JP2679068B2 - Thermal transfer copying machine - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention includes a thermal transfer type printing section using a thermal head and a thermal ink sheet, and an image sensor section for reading a document image, and copies a document onto plain paper. The present invention relates to a thermal transfer copying apparatus configured to do so. 2. Description of the Related Art One of the most common types of paper that uses cut-type paper in the paper feeding method of a thermal transfer copying machine and is compatible with various paper sizes, as shown in FIG. Touch the fixed guide 21 so that it is in the position,
For the large size to the small size, the structure is such that the position of the variable guide 22 on the opposite side can be changed, and the transfer roller 59 and the thermal head which are pressed against the thermal head 50 via the bearing 89 by the pressing spring 88. There is one in which the copy paper 12 is fed into the nip formed by 50 and 50. Problems to be Solved by the Invention However, in the case of the above structure, the thickness for copying
There is no problem with paper of any size as long as it is about 100μ, but if you use a small paper with a thickness of 300μ, such as a postcard or business card, the transfer roller will be thicker as shown in Fig. 9b. However, there is a problem in that it is impossible to apply a constant pressure to the entire sheet of paper due to the inclination, and printing is greatly reduced on one fixed guide side. In view of the above problems, the present invention provides a thermal transfer copying apparatus that is compact and can handle a wide range of paper sizes and thicknesses. Means for Solving the Problems To solve the above problems, the thermal transfer copying apparatus of the present invention is supplied by a thermal head, and a supply shaft and a take-up shaft arranged on both sides of the thermal head. A printing guide including a thermal ink sheet, a transfer roller in pressure contact with the thermal head, and a fixed guide for feeding the copy paper to a nip formed by the thermal ink sheet and the transfer roller in one direction of the thermal head. Depending on the size and thickness of the paper to be used and the size and thickness of the paper to be used, the pressing force of the transfer roller against the thermal head can be changed so that only the fixed guide end side can be increased or decreased. It is composed of and. With the above-described structure, the present invention reduces the pressing force on the guided side in the case of thin paper and reduces the pressing force on the guided side in the case of thick paper and particularly narrow width (for example, postcards and business cards). By increasing the size, uniform printing can be performed on a wide range of paper. Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of a thermal transfer copying apparatus according to one embodiment of the present invention. In FIG. 1, there is a platen glass 2 on which a document to be copied is placed on the front side of a main body 1, and a platen on which a document 3 placed on the platen 2 is pressed so as to be brought into close contact with the platen glass 2. The cover 4
It is supported to be openable and closable with the back side 5 as a fulcrum. The platen glass 2 is arranged to be horizontally long when viewed from the front so that an A4 size document can be placed horizontally. On the rear side of the main body 1, a print unit 10 for copying an image on copy paper is provided. The print unit 10 has a copy paper insertion slot for inserting copy paper.
11 is opened, and one end of the copy paper 12 is inserted.
The inserted copy paper 12 leans on and is held by the guide cover 13 so as not to fall down and fall out of the insertion slot 11. The guide lid 13 is hinged at the innermost position of the main body 1 and can be opened and closed. When the main body 1 is not used, the guide lid 13 is closed to cover the copy paper insertion slot 11 and the like. An opening of the copy sheet discharge port 14 is provided in front of the copy sheet insertion port 11, and the guide plate 15 that forms the opening is the second
As shown in the figure, the copy paper 12 is inclined so as to change the feed direction of the copy paper 12 by 90 ° or more. The copy paper 12 can be used up to the maximum size of A4 size paper. The A4 size paper is fed in the longitudinal direction, and is copied upward from the copy paper discharge port 14 and comes out. The copy paper 12 coming out from the copy paper discharge port 14 is printed and discharged in such a direction that the printed copy image can be viewed from the near side, and when the copy paper has low rigidity, It falls down to the copy paper insertion slot 11 side. Therefore, the person who makes the copy can perform the copy operation while always checking the print surface printed from the near side. In the present embodiment, the original 3 is the left front end 20 of the original platen glass 2.
And the copy sheet 12 is set so as to be aligned with the right end (fixed guide) 21 of the copy sheet insertion slot 11. When making a copy on paper that is narrower than A4 size, slide the copy paper guide (sliding guide) 22 that is slidably provided in the copy paper insertion slot 11 to match the width of the copy paper. I have to. A pressing force switching lever 86 depending on the type of paper is provided on the right side of the copy paper discharge port 14. A start button 23 is provided on the upper surface of the main body 1, and a power switch 24 is provided on the left side of the main body. FIG. 3 is a cross-sectional view of the image sensor unit provided on the lower side of the platen glass 2. In the image sensor unit 30, a sensor main body 33 is mounted on a sensor base 32 which is slidably guided by a guide shaft 31 fixed to the main body 1. The sensor body 33 has an illumination LED array 34 for illuminating the original.
And a light-converging fiber lens 35 for forming and projecting an optical image of the original at the same magnification, and a contact-type image sensor 36 provided on the image forming surface of the original image. If the positional relationship between the original 3 placed on the platen glass 2 and the contact image sensor 36 is not set correctly, the light image projected on the contact image sensor 36 will be out of focus, and the contact image An appropriate output signal cannot be obtained from the sensor 36. In the present embodiment, rollers 37 are provided at the front and rear ends of the sensor body 33 in order to accurately determine the distance between the document surface and the contact type image sensor 36. The sensor body 33 is pushed up by a compression spring 38 provided between the sensor body 33 and slides while rotating in contact with the lower surface of the document table glass 2. Therefore, if the thickness of the platen glass 2 is kept constant, the copy surface of the document placed on the platen glass 2 and the contact type image sensor 36 can always be kept constant. FIG. 4 is a perspective view showing a driving method of the image sensor unit. A guide shaft 31 is fixed along the longitudinal direction of the platen glass 2, and guided by the guide shaft 31, the image sensor unit 30 is moved by rollers 37 to the platen glass 2.
The fixed end 41 is pulled by the belt 40 while sliding on the lower surface of the device, and moves left and right. The belt 40 is stretched between left and right ends of the main body 1 and is driven by rotation of a pulse motor 42. The image sensor unit 30 reciprocates by driving the pulse motor 42 between the origin switch 43 and the end switch 44. The power supply to the LED array 34 of the image sensor unit 30 or the output from the image sensor 36 is connected to the main body through a flat line 39. As shown in FIG. 2, the end surface type thermal head 50 is mounted substantially upward from the substrate bottom of the main body 1. Thermal heads have been used in thermal recording facsimile machines, electronic typewriters, word processors, printers for personal computers, etc. because of their features such as maintenance-free noise and low cost. A printed board, circuit elements, and a heating element section in which fine heating elements of, for example, 8 dots per 1 mm are arranged in a line on one side of a flat board. Although it has the advantage of being easy, the occupied area occupied by the thermal head becomes large, which is not desirable in terms of making the apparatus compact. On the other hand, the thermal head 50 used in this embodiment is called an end face type, and as shown in FIG. 6, after the end face part of the alumina substrate is chamfered, a glass glaze layer is formed on the end face 51 and the side face 52. A generating resistor film is formed on the glass glaze layer on the end face 51, and the heat generating resistor film is connected to the circuit element 60 on the side surface by an electrode film. In the present embodiment, the heating element formed on the end face 51 is constituted by a heating element divided into 8 dots per mm over an A4 size 210 mm width. However, it is not always necessary to have the same length as the paper width, and it is sufficient that the paper has the same length as the image forming dimension on the paper. The surface of the heating element is protected by a wear-resistant protective film. The end-face type thermal head has the features that the heating element surface has a convex shape, good thermal transfer characteristics, good linearity of the heating element formation surface, uniform print density can be obtained, and the head is compact. Have. Second
As shown in the figure, a supply shaft 53 and a take-up shaft 54 for the thermal ink sheet are arranged on both sides of the end face type thermal head. A thermal ink sheet 55 is wound around the supply shaft 53 with its thermal ink surface facing outward.
Reference numeral 55 denotes a metallic weight shaft 56 which is tensioned on the lower side, and is led to the end surface 51 of the heating element of the thermal head 50. As shown in FIG. 5, the heating element end surface 51 is pressed from above by a transfer roller 59 made of a rubber material held on a roller frame 58 that can be opened and closed about a fulcrum 57 as a rotation center. The transfer roller 59 has a length of 220 mm,
The diameter of the central part is 20 mm, and both ends are 0.15 in diameter each
It has the shape of a small scallop. 20mm diameter in the center
Within the range of 70 mm, the portion with a diameter of 19.85 mm at both ends from that position is a finish with a linear taper. In this manner, the transfer roller 59 is shaped like a trapezoid, and both ends thereof are pressed with a spring of about 1.2 kg on one side, so that the adhesion between the transfer roller 59 and the end surface 51 of the heating element is improved, and a uniform density is obtained over the entire width. . The transfer roller 59 also serves to prevent wrinkles that are likely to occur on the thermal ink sheet 55 and the copy paper 12. Although the tapered transfer rollers are connected in a straight line as the shape of the transfer roller, in the present embodiment, connecting them by a straight line rather than connecting them by a curved line is more effective for wrinkles. Immediately to the left of the contact surface of the transfer roller 59 on the heating element end face 51, a blade 61 made of a plastic material whose details are shown in FIG. 6 is fixed. The thermal ink sheet 55 that has passed through the heating element end surface 51 is wound around the winding shaft 54 such that the thermal ink surface is inside. As shown in FIG. 6, the edge 62 of the blade 61 is tangential to the transfer roller 59 pressed against the end surface 51 of the heating element and is about 7 mm away from the contact position on the downstream side in the copy paper feed direction. Therefore, the copy paper 12 is transferred between the transfer roller 59 and the thermal ink sheet 55.
The transfer roller 59 and the thermal head
During the period from when the ink is pressed and heated by 50 and the ink is transferred to the copy sheet 12 to the etch 62, the copy sheet 12
The thermal ink sheet 55 is sent in close contact with the thermal ink sheet 55 for a certain period of time, after which the thermal ink sheet 55 turns sharply downward at the edge 62, and the copy paper 12 proceeds straight.
The angle of the edge 62 of the blade 61 is smaller than 90 °,
The downward change in the direction of the heat-sensitive ink sheet 55 is made sharp. Then, the heat-sensitive ink sheet 55 can be wound around the winding shaft 54 at an angle θ with respect to the feeding direction. Angle θ is 30
If it is greater than or equal to ゜, it acts on separation of the copy paper 12, but it is preferably 60 ゜ to 90 ゜. It should be noted that if the angle is set to 90 ° or more, the separation effect is more increased, but the arrangement of the thermal head 50 changes. The transfer of the ink to the copy paper 12 is heated by the thermal head 50, and is separated after a certain time,
The ink transferred to the copy paper 12 is peeled off after the heat is sufficiently absorbed by the surface of the copy paper, so that good transfer can be performed without the ink being transferred to the thermal ink sheet side again. . Further, the position of the edge 62 where the thermal ink sheet 55 and the copy paper 12 are separated is in the tangential direction of the transfer roller 59, and the copy paper 12 tries to move straight due to its rigidity, whereas the thermal ink sheet 55 Makes a sharp change in direction at the edge 62, so that the copy paper 12 and the thermal ink sheet 55 are separated well. The heat-sensitive ink sheet supply shaft 53 and the take-up shaft 54 are held by a casing 70 as shown in FIGS. 2 and 5. The ink sheet cartridge 71 includes a casing 70, a supply shaft 53, a take-up shaft 54, and a weight shaft 5.
6, the thermal ink sheet 55, and the ink sheet cartridge 71 is used for copying when using the thermal head 50 from above.
It is used by loading into the part. Ink sheet cartridge
The casing 70 has an opening 72 on the lower surface thereof through which the thermal head 50 can be inserted, and a thermal head 50 on the upper surface.
The opening 73 allows the upper surface of the heating element end face 51 to slightly protrude.
Is provided. A felt is used as a bearing for the supply shaft 53. The felt is fixed to the casing 70, and the friction when the supply shaft 53 rotates causes a friction when the heat-sensitive ink sheet 55 is wound around the take-up shaft 54. It works to give tension. Similarly, the weight shaft 56 also functions to absorb torque fluctuations when the thermal ink sheet 55 is wound up and to provide a back tension.
Upper surface 83, 8 of casing 70 of ink sheet cartridge 71
Reference numeral 4 also serves as a guide surface of the copy sheet 12, as shown in FIG. The upper surface 83 on the entrance side is so high that when the copy paper 12 is inserted, the leading edge of the upper surface 83 just leads to the nip formed by the transfer roller 59 and the end surface 51 of the heating element of the thermal head 50. The upper surface 84 on the outlet side is separated from the thermal ink sheet 55 at the edge 62 of the blade 61 after the transfer of the ink, and the leading edge of the copy paper is not pulled down by the thermal ink sheet 55 when the copy paper 12 moves straight as it is. Such a guide surface is formed. Top surface 84 is copy paper 12
Is guided to the copy paper outlet 14. Top surface 84
The reason that the step 85 is provided in the middle is that if the previous copy operation is completed and the next copy is made as it is, the previous copy paper is pushed by the leading edge of the previous copy paper, and it falls into this step 85 and is held It is provided for working. The winding shaft 54 of the thermal ink sheet and the transfer roller 59 are driven by the same pulse motor (not shown). The driving force of the pulse motor is transmitted to the transfer roller 59 via a gear train for reduction, while the driving force of the winding shaft 54 is provided with a slip mechanism including a felt and a spring in the middle. Yes,
Even when the thickness of the thermal ink sheet 55 wound on the winding shaft 54 changes and the diameter increases, a certain amount of the thermal ink sheet 55 always fed at the peripheral speed of the transfer roller 59 is reliably wound. . When the same pulse number is applied, the pulse motor for driving the transfer roller 59 and the pulse motor 42 for driving the image sensor unit 30 move the copy sensor 12 by the transfer roller 59 and move the image sensor unit 30. The reduction ratio is set so that the amounts are equal. In general, black is used for general copying. In this embodiment, the thermal ink sheet 55 is coated with black ink, but is not limited to black. Various thermal ink sheets such as green, yellow, cyan, magenta, brown, gold, silver and the like can be used. In order to replace the thermal ink sheet 55, the roller frame 58 is opened upward and the ink sheet cartridge 71 is attached and detached (FIG. 5). Next, a procedure of actually copying according to this embodiment will be described. First, after confirming that the ink sheet cartridge 71 is set correctly, turn on the power switch 24
Insert The platen cover 4 is opened, and the document 3 to be copied is set on the platen glass 2 face down. The copy paper 12 is inserted from the copy paper insertion slot 11. Copy paper
Adjust the copy paper guide 22 to fit the width of 12. Insert the copy paper 12 into the copy paper insertion slot 11 and
When the leading end of the copy paper 12 reaches the nip portion between the heat sensitive ink sheet 55 covering the end surface 51 of the heating element of the thermal head 50 and the thermal paper 50, the paper sensor 75 is turned on and the copy is ready. When the copy start button 23 is pressed in this state, the pulse motor 42 and the pulse motor for driving the transfer roller 59 start rotating, and the image sensor unit 30 starts scanning the original 3 and the transfer roller 59 starts rotating, and the copy paper 12 Is sent, the heating element of the thermal head 50 is heated according to the image of the original 3, and the melted ink is transferred to the copy paper 12 according to the image of the thermal ink sheet 55. In the present embodiment, the copy paper guide 22 is adjusted according to the width of the copy paper 12. Next, the adjustment mechanism will be described. Regarding the sliding movement of the copy paper guide 22, the movement of the copy paper guide 22 is transmitted to the slide volume through the reduction mechanism by the rack and the gear. The resistance value of this slide volume is electrically detected, and the width is approximately 5 mm at both ends in the width direction according to the size of the copy paper guide 22 according to the value.
The part 81 which is not printed is made. Although it is possible to continuously change the printing width according to the numerical value of the slide volume, in the present embodiment, the printing width is changed stepwise to a generally used paper size A4, B5, A5, B6, or the like. I have. However, it is not limited to this. The leading edge of the copy paper 12 and the copy paper guide 22 correspond to the set paper width, and each of them is 5 m as shown in FIG.
Unprinted portions 80 and 81 are formed about m. Copy paper 12
The printing is stopped when the trailing edge of the copy paper 12 passes the paper sensor 75, so that the trailing edge of the copy paper 12 also has a portion 82 where about 5 mm is not printed. The non-printing portion 80 at the leading end of the copy paper 12
When the thermal ink sheet 55 starts to be separated at the edge 62, there is a great effect of reliably separating the sheet. The non-printing sections 81 on both sides of the copy paper 12
When the width is wider than 12, the heat is applied to the thermal head 50 up to the portion where the copy paper 12 is not present, so that unnecessary ink is prevented from being transferred to the transfer roller 59. When the image sensor unit 30 reaches the end point switch 44, it starts returning. However, the transfer roller 59 is a paper sensor 75
Continue turning as long as it detects that there is paper. Therefore, even when the copy paper having an extremely long length comes and the scanning of the image sensor unit 30 is completed, the copy paper 12
Will continue to be sent, so there will be no paper jams. When a copy paper having a short length arrives, the paper sensor 75 detects the end of the paper, and after a while, the transfer roller 59
Since the rotation of the ink is stopped, the excessive thermal ink sheet is not excessively used. The image sensor unit 30 returns to the same start position as before the start of scanning and stops. In the present embodiment, when the copy paper is set in the copy paper insertion slot 11 again during the return operation until the image sensor unit 30 returns to the start position, when the image sensor unit returns to the start position, the next automatically. Is started, which is convenient for making multiple copies continuously. FIG. 8A is a sectional view of a portion where the transfer roller 59 is pressed against the thermal head 50. Bearings 89 are attached to both sides of the rotary shaft of the transfer roller 59.
88 pushes the transfer roller 59 against the thermal head 50. Of the pressing force applied to the thermal head 50, the lever 87 is attached around the shaft 90 as the center of rotation as shown in the figure only on the side where the paper 12 is guided and fed by the right end 21 of the copy paper insertion opening 11. . Further, the lever 87 is brought into the state of FIG. 8b by moving the pressing switching lever 86 in the direction of the arrow by the sheet, and the pressing force increases by the thickness of the slide portion 91 below the pressing switching lever 86. There is. The pressure switch lever 86 is set to the state shown in FIG. 8a when using normal ordinary copy paper, and is set to the state shown in FIG. 8b when using small paper, and the pressing force is set in both cases. The lower slide portion 91 of the pressure switch lever 86 so that the
The thickness of is set. EFFECTS OF THE INVENTION As can be seen from the above description, the present invention provides a thermal head, a thermal ink sheet supplied by a supply shaft and a winding shaft arranged on both sides of the thermal head, and a pressure contact with the thermal head. Printing means consisting of a transfer roller,
Copy paper insertion slot for setting the copy paper into the nip formed by the heat-sensitive ink sheet and the transfer roller so that the copy head is moved toward one side of the thermal head so as to be fed, and the size and thickness of the paper used. According to the above, the pressing force of the transfer roller to the thermal head can be switched so that it can be increased or decreased only on the fixed guide end side. As a result, balanced printing can be performed on a wide range of papers with a simple mechanism, and the entire copying machine can be made compact. In addition, the paper can be guided only on one side, and the position of the original can be easily adjusted, so that a compact copying machine with excellent operability can be provided. As is clear from the above description, the present invention can be used for one-touch switching from thick paper to thin paper, and even for papers of different widths, only one guide plate is required to move on one side for easy operation. It has the excellent feature that

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a thermal transfer copying apparatus according to an embodiment of the present invention, FIG. 3 is a sectional view of an image sensor unit of the present invention, and FIG. 4 is an image sensor unit of the present invention. FIG. 2 is a cross-sectional view of the main part of the print part of the present invention, and FIG. 5 is a cross-sectional view of the main part of the print part of the present invention showing the roller frame opened to replace the ink sheet cartridge. 6 is a sectional view showing the details of the thermal head of the printing unit of the present invention, FIG. 7 is a plan view of copy paper for explaining the print width of the present invention, and FIG. 8 is an operation explanatory view of the above embodiment, FIG. 9 is a block diagram of a conventional thermal transfer copying apparatus. 1 ... body, 2 ... platen glass, 3 ... manuscript, 10 ...
Print section, 11: Copy paper insertion slot, 12: Copy paper, 14: Copy paper discharge port, 22: Copy paper guide, 30, Image sensor unit, 33: Sensor body, 34: LED array , 35: Light converging fiber lens, 36: Image sensor, 37: Roller, 38: Spring, 50: Thermal head, 53: Supply shaft, 54: Winding shaft, 55: Thermal ink Seat, 56 ... Weight axis, 59 ...
... Transfer roller, 61 ... Blade, 71 ... Ink sheet cartridge, 72,73 ... Opening, 83,84 ... Top surface.

Claims (1)

(57) [Claims] A thermal head, a thermal ink sheet supplied by a supply shaft and a take-up shaft disposed on both sides of the thermal head, a printing means comprising a transfer roller in pressure contact with the thermal head, and the thermal ink sheet and transfer A copy sheet insertion port for setting a copy sheet in alignment with a fixed guide end so as to send the copy sheet toward the one side of the thermal head in a nip formed by a roller, and the transfer roller according to the size and thickness of the sheet to be used. And a pressing force switching means capable of changing the pressing force applied to the thermal head so as to increase or decrease only on the fixed guide end side.