JP2524500B2 - Thermal transfer copying machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention includes a thermal transfer type printing section using an end face type thermal head and a thermal ink sheet, and an image sensor section for reading an original image. To a thermal transfer copying apparatus in which is copied on plain paper.

(Conventional example) In recent years, various types of copying apparatuses have been realized and spread. In general, a direct printing type copying apparatus using surface-treated paper such as thermosensitive coloring, and an electrostatic type electrophotographic copying apparatus using plain paper are well known.

There is an electrophotographic copying machine as an apparatus for copying using plain paper that has not been subjected to surface treatment, and a mechanism such as charging, exposure, development, transfer, and cleaning is arranged around a photosensitive drum such as selenium. After charging the surface of the rotating photosensitive drum, the irradiation light image of the original is slit-exposed sequentially using optical means such as a mirror and a lens to develop the latent image into a visible image by developing the toner into a visible image. The toner image is transferred onto plain paper fed, and the copy paper on which the toner image has been transferred is fixed by heating and pressing to obtain a copy.

(Problems to be solved by the invention) However, in the direct printing type copying apparatus described above,
Although the structure is simple, miniaturization is possible, but plain paper cannot be used.

Further, in an electrophotographic copying apparatus that can use plain paper, a certain amount of volume is required because slit exposure is performed by moving an optical system such as a mirror and a lens. For this reason, there is a limit in reducing the configuration, and it has been difficult to make the apparatus compact. Further, in order to heat and fix the toner image, it is necessary to provide a fixing device having a heating source of about 1 kW, which causes an increase in power consumption and an increase in the temperature inside the apparatus. Therefore, it is necessary to provide a preheat control unit for saving power consumption, and to provide an exhaust fan for exhausting the temperature-raised air out of the apparatus.

Furthermore, because a fine powder toner is used for development,
The toner powder is scattered in the machine, thereby soiling the machine and adversely affecting the copied image. For this reason, in order to obtain a high-quality stable copy, various problems have occurred such that a maintenance work for periodically cleaning the scattered toner powder is required.

In view of the above problems, the present invention is compact, lightweight,
Another object of the present invention is to provide a thermal transfer copying apparatus which does not require maintenance as in the prior art.

(Means for Solving Problems) In order to solve the above problems, a thermal transfer copying apparatus according to the present invention includes a copy paper precut by a thermal head and a transfer roller, and a continuous sheet thermal ink sheet. A printing means that is closely contacted to perform thermal transfer,
An image sensor unit configured to scan an original to be copied and read the original is provided with a paper sensor for detecting the presence or absence of copy paper in the copy paper insertion portion to the printing means, and the above-mentioned operation is performed for a certain time after the start of copying. A non-printing portion is provided on the copy paper without rotating the transfer roller and energizing the thermal head, and after detecting the trailing edge of the copy paper with the copy paper presence / absence detection sensor, the power supply to the thermal head is stopped first. After the transfer roller is rotated for a certain period of time, when the document scanning of the image sensor unit is completed before the trailing edge of the copy sheet is detected, the thermal head is deenergized at that point, and the copy sheet is transferred to the transfer roller. The transfer roller is configured to rotate until the passage is completed.

(Operation) According to the present invention, with the above-described configuration, a document image read by an image sensor is printed by a thermal head via a thermal ink sheet, and can be copied to plain paper that has not been subjected to surface treatment. .

Further, since the printing means is controlled so as to form a non-printing portion at each of the leading end portion and the trailing end portion of the copy paper, the thermal head is energized and the ink is transferred to the transfer roller despite the absence of the copy paper. Can be prevented.

(Example) Hereinafter, one example 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 an 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. A printing unit 10 for copying an image on a copy sheet is provided on the rear side of the main body 1. The print unit 10 has a copy paper insertion slot for inserting copy paper.
11 is opened, and one end of 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 fourth
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, a person who makes a copy can always make a copy operation while checking the printed surface from the front side.

In the present embodiment, the original 3 is the left front end 20 of the original platen glass 2.
The copy paper 12 is set in accordance with the right end 21 of the copy paper insertion slot 11. When making a copy on a sheet having a width smaller than the A4 size, a copy sheet guide 22 slidably provided in the copy sheet insertion port 11 is slid so as to match the width of the copy sheet.

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. 2 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.
Further, a light converging fiber lens 35 for forming and projecting a light image of the original at an equal size and a contact image sensor 36 provided on the image forming surface of the original image are attached.

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. 3 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 is reciprocated between the origin switch 43 and the end point switch 44 by being driven by the pulse motor 42. 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 side by a flat line 39.

As shown in FIG. 4, the end face type thermal head 50 is mounted substantially upward from the substrate bottom of the main body 1.

Conventionally, thermal heads have been used for thermal recording type facsimiles, electronic typewriters, word processors, printers for personal computers, etc. due to their features such as maintenance-free noiselessness, low price, etc. It is called a printed circuit board, a circuit element, and a heating element part 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 to manufacture due to the planar arrangement, it occupies a large area occupied by the thermal head, which is not desirable in terms of downsizing of the device.

On the other hand, the thermal head 50 used in the present embodiment is called an end face type. As shown in FIG. 6, a glass glaze layer is formed on the end face 51 and the side face 52 after chamfering the end face of the alumina substrate. A heating resistor film is formed on the glass glaze layer on the end face 51, and the heating 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. Fourth
As shown in the drawing, a supply shaft 53 and a take-up shaft 54 for the thermal ink sheet are arranged on both sides of the end surface 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 end face 51 of the heating element is pressed from above by a transfer roller 59 made of a rubber material and held by a roller frame 58 which 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 separated by about 7 mm from the contact position on the downstream side in the copy paper feeding direction in the tangential direction of the transfer roller 59 pressed against the end surface 51 of the heating element. 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
50, the ink is transferred to the copy paper 12 until the edge 62 is reached.
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 thermal ink sheet 55 is 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 the structure is such that it separates after a certain period of time passes,
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 it is not transferred to the heat-sensitive ink sheet side again, and good transfer is performed. .

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 supply shaft 53 and the take-up shaft 54 for the thermal ink sheet are held in a casing 70 as shown in FIGS. The ink sheet cartridge 71 includes a casing 70, a supply shaft 53, a winding 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 by the edge 62 of the blade 61 after the transfer of the ink, and when the copy paper 12 goes straight as it is, the tip of the copy paper is pulled by the thermal ink sheet 55 and does not collapse. 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 why the step 85 is provided in the middle of the process is that when 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 falls and is held in this step 85. It is provided for the purpose of 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 through a gear train for deceleration, while the driving force of the winding shaft 54 is provided with a slip mechanism including a felt and a spring. Cage,
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.

Generally, black is used for general copying, and the thermal ink sheet 55 used in this embodiment is also coated with black ink. However, the thermal ink sheet 55 is not limited to black, and red, blue, Various thermal ink sheets such as green, yellow, cyan, magenta, brown, gold and silver can be used. To replace the heat-sensitive ink sheet 55, the roller frame 58 is opened upward and the ink sheet cartridge 71 is attached / detached (FIG. 5).

Next, a procedure of actually copying according to the present embodiment will be described. First, after confirming that the ink sheet cartridge 71 is set correctly,
Insert 24. Open the platen cover 4 and place the platen glass 2
The original 3 to be copied is set downward on. The copy paper 12 is inserted from the copy paper insertion slot 11. The copy paper guide 22 is adjusted according to the width of the copy paper 12. When the copy paper 12 is inserted into the copy paper insertion slot 11 and the leading edge of the copy paper 12 reaches the nip portion between the transfer roller 59 and the thermal ink sheet 55 covering the end surface 51 of the heating element of the thermal head 50, the paper sensor 12 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 to rotate, the image sensor unit 30 starts scanning the original 3, and the transfer roller 59 also starts to rotate, so that the copy sheet 12 When the sheet is sent, the heating element of the thermal head 50 is heated according to the image on the original 3, and the melted ink is transferred onto the copy paper 12 according to the image on 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.

As the copy paper guide 22 slides, the movement of the copy paper guide 22 is transmitted to the slide volume via a speed reduction mechanism formed by a rack and gears. The resistance value of this slide volume is electrically detected, and depending on the value, depending on the size of the copy paper guide 22, the width direction is approximately 5 mm at both ends.
The non-printed part 81 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 short copy paper 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.

(Effects of the Invention) The present invention has the following excellent effects.

(1) The original image read by the image sensor is printed by the thermal head via the thermal ink sheet, and can be copied on plain paper that has not been subjected to surface treatment.

(2) Since the printing means is controlled so as to form non-printed portions on the leading edge and the trailing edge of the copy sheet, the thermal head is energized and the ink is transferred to the transfer roller despite the absence of the copy sheet. Can be prevented.

[Brief description of drawings]

FIG. 1 is a perspective view of a thermal transfer copying apparatus according to one embodiment of the present invention, FIG. 2 is a sectional view of an image sensor unit of the present invention, FIG. 3 is a perspective view of the image sensor unit of the present invention, and FIG. FIG. 5 is a cross-sectional view of a main part of the printing unit of the present invention, FIG. 5 is a cross-sectional view of a main part showing that the roller frame of the printing unit of the present invention is opened and the ink sheet cartridge is replaced, and FIG. FIG. 7 is a cross-sectional view showing the details of the thermal head of the printing section. FIG. 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] 1. A printing means adapted to perform heat-sensitive transfer by bringing a thermal paper and a transfer roller into close contact with a copy paper and a continuous sheet of heat-sensitive ink sheet, and a document to be copied is scanned to scan the document. Is provided with an image sensor unit for reading and a paper sensor for detecting the presence / absence of copy paper in the copy paper insertion portion to the printing means, and only the transfer roller is rotated for a certain time after the start of copying to energize the thermal head. Not to provide a non-printing section on the copy paper, after detecting the copy paper rear end by the copy paper presence detection paper sensor, first stop the energization to the thermal head and then rotate the transfer roller for a certain time, If the document scanning of the image sensor unit is completed before the trailing edge of copy paper is detected, the thermal head is moved to that point. The energization is stopped, thermal transfer copying machine until the copy sheet is completed passes through the transfer roller, characterized in that so as to rotate the transfer roller.