JPH01195071A - Image forming device - Google Patents

Abstract

PURPOSE:To enable a smaller machine size, reduce non-image areas, prevent slippage from occurring in feeding a recording medium and contrive higher printing accuracy, by feeding the recording medium by supporting the medium by a loop form belt having a circumferential length greater than the length of the medium, and using a metal as a base material for the belt. CONSTITUTION:A belt 24 has a two-layer structure which comprises a metallic layer 26a as a base comprising a stainless steel sheet or the like and a rubber layer 26b the surface of which constitutes a paper support surface 24a. A paper P supplied from a paper-supplying cassette 35 is guided through a register roller pair 40 to a position between the belt 24 and a pressing roller 25. Then, a platen roller 25 is rotated forward, and a leading end part of the paper P making close contact with the belt 24 is fed to a predetermined position while being clamped between a thermal transfer ribbon 27 and the belt 24. Subsequently, the heat generating elements of a thermal head 21 provided along the axial direction of the platen roller 22 are operated to generate heat according to image data, whereby an ink 41 of the ribbon 27 is transferred onto the paper P. Then, the platen roller 22 is rotated reversely to feed the paper P backward, and transferring in another color is conducted.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an improvement in an image forming apparatus applied to, for example, a thermal transfer printer or a thermal transfer copying machine.

(Prior Art) In recent years, a plurality of colorants (inks) of a transfer material (thermal transfer ribbon) are used on a recording medium (paper) that is supported and transferred by a support and transfer means.
A thermal transfer type image forming apparatus has been developed and put into practical use, which melts and transfers the image using a heat-sensitive recording head (thermal head) to form a desired color image. In order to form accurate color images in this type of apparatus, it is necessary to reliably support and transport the paper.

12 and 13 show different conventional examples, and the one shown in FIG. 12 is called a platen grip method, in which a thermal transfer ribbon C is interposed between a platen roll a and a thermal head b. Along with paper P
A gripper d is attached to the platen roll a to pinch the paper P, and an image is formed while wrapping the paper P around the platen roll a.The platen roll a has an outer circumference equal to or longer than the length of the paper P. . The system shown in Fig. 13 is called a drum grip system, in which a drum f is provided separately from the platen roll a, and has a gripper e that serves to hold the paper P. It is configured to have an outer periphery such as a gap and a gap. In addition, the first
The same parts as in FIG. 2 are designated by the same reference numerals, and the description thereof will be omitted.

(Problem to be Solved by the Invention) However, the former platen grip type not only requires a large-diameter cylindrical platen roll a, but also has a large thermal head b, resulting in an increase in the size of the device. There are problems like this. In addition, the latter drum grip type requires a drum f with a large diameter and is large in size like the former, and the distance between the heat generating part of the thermal head b and the grip e is large, resulting in a large non-image forming part. There was a problem with it becoming.

The present invention has been made based on the above circumstances, and its objectives are to make it possible to miniaturize the machine, reduce the size of the non-image area, and produce images with high printing accuracy without shifting of the recording medium. An object of the present invention is to provide an image forming apparatus that can perform image forming.

"Structure of the Invention" (Means for Solving the Problems) In order to achieve the above object, the present invention provides for melt-transferring a colorant on a transfer material to a recording medium supported and transferred by a support and transfer means via a thermal recording head. In a thermal transfer type image forming apparatus, the supporting and transporting means is wound around a platen roller and has a longer circumference than the recording medium, and frictionally transports the recording medium. It has a structure in which the base material is metal and the surface is a two-layered endless belt made of rubber.

(Function) That is, with the above configuration, the present invention supports and transports a recording medium such as a paper not with a cylinder but with an endless belt having a circumference longer than the recording medium, so that space can be saved and flexible. It is possible to make the machine smaller, and it is also possible to reduce the diameter of the arc of the portion facing the thermal recording head, thereby making it possible to reduce the size of the non-image area. Moreover, since the base material of the endless belt is metal, it not only has low expansion and contraction and excellent durability, but also has improved belt width processing accuracy and no horizontal wobbling. This creates a large frictional force with the recording medium, making it possible to transfer the recording medium with high precision and stability, and to improve printing accuracy, especially when printing in other colors, which requires repeated transfers. Become.

(Embodiment) Hereinafter, one embodiment of the present invention will be described with reference to FIGS. 1 to 8.

FIG. 3 shows the appearance of an image forming apparatus to which the present invention is applied, and FIG. 4 shows its schematic configuration.

3 and 4, reference numeral 1 in the figure is the main body of the image forming apparatus, and an operation panel 1 is provided on the upper front of the apparatus main body 1.
A is formed.

Further, a document table 2 having a document holding cover 3 on the left side is provided on the upper surface of the apparatus main body, and the lower side of the document table 2 inside the apparatus main body 1 is used to hold a document set on the document table 2. There is a document scanning unit (scanner unit) 4 that scans the
The right side of the apparatus main body 1 is an image forming section (printer section) 5. The operation panel section 1a includes a display section 6. Operation/display components such as a numeric keypad 7 and a start button 8 are provided.

Further, as shown in FIG. 4, the document scanning section 4 optically scans the document set on the document table 2 by reciprocating along the lower surface of the document table 2 through the movable scanning section 9 of the exposure optical system. The optical information is scanned, and this optical information is photoelectrically converted and input to the image forming section 5.

Further, the image forming section 5 has a configuration as shown in FIGS. 4 and 5. That is, a support and transfer means 20 is provided which is located approximately at the center of the upper part of the image forming section 5 to hold and transfer a recording medium (hereinafter referred to as paper) P, and a support and transfer means 20 is provided in front of the support and transfer means 20 (see FIG. 5). A thermosensitive recording head (hereinafter referred to as a thermal head) 21 is arranged so as to be movable toward and away from the support and transfer means 20 (in the left direction).

As shown in FIG. 5, the support transfer means 20 includes a platen roller 2 that is provided at a position facing the thermal head 2 and is driven via a drive force transmission system (not shown).
2, and a driven roller 23 parallel to this platen roller 22.
and an endless belt 24 which is stretched horizontally via these rollers 22 and 23 and whose outer peripheral surface serves as a paper support surface 24a as a recording medium support surface.

The belt 24 has a circumference longer than the paper P and a width wider than the paper P.As shown in FIG. This state is such that the paper P is brought into close contact with the paper support surface 24a.

Further, as shown in FIG. 2, the belt 24 has a two-layer structure consisting of a metal layer 26a made of a thin plate of stainless steel or the like and a rubber layer 26b whose surface serves as a paper support surface (recording medium support surface) 24a. The two layers are completely bonded together.

Since the paper support surface (recording medium support surface) 24a is a rubber layer 26b that is subject to a large frictional force, the paper P is conveyed without being displaced. In addition, the platen roller 22 can be a metal roller that does not cause a nip by ensuring that the nip necessary for printing is obtained by nipping only the rubber layer 26a.

Further, as shown in FIGS. 1 and 5, a transfer system (hereinafter referred to as
A thermal transfer ribbon (27) is interposed therebetween. The thermal transfer ribbon 27 has both ends wound around a core 2.
The ribbon cassette 31 (see FIG. 4) is assembled into a case 30 together with 8 and 29 to form a cassette. It is now possible. The cassette insertion/ejection port 32 is normally closed by a lid 33, and when replacing the ribbon cassette 31, the lid 33 must be opened.

Further, as shown in FIG. 5, a paper feed cassette 35 is mounted below the cassette mounting section where the ribbon cassette 31 is mounted, and the paper P in this paper feed cassette 35 is fed as a paper feeding means. A paper roller 36 is used to take out one sheet at a time.

The taken out paper P is guided between the thermal transfer ribbon 27 and the belt 24 of the support and transfer means 20 via a paper guide path 39 formed by mutually opposing surfaces of the guide plates 37 and 38. ing. Further, a pair of registration rollers 40 is arranged in the middle of the three paper guide paths to align the leading edge of the paper P and adjust the paper feeding timing.

In this way, the fed paper P is transferred to the presser roller 25.
Due to the action of
4, and the portion of the thermal head 21 facing the heat generating portion (not shown) is securely supported.

On the other hand, the thermal head 21 presses the paper P through the thermal transfer ribbon 27 against a portion of the belt 24 supported by the platen roller 22, and as shown in FIG. is heated and melted and transferred onto paper P.

The thermal transfer ribbon 27 may be provided with yellow (Y), magenta (M), and cyan (C) ink portions arranged side by side in a size approximately equal to that of the paper P, as shown in the range shown in FIG.
Alternatively, as shown by the range opening in FIG. 7, yellow (Y), magenta (M), cyan (C), and black CB) ink portions are arranged side by side with approximately the same size as paper P, and 1 After each color is transferred, the paper P is returned to its original position, and a full-color image is obtained by accurately overlapping one after another.

Further, as shown in FIG. 8, the image forming apparatus includes a document scanning section (scanner section) 41, a color conversion section 45. Memory section 461 Image forming section (printer section) 5. and an overall control section 47.

Then, the green (G) detected by the original scanning unit 4
), yellow (Y), and cyan (C) are converted by the color conversion unit 45 into the colors of the print medium, that is, magenta (M), yellow (Y), and cyan (C). The color converted values are stored in the memory section 46 together with the position information on the original document for each color. The image forming section 5 prints magenta (M), yellow (Y), and cyan (C) based on the values read out from the memory section 46.

Black (B) [Black (B) is magenta (M), yellow (Y)
, cyan (C) AND output] is transferred onto paper P. It should be noted that the overall control section 47 controls the document scanning section 41
Color conversion unit 45. Memory unit 46° controls the entire image forming unit 5.

Note that the pair of paper ejection rollers 48 and the paper ejection tray 49 shown in FIG.
It can be removed from.

Note that 50 is a peeling claw serving as a peeling means for peeling off the paper P that is in close contact with the belt 24, and is configured to peel off the paper P and guide it to the pair of paper discharge rollers 48.

Further, as shown in FIG. 1, the thermal head 21 is configured to be movable by τJ method X in the direction toward and away from the belt 24 by a head actuating means (not shown). The configuration is such that a gap δ into which the thermal transfer ribbon 27 stretched via the ribbon guide 51, 51 can be inserted can be secured between the thermal head 21 and the belt 24 as necessary, and the movement of the paper P is The operation and attachment/detachment of the ribbon cassette 31 can be performed easily and reliably.

Next, the operation of the image forming apparatus configured as described above will be explained with reference to FIG. 5.

First, the paper P supplied from the paper feed cassette 35 is guided between the belt 24 and the presser roller 25 via the pair of curling rollers 40 . Next, the platen roller 22 rotates in the forward direction (in the direction of the solid line arrow) using a pulse motor (not shown) as a driving source, and as the belt 24 travels as a result of this rotation, the leading end of the platen roller 22 touches the thermal transfer ribbon 2 while being in close contact with the belt 24.
7 and the belt 24 and transported to a predetermined position.

Next, as the platen roller 22 is moved at a predetermined speed, a heating element (not shown) of a thermal head 21 formed in a line tod shape along the axial direction of the platen roller 22 generates heat according to the image information, and thermal transfer is performed. ribbon 27
The ink 41 is transferred onto the paper P.

Further, at this time, the paper P is transported in close contact with the belt 24 by the action of the presser rollers 25, 25, so that no deviation occurs between the paper P and the belt 24.

Then, the paper P onto which the ink 41 of one color has been transferred is reversely transported by rotating the platen roller 22 in the opposite direction (in the direction of the dashed arrow), and the transfer in a different color is performed again.

In this way, multiple colors are transferred by reciprocating the paper P a plurality of times, and the paper P on which all the colors of ink 41 have been transferred is peeled off from the belt 24 by the peeling claw 50 and passed through the pair of paper ejection rollers 48. The paper will be ejected four paper ejection trays above.

In the above-mentioned embodiment, the presser rollers 25, 25 are brought into contact with the belt 24 as a contact means for ensuring good contact of the paper P with the belt 24, but as shown in FIG. presser roller 25,
25 may be movable so that it can be largely displaced from the belt 24. Furthermore, as shown in FIG. 10, presser claws 62,62 may be arranged in place of the presser rollers 25,25. Furthermore, as shown in FIG. 11, the presser claws 62, 62 may be movable.

In addition, it goes without saying that the present invention can be modified in various ways without departing from the gist thereof.

[Effects of the Invention] As explained above, according to the present invention, since the recording medium such as paper is supported and transported not by a cylinder but by an endless rubber belt having a circumference longer than the recording medium, space is saved. can be used flexibly, making it possible to downsize the machine, and also making it possible to reduce the diameter of the arc of the portion facing the thermal recording head, thereby making it possible to reduce the size of the non-image area. Furthermore, since the base material of the endless belt is metal, it not only has less expansion and contraction and is highly durable, but also has improved belt width machining accuracy and no lateral wobbling, and the contact surface with the recording medium is made of rubber. Therefore, a large frictional force can be obtained between the recording medium and the recording medium, making it possible to transfer the recording medium with high precision and stability.
In particular, it is possible to provide an image forming apparatus that can improve printing accuracy in the case of printing in other colors, which requires repeated transportation and recording.

[Brief explanation of the drawing]

1 to 8 show an embodiment of the present invention,
Fig. 1 is a schematic configuration diagram of the main parts, Fig. 2 is a sectional view of the rubber belt, Fig. 3 is an external perspective view of the image forming apparatus, and Fig. 4 is a partially cutaway perspective view. 5 is a schematic side view of the image forming section, FIG. 6 is a perspective view showing the transfer operation state, FIG. 7 is a plan view showing the thermal transfer ribbon, and FIG. 8 is a block diagram showing the configuration of the control device. , FIGS. 9 to 11 are views showing different modifications of the paper holding means, and FIGS. 12 and 13 are views showing the main components of different conventional examples. P...Recording medium (paper), 20...Supporting and transporting means, 2
1. Heat-sensitive recording head (thermal head), 22... platen roller, 24... endless rubber belt, 24a...
- Recording medium support surface (paper support surface), 26a... Metal layer, 26b... Rubber layer, 27... Transfer plate (thermal transfer ribbon), 41... Colorant (ink). Applicant's representative Patent attorney Takehiko Suzue -]6 - Figure 1 Figure 2 Figure 3 Figure 12

Claims (1)

[Claims] In a thermal transfer type image forming apparatus that melts and transfers colorant on a transfer material via a thermal recording head to a recording medium supported and transferred by a support and transfer means, the support and transfer means includes a platen roller and a roller wound around the platen roller. A configuration comprising: an endless belt that is stretched in a suspended state, has a circumference longer than the recording medium, frictionally conveys the recording medium, and has a two-layer structure in which the base material is metal and the surface is made of rubber. An image forming apparatus characterized by: