JP2009078882A - Image forming device and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming device capable of recorrecting skew of recording material. <P>SOLUTION: The image forming device is provided with a printing head 101, a reference plate 106 and a pair of carrying rollers 104a, 104b. The image forming device is further provided with detection means 105a, 105b for detecting the skew state of printing paper P nipped by the pair of carrying rollers 104a, 104b; a carrying control means for performing control to carry the printing paper P to the reverse direction and then carry it to the carrying direction again when skew of the printing paper P is detected by the detection means 105a, 105b; and a regulation member control means for controlling whether or not the reference plate 106 is retracted from the top face of a carrying passage during carrying of the printing paper P to the reverse direction by the carrying control means in accordance with the skew direction of the printing paper P detected by the detection means 105a, 105b. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image forming apparatus that records an image on a recording material.

  An image forming apparatus having functions such as a printer, a copying machine, and a facsimile has a printing head as a recording unit, and records an image (including characters and symbols) on a recording material such as printing paper based on image information. It is configured to

  As the recording material, sheet materials of various materials such as paper, cloth, plastic sheet, OHP sheet, and the like are used.

  Recording methods in the image forming apparatus include a serial type and a line type. The serial type is a system that records an image while alternately repeating the operation of moving the printing head back and forth in the direction orthogonal to the recording material conveyance direction (main scanning) and the conveyance of the recording material (sub scanning). is there.

  On the other hand, the line type uses a long printing head extending in a direction orthogonal to the recording material conveyance direction, so that an image can be obtained only by conveying the recording material (sub-scanning) while recording one line at a time. Is a method of recording.

  Further, the image forming apparatus can be classified into a thermal transfer type, a thermal type, an ink jet type, a laser beam type, a wire dot type, and the like according to a recording method. Among them, the thermal transfer type presses the recording material and the printing head across the ink sheet, and runs the ink sheet while synchronizing with the conveyance of the recording material, thereby heating and transferring the ink to record the image. Type recording system.

  The thermal transfer type image forming apparatus further includes a sublimation type and a melt type. In an image forming apparatus that records an image by transferring ink as in a thermal transfer type image forming apparatus, two types of consumables are used: an ink sheet impregnated with ink and a recording material onto which the ink is transferred. It is done.

  The recording operation in the conventional thermal transfer type image forming apparatus will be described below with reference to the schematic diagram of FIG.

  As shown in FIG. 10, the printing head 1001 is configured by a heating unit having a plurality of heating elements 1001a. Then, the heating element 1001a is selectively heated according to the image information, and the ink 1003b uniformly applied on the ink sheet 1003a is heated.

  A platen 1002 is disposed at a position facing the printing head 1001 across the conveyance path of the recording material P. Then, the printing head 1001 is pressed against the platen 1002, and the ink sheet 1003a unwound from the supply bobbin shaft 1003c and the recording material P are pressure-bonded to each other with an appropriate pressure, whereby heat transfer to the recording material P is performed. Is done.

  In addition, the heat transfer to the recording material P is performed by recording the recording material P in the transport direction X by the rotational drive of the capstan roller 1004a (active side) and the pinch roller 1004b (passive side) arranged opposite to each other. This is done by conveying from the start position to the recording end position. During this time, the ink sheet 1003a peeled off from the recording material P is wound around the take-up bobbin shaft 1003d.

  By the way, in the recording of a color image by such heat transfer, a desired image can be obtained by sequentially superimposing a plurality of colors on the recording material P. Therefore, the above-described recording operation is repeated a plurality of times by returning the recording material P conveyed to the recording end position to the recording start position again by rotating the capstan roller 1004a and the pinch roller 1004b facing each other in the reverse direction. There is a need.

  At this time, if the phase of the recording material P and the capstan roller 1004a which is the active side is shifted during the color image recording operation, a plurality of colors sequentially superimposed on the recording material P are shifted, and the image quality Lead to a decline.

  In order to solve such a problem, it is general to press the pinch roller 1004b against the capstan roller 1004a with a certain pressure or more. Further, in some cases, it is common to provide a protrusion (grip portion) that pierces the back surface of the recording material P to a depth that does not cause the recording material to be displaced on a part of the surface of the capstan roller 1004a.

  For this reason, the force that the capstan roller 1004a and the pinch roller 1004b sandwich and transport the recording material P is stronger than the transport force of other transport rollers made of rubber or the like, and the displacement due to slipping or deformation of the rollers occurs. Hard to occur. This makes it possible to accurately control the conveyance amount of the recording material.

  However, such a configuration includes a possibility of causing a serious jam that cannot be restored by the user himself / herself when the recording material P is fed into the conveyance path in a skewed state.

  For example, when a part of the recording material protrudes from the conveyance path, there is a possibility that a part of the recording material may be damaged by contacting a component provided outside the conveyance path. Furthermore, if the recording material P is continuously transported in the transport direction X in such a state, a part of the recording material is severely damaged, and the user cannot take out the recording material P from the apparatus. . In addition, there is a possibility that the apparatus may be abnormal due to damaged recording material fragments or deformation of components.

  For this reason, in such an image forming apparatus, when the recording material P is skewed, it is important to quickly detect this.

  Under such a background, two detection sensors are arranged at the same phase position on a line orthogonal to the conveyance direction of the recording material P to detect both ends of the recording material P, and left and right detection timings. There has been proposed an image forming apparatus that detects skew from the deviation (see, for example, Patent Document 1).

  According to the document, after one end of the leading end portion of the recording material P is detected by one of the two detection sensors, the recording material is detected until the other detection sensor detects the other end of the leading end portion of the recording material P. Transport P. Then, the number of steps input to the stepping motor for transporting the recording material P is recorded, and compared with a preset default value to determine the presence or absence of skew. Further, the amount of skew of the recording material can be obtained by calculating the number of steps recorded at this time according to the width of the recording material size.

  In addition to the above document, as a conventional example of positively recorrecting the recording material in accordance with the calculated skew amount, an image reading apparatus that corrects the document conveyance direction by changing the pressure distribution of the opposing rollers. It has been proposed (see, for example, Patent Document 2).

According to this document, a plurality of document detection sensors are arranged in parallel with the document reading line, and the support means configured to rotatably support the opposing roller of the document transport roller is rotated. Thereby, the pressing state of the opposing roller can be changed, and the relative position between the document conveying roller and the shaft core can be changed. As a result, according to the skew amount at the leading edge of the document, the opposing roller can be moved to recorrect the skew of the document, and the document can be conveyed to the reading unit without skew.
JP 2000-94807 A Japanese Patent Laid-Open No. 08-56280

  However, in the case of the configuration described in Patent Document 2, a dedicated moving means for moving the opposing roller is required in order to recorrect the skew of the recording material. For this reason, there is a problem that the structure of the apparatus becomes complicated and becomes an obstacle in reducing the size and cost of the apparatus.

  The present invention has been made in view of the above problems, and an object thereof is to provide an image forming apparatus capable of re-correcting skew of a recording material without newly adding a dedicated mechanism. . More specifically, by making the existing skew correction means function effectively even at the time of re-correction, when the recording material is reversely conveyed, or when the recording material is reversely conveyed and then re-conveyed, the recording material An object of the present invention is to provide an image forming apparatus that corrects the skew of the image.

In order to achieve the above object, an image forming apparatus according to the present invention has the following configuration. That is,
A print head for recording an image on a recording material;
A regulating member that regulates the position of one side surface of the recording material conveyed to the recording position for recording an image by the printing head on the conveyance path of the recording material;
An image forming apparatus comprising a pair of rollers disposed opposite to the recording position on the downstream side in the transport direction of the recording material and sandwiching and transporting the recording material,
Detecting means for detecting a skew state of the recording material sandwiched between the pair of rollers;
Conveyance for controlling the recording material to be conveyed toward the recording position again after the recording material is conveyed in the reverse direction when the detection unit detects the skew of the recording material as the skew state. Control means;
Based on the skew direction of the recording material detected by the detection means as the skew state, the transporting means moves the regulating member when the recording material is transported in the reverse direction. And a regulating member control means for controlling whether or not to retract from the route.

  According to the present invention, it is possible to provide an image forming apparatus capable of recorrecting skew of a recording material without newly adding a dedicated mechanism. More specifically, by making the existing skew correction means function effectively even at the time of re-correction, when the recording material is transported in the reverse direction, or when the recording material is transported in the reverse direction and then transported again, the recording material is recorded. It is possible to provide an image forming apparatus that re-corrects the skew.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[First Embodiment]
1. Configuration of Image Forming Apparatus FIG. 1 is a diagram showing a configuration of an image forming apparatus 100 according to the first embodiment of the present invention. In FIG. 1, 101 is a thermal head that is a printing head, 102 is a platen roller, 104a is a serrated roller that is a capstan roller, and 104b is a pinch roller.

  Reference numeral 105 denotes a detection sensor that is a detecting means for detecting the leading end of the printing paper that is a recording material. Reference numeral 106 denotes a reference plate (regulating member) that corrects skew by regulating the position of one side surface of the printing paper. It is. Reference numeral 107 denotes a paper conveyance roller, 108 denotes a paper conveyance stepping motor, and 109 denotes a transmission belt for transmitting the power of the stepping motor.

  Note that P is an L-size printing paper that is a recording material to be processed by the image forming apparatus 100.

  In the case of the image forming apparatus 100, a reference plate 106, a paper transport roller 107, a thermal head 101, a platen roller 102, a jagged roller 104 a, a pinch roller 104 b, and a detection sensor are disposed in the transport path (area indicated by dotted lines) of the printing paper P. 105a and 105b are arranged. These are arranged in order from the upstream side to the downstream side in the conveyance direction (X) of the printing paper P. Further, the jagged roller 104a and the pinch roller 104b are arranged as a pair of rollers so as to face each other through the conveyance path of the printing paper P.

  The two detection sensors 105a and 105b are close to each other at the same phase position on a line perpendicular to the conveyance direction of the printing paper P, that is, on a line parallel to the main scanning direction of the thermal head 101, on the downstream side of the jagged roller 104a. Placed in position. As a result, it is possible to detect both ends of the front end of the printing paper P. The detection method of the detection sensors 105a and 105b may be a transmission type, a reflection type, or a mechanical type.

2. Flow of Recording Operation in Image Forming Apparatus Next, an outline of the recording operation in the image forming apparatus 100 will be described. When the user selects execution of image recording, first, the printing paper P is first separated from a storage cassette (not shown) by a separating means (not shown) such as a paper feed roller and conveyed into a conveying path.

  The printing paper P eventually reaches the paper transport roller 107 and is transported further downstream by the paper transport roller 107. At this time, since the reference plate 106 is arranged on one side in the conveyance path, one side surface of the printing paper P comes into contact with the reference surface provided by the side surface of the reference plate 106. As a result, the printing paper P is conveyed downstream in a state along the reference plane.

  Here, even if the paper transport roller 107 transports the printing paper P in a skewed state, the skew feeding is corrected by having one side surface of the printing paper P along the reference surface.

  In order to make it easier to correct the skew, it is possible to take measures such as inclining the paper conveyance roller 107 with respect to the conveyance direction (X) or conveying the printing paper P in an inclined state in advance.

  The leading end portion of the printing paper P whose skew has been corrected by the reference plate 106 passes through the gap (recording position) between the thermal head 101 and the platen roller 102, and is eventually held between the jagged roller 104a and the pinch roller 104b. The printing paper P conveyed further downstream in the conveying direction from here is detected by the two detection sensors 105 at both ends of the leading end portion and temporarily stops. In this state, it is possible to record an image by pressing the thermal head 101 against the platen roller 102.

3. Description of skew of printing paper in the recording operation Next, with reference to FIGS. 2 to 4 will be described in detail with respect to the skew of the printing paper P that occurs during the recording operation of the image forming apparatus 100 according to this embodiment.

  The image forming apparatus 100 as described above has a configuration in which a part of the printing paper P during or after skew correction is exposed to the outside of the apparatus by shortening the conveyance path or diversifying the printing paper size. There are many cases.

  In such a configuration, the user and other obstacles can easily come into contact with the printing paper P before being sandwiched between the jagged roller 104a and the pinch roller 104b, and thus there is a possibility that a new skew will occur. high.

  Further, when a user or another obstacle comes into contact with the printing paper P before skew correction, a large skew that cannot be corrected by the reference plate 106 occurs.

Here, the types of skew that are expected to occur in the image forming apparatus 100 according to the present embodiment can be roughly divided into the following three types.
(1) As shown in FIG. 2, the skew in which the leading end of the printing paper P turns around the reference plate 106 (2) As shown in FIG. 3, the mark is placed between the transport surface and the retractable reference plate 106. Skew in which the drawing paper P sunk (3) As shown in FIG. 4, the skew in which the leading edge of the printing paper P is separated from the reference plate 106 Hereinafter, the cause of occurrence of each skew state shown in FIGS. .

  In the skew state as shown in FIG. 2, since the thermal head 101 is disposed between the reference plate 106 and the serrated roller 104a, the reference plate 106 cannot be extended to the position of the serrated roller 104a. This is caused by a gap between them.

  As described above, in the case of the image forming apparatus 100 according to the present embodiment, each component moves from the upstream side to the downstream side in the conveyance direction (X) of the printing paper from the reference plate 106, the thermal head 101, the knurled roller 104a, and the detection. Sensors 105 are arranged in order. With such an arrangement, an image can be recorded when the printing paper P is sandwiched between the jagged roller 104a and the pinch roller 104b, so that there is an advantage that the time required for image recording can be minimized.

  On the other hand, as a result, the thermal head 101 is disposed at a position close to the upstream side of the jagged roller 104a, and the reference plate 106 cannot be extended to just before the jagged roller 104a. For this reason, the leading edge of the printing paper P turns into the gap between the reference plate 106 and the serrated roller 104a, and skewing as shown in FIG. 2 occurs.

  The skew state as shown in FIG. 3 is caused by adopting a configuration in which the reference plate 106 is retracted from the conveyance surface by shortening the conveyance path or diversifying the printing paper size as described above. More specifically, this occurs when the reference plate 106 is lifted by the printing paper P and the printing paper P enters the transport surface. Alternatively, although the reference plate 106 is in the retracted state, the printing paper P enters and the printing paper P is sandwiched between the reference plate 106 and the conveying surface, so that the reference plate 106 cannot return to the normal position. Occurs.

  Further, the skew state as shown in FIG. 4 occurs because the side surface of the printing paper P is not sufficiently in contact with the reference plate 106. This is because the conveyance path of the printing paper P is wide and the printing paper P passes through a range away from the reference plate 106 and the side surface does not contact the reference plate 106 or even if it contacts, the skew is sufficiently corrected. This occurs due to reaching the jagged roller 104a without being performed.

4). Flow of Processing When Printing Paper is Skewed Next, a processing flow when skewing of printing paper is detected during the recording operation of the image forming apparatus 100 will be described with reference to FIG.

  FIG. 5 is a flowchart showing a processing flow of the image forming apparatus 100 when the skew of the printing paper P is detected.

  In step S501, the detection sensor 105a and the detection sensor 105b detect the leading end of the printing paper P.

  In step S502, the amount of deviation between the timing at which the detection sensor 105a detects the leading edge of the printing paper P and the timing at which the detection sensor 105b detects the leading edge of the printing paper P is measured, and the skew amount of the printing paper P is determined. calculate. It should be noted that the shift amount of the detection timing of the two detection sensors 105a and 105b is measured by the number of driving steps of the stepping motor 108 required for transporting the printing paper P.

  Thus, by measuring the detection timing shift amount of the detection sensors 105a and 105b, it is possible to determine whether or not the skew of the printing paper P causes a serious jam.

  Specifically, if it is determined in step S502 that the detection timing deviation amount is less than a preset reference value (reference value 1), it is determined that the degree of skew of the printing paper P is small. The process proceeds to step S503. In step S503, the conveyance is continued as it is.

  On the other hand, if it is determined in step S502 that the detection timing deviation amount is equal to or greater than a preset reference value (reference value 1) and less than the reference value 2, skew of the printing paper P is in the middle. It is determined that the degree is approximately, and the process proceeds to step S504. In step S504, the conveyance is temporarily stopped and then reversely conveyed by a certain amount, and the skew of the printing paper P is corrected and re-conveyed (details of the re-conveyance control will be described later).

  On the other hand, if it is determined in step S502 that the detection timing deviation amount is greater than or equal to a preset reference value (reference value 2), it is determined that the skew of the printing paper P is large, and the process proceeds to step S505. . In step S505, it is difficult to correct the skew of the printing paper P, and the printing paper P is discharged.

  As described above, the processing is switched according to the skew amount of the printing paper P, so that the printing paper P cannot be taken out from the apparatus, or the damaged printing paper P is broken or a component is deformed. It is possible to prevent the occurrence of abnormalities.

5). Process Flow in Re-Transport Control Next, details of the re-transport control process (step S504) in the image forming apparatus 100 will be described with reference to FIG. FIG. 6 is a flowchart showing the flow of the re-conveyance control process in the image forming apparatus 100.

  In step S601, it is determined which detection timing is earlier between the detection timing of the leading edge of the printing paper P by the detection sensor 105a and the detection timing of the leading edge of the printing paper P by the detection sensor 105b.

  If it is determined in step S601 that the detection timing of the leading edge of the printing paper P by the detection sensor 105a is earlier, it is determined that the printing paper P is skewed in the direction opposite to the reference plate 106. The process proceeds to step S602.

  In step S602, the reference plate 106 is retracted from the conveyance path (regulating member control means) so that the printing paper P does not come into contact with the reference plate 106 when the printing paper P is reversely conveyed, and then the process proceeds to step S603. move on.

  On the other hand, if it is determined in step S601 that the detection timing of the leading edge of the printing paper P by the detection sensor 105b is earlier, it is determined that the printing paper P is skewed toward the reference plate 106 side. The process directly proceeds to step S603 while leaving the reference plate 106 as it is.

  In step S603, the printing paper P is conveyed by a certain amount (reverse conveyance) in the direction opposite to the conveyance direction (X) (conveyance control means). When the reverse conveyance of the printing paper P is completed, it is determined in step S604 whether or not the reference plate 106 has been retracted.

  Since it is determined in step S602 that the reference plate 106 has been retracted, if it is determined in step S604 that the reference plate 106 has been retracted, the process proceeds to step S605, where the reference plate 106 is set on the transport path, and then, in step S606. move on.

  On the other hand, if it is determined in step S604 that the reference plate 106 has already been set, the process proceeds directly to step S606.

  In step S606, the printing paper P is transported again in the transport direction (X) from the reverse transported position.

6). Specific Example of Re-Transfer Control Subsequently, a specific example of the re-transfer control process described with reference to FIG. 6 is used with reference to FIGS. 7 to 9 while corresponding to each skew state shown in FIGS. explain.

6.1 When the re-transport control processing detection sensors 105a and 105b for the skew state shown in FIG. 2 detect the skew in the wraparound direction as shown in FIG. 2 (determined that the detection timing of the detection sensor 105b is earlier) In the case where the reference plate 106 is not retracted, the reverse conveyance is started without retracting the reference plate 106 (FIG. 7A).

  During reverse conveyance, the reference plate 106 remains on the conveyance path, so that the end surface of the printing paper P comes into contact with the reference surface of the reference plate 106 (FIG. 7B).

  At this time, the photographic paper P is in a state in which it is removed from both the jagged roller 104a and the pinch roller 104b and is reversely conveyed only by the paper conveying roller 107. Therefore, as shown in FIG. 7C, the end surface of the printing paper P advances along the reference surface of the reference plate 106, and the skew is gradually corrected.

  As a result, when the reverse conveyance is completed, the skew of the printing paper P is corrected again at the time of FIG. 7D, and the printing paper P is in a state orthogonal to the main scanning direction of the thermal head 101 at the time of the re-transportation. It has become.

6.2 Re-transfer control process for the skew state shown in FIG. 3 When the subtraction as shown in FIG. 3 occurs and the detection sensors 105a and 105b detect this (if the detection timing of the detection sensor 105a is earlier) If it is determined, the image forming apparatus 100 starts the reverse conveyance after retracting the reference plate 106 (FIG. 8A).

  During reverse conveyance, the reference plate 106 is retracted, so that the surface of the printing paper P is not damaged. Further, since the conveyance resistance of the photographic paper P is also reduced, as shown in FIG. 8B, the photographic paper P is stably reverse-conveyed by the paper conveyance roller 107 even after the photographic paper P is pulled out of the jagged roller 104a and the pinch roller 104b. The Rukoto.

  As a result, at the time of FIG. 8C when the reverse conveyance is completed, the printing paper P is stopped at the re-conveyance start position while being skewed. When the printing paper P is forwardly conveyed again from this state to the downstream side, the side surface of the printing paper P comes into contact with the reference plate 106, so that the paper is normally conveyed along the reference surface, and the skew is recorrected. Is done.

6.3 Re-transport control processing for the skew state shown in FIG. 4 A separation as shown in FIG. 4 occurs, and the detection result when the detection sensors 105a and 105b detect the separation causes the intrusion shown in FIG. In the configuration shown in this embodiment, the skew state in FIG. 3 and the skew state in FIG. 4 cannot be distinguished.

  Therefore, similarly to the case where the dive shown in FIG. 3 occurs, the reference plate 106 is retracted and then reversely transported to the re-transport start position ((a) to (c) of FIG. 9). Then, the skew is recorrected by the reference plate 106 at the time of re-conveyance.

  As is clear from the above description, the image forming apparatus according to the present embodiment is configured to switch the continuation / re-conveyance / discharge process depending on the skew of the printing paper P. Further, when re-conveyance is selected, the reference plate is switched between retraction / non-retraction for reverse conveyance according to the skew direction.

  As a result, the skew of the printing paper P can be recorrected during reverse conveyance or reconveyance, and it is not necessary to add a new mechanism for recorrection. In addition, it is possible to avoid damage to the printing paper P in the recorrection of the skew feeding.

[Second Embodiment]
In the first embodiment, the transport amount when the printing paper P is transported in the reverse direction in step S603 is not particularly mentioned. However, the transport amount during the reverse transport is changed according to the skew feeding amount of the printing paper P. You may do it.

  For example, when the detected skew amount is large, the re-conveyance start position is set to a position relatively far from the detection sensor 105, and the reverse conveyance amount is increased. On the other hand, when the detected skew amount is small, the re-conveyance start position is set to a position relatively close to the detection sensor 105, and the reverse conveyance amount is reduced. With such a configuration, it is possible to shorten the time required for re-conveying and to minimize damage and stress on the printing paper P.

  Furthermore, the conveyance amount during reverse conveyance may be changed according to the size of the printing paper P.

  For example, when a plurality of printing paper sizes are used, if the width in the main scanning direction and the width in the sub scanning direction of the printing paper size are large, even if the skew angle is relatively small, the downstream side of the printing paper P The end portion is greatly shaken and jamming is likely to occur. For this reason, when the printing paper size is large, it is necessary to reversely transport the printing paper more than other sizes. In this way, by properly using the transport amount during reverse transport as a specified value specific to the printing paper size, it is possible to effectively avoid jamming.

  In the first embodiment, the re-transport control process (step S504) is executed only once for one printing paper P. However, the present invention is not particularly limited to this.

  For example, if it is determined that it is necessary based on the detection result of the skew amount, the re-conveyance control process may be repeatedly executed several times. By executing such control, when the skew is relatively large, it becomes possible to correct the skew more effectively than attempting a large correction at once, and scratches and stress on the printing paper P can be obtained. Can be suppressed.

  When such control is performed, in the second and subsequent re-transport control for the same printing paper, the skew amount detected again is compared with the skew amount detected in the last re-transport control. The change may be calculated. If the amount of this change is equal to or less than a certain threshold value, it may be determined that the effect obtained even after repeating the re-transfer control is small, and the re-transfer control is stopped.

  Note that the control for changing the re-transport start position and the control for determining the number of repetitions of the re-transport control according to the skew amount detected as described above may be used together. However, the present invention is effective even when control using only one of them, or control in which the re-transfer start position and the number of re-transfer control are always constant is used.

[Other Embodiments]
Note that the present invention can be applied to a system (for example, a copier, a facsimile machine, etc.) consisting of a single device even when applied to a system composed of a plurality of devices (for example, a host computer, interface device, reader, printer, etc.). You may apply.

  Needless to say, the object of the present invention can also be achieved by supplying a system or apparatus with a storage medium storing software program codes for realizing the functions of the above-described embodiments. In this case, the above functions are realized by the computer (or CPU or MPU) of the system or apparatus reading and executing the program code stored in the storage medium. In this case, the storage medium storing the program code constitutes the present invention.

  As a storage medium for supplying the program code, for example, a floppy (registered trademark) disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD-R, magnetic tape, nonvolatile memory card, ROM, or the like is used. be able to.

  Further, the present invention is not limited to the case where the functions of the above-described embodiments are realized by executing the program code read by the computer. For example, an OS (operating system) running on a computer performs part or all of actual processing based on an instruction of the program code, and the functions of the above-described embodiments may be realized by the processing. Needless to say, it is included.

  Further, when the program code read from the storage medium is written in a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, the functions of the above-described embodiments are realized. Is also included. That is, after the program code is written in the memory, the CPU or the like provided in the function expansion board or function expansion unit performs part or all of the actual processing based on the instruction of the program code, and is realized by the processing. This is also included.

1 is a diagram illustrating a configuration of an image forming apparatus according to a first embodiment of the present invention. It is a figure which shows an example of the skew state of the printing paper at the time of image recording operation, and is a figure which shows a mode that it skewed greatly in the direction which wraps around a reference | standard board. It is a figure which shows an example of the skew state of the printing paper at the time of image recording operation | movement, and is a figure which shows a mode that it skewed greatly in the direction which sunk into a reference | standard board. It is a figure which shows an example of the skew state of the printing paper at the time of image recording operation, and is a figure which shows a mode that it skewed greatly in the direction away from a reference | standard board. 3 is a flowchart illustrating a processing flow of the image forming apparatus 100 when the printing paper P is skewed. It is a flowchart which shows the detail of a re-transport control process. It is a figure which shows the specific example of a re-transport control process. It is a figure which shows the specific example of a re-transport control process. It is a figure which shows the specific example of a re-transport control process. FIG. 10 is a schematic diagram for explaining a recording operation in a conventional thermal transfer type image forming apparatus.

Explanation of symbols

101 Printing head (thermal head)
102 Platen roller 104a Capstan roller (Giza roller)
104b Pinch rollers 105a, b Detection sensor 106 Reference plate 107 Paper conveying roller 108 Stepping motor 109 Transmission belt for transmitting the power of the stepping motor Plate size printing paper

Claims (7)

A print head for recording an image on a recording material;
A regulating member that regulates the position of one side surface of the recording material conveyed to the recording position for recording an image by the printing head on the conveyance path of the recording material;
An image forming apparatus comprising a pair of rollers disposed opposite to the recording position on the downstream side in the transport direction of the recording material and sandwiching and transporting the recording material,
Detecting means for detecting a skew state of the recording material sandwiched between the pair of rollers;
Conveyance for controlling the recording material to be conveyed toward the recording position again after the recording material is conveyed in the reverse direction when the detection unit detects the skew of the recording material as the skew state. Control means;
Based on the skew direction of the recording material detected by the detection means as the skew state, the transporting means moves the regulating member when the recording material is transported in the reverse direction. An image forming apparatus comprising: a regulating member control unit that controls whether or not to retract from the path.   The restricting member control means is configured to detect the restricting member when the detecting means detects that the recording material is skewed in a direction opposite to a direction in which the restricting member is disposed as the skew state. The image forming apparatus according to claim 1, wherein the image forming apparatus is controlled so as to be retracted from the conveyance path.   The transport control means, when performing the control for the same recording material a plurality of times, the skew amount detected last by the detection means as the skew state and the skew detected before that. The image forming apparatus according to claim 1, wherein the control is stopped when a difference from the line amount is equal to or less than a predetermined threshold value.   2. The image formation according to claim 1, wherein the transport control unit changes a transport amount when transporting in a reverse direction according to the skew amount detected by the detection unit as the skew state. apparatus.   The image forming apparatus according to claim 1, wherein the transport control unit changes a transport amount when transporting in a reverse direction according to a size of the recording material. A print head for recording an image on a recording material;
A regulating member that regulates the position of one side surface of the recording material conveyed to the recording position for recording an image by the printing head on the conveyance path of the recording material;
An image forming method in an image forming apparatus comprising a pair of rollers disposed opposite to the recording position on the downstream side in the transport direction of the recording material and sandwiching and transporting the recording material,
A detection step of detecting a skew state of the recording material sandwiched between the pair of rollers;
A conveyance control step for controlling the recording material to be conveyed in the reverse direction when the skew of the recording material is detected in the detection step as the skew state;
As the skew state, based on the skew direction of the recording material detected in the detection step, the transporting of the regulating member in the reverse direction of the recording material in the transporting step is performed. A regulating member control step for controlling whether or not to retract from the path;
A re-transport control step for controlling the recording material transported in the transport step to transport again toward the recording position; and
An image forming method comprising: A program for causing a computer to execute the image forming method according to claim 6.

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