JP5804826B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus that forms an image on a recording sheet wound in a roll shape.

  Among image forming apparatuses, there is a type that uses a large recording sheet having a sheet size of A2 or more. In this type of image forming apparatus, recording paper wound in a roll shape is generally used in addition to cut paper. Hereinafter, the portion pulled out from the roll paper is referred to as a paper portion. In general, the paper portion is drawn from the roll paper by a conveyance roller. Since the roll paper used in a large format printer is heavy, the load for pulling out the paper portion becomes large. Therefore, there is a possibility that the recording paper is broken only by the driving force of the transport motor that drives the transport roller. Therefore, Patent Documents 1 and 2 disclose a technique in which a roll motor for rotating roll paper is provided and the roll motor is driven together with the conveyance motor to pull out the paper portion.

  Patent Document 1 discloses an image forming apparatus that includes a sheet conveying roller, a roll motor, a conveying motor, a tension measuring unit that measures a tension generated on the roll paper, and a motor control unit. In this image forming apparatus, the motor control unit controls driving of at least one of the roll motor and the carry motor based on the measurement result of the tension measuring unit. As a result, each motor is feedback-controlled based on the tension accurately measured by the tension measuring means to determine the roll feed amount. Thereby, the tension acting on the roll paper can be appropriately controlled, and the fluctuation of the tension due to the change in the roll diameter of the roll paper can be prevented.

  On the other hand, in Patent Document 2, a sheet conveying roller, a conveying motor, a feeding roller disposed so as to be in contact with the outer peripheral surface of the roll paper, a feeding roll motor that rotates the feeding roller, and a control unit are provided. An image forming apparatus having the same is disclosed. In this image forming apparatus, the control unit rotates the feeding roller using the printing time and the conveyance time. As a result, the roll paper is fed in the direction corresponding to the paper feed amount required for the paper feed operation by the paper feed roller between the end of the paper feed operation by the paper feed roller and the start of the next feed operation. Rotate to As a result, the roll paper always has a slack, and the conveyance accuracy can be improved without being affected by the inertia load of the roll paper.

JP 2009-263044 A JP 2007-203564 A

  In the image forming apparatus disclosed in Patent Document 1, a recording sheet is conveyed by a sheet conveying roller in a state where a tension is always applied to the sheet unit (a pulled state). There are various types of recording paper, such as glossy paper on which a receiving layer for improving ink fixability is formed on the recording surface, the recording surface is easily damaged. When transporting such recording paper, in a transport mode in which tension is always applied to the paper portion, there is a high possibility that the paper portion will rub in the transport path and scratches or rubbing marks etc. will occur on the recording surface. .

  On the other hand, the image forming apparatus disclosed in Patent Document 2 is transported in a state in which no tension is applied to the paper portion (slack), so that the paper portion can be prevented from rubbing against the transport path. Therefore, it is suitable for transporting recording paper whose recording surface is easily damaged, such as the glossy paper described above. However, in this image forming apparatus, since no tension is applied to the paper portion, it is difficult to correct the skew when the paper portion is skewed. Therefore, the image forming apparatus disclosed in Patent Document 2 is not suitable for transporting recording paper that is not easily scratched or rubbed, such as plain paper or coated paper.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus capable of optimizing the conveyance form according to the type of recording paper.

To achieve the above object, an image forming apparatus of the present invention includes a paper feed mechanism for feeding the transport path from the tip of the recording paper by rotating a recording sheet wound in a roll shape, conveyed in the conveying path a transport mechanism for transporting the recording paper, an image recording unit for recording an image on said recording sheet, when the recording sheet is classified into the first type is easily scratched, wherein the recording sheet from the conveying path It includes a section for slack Oite the recording sheet in the convey time that will be conveyed to the image recording unit, and selects a first control mode that does not include a section to pull the recording paper, the recording paper is the first If classified as a second type of hard scratched than one type, characterized in that it comprises a control unit for selecting the second control mode including a section to pull the recording paper in the conveying period.
Another image forming apparatus according to the present invention includes a paper feed mechanism that rotates a recording paper wound in a roll shape and sends the recording paper from a leading end portion of the recording paper to a conveyance path, and the recording paper fed to the conveyance path. When the transport mechanism, the image recording unit that records an image on the recording paper, and the recording paper are classified as the first type that is easily damaged, the recording paper is transported from the transport path to the image recording unit. A first control mode is selected that includes a section in which the recording paper is slackened within a conveying period and does not include a section in which the recording paper is pulled, and the recording paper is less damaged than the first type. When a third type of recording paper that is slippery among the second type of recording paper is used, the second type includes a section in which the recording paper is pulled during the transport period. When a control mode is selected and the recording sheet is classified as the second type, among the second type recording sheets, there is a fourth type recording sheet that is less slippery than the third type recording sheet. And a control unit that selects a third control mode in which the recording sheet is always pulled within the conveyance period.

  According to the present invention, it is possible to optimize the conveyance form according to the type of recording paper.

1 is a perspective view showing an embodiment of an image forming apparatus of the present invention. It is sectional drawing of the image forming apparatus shown in FIG. FIG. 2 is a perspective view illustrating a configuration of a part of a sheet feeding mechanism provided in the image apparatus illustrated in FIG. 1. FIG. 2 is a cross-sectional view illustrating a configuration of a sheet feeding mechanism provided in the image apparatus illustrated in FIG. 1. FIG. 2 is a cross-sectional view illustrating a configuration of a transport mechanism provided in the image apparatus illustrated in FIG. 1. FIG. 2 is a block diagram illustrating an electrical control configuration of the image forming apparatus illustrated in FIG. 1. FIG. 6 is a relationship diagram of recording paper conveyance speed and slack. It is a timing chart which shows the relation between the speed and the amount of slack in the first control mode. It is a timing chart which shows the relationship between the speed | rate and the amount of slack in a 2nd control mode. FIG. 6 is a diagram illustrating a relationship between a conveyance force of a conveyance roller and a back tension when the roll paper is in a skew state. It is a figure which shows the conveyance force which acts on a paper part when a roll paper is skewed. FIG. 6 is a diagram illustrating a correspondence relationship between a plurality of predetermined recording sheets and a control mode. 3 is a flowchart illustrating an operation procedure of the image forming apparatus according to the first embodiment. It is a timing chart which shows the relationship between the speed in the 2nd control mode of 2nd Embodiment, and the amount of slack. It is a block diagram which shows the electrical control part structure of the image forming apparatus of the 3rd Embodiment of this invention. FIG. 6 is a diagram illustrating a correspondence relationship between a plurality of predetermined recording sheets and a control mode. 10 is a flowchart illustrating an operation procedure of the image forming apparatus according to the third embodiment.

(First embodiment)
FIG. 1 is a perspective view showing an embodiment of an image forming apparatus of the present invention. FIG. 2 is a cross-sectional view of the image forming apparatus shown in FIG. FIG. 3 is a perspective view showing a partial configuration of a paper feed mechanism provided in the image forming apparatus shown in FIG.

  The image forming apparatus 1 of the present embodiment uses roll paper 6a, which is a recording paper wound in a roll shape, as a recording medium. As shown in FIG. 3, in the roll paper 6a, the spool shaft 5 penetrates the paper tube 15 located at the center of winding. The reference side loading section 26a of the reference side roll paper holder 26 attached to the spool shaft 5 bites into the inner wall of the paper tube 15 by the elastic force in the radial direction, so that the paper tube 15 is fixed to the reference side roll paper holder 26. Is done. Further, the paper tube 15 is held by the non-reference-side roll paper holder 27 by passing the non-reference-side roll paper holder 27 through the spool shaft 5 from the opposite side of the reference-side roll paper holder 26 so as to sandwich the roll paper 6a. . The non-reference-side roll paper holder 27 is provided with a non-reference-side loading portion 27a, and the non-reference-side loading portion 27a bites into the inner wall of the paper tube 15 by the elastic force in the radial direction so that the paper tube 15 is non-referenced. It is fixed to the side roll paper holder 27. Since both ends of the spool shaft 5 are rotatably held by the image forming apparatus 1, the roll paper 6a is also rotatably held (see FIG. 1).

  The roll paper 6a held in the image forming apparatus 1 is rotated counterclockwise (CCW), whereby the leading end portion of the paper portion 6b is formed in the conveyance path 9 formed between the outer guide 7 and the inner guide 8. (See FIG. 2). A paper detection sensor (not shown) is provided in the middle of the conveyance path 9. When the paper detection sensor detects the leading end of the paper portion 6b, the transport motor 24 located on the downstream side of the transport path 9 rotates the transport roller 10 counterclockwise. When the leading end of the paper section 6b reaches between the transport roller 10 and the pinch roller 11, the paper section 6b is sandwiched between the transport roller 10 and the pinch roller 11 and transported to the image recording section 30 positioned forward in the transport direction. Is done. At this time, the sheet width detection unit 13 detects the sheet width and skew amount by the sheet end detection sensor 13 mounted on the carriage 3.

  The image recording unit 30 includes a recording head 2 (see FIG. 1) that records an image on the paper unit 6b, a carriage 3 on which the recording head 2 is mounted, and a platen 12 that faces the recording head 2. The carriage 3 is supported by a carriage shaft 4 (see FIG. 1) and a guide rail that are arranged in parallel with each other on the image forming apparatus 1 so as to be reciprocally movable. In the image recording unit 30, when the paper unit 6b is conveyed onto the platen 12, the carriage 3 reciprocates in the direction of arrow D1 (see FIG. 1). As the carriage 3 reciprocates, the recording head 2 records an image for one line on the paper portion 6b. Thereafter, when the conveying roller 10 and the pinch roller 11 convey the paper portion 6b by a predetermined pitch in the conveying direction A (see FIG. 2), the carriage 3 moves back and forth again, and the recording head 2 records the next line image. By repeating this operation, an image is recorded on the entire sheet portion 6b. The recorded paper portion 6 b is conveyed toward the paper discharge cover 14 outside the image forming apparatus 1. When the recording operation is completed, the paper portion 6b is conveyed to a predetermined cutting position by the conveying roller 10 and the pinch roller 11. Thereafter, the paper portion 6 b is cut into the cutter 29. The cut paper portion 6b is stored from the paper discharge cover 14 into a paper discharge basket (not shown).

  Next, a paper feed mechanism 40 that rotates the roll paper 6a and feeds the roll paper 6a from the leading end of the paper portion 6b to the conveyance path 9 will be described with reference to FIG. FIG. 4 is a cross-sectional view showing the configuration of the paper feed mechanism 40.

  The spool shaft 5 holding the roll paper 6 a is connected to the roll input gear 18 via the roll gear 17 provided at the end of the reference-side roll paper holder 26. The roll input gear 18 is connected to the gear 19 a of the roll motor 19. The roll motor 19 applies a driving force to the roll paper 6 a via the roll input gear 18 and the roll gear 17. The encoder film 20 is affixed to the roll input gear 18, and drive control is performed by detecting the rotation operation of the encoder film 20 by the encoder sensor 21. This drive control mainly includes no load, excitation by a predetermined force, and roll paper reverse rotation drive. Excitation with a predetermined force is a so-called roll back tension control, which is carried while applying the back tension to the recording paper, thereby performing skew correction and slack removal during paper setting. The back tension load is adjusted by controlling the torque generated by the roll motor 19 by adjusting the current flowing through the roll motor 19.

  Next, the transport mechanism 50 that transports the paper section 6b from the transport path 9 to the image recording section 30 will be described. FIG. 5 is a cross-sectional view showing the configuration of the transport mechanism 50.

  The conveyance roller 10 is connected to a conveyance input gear 23 via a conveyance gear 22 provided at an end thereof. The transport input gear 23 is connected to the gear 24 a of the transport motor 24. The transport motor 24 applies a transport force to the transport roller 10 via the transport input gear 23 and the transport gear 22. The encoder film 28 is affixed to the conveyance input gear 23, and drive control is performed by detecting the rotation operation of the encoder film 28 by the encoder sensor 25.

  FIG. 6 is a block diagram showing an electrical control configuration of the image forming apparatus shown in FIG.

  In the block diagram shown in FIG. 6, the control unit 100 is a component for controlling the roll motor 19 and the transport motor 24, and includes a main control unit 110, a roll motor control unit 120, and a transport motor control unit 130. Have. Each control unit includes a CPU (Central Processor Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. The main control unit 110 gives a command to both the roll motor control unit 120 and the conveyance motor control unit 130 in order to drive the roll motor 19 and the conveyance motor 24 in correlation. The roll motor control unit 120 has a first control mode and a second control mode, and switches the control mode based on the recording information indicating the type of the roll paper 6a.

  FIG. 7 is a diagram illustrating the relationship between the conveyance speed and slackness of the paper section 6b. In FIG. 7, the tension Tpap is a tension applied to the paper portion 6b between the transport roller 10 and the roll paper 6a (in the transport path). The transport speed Vlf is the transport speed (circumferential speed) of the transport roller 10. The feed speed Vroll is a feed speed (circumferential speed) of the roll paper 6a. The slack amount Spap is a slack amount of the paper portion 6b between the transport roller 10 and the roll paper 6a (in the transport path). The conveyance speed Vpap is the conveyance speed of the paper section 6b. Regarding the transport speed Vlf, the feed speed Vroll, and the transport speed Vpap, the directions of the arrows in the figure are positive values. Regarding the slack amount Spap, the state where there is no slack is set to 0, and the slack amount is displayed as an absolute value. The force relationships in the waveform diagrams shown below will be described with reference to the direction of FIG.

  Next, the first control mode and the second control mode will be described.

  FIG. 8 is a timing chart showing the relationship between the speed and the slack amount in the first control mode. FIG. 9 is a timing chart showing the relationship between the speed and the slack amount in the second control mode.

  First, the first control mode will be described. In the upper graph shown in FIG. 8, the vertical axis indicates the transport speed Vlf of the transport roller 10, and the horizontal axis indicates time T. In the middle graph of FIG. 8, the vertical axis indicates the feed speed Vroll of the roll paper 6a, and the horizontal axis indicates time T. In the lower graph of FIG. 8, the vertical axis represents the slack amount Spap of the paper portion 6 b, and the horizontal axis represents time T. The conveyance speed Vlf of the conveyance roller 10 has an operation waveform having an acceleration region (Tb−Tc), a constant velocity region (Tc−Td), and a deceleration region (Td−Te). In the present embodiment, the roll paper 6a is sent out in the feeding direction at a time Ta before a time Tb when the transport roller 10 starts to operate. The slack amount Spap is formed between the start time Ta of the roll paper 6a feeding operation and the acceleration region end time Tc of the transport roller 10 due to the difference between the transport speed of the roll paper 6a and the transport speed of the transport roller 10. When the acceleration region (Tb-Tc) of the transport roller 10 ends and enters the constant speed region (Tc-Td) and the deceleration region (Td-Te), the roll paper 6a transports the transport speed following the transport roller 10 (Vlf = Vroll). ). Therefore, the slack amount Spap is kept constant. The slack amount Spa may be a minimum slack that does not affect the paper feeding operation of the transport roller 10. After the operation end time Te of the transport roller 10, the roll motor 19 is rotated in the direction opposite to the transport direction, and the slack is removed until a time Tf at which the slack amount of the paper section 6b becomes Spap = 0. The slack removal of the paper section 6b is completed between the operation stop time Te of the transport roller 10 and the operation start time Ta 'of the next roll paper. The above operation is performed every time the conveyance roller 10 is intermittently conveyed.

  As described above, the first control mode has a section in which the slack amount Spap> 0 within the transport period in which the paper section 6b is transported from the transport path 9 to the image recording section 30. In a section where the slack amount Spap> 0, the tension applied to the paper portion 6b between the transport roller 10 and the roll paper 6a is Tpap = 0. As a result, the paper portion 6b is conveyed in a slack state (a state in which no tension Tpap is applied). As a result, it is possible to suppress scratches, rubbing marks, etc. on the recording surface caused by the rubbing of the sheet portion 6b against the inner guide 8 (see FIG. 2), and stable sheet conveyance is possible.

  In the first control mode of the present embodiment, the paper feeding operation start timing Ta of the roll paper 6a is advanced from the feeding operation timing Tb of the transport roller 10, thereby causing the paper portion 6b to become slack and performing the paper feeding operation (Tb− Te) is set to Tpap = 0. However, as long as the control method sets Tpap = 0 during the paper feeding operation (Tb−Te), another control method may be set as the first control mode. Other control methods include, for example, control for making the feed speed Vroll of the roll paper 6a faster than the transport speed Vlf of the transport roller 10, control for causing the paper portion 6b to slack before recording, and constantly maintaining the slack amount, etc. It is.

  Next, the second control mode will be described. The vertical and horizontal axes of the three graphs shown in FIG. 9 are the same as those in FIG. 8 showing the first control mode. The transport speed Vlf of the transport roller 10 has an operation waveform having an acceleration region (Ta-Tc), a constant speed region (Tc-Te), and a deceleration region (Te-Tf), as in the first control mode. Unlike the first control mode, the roll paper 6a is sent to the transport path 9 at the same time as the time Ta during which the transport roller 10 operates. However, the acceleration of the roll paper 6a is not constant, and the acceleration is smaller than that of the transport roller 10 in the initial stage of rotation (Ta-Tb). Therefore, at the initial stage of rotation (Ta-Tb), the conveyance speed Vlf of the conveyance roller 10> the feed speed Vroll of the roll paper 6a, so that not only the slack amount Spap becomes zero but also the tension applied to the paper portion 6b (back tension). ) Tpap> 0. Thereafter (Tb−Tc), the acceleration of the roll paper 6 a exceeds the acceleration of the transport roller 10. Therefore, since the conveyance speed Vlf <feed speed Vroll, the slack amount Spap> 0. The operation after the feed speed Vroll of the roll paper 6a enters the constant speed region (Td) is the same as that in the first control mode.

  Here, with reference to FIGS. 10 and 11, a mechanism for correcting the skew of the paper portion 6b in the paper conveyance will be described. FIG. 10 is a diagram illustrating the relationship between the conveyance force of the conveyance roller and the back tension when the roll paper is in a skew state. FIG. 11 is a diagram illustrating a conveying force that acts on the paper portion when the roll paper is in a skew state. When the paper portion 6b is skewed to the P2 side and conveyed in a state where the back tension is applied (Tpap> 0), the P1 side end portion of the paper portion 6b is stretched and the P2 side end portion is loosened. Therefore, the back tension B becomes stronger at the P1 side end and becomes weaker at the P2 side end. On the other hand, the conveying force H applied to the paper portion 6b by the conveying roller 10 and the pinch roller 11 is equal for both the end portion on the P1 side and the end portion on the P2 side regardless of the presence or absence of skew. Accordingly, the distribution of the conveyance force H and the back tension B in the width direction of the paper portion 6b is as shown in FIG. Further, the effective transport force F actually acting on the paper portion 6b is the difference between the transport force H and the back tension B. Therefore, as shown in FIG. 11, the effective conveyance force F becomes stronger at the P2 side end and becomes weaker at the P1 side end. Therefore, the skew of the paper portion 6b is corrected from the end portion on the P2 side to the end portion on the P1 side. In other words, the skew correction of the paper portion 6b is performed as the back tension magnitude and the difference in the back tension between the P2 side end portion and the P1 side end portion increase, and as the transport force H from the transport roller 10 decreases. The effect of skew correction is great.

  The second control mode of the present embodiment has a section in which the slack amount Spap is zero and the back tension is applied to the paper portion 6b (Tpap> 0) at the initial stage of the paper feeding operation of the transport roller 10 (Ta-Tb). As a result, even when the paper portion 6b is skewed, it is possible to correct the skew while performing the recording operation.

  In the second control mode of the present embodiment, the paper sheet 6b is temporarily stretched by changing the acceleration of the roll paper 6a, and Tpap> 0 is set at the initial stage of paper feeding operation (Ta-Tb). However, any other control method may be set to the second control mode as long as it is a control method in which Tpap> 0 at the initial stage of the paper feeding operation (Ta-Tb). The other control methods include, for example, control for making the paper feed timing of the transport roller 10 faster than the paper feed timing of the roll paper 6a, control for always making the transport speed Vlf of the transport roller 10 faster than the feed speed Vroll of the roll paper 6a, and the like. .

  Next, the operation of the image forming apparatus according to the present embodiment will be described with reference to FIGS. FIG. 12 is a diagram illustrating a correspondence relationship between a plurality of types of predetermined recording sheets and the control mode described above. FIG. 13 is a flowchart showing an operation procedure of the image forming apparatus of this embodiment.

  As described above, the first control mode can suppress the occurrence of scratches, rubbing traces, or the like on the recording surface. For this reason, as shown in FIG. 12, paper type A classified as a recording paper that easily causes scratches such as glossy paper and proof paper is associated with the first control mode.

  On the other hand, in the second control mode, as described above, even when the paper portion 6b is skewed, it is possible to correct skew while performing the recording operation. Therefore, the paper type B classified as a scratch-resistant recording paper such as plain paper or coated paper is associated with the second control mode.

  In the flowchart shown in FIG. 13, along with the feeding of the roll paper 6a (step S01), the recording information indicating the type of the roll paper 6a previously selected by the user is input to the main control unit 110 (step S02). ). The main control unit 110 determines the type of the roll paper 6a based on the input recording information (step S03). When the type of roll paper 6a indicated in the recording information is paper type A, the main control unit 110 causes the roll motor control unit 120 to convey the paper unit 6b by a predetermined amount (for example, 300 mm) in the first control mode. At this time, the main control unit 110 detects the skew amount based on the end position of the sheet unit 6b before and after the conveyance detected by the sheet end detection sensor 13 (step S04). After that, the main control unit 110 determines whether or not the detected skew amount is below a predetermined allowable value ob1 (step S5). When the skew amount is less than the allowable value ob1, the main control unit 110 performs recording in the first control mode (step S06). Thereafter, when recording in the first control mode is completed (step S08), a standby state is set. If the skew amount is greater than or equal to the allowable value ob1, a warning is given to the user that the roll paper 6a is to be set again (step S07).

  When the type of the roll paper 6a indicated in the recording information in step S03 is the paper type B, the main control unit 110 causes the roll motor control unit 120 to move the paper unit 6b to a predetermined amount (for example, 300 mm) in the second control mode. Transport. At this time, the main control unit 110 detects the amount of skew as in step S04 (step S09). Thereafter, the main control unit 110 determines whether or not the detected skew amount is below a predetermined allowable value ob2 (step S10). When the skew amount is less than the allowable value ob2, the main control unit 110 performs recording in the second control mode (step S11). Thereafter, when the recording in the second control mode is completed (step S13), the standby state is set. If the skew amount is greater than or equal to the allowable value ob2, a warning is given to the user that the roll paper 6a is to be set again (step S12).

  In the present embodiment, the allowable value of the skew feed amount has a magnitude relationship of ob1 <ob2. This is because in the first control mode, the paper portion 6b is transported without applying tension, and thus it is difficult to correct the skew of the paper portion 6b. For this reason, the allowable value of the skew amount of the paper portion 6b becomes stricter (smaller) than that in the second control mode so as not to affect image formation.

  According to the image forming apparatus of the present embodiment, when the recording paper is easily damaged such as glossy paper or proof paper, the first control mode for conveying the recording paper without applying tension (in a slack state) is provided. Selected. For this reason, it is possible to suppress the recording surface from being scratched or rubbed. On the other hand, when the recording paper is a kind that is not easily damaged, such as plain paper or coated paper, the second control mode is selected in which the recording paper is conveyed with tension applied (in a pulled state). Therefore, it becomes difficult for the paper portion 6b to skew, and the setting operation of the roll paper 6a is simplified.

(Second Embodiment)
Next, a second embodiment of the image forming apparatus of the present invention will be described. The same constituent elements as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. In the present embodiment, the content of the second control mode is different from that of the first embodiment.

  The second control mode of the present embodiment will be described with reference to FIG. FIG. 14 is a timing chart showing the relationship between the speed and the slack amount in the second control mode of the present embodiment.

  The vertical and horizontal axes of the three graphs shown in FIG. 14 are the same as those in FIGS. 8 and 9, respectively. Similarly to the first control mode and the second control mode of the first embodiment, the conveyance speed Vlf of the conveyance roller 10 is an acceleration region (Ta-Tc), a constant velocity region (Tc-Te), and a deceleration region (Te -Tf). In the present embodiment, the feed speed Vroll of the roll paper 6a also has an acceleration region (Ta-Tc), a constant speed region (Tc-Te), and a deceleration region (Te-Tf), similarly to the transport speed Vlf of the transport roller 10. It becomes an operation waveform. Therefore, during the transport operation of the transport roller 10 (Ta−Tf), the slack amount Spap is always zero, and the back tension is always applied to the paper portion 6b (Tpap> 0). As a result, the sheet portion 6b is conveyed in a state in which the tension Tpap is always applied, so that the effect of skew correction is further increased.

  As described above, in the second control mode of the present embodiment, the tension Tpap is always applied to the paper section 6b during the transport period in which the paper section 6b is transported from the transport path 9 to the image recording section 30. Accordingly, even when the tension Tpap applied to the paper portion 6b is the same as that in the first embodiment, the time during which the tension is applied is longer than that in the first embodiment. Therefore, the effect of skew correction is greater than that in the first embodiment. Thereby, in the present embodiment, the allowable value ob2 of the skew amount of the paper portion 6b in the second control mode can be made looser (larger) than the value of the first embodiment.

(Third embodiment)
Next, a third embodiment of the image forming apparatus of the present invention will be described. The same components as those in the first embodiment and the second embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  FIG. 15 is a block diagram showing an electrical control configuration of the image forming apparatus of the present embodiment. FIG. 16 is a diagram illustrating a correspondence relationship between a plurality of predetermined recording paper types and control modes. FIG. 17 is a flowchart showing an operation procedure of the image forming apparatus of the present embodiment.

  In the present embodiment, the roll motor control unit 121 has three control modes: a first control mode, a second control mode, and a third control mode. The contents of the third control mode are the same as those of the second control mode of the second embodiment.

  In the first control mode, as described in the first embodiment, it is possible to suppress the occurrence of scratches, scratches, or the like on the recording surface. Therefore, as shown in FIG. 16, paper type A classified as a scratch-sensitive recording paper such as glossy paper or proof paper is associated with the first control mode.

  In the second control mode, as described in the first embodiment, it is possible to correct the skew while performing the recording operation even when the paper portion 6b is skewed. Further, it is possible to suppress the possibility that the paper portion 6b slips and affects the conveyance accuracy (the feed amount decreases). For this reason, the recording paper having a small thickness and a low conveying force H (the paper portion 6b is slidable with respect to the conveying roller 10 and the pinch roller 11) is weak. The paper type B1 to be classified is associated with the second control mode.

  In the third control mode, as described in the second embodiment, even when the paper portion 6b is skewed, it is possible to always correct skew while performing a recording operation. The effect is increased. Therefore, as shown in FIG. 16, the paper classified as the recording paper has a large conveyance force H such as plain paper or thin coated paper, etc. (the paper portion 6b is hard to slip with respect to the conveyance roller 10 and the pinch roller 11). Type B2 is associated with the third control mode.

  In the flowchart shown in FIG. 17, with the roll paper 6a being fed (step S31), the recording information indicating the type of the roll paper 6a previously selected by the user is input to the main control unit 110 (step S32). ). The main control unit 110 determines the type of the roll paper 6a based on the input recording information (step S33). When the type of the roll paper 6a indicated in the recording information is the paper type A described above, the main control unit 110 conveys the paper unit 6b to the roll motor control unit 120 by a predetermined amount (for example, 300 mm) in the first control mode. Let At this time, the main control unit 110 detects the skew amount based on the edge position of the paper part 6b before and after the conveyance detected by the paper edge detection sensor 13 (step S34). Thereafter, the main control unit 110 determines whether or not the detected skew amount is below a predetermined allowable value ob1 (step S35). When the skew amount is less than the allowable value ob1, the main control unit 110 performs printing for recording in the first control mode (step S36). Thereafter, when the recording in the first control mode is completed (step S38), a standby state is set. If the skew amount is greater than or equal to the allowable value ob1, a warning is given to the user that the roll paper 6a is to be set again (step S37).

  When the type of the roll paper 6a indicated in the recording information in step S33 is the paper type B1 described above, the main control unit 110 causes the roll motor control unit 120 to transfer the paper unit 6b to a predetermined amount (for example, in the second control mode). , 300 mm). At this time, the main control unit 110 detects the amount of skew as in step S34 (step S39). Thereafter, the main control unit 110 determines whether or not the detected skew amount is below a predetermined allowable value ob2 (step S40). When the skew amount is less than the allowable value ob2, the main control unit 110 performs recording in the second control mode (step S41). When the recording in the second control mode is completed (step S43), the standby state is entered. If the skew amount is greater than or equal to the allowable value ob2, the user is warned that the roll paper 6a is to be set again (step S42).

  When the type of the roll paper 6a indicated in the recording information in step S33 is the paper type B2 described above, the main control unit 110 causes the roll motor control unit 120 to transfer the paper unit 6b to a predetermined amount (for example, in the third control mode). , 300 mm). At this time, the main controller 100 detects the skew amount in the same manner as steps S34 and S39 (step S44). Thereafter, the main control unit 110 determines whether or not the detected skew amount is below a predetermined allowable value ob3 (step S45). When the skew amount is less than the allowable value ob3, the main control unit 110 performs recording in the third control mode (step S46). When the recording in the third control mode is completed (step S48), the standby state is entered. If the skew amount is greater than or equal to the allowable value ob3, a warning is given to the user that the roll paper 6a should be set again (step S47).

  In the present embodiment, the allowable value of the skew amount of the paper portion 6b has a magnitude relationship of ob1 <ob2 <ob3, but ob1 <ob2 = ob3 may be satisfied.

  According to the image forming apparatus of the present embodiment, when the recording paper is of a type that is easily damaged such as glossy paper or proof paper, the first control mode for conveying the recording paper without applying tension is selected. For this reason, it is possible to suppress the recording surface from being scratched or rubbed.

  If the recording paper is slippery, such as thick coated paper, which may affect the conveyance accuracy (reducing the feeding amount), remove the paper with a section where tension is applied to the roll paper and a section where it is not applied. The second control mode for carrying is selected. For this reason, it is possible to correct the skew while performing the recording operation, suppress the slip of the paper portion 6b, and reduce the influence on the conveyance accuracy.

  When the recording paper is a non-slip type such as plain paper or thin coated paper, the third control mode is selected in which the roll paper is always applied with tension and conveyed. Therefore, the effect of skew correction can be further increased compared to the second control mode.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 9 Conveyance path 30 Image recording part 40 Paper feed mechanism 50 Conveyance mechanism 100 Control part

Claims (5)

A paper feed mechanism for feeding the transport path from the tip of the recording paper by rotating a recording paper wound into a roll,
A transport mechanism for transporting the recording paper sent to the transport path;
An image recording unit for recording an image on the recording paper;
Wherein when the recording paper is classified into the first type is easily scratched, it includes a section for slack Oite the recording sheet in the conveying period in which the recording paper is Ru is transported from the transport path to said image recording section, and, When the first control mode that does not include the section in which the recording paper is pulled is selected and the recording paper is classified as the second type that is less likely to be damaged than the first type, the recording paper is pulled within the transport period. A control unit for selecting a second control mode including a section to be
An image forming apparatus comprising: A paper feed mechanism that rotates the recording paper wound in a roll and sends it to the transport path from the leading end of the recording paper;
A transport mechanism for transporting the recording paper sent to the transport path;
An image recording unit for recording an image on the recording paper;
When the recording paper is classified as a first type that is easily damaged, the recording paper includes a section in which the recording paper is loosened during a conveyance period in which the recording paper is conveyed from the conveyance path to the image recording unit, and the recording When the first control mode that does not include the section in which the sheet is pulled is selected and the recording sheet is classified as the second type that is less likely to be scratched than the first type, the second type of recording sheet When a slippery third type recording paper is used, the second control mode including a section in which the recording paper is pulled within the transport period is selected, and the recording paper is classified into the second type When the fourth type recording paper that is less slippery than the third type recording paper is used among the second type recording papers, the recording paper is always pulled within the transport period. A control unit for selecting a third control mode to al,
An image forming apparatus comprising: The second control mode is characterized in that it comprises a section for slack section and the recording sheet to pull the recording paper, the image forming apparatus according to claim 1 or 2. At least glossy paper and the proof sheet are classified into the first type, at least coated paper and plain paper you characterized by being classified into the second type, according to any one of claims 1 to 3 Image forming apparatus. If the first control mode is selected and the skew amount of the recording paper is equal to or greater than the first skew amount, the user is notified of refeeding, the second control mode is selected, and the case skew amount of the recording paper of the second skew feeding amount or more greater than the first amount of skew, you further comprising a notification means for notifying a re-feed the user, wherein Item 5. The image forming apparatus according to any one of Items 1 to 4 .

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