1304a and the guide portion 1305a can be detached from the attaching / detaching portion 1306. Therefore, in this example, only the portion where the slack is formed in the second transport unit 1304 is configured to be detachable.

  In the print medium conveying apparatus 300 described above, when it is not necessary to print a short sheet such as a postcard, the skew feeding correction apparatus 400 may be used in the configuration of FIG. In this case, the sheet S having a length shorter than the roller pitch L1 between the first transport unit 303 and the holding unit 402 cannot be transported, but the sheet transport is possible if the sheet is L1 or more. Even with thick paper with high rigidity, a sufficient space for forming slack is ensured by arranging the guide portion 308, so that it is possible to correct the skew of the paper.

  On the other hand, when printing a short sheet, the skew feeding correction device 400 shown in FIG. 2 may be used. In this case, the paper S can be transported up to the roller pitch L2 between the second transport unit 304 and the holding unit 402, and cannot be transported without the second transport unit 304. Even short paper can be transported.

  If such an attachment / detachment method is adopted, there is no need to provide a drive system or a control structure for changing the position of the transport unit, so that the second transport unit can be provided according to the needs of the user without increasing the cost of the apparatus. By attaching and detaching 304, it is possible to print short paper such as postcards and thick paper with high rigidity, and it is possible to provide an image forming apparatus capable of handling paper of various lengths.

DESCRIPTION OF SYMBOLS 100 Image forming apparatus 200 Paper feeding apparatus 201a Paper feeding tray 201b Paper feeding tray 300 Print medium conveying apparatus 301 Conveying path 302 Conveying roller pair 303 First conveying section 303a Roller section 303b Roller section 304 Second conveying section 304a Roller section 304b Roller 305a guide unit 305b guide unit 306 attachment / detachment mechanism 307 drive transmission unit 308 guide unit 308a guide unit 400 skew correction device 401 contact unit 402 holding unit 500 image carrier 501 intermediate transfer belt 600 secondary transfer device 700 fixing device 1304 second Conveying unit 1304a Roller unit 1304b Roller unit 1305a Guide unit 1305b Guide unit 1306 Detachable unit 3000 Print medium conveying apparatus

JP 2008-024507 A

Claims (6)

A transport path that is a path through which the print medium is transported;
A contact portion that comes into contact with a front portion in the conveyance direction of the print medium and stops conveyance of the print medium;
A holding part for holding the front part of the print medium in contact with the contact part;
A first transport unit that transports the print medium so as to abut against the contact unit, and forms slack in the print medium with the holding unit that holds the print medium;
The printing unit is provided on the holding unit side in the transport direction with respect to the first transport unit, transports the print medium so as to abut against the contact unit, and holds the print medium with the print unit. A detachable part that is detachable from the second transport part for forming a slack in the medium ,
The second transport unit includes a roller unit provided on each of an upper surface side and a lower surface side of the print medium, and a guide unit that guides the print medium from both sides independently of the transport path,
The attachment / detachment part can remove the roller part and the guide part of the second transport part.
Print media transport device, wherein the this. The detachable unit is configured to space is removed and the roller portion and the guide portion of the second conveying section, the printing medium according to claim 1, characterized in that is attachable to another guide portion is a separate member Conveying device. A transport path that is a path through which the print medium is transported;
A contact portion that comes into contact with a front portion in the conveyance direction of the print medium and stops conveyance of the print medium;
A holding part for holding the front part of the print medium in contact with the contact part;
A first transport unit that transports the print medium so as to abut against the contact unit, and forms slack in the print medium with the holding unit that holds the print medium;
The printing unit is provided on the holding unit side in the transport direction with respect to the first transport unit, transports the print medium so as to abut against the contact unit, and holds the print medium with the print unit. A detachable part that is detachable from the second transport part for forming a slack in the medium,
The second transport unit includes a roller unit provided on each of an upper surface side and a lower surface side of the print medium,
The attachment / detachment portion can attach / detach only the roller on the side where the slack is formed in the roller portion of the second transport portion.
A print medium conveying apparatus characterized by the above. The first conveyor, and the printing medium conveying apparatus according to any one of claims 1 to 3, further comprising a driving unit for driving both of the second transporter. Printing medium feeding apparatus according to claim 1, characterized in that it comprises a rotational force of said first conveyor further transmission unit for transmitting to said second transport section. An image forming apparatus provided with a printing medium conveying apparatus according to any one of claims 1-5.

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