JP2008030924A - Paper sheet conveying mechanism and recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper sheet conveying mechanism capable of reliably protecting projections of a capstan roller with an inexpensive constitution even when the distance of a pinch roller relative to the capstan roller is reduced, and maintaining the high paper feed accuracy, and to provide a recording device. <P>SOLUTION: A paper sheet conveying mechanism comprises a capstan roller 11 having projections 11a on its circumferential surface, a pinch roller 12 facing the capstan roller, and a pressing means 14 for pressing the pinch roller against the capstan roller, and further comprises a pressure-releasing means 15 for releasing the pressure of the pressing means, and a spacer 16 which is arranged to be held between the pinch roller and a part having no projections of the capstan roller while being pressed by the pressing means. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a sheet conveying mechanism that conveys a sheet by sandwiching a sheet with a capstan roller and a pinch roller, and a recording apparatus including the sheet conveying mechanism.

  Recording devices (printing devices, printing devices, etc.) as computer output devices or digital video output devices can be classified into thermal transfer type, thermal type, ink jet type, laser type, wire dot type, etc. according to the recording method. Among them, the thermal transfer recording apparatus uses an ink sheet to which ink is applied, drives a thermal head based on recording information, and thermally transfers the ink on the ink sheet to a sheet-like recording material (hereinafter referred to as paper). It is configured. That is, a plurality of heating elements arranged in the main scanning direction (direction intersecting with the paper feeding direction) of the thermal head are selectively driven. In synchronization with this, by feeding the ink sheet and paper in the sub-scanning direction, an image (including characters and symbols) is formed on the paper while collectively recording for each dot line.

  In recent years, with the progress of input devices that handle images such as digital cameras, digital video cameras, and scanners on the input side, the degree of attention to the above-described thermal transfer recording apparatus has increased. This thermal transfer recording apparatus is a recording apparatus suitable for printing out electronic image information captured by a still camera or a video camera that stores a still image via a computer or a recording medium. For example, in a recording apparatus of another recording method such as an ink jet recording apparatus, since there is only a binary selection of whether or not to form dots, an apparent resolution can be obtained by a technique such as error diffusion while forming small dots on a sheet. Try to get gradation. On the other hand, in the thermal transfer recording apparatus, the amount of heat for each pixel can be easily controlled (changed), so that a large gradation can be obtained for one pixel. Compared with, smooth and high-quality images can be obtained.

  Further, in the thermal transfer recording apparatus, the performance of the thermal head as the recording means and the material performance of the paper as the recording medium are improved, so that it is possible to obtain an image print that is not inferior to a silver halide photograph even in the finished quality. For this reason, in order to keep pace with the recent progress of digital cameras, it is attracting attention as a printing apparatus for natural images. Furthermore, a system that prints out without directly connecting a thermal transfer recording apparatus and an imaging device such as a digital camera or a digital video camera has appeared. In addition, there is a system in which these are integrated to directly print out captured image information without using an information processing device such as a computer. According to such a system, image information from a digital camera or digital video camera can be easily printed out photographically, and the degree of attention to the thermal transfer recording apparatus is increasing.

  On the other hand, in a thermal transfer recording apparatus, in order to perform full-color printing, it is necessary to repeatedly transfer a plurality of colors of ink, so that each time printing of each color is performed, the paper is conveyed in the reverse direction. . That is, printing is performed while paper is fed by a capstan roller and a pinch roller provided downstream in the printing direction, and after the printing of the first color is completed, the pressure contact of the thermal head is released for printing of the next color. In this state, the capstan roller and the pinch roller are rotated in the opposite directions to the time of printing, and the sheet is returned to the printing start position. The second and subsequent colors are printed by the same operation as the first color.

  In the recording operation as described above, since the paper is reciprocated several times to superimpose colors, if the paper is displaced, the color is shifted as it is, and the quality of the image is lowered. Therefore, as a capstan roller, a roller manufactured by a special processing method in which a protrusion of several tens of microns is formed on the surface of a metal shaft is generally used instead of a normal rubber roller. As a method for processing the protrusion, a method by rolling, pressing, or etching has been proposed. The processing methods for these protrusions are disclosed in Patent Documents 1 to 8. However, even in a capstan roller manufactured by any of these processing methods, the protrusions are very fine and easily deformed by an external force. And if it is deformed, the original performance cannot be maintained and the paper is displaced, and the image quality is deteriorated due to the color displacement. This is no exception even when the peripheral surface of the capstan roller is pressed by a pinch roller.

  However, when there is a sheet between the capstan roller and the pinch roller, the protrusion will not be deformed even if it is pressurized. However, if pressure is applied with no paper between the capstan roller and the pinch roller, the projections are deformed. Therefore, it is necessary to protect the capstan roller protrusion from the pinch roller. As a paper transport mechanism provided with means for protecting the capstan roller protrusion, three configuration examples as described below have been proposed. FIGS. 5A and 5B show a state of the first configuration example of the conventional paper transport mechanism during paper feeding, where FIG. 5A is a partial front view and FIG. 5B is a side view. FIG. 6 is a side view showing the state of the paper transport mechanism of FIG. 5 when there is no paper. This first configuration provides a mechanism for separating the pinch roller from the capstan roller when there is no sheet.

5 and 6, a protrusion 101 a is formed on a part of the peripheral surface of the capstan roller 101, so that the pinch roller 102 rotatably supported by the support lever 103 can be pressed against the capstan roller 101. It is arranged. The pinch roller 102 is pivotally supported by the support lever 103 at both end shaft portions 102a. The support lever 103 is arranged to be swingable about a shaft 103a. When the support lever 103 is urged by the spring 104, the pinch roller 102 is pressed against the capstan roller 101. The support lever 103 can be rotated to the position shown in FIG. 6 against the spring 104 by moving the slide member 105 in the left direction in the figure. In this rotational position, the pinch roller 102 is separated from the capstan roller 101.

  As shown in FIG. 5, when transporting the paper P that is the recording material, the pinch roller 102 on the support lever 103 is pressed against the capstan roller 101 by the spring 104, and the paper P is sandwiched by the nip portion. . When the sheet P is not present, as shown in FIG. 6, the support member 103 is rotated counterclockwise against the spring 104 by moving the slide member 105 by the distance D in the left direction in the figure. As a result, the pinch roller 102 is separated from the capstan roller 101. As described above, the pinch roller 102 is pressed when the paper is conveyed, and the pinch roller 102 is separated when the paper is not present. This protects the protrusions 101a of the capstan roller 101 from being deformed by direct contact with the pinch roller 102.

  7A and 7B show a state during paper feeding of a second configuration example of a conventional paper transport mechanism, where FIG. 7A is a partial front view and FIG. 7B is a side view. FIG. 8 is a side view showing the state of the paper transport mechanism of FIG. 7 when there is no paper. In this second configuration example, a sleeve member 106 is provided to ensure a gap for preventing the pinch roller from interfering with the projection of the capstan roller. 7 and 8, a protrusion 101a is formed on a part of the capstan roller 101, and the pinch roller 103 on the support lever 103 is urged toward the capstan roller by a spring 104.

  Therefore, a sleeve member 106 that is coaxially rotatable is fitted to the shaft portion 102 a of the pinch roller 102. The sleeve member 106 is disposed so as to be capable of being pressed against the peripheral surfaces of both end portions of the capstan roller 101. The outer diameter of the sleeve member is selected so as to ensure a minute gap between the two so that the pinch roller 102 does not come into contact with the projection of the capstan roller 101. For example, the height of the protrusion 101a is usually about 70 microns (μm), and the thickness of the paper P is usually about 200 microns. Therefore, the outer diameter of the sleeve member 106 is selected so that the gap between the capstan roller 101 and the pinch roller 102 is about 100 microns when the sleeve member 106 is pressed against the capstan roller 101. . As a result, a gap of about 30 microns is guaranteed between the protrusion 101a and the pinch roller 102, and the two do not come into contact with each other.

  That is, as shown in FIG. 7, when a paper P of about 200 microns is sandwiched, a gap A of about 100 microns is generated between the sleeve member 106 and the pinch roller 102. For this reason, the paper P can be clamped with an appropriate pressure between the capstan roller and the pinch roller. On the other hand, when there is no sheet as shown in FIG. 8, the sleeve member 106 can guarantee a gap of about 30 microns between the pinch roller and the projection 101a of the capstan roller. Accordingly, the contact between the pinch roller 102 and the protrusion 101a can be eliminated, and the protrusion 101a can be protected from deformation or damage. Here, the sleeve member 106 is formed as a separate component from the pinch roller 102. The reason for this is that if they are integrally formed, it is necessary to cut the range B shown in FIG. 8, which increases the number of processing steps for the component, makes the component expensive, and tends to reduce the dimensional accuracy. .

  9A and 9B show a state of the third configuration example of the conventional paper transport mechanism during paper feeding. FIG. 9A is a partial front view, and FIG. 9B is a side view. FIG. 10 is a side view showing a state of the paper transport mechanism of FIG. 9 when there is no paper. In the third configuration example, a rubber member 107 is provided on the peripheral surface of the pinch roller for protecting the projection of the capstan roller. 9 and 10, a rubber member 107 is provided on the peripheral surface of the pinch roller 102 and in a range facing the protrusion 101 a of the capstan roller 101. The rubber member 107 is formed of a rubber-like elastic body having a uniform thickness attached to the peripheral surface of the pinch roller 102. When the paper P is present, as shown in FIG. 9, the paper is sandwiched between the protrusion 101a and the rubber member 107 and conveyed in this state. When there is no sheet, the rubber member 107 is pressed against the protrusion 101a. The paper transport mechanism according to the third configuration example is different from the paper transport mechanism according to the second configuration example of FIGS. 7 and 8 in the above points, but has substantially the same configuration in other points. . According to the third configuration example, when there is no sheet between the capstan roller 101 and the pinch roller 102, the protrusion 101a of the capstan roller can be protected from the pinch roller by the rubber member 107.

Japanese Patent No. 3413064 Japanese Patent No. 3271039 Japanese Patent No. 3271848 Japanese Patent No. 3626286 Japanese Patent No. 3670112 Japanese Patent No. 3707578 JP-A-8-263596 Japanese Patent Publication No. 4-2511

However, each of the above-described three configuration examples of the conventional paper transport mechanism has the following problems to be solved.
That is, in the first configuration example shown in FIGS. 5 and 6, a drive source for moving the slide member 105 greatly is required to separate the pinch roller 102 from the capstan roller 101. For this reason, there exists a subject that labor saving and size reduction of an apparatus will become difficult.
In addition, since a sheet inherently exists between the pinch roller and the capstan roller, it is conceivable that jamming (paper jam) or the like of the sheet occurs when the pinch roller is in pressure contact. Further, there is a possibility that the pinch roller and the capstan roller are pressed against each other in the absence of the sheet. In this way, when an abnormal operation such as jamming is assumed, there is a possibility that the projection of the capstan roller cannot be protected.

In the second configuration example in which the sleeve member 106 of FIGS. 7 and 8 is provided, the sleeve member is in pressure contact even when there is no sheet, and thus there is a disadvantage that the rotational load of the roller is large. Further, since the sleeve member 106 is required to have a very high processing accuracy, there is a disadvantage that it becomes a high-priced part.
FIG. 11 is an enlarged partial front view showing the state of the second configuration example of FIG. FIG. 11 also illustrates a case where the height of the protrusion 101a is 70 microns (μm) and the paper thickness is 200 microns. In order to reliably protect the protrusion 101a when there is no sheet, it is necessary to ensure that the step A in FIG. 11 is 70 microns or more. Further, in order to securely hold the sheet when it is present, the step A must be 270 microns or less.

  Here, the pinch roller 102 and the sleeve member 106 are separate parts, and each has a part tolerance. In such a case, the design value is generally set to a median value between the upper limit and the lower limit. Therefore, if the design value is set to 170 microns, which is the median value of 70 microns and 270 microns, the margin to the upper limit and the lower limit is 100 microns. On the other hand, the level difference A is determined by two parts, that is, a pinch roller and a sleeve member. Therefore, each of these two parts needs to have a machining accuracy of less than ± 50 microns. The processing accuracy of 50 microns is a level that can be processed with the current processing technology, but is a very high processing level. For this reason, there is an inconvenience that the component unit price of the pinch roller and the sleeve member is increased.

  In the third configuration example in which the rubber member 107 of FIGS. 9 and 10 is provided, the rubber member 107 is elastically deformed to increase the pressure contact area, so that the clamping pressure acting on the paper is reduced. For this reason, there are inconveniences that the paper feeding accuracy is lowered and color misregistration of the recorded image is likely to occur. In addition, there is a disadvantage that the number of processing steps is increased by the amount of the rubber member 107 and the parts price is increased.

  The present invention has been made to solve the above-described conventional technical problems. An object of the present invention is to provide a sheet transport mechanism and a recording apparatus that can reliably protect the protrusion of the capstan roller even if the distance between the pinch roller and the capstan roller is reduced, with an inexpensive configuration. . Another object of the present invention is to provide a paper transport mechanism and a recording apparatus that can maintain high paper feed accuracy.

  In order to achieve the above object, a paper transport mechanism according to the present invention includes a capstan roller having a protrusion formed on a peripheral surface and rotatably supported, and a pinch rotatably supported to face the capstan roller. A roller, a pressurizing unit that presses the pinch roller against the capstan roller, a pressure release unit that releases the pressing force of the pressurizing unit, and a pinch roller that is pressed by the pressurizing unit. And a spacer disposed so as to be sandwiched between the peripheral surface and a portion of the peripheral surface of the capstan roller where the protrusion does not exist.

  According to the present invention, it is possible to provide a sheet transport mechanism and a recording apparatus that can reliably protect the protrusions of the capstan roller even if the distance between the pinch roller and the capstan roller is reduced with an inexpensive configuration. In addition, according to the present invention, a paper transport mechanism and a recording apparatus that can maintain high paper feed accuracy are provided.

  Embodiments of the present invention will be specifically described below with reference to the drawings. Note that the same reference numerals denote the same or corresponding parts throughout the drawings. FIG. 1 is a longitudinal sectional view showing a state during printing of an embodiment of a recording apparatus provided with a paper transport mechanism according to the present invention. FIG. 2 is a longitudinal sectional view showing a state when the paper is reversely conveyed by the recording apparatus of FIG. In FIG. 1 and FIG. 2, the paper P, which is a recording material, is nipped together with the ink sheet 2 in a nip portion between the thermal head 1 and the platen roller 3 so as to be conveyed (paper feed). In this state, the paper P is transported by the rotation of the capstan roller 11 provided downstream in the recording direction (sub-scanning direction of the thermal head 1) and the pinch roller 12 that is pressed so as to be driven to rotate. The capstan roller 11 and the pinch roller 12 constitute a paper transport mechanism that transports the paper P.

  The ink sheet 2 is taken up by the take-up reel 5 from the supply reel 6 through the heat generating surface of the thermal head 1. During printing (during recording), the ink sheet 2 and the paper P are superposed and conveyed while being in pressure contact between the heat generating surface of the thermal head and the platen roller 3. Simultaneously with the conveyance of the ink sheet 2 and the paper P, the ink on the ink sheet 2 is thermally transferred to the paper P by driving (energizing) the heat generating portion of the thermal head 1 facing the ink sheet 2. The heat generating portion of the thermal head 1 is formed of a ceramic substrate on which a plurality of heat generating elements are arranged, and a desired image (including characters and symbols) is selectively driven based on the image information. ) Will be printed. The conveyance of the paper P is performed by rotating the capstan roller 11 by the conveyance motor 10. A sheet conveying force is obtained by the pinch roller 12 pressed against the rotating capstan roller. As the material of the recording paper P, various materials can be used as long as they can record images, such as paper, photographic printing paper, plastic sheet, OHP sheet, envelope or cloth. it can.

  The color recording ink sheet 2 is provided with a heat-sensitive color developing layer of each color such as yellow, magenta, and cyan, and a color image is formed by sequentially transferring these layers by thermal transfer. Therefore, for example, when printing of the first color of yellow is completed, the thermal head 1 is separated from the platen roller 3 as shown in FIG. In this state, the capstan roller 11 is rotated in the opposite direction to the time of printing to return the paper to the printing start position, and the second and subsequent colors are printed by the same operation. The thermal head 1 according to the present embodiment includes a flat plate-like heat generating portion in which a plurality of heat generating elements are arranged, and a heat radiating member in which the heat generating portion is attached with an adhesive having excellent thermal conductivity. . The pressing force between the thermal head 1 and the platen roller 3 is about 3 kgf to 5 kgf per 100 mm length in the main scanning direction (direction intersecting (usually orthogonal) to the recording direction) of the thermal head.

  The capstan roller 11 and the pinch roller 12 in FIGS. 1 and 2 constitute a paper transport mechanism. FIGS. 3A and 3B are views showing a state of the paper transport mechanism according to the embodiment of the present invention during paper transport, where FIG. 3A is a partial front view and FIG. 3B is a side view. 4A and 4B are diagrams illustrating a state when the sheet transport mechanism of FIG. 3 does not exist, in which FIG. 4A is a partial front view, and FIG. 4B is a side view. 1 and 2, a protrusion 11a is formed on a part of the peripheral surface of the capstan roller 11 made of a metal material. The capstan roller 11 is rotatably supported by a support lever 13. A pinch roller 12 is arranged so as to be capable of being pressed. The pinch roller 12 is rotatably supported by the support lever 13 at both end shaft portions 12a. The support lever 13 is pivotally supported about a support shaft 13a so as to be swingable.

  The shaft portions 12a at both ends of the pinch roller 12 are rotatably supported by being fitted into elongated holes 13b formed in the support lever 13 in the vertical direction. Each support lever 12 that supports the shaft portions 12 a at both ends of the pinch roller is urged by a spring (tensile coil spring) 14 in a direction in which the pinch roller 12 is pressed against the capstan roller 11. Reference numeral 15 denotes a slide member that acts on the support lever 13. The slide member 15 is slidably movable in the left-right direction in the figure, and is arranged to be engageable with the lower end portion of the lever member 13. That is, by moving the slide member 15 leftward in the drawing, each support lever 13 can be rotated and displaced to the position shown in FIG. 4B against the spring 14.

  The protrusions 11a of the metal capstan roller 11 are surface portions formed to prevent minute fluctuations in the transport amount of the paper P, and are provided in the vicinity of both ends of the peripheral surface of the capstan roller. The protrusion 11a may be formed, for example, by plastically deforming the peripheral surface of the capstan roller 11, or may be formed by attaching another member on which the protrusion is formed to the peripheral surface of the capstan roller. it can. Therefore, spacers 16 that can be sandwiched between the peripheral surface of the capstan roller and the peripheral surface of the pinch roller are provided in regions other than the protrusions 11a at both ends of the peripheral surface of the capstan roller 11. The spacer 16 is formed of a flat plate member having a predetermined thickness obtained by pressing a metal plate. The spacer 16 is formed of, for example, a stainless steel flat plate material. The spacer 16 made of this metal flat plate member is pressed and clamped between the capstan roller and the pinch roller 12. When the sheet 16 is not present, the spacer 16 is urged by a spring 14 counterclockwise as shown in FIG. It is sandwiched between the peripheral surface of the pinch roller 12.

  The spring 14 constitutes a pressing means that acts on the lever member 13 to press the pinch roller 12 against the capstan roller 11 via the lever member. The pressing force by the spring 14 is transmitted to the pinch roller 12 by pressing the shaft portion 12a downward at the upper end edge of the long hole 13b of the lever member 13 as shown in FIG. The slide member 15 acts on the lever member 13 to constitute a pressure releasing means for releasing the pressing force of the pinch roller 12 against the capstan roller 11 against the spring 14. By moving the slide member 15 as the pressure release means by a distance D in the left direction in the figure, the lever member 13 is slightly rotated clockwise in the figure about the support shaft 13a against the spring 14 as the pressure means. Only turn and displace. Thereby, as shown in FIG. 4B, the downward pressing force of the shaft portion 12a by the upper end edge of the long hole is released. For this reason, the pressure contact force (pressing force) of the pinch roller 12 with respect to the capstan roller 11 is released.

Next, a specific configuration and operation of the paper transport mechanism according to the present embodiment shown in FIGS. 3 and 4 will be described. Here, the height of the protrusion 11a of the capstan roller 11 is about 70 microns, and the thickness of the paper P is about 200 microns. Further, as described later, the thickness of the spacer 16 and its tolerance can be set to about 100 to 170 microns, that is, about 135 microns ± 30 microns, so that a normal sheet metal material can be used as it is. Is possible.
That is, when the paper P, which is a recording material, is conveyed, there is a paper having a thickness of about 200 microns between the capstan roller 11 and the pinch roller 12. In this state, as shown in FIG. 3, a gap A of about 100 microns can be ensured between the peripheral surface of the pinch roller 12 and the spacer 16, and the capstan roller (its protrusion 11a) is interposed via the paper P. Appropriate pressure is generated between the pinch roller and the pinch roller. For this reason, it is possible to reliably hold the sheet and convey it with high accuracy.

  On the other hand, when the sheet P does not exist, the slide member 15 moves by a distance D in the left direction as shown in FIG. As a result, the support lever 13 is rotationally displaced by a predetermined amount in the clockwise direction in the figure against the spring 14. Therefore, the thickness of the spacer 16 is selected so that a minimum gap is guaranteed between the pinch roller 12 and the capstan roller 11 so that the pinch roller 12 does not come into contact with the protrusion 11a even when no sheet is present. In the present embodiment, as described above, the height of the protrusion 11a is usually about 70 microns, and the thickness of the paper P is usually about 200 microns. Therefore, when there is no sheet, a gap B of a distance obtained by subtracting the height of the protrusion 11a from the lower limit value of the thickness of the spacer 16 can be secured between the capstan roller 11 and the pinch roller 2. Therefore, the value of the gap B can guarantee at least “100 microns−70 microns = 30 microns”.

From this point of view, in this embodiment, the height of the protrusion 11a of the capstan roller 11 is selected to be 100 microns or less, and the thickness of the spacer 16 is selected to be 100 microns or more. Thus, according to the present embodiment, by arranging the spacer 16 made of a flat plate member obtained by pressing a metal plate, even when there is no sheet, the pinch roller 12 and the capstan roller 11 have a protrusion 30a. Micron gaps are guaranteed. Accordingly, in any case, the pinch roller can be prevented from coming into contact with the protrusion 11a of the capstan roller, and the protrusion 11a can be reliably protected from the pinch roller.
Further, according to the present embodiment, since the capstan roller protrusion 11a is protected by arranging the spacer 16, the protrusion 1a can be securely inserted, including the case of an abnormal transport operation such as jamming (paper jam). It becomes possible to protect.

As described above, in the present embodiment, the transport mechanisms as shown in FIGS. 3 and 4 are disposed on both sides of the pinch roller 12 in the axial direction. For this reason, the above-mentioned effect by the spacer 16 is similarly realized in each of both sides.
Furthermore, according to this embodiment, since the protrusion 11a is protected by the spacer 16, it is not necessary to separate the pinch roller 12 greatly, and the slide member 15 can even release the applied pressure to the extent that resistance to rotation does not occur. That's fine. For this reason, the moving amount D of the slide member 15 can be reduced as compared with the first conventional configuration example shown in FIGS. Accordingly, the amount of work for moving the slide member 15 can thereby be reduced, and it is possible to save labor and reduce the size of the device as a drive source.

In addition, according to the present embodiment, the thickness in the thickness direction of a normal sheet metal material has an accuracy of about ± 30 microns even with the raw material, so that when the spacer 16 is formed of a metal sheet metal plate, high-precision processing is performed. The accuracy of the design requirements can be satisfied even without applying. The conspicuousness of such an operational effect is apparent when compared with the sleeve 106 in the second conventional configuration example shown in FIGS. Further, according to the present embodiment, since the pressing force that presses the pinch roller 12 when the paper P is not present is released, it is possible to save labor such as a motor that serves as a rotational drive source of the roller. .
Further, according to the present embodiment, since a rubber-like elastic body such as the rubber member 107 of the third conventional configuration example shown in FIGS. 9 and 10 is not used, the sheet conveyance due to the decrease in the pressure contact force of the pinch roller is performed. There is no occurrence of color misregistration due to minute fluctuations in the amount. Furthermore, it can be set as an inexpensive structure by the amount which does not use a rubber member.

In the above embodiment, the thickness of the paper P and the thickness of the spacer 16 have been described with specific numerical examples. However, the dimensional relationship is such that a gap is secured between the protrusion 11 a and the pinch roller 12. If it is, it will not be limited to those values.
In addition, as described above, the tolerance of the thickness of the spacer 16 needs to have an accuracy of about ± 30 microns, but by using a metal sheet metal plate in the thickness direction, the accuracy can be secured even with the material as it is. Can do. Of course, the material, the processing method, and the processing means are not limited as long as the accuracy of the design request can be ensured.

  The paper transport mechanism according to the present invention is not limited to a single recording apparatus such as a printer, a copying machine, a facsimile machine, or a captured image forming apparatus, and can be widely applied. Further, the paper transport mechanism according to the present invention can be widely applied as a paper transport mechanism in a composite apparatus combining these or a composite apparatus such as a computer system.

FIG. 3 is a longitudinal sectional view illustrating a state at the time of printing in an embodiment of a recording apparatus including a paper transport mechanism according to the present invention. FIG. 2 is a longitudinal sectional view illustrating a state when a sheet is reversely conveyed by the recording apparatus of FIG. 1. 2A and 2B are diagrams illustrating a state during sheet conveyance of an embodiment of the sheet conveyance mechanism according to the present invention, in which FIG. 3A is a partial front view, and FIG. FIGS. 4A and 4B are diagrams illustrating a state when there is no sheet in the sheet transport mechanism of FIG. 3, in which FIG. 3A is a partial front view, and FIG. The state at the time of paper feeding of the 1st structural example of the conventional paper conveyance mechanism is shown, (a) is a partial front view, (b) is a side view. FIG. 6 is a side view showing a state when the paper transport mechanism of FIG. 5 is out of paper. The state at the time of paper feeding of the 2nd structural example of the conventional paper conveyance mechanism is shown, (a) is a partial front view, (b) is a side view. FIG. 8 is a side view showing a state of the paper transport mechanism of FIG. 7 when there is no paper. The state at the time of paper feeding of the 3rd structural example of the conventional paper conveyance mechanism is shown, (a) is a partial front view, (b) is a side view. FIG. 10 is a side view showing a state of the paper transport mechanism of FIG. 9 when there is no paper. It is a partial front view which expands and shows the state of the 2nd structural example of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Thermal head 2 Ink sheet 3 Platen roller 10 Conveyance motor 11 Capstan roller 11a Protrusion 12 Pinch roller 13 Lever member 13b Long hole 14 Pressurizing means (spring)
15 Pressure release means (slide member)
16 Spacer (Metal flat plate member)
P paper (recording material)

Claims (8)

A capstan roller having a protrusion formed on the peripheral surface and rotatably supported;
A pinch roller rotatably supported to face the capstan roller;
Pressure means for pressing the pinch roller against the capstan roller;
A pressure release means for releasing the pressing force of the pressure means;
A spacer disposed so as to be sandwiched between a peripheral surface of the pinch roller and a portion of the peripheral surface of the capstan roller where the protrusion does not exist while being pressed by the pressing means;
A paper transport mechanism comprising:   2. The sheet conveying mechanism according to claim 1, wherein the height of the projection of the capstan roller is 100 microns or less.   3. The paper transport mechanism according to claim 1, wherein the projection of the capstan roller is formed by plastic deformation of the capstan roller.   The paper transport mechanism according to claim 1, wherein the protrusion of the capstan roller is formed by attaching another member on which the protrusion is formed to the capstan roller.   The paper transport mechanism according to any one of claims 1 to 4, wherein the spacer has a thickness of 100 microns or more.   6. The paper transport mechanism according to claim 1, wherein the spacer is a flat plate member obtained by pressing a metal plate.   The paper transport mechanism according to claim 1, wherein a material of the spacer is stainless steel. A paper transport mechanism according to any one of claims 1 to 7,
A thermal head having a heating portion in which a plurality of heating resistors are arranged;
An ink sheet coated with ink; and
With
A recording apparatus that records on a sheet conveyed by the sheet conveying mechanism by thermally transferring ink of the ink sheet by the thermal head based on image information.

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