JP6201396B2 - 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, a printing medium conveyance device according to the present invention includes a conveyance path that is a path through which a printing medium is conveyed, and projects in the conveyance path in the conveyance direction of the printing medium A contact portion that comes into contact with the front portion, a holding portion that holds the print medium in contact with the contact portion, and transports the print medium, and holds the print medium after the print medium comes into contact with the contact portion. A first conveying unit that forms a slack by conveying the printing medium by a predetermined distance between the holding unit and the holding unit, and is provided on the downstream side of the conveying path from the first conveying unit. A second transport unit that transports the print medium by a predetermined distance and forms a slack between the print medium and the holding unit that holds the print medium after the print medium contacts the contact unit; The second transport unit includes: The site present on a side where slack is formed on the printing medium by being carried in the serial transport path, are movable in to the conveyance path outer guide portion for guiding the conveying direction of the printing medium And the guide portion moves to a side where the slack is formed in a state where a portion of the second transport portion on the side where the slack is formed in the transport path is moved out of the transport path. A derivation unit for deriving the print medium is provided .

  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 plan view of the printing medium conveyance device in a state where the second conveyance unit of the embodiment is moved. FIG. 4 is a plan view of the printing medium conveyance device in a state where the second conveyance unit of the embodiment is moved. FIG. 5 is a plan view of the printing medium conveyance device in a state where the second conveyance unit of the embodiment is moved. FIG. 6 is a perspective view illustrating one end portion of the second transport unit according to the embodiment. FIG. 7 is a configuration diagram illustrating a cross section of the bent portion of the guide plate when the second transport unit of the embodiment is viewed from the arrow A. FIG. 8 is a table showing the conditions of the second transport unit used for each paper type in the image forming apparatus of the embodiment.

  FIG. 1 is a side cross-sectional 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, a secondary transfer device 500, an image carrier 600, and a fixing device 700.

  The image carrier 600 is an image carrier 600Y, 600M, 600C, 600Bk 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 600Y, 600M, 600C, and 600Bk 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 shown in FIG. 2, the print medium conveyance device 300 includes 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.

  The guide unit 305a and the guide unit 305b of the second transport unit 304 are connected to each other. The second transport unit 304 is supported in the transport path 301 so as to be rotatable around a roller unit 304b on the side opposite to the side where slack is formed.

  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. 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 portion in the transport direction of the paper S to stop the transport of the paper S. In the present embodiment, the contact portion 401 is configured so 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 and the holding portion 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 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 500. Then, the secondary transfer device 500 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 in which the print medium transport apparatus 300 has moved the second transport unit 304 out of the transport path 301. When printing, when the length of the sheet S selected as the printing sheet of the image forming apparatus 100 is longer than the roller pitch L1 between the holding unit 402 and the first conveying unit 303, the second conveying unit The roller unit 304a and the guide unit 305a of 304 are rotated forward in the transport direction around the rotation axis of the roller unit 304b. By rotating the second transport unit 304, the roller unit 304a and the guide unit 305a are moved out of the transport path 301 from the side where the slack of the transport path 301 is formed. Even in the state after the rotation, the guide unit 305a and the guide unit 305b are in a state where the surface different from that before the rotation faces the conveyance path 301, and the sheet S conveyed on the conveyance path 301 can be guided. Yes. Although FIG. 3 shows a state where it is rotated about 90 degrees, this rotation angle may be other than 90 degrees by appropriately setting the bent portion of the guide portion.

  FIG. 4 is a side view showing another configuration of the second transport unit. As shown in FIG. 4, the second transport unit 1304 includes roller units 1304a and 1304b and a guide unit 1305a. In the case of FIG. 4, the roller portion 1304 b is configured to protrude from the guide plate that constitutes the conveyance path 301. The roller unit 1305 a is connected to the roller unit 303 a of the first transport unit 303 by the plate member 310. The plate member 310 can rotate around the rotation axis of the roller portion 303 a of the first transport unit 303. As shown in FIG. 4, the roller portion 1304a and the guide portion 1304a are moved to the upper side (for example, about 45 degrees as shown) that does not hinder the formation of slack in the paper S.

  FIG. 5 is a side view showing the configuration after the movement of another second transport unit. In FIG. 5, the 2nd conveyance part 2304 is equipped with roller part 2304a, 2304b and guide part 2305a, 2305b. In the case of FIG. 5, the roller portion 2304 b is configured to protrude from the guide plate that constitutes the conveyance path 301. The roller units 2304a and 2304b of the second transport unit 2304 are connected to each other. The second transport unit 2304 is supported so as to be rotatable about the roller unit 2304b on the side opposite to the side where slack is formed in the transport path 301. The rotation angle at this time is larger than the example shown in FIG. 3, but the rotation angle is adjusted so that the guide portion 2305 b is positioned at a position along the conveyance path 301 even after the guide portion 2305 b is moved. In addition, the guide part 2305b is comprised so that attachment or detachment is possible, for example, and it does not become a hindrance when the 2nd conveyance part 2304 rotates.

  In the printing medium conveyance device 300 described above, when it is not necessary to print a short sheet such as a postcard, the skew feeding correction device 400 is used in a configuration in which the second conveyance unit 304 is moved out of the conveyance path 301. You can do it. In this case, a sheet having a length shorter than the roller pitch L1 between the first transport unit 303 and the holding unit 402 cannot be transported, but a sheet of L1 or more can be transported and is rigid. Even when the thick paper is high, a sufficient space for forming a slack is secured by arranging the guide portion 305, so that the skew of the paper can be corrected.

  On the other hand, when printing a short sheet, the second transport unit 304 may be used in a configuration in which the second transport unit 304 is moved into the transport path 301. 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. Short paper can also be conveyed.

  If such a movement method is adopted, it is not necessary 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 used as required by the user without increasing the cost of the apparatus. By moving 304, it is possible to print short paper such as a postcard and thick paper with high rigidity, and it is possible to provide an image forming apparatus capable of handling paper of various lengths.

  In addition to the above-described movement method of rotating the second conveyance unit 304, sagging of the conveyance path 301 is formed by moving the second conveyance unit to the upper side or to the left and right sides. Although it is necessary to secure a movable space for the image forming apparatus, it is possible to adopt a configuration for retracting from the position.

  Further, instead of manually moving the second transport unit, it is determined whether or not the second transport unit is to be moved based on the size of the sheet designated at the time of printing, and if necessary, the second transport unit is determined. It is also possible to adopt a configuration in which the movement is performed by controlling the driving device of the unit.

  Next, means for moving the second transport unit will be described with reference to FIGS. FIG. 6 is a perspective view showing one end portion of the second transport unit 304. FIG. 7 is a configuration diagram showing a cross section of the bent portion 305c of the guide portion 305b when viewed from the arrow A in FIG. As shown in FIG. 6, a bent portion 305c is formed at the end of the guide portion 305b, and a pulley 323 and a bearing 322 are formed. The pulley 323 and the bearing 322 are press-fitted in advance and integrally configured. As shown in the cross-sectional view of FIG. 7, the flange portion of the pulley 323 is inserted into the hole portion of the bending portion 305c, and a fixing member such as a screw is inserted. 324 is fixed. The shaft 304c of the second transport roller 304b is inserted into the bearing 322 and supported by the frame of the skew feeding correction device 400. Similarly, the shaft 304c of the second transport roller 304b is inserted into the bending portion 305e on the opposite side via the bearing 322, and the gear 326 is inserted into the shaft 304c by being fastened or rotated. Further, the shaft 304c is supported on the frame of the skew correction device 400 on the far side via the bearing 322, and the second transport unit 304 is supported rotatably about the shaft 304c.

  A driving unit 328 is attached to the frame of the skew feeding correction device 400 for the conveyance drive of the print medium, and the rotation drive is transmitted to the gear 327 via the belt 321, so that the first conveyance roller unit 303 b of the first conveyance unit 303 is transmitted. Is driven. Further, the drive is transmitted to the gear 326 via the gear 307, and the second transport roller 304b is rotationally driven, so that the first transport unit 303 and the second transport unit 304 are transported simultaneously.

In addition, a drive unit 325 (drive unit) and a sensor 320 are fixed to a frame (not shown) of the skew feeding correction device 400 or the paper transport device 500, and are fixed independently from the rotatable second transport unit. Has been. Then, the rotation of the driving unit 325 drives the pulley 323 via the belt 321, so that the second transport unit 304 can freely rotate. Further, the bending portion 305 c has a filler portion 305 d, and serves as a shielding plate for the sensor 320 according to the rotation of the second transport unit 304. The driving unit 325 stops or drives the forward / reverse rotation of the driving unit 325 based on the transmission or shielding signal of the sensor, and controls the movement of the second transport unit 304 to any one of FIGS .

  Note that the control method of the driving unit 325 is not limited to this, and in the case of an AC stepping motor, a method of counting and controlling a predetermined number of predetermined pulses at the time of forward and reverse rotation, and the rotation angle of the second transport unit 304 are physically 2 and 3 can be controlled by a simple stopper or the like, a control method of detecting or driving or stopping the overcurrent of the DC motor is also possible.

  In general, when starting a printing operation, an operator uses an operation panel (not shown) or the like in advance to determine the size, thickness, and type of the paper S loaded in the paper feeder 200 (plain paper, coated paper, envelope, presence / absence of punch holes, etc. ) Is selected. With respect to the width and length of the paper, the width and length can be specified from the selected size information if it is a general standard size such as A4 or A3. It is also possible to directly input the width and length of the paper S as the irregular size. From these paper length information, the second transport unit 304 selects whether to start the printing operation in either FIG. 2 or FIG. FIG. 8 is a table showing the position information of the second transport unit determined by the combination of the position of the second transport unit 304 corresponding to the sheet thickness, the sheet length, and the sheet type. It is stored in a storage unit such as a hard disk of the forming apparatus.

  As shown in FIG. 8, for example, assuming that the paper length L and the slack formation length during skew correction are Lbf, FIG. 3 is selected if L> L1 + Lbf. Further, when L ≦ L1 + Lbf, FIG. 2 is selected. Further, in addition to the paper length L, the selection can be made by a combination of the paper thickness and the paper type. For example, if the paper thickness T and the paper type are K, a matrix as shown in FIG. 8 is stored in a storage device (not shown) in advance, and conditions that meet the conditions of FIG. 8 are selected from the obtained paper information. Similarly, the user selects whether to start the printing operation in either FIG. 2 or FIG. The length information, the thickness information, the paper type information, and the like may be acquired by a user-selected information or may be acquired by measurement.

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 Part 304c Shaft 305a Guide part 305b Guide part 305c Bending part 305d Filler part 305e Bending part 307 Drive transmission part 320 Sensor 321 Belt 322 Bearing 323 Pulley 324 Fixing member 325 Driving means 326 Gear 327 Gear 328 Driving means 400 Skew contact correcting device 401 Section 402 Holding section 500 Secondary transfer apparatus 501 Intermediate transfer belt 600 Image carrier 700 Fixing apparatus

JP 2008-024507 A

Claims (8)

A transport path that is a path through which the print medium is transported;
A contact portion that protrudes into the transport path and contacts a front portion in the transport direction of the print medium;
A holding unit for holding the print medium in contact with the contact unit;
First, the print medium is transported, and after the print medium comes into contact with the contact portion, the print medium is transported by a predetermined distance from the holding portion that holds the print medium to form a slack. A transport section;
Provided on the downstream side of the transport path from the first transport unit, transports the print medium, and after the print medium comes into contact with the contact unit, between the hold unit that holds the print medium A second transport unit for transporting the print medium by a predetermined distance to form a slack;
With
The second transport unit is
A portion that is present on the side where slack is formed in the print medium by being conveyed in the conveyance path is configured to be movable out of the conveyance path ,
A guide unit for guiding a conveyance direction of the print medium;
The guide unit moves the print medium to a side where the slack is formed in a state where a portion of the second transport unit on the side where the slack is formed is moved to the outside of the transport path. A print medium conveying apparatus comprising a deriving unit for deriving the image . The guide portion can guide the print medium even when a portion of the second conveyance portion on the side where the slack is formed in the conveyance path is located inside or outside the conveyance path. print media transport apparatus according to claim 1, characterized in that it is configured to. The second transport unit includes a pair of roller units provided on an upper surface side and a lower surface side of the print medium,
2. The printing according to claim 1 , wherein the second transport unit is configured to be rotatable around a rotation axis of the roller unit on the side where the slack is not formed, of the pair of roller units. Medium transport device. A length acquisition unit that acquires the length of the print medium in the transport direction;
A determination unit that determines whether the acquired length is greater than a predetermined threshold;
When it is determined that the length is equal to or less than the threshold value , a portion that is present on the side where the slack is formed in the transport path of the second transport unit is positioned in the transport path. When the second transport unit is driven and the length is determined to be larger than the threshold value, there is a portion that exists on the side where the slack is formed in the transport path of the second transport unit. A drive unit that drives the second transport unit to be located outside the transport path;
The print medium conveying apparatus according to claim 1, further comprising: A filler part at least at one end of the guide part of the second transport part, and a sensor at a position where the filler part is detected;
The drive unit stops or drives forward / reverse rotation based on the transmission or shielding signal of the sensor, and controls the movement of the second transport unit in and out of the transport path.
The print medium carrying device according to claim 4 . A storage unit storing position information of the second transport unit determined by a combination of information on the length of the print medium and information on the thickness of the print medium;
A thickness acquisition unit for acquiring information on the thickness of the print medium;
Further comprising
The drive unit determines a position to move the second transport unit with reference to the storage unit from the acquired information on the length of the print medium and the information on the thickness of the print medium. The printing medium conveying apparatus according to claim 4 , wherein the two conveying units are controlled to move in and out of the conveying path. A storage unit storing position information of the second transport unit determined by a combination of information on the length of the print medium, information on the thickness of the print medium, and information on the type of the print medium;
A thickness acquisition unit for acquiring information on the thickness of the print medium;
A type acquisition unit for acquiring information on the type of the print medium;
Further comprising
The drive unit refers to the storage unit based on the acquired information on the length of the print medium, information on the thickness of the print medium, and information on the type of the print medium. The printing medium conveyance device according to claim 4 , wherein a position to be moved is determined, and the second conveyance unit is controlled to move in and out of the conveyance path. An image forming apparatus provided with a printing medium conveying apparatus according to any one of claims 1-7.

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