JPH04161367A - Ink sheet drive mechanism for image formation device - Google Patents

Abstract

PURPOSE:To send an ink sheet adding a proper tension thereto constantly so as to obtain excellent print images by providing a friction member on a member to be driven of a drive axial core of an ink sheet cartridge and driving the drive axial core through the friction member. CONSTITUTION:A housing 99 of a cartridge 100 is fixed to a cartridge holder such that friction pads 101a and 102a abut against tip faces of sliders 113 and 118 respectively. The second slider 118 disposed in a position for sending out an ink sheet is energized by a pressing spring 119. A sliding face 118d of the slider is pressing the friction pad 102a of the cartridge 100. As the slider 118 is unrotatable, a slip occurs between the sliding face 118d and the friction pad 102a, so that a winding core 102 for sending out the ink sheet can rotate by giving a predetermined back tension to the ink sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ink sheet drive mechanism in an image forming apparatus using an ink sheet held by a cartridge.

[Prior art] Conventionally, plural, for example, Y (yellow), M (magenta)
, C (cyan) ink sheets arranged sequentially at equal intervals, using an ink sheet cartridge configured to wind up an ink sheet from one core to the other. 2. Description of the Related Art An image forming apparatus is known in which a color image is formed by pressing an image forming means against a sheet through the ink sheet to superimpose images of three colors on one recording sheet.

In such an image forming apparatus, an ink sheet and a recording sheet are pressed against a platen roller by a thermal head, and the platen roller is driven to feed the ink sheet along with the recording sheet. Therefore, if the ink sheet becomes loose,
There is a risk that this may wrap around rollers located around the paper, causing paper feeding failures, or may be printed in a wrinkled state, and the wrinkles may appear on the screen, causing deterioration in image quality. For this reason, it is necessary to always maintain a predetermined tension on the ink sheet. Therefore, when winding up an ink sheet, the winding core on the winding side of the ink sheet rotates at a slightly higher speed than the feeding speed of the ink sheet by the platen roller, while maintaining a predetermined tension on the ink sheet. It is necessary to maintain the driving torque, and the core on the feeding side of the ink sheet requires friction torque in the direction opposite to the direction of rotation in which the ink sheet is fed out.

For this purpose, conventionally, a friction plate is sandwiched between the input shaft and the output shaft, and when the load torque on the output side exceeds a certain level, the friction plate starts to slide, and the torque limiter that controls torque transmission and rotation speed is activated by the ink sheet. It is used on both the winding side and the sending side.

Torque limiters configured as described above are provided on the ink sheet winding side and the feeding side of the image forming apparatus main body, and the ink sheet winding motor is connected to the input shaft on the winding side, while the ink sheet winding motor is connected to the input shaft on the winding side. The input shaft on the side is fixed so that it cannot rotate.

When the ink sheet cartridge is installed in the image forming apparatus, the output shafts of both torque limiters are fitted into the fitting portions of the ink sheet cartridge, respectively.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional apparatus, it is necessary to provide torque limiters on the winding side and the sending side, respectively, in order to give tension to the ink sheet in the main body of the image forming apparatus. A fitting mechanism between the ink sheet cartridge and the torque limiter is also required on the ink sheet cartridge side. This type of fitting mechanism tends to vary from cartridge to cartridge, and as a result, insufficient fitting or incorrect fitting may cause problems such as the ink sheet not being wound up on the ink sheet winding side, and the ink sheet may not be fed properly. On the side, there are problems such as not being able to obtain the necessary friction torque or generating more friction torque than necessary.
There is a problem in moving the ink sheet. Furthermore, the conventional apparatus requires complicated mechanisms on both the image forming apparatus main body and the ink sheet cartridge, leading to an increase in the number of parts, which leads to an increase in cost, and also increases the failure rate.

The present invention was made in order to solve the above-mentioned problems in conventional image forming apparatuses, and does not require any complicated mechanism on either the ink sheet cartridge side or the image forming apparatus main body side. It is an object of the present invention to provide an ink sheet drive mechanism for an image forming apparatus that can always feed an ink sheet with appropriate tension applied thereto, thereby obtaining a good printed image.

[Means for Solving the Problems] An ink sheet drive mechanism according to one aspect of the present invention includes an ink cartridge having an ink sheet stretched between two shafts, and an ink sheet driven from one shaft to the other shaft. It is used in an image recording apparatus that has a printing means that records on a recording sheet that is brought into close contact with the ink sheet while winding up an ink sheet, and a driving means that drives a driving side axis and a driven side on the device main body side. A braking means for applying a braking force to the shaft core is provided, a friction member is provided on the drive side shaft driven member of the ink sheet cartridge, and the drive side shaft is driven via the friction member. .

An ink sheet drive mechanism according to another aspect of the present invention includes two
An ink cartridge having an ink sheet stretched between the cores of a book, and a printing device that records on a recording sheet that is brought into close contact with the ink sheet while winding the ink sheet from one core to the other core. used in an image recording apparatus having an ink sheet cartridge, a driving means for driving a driving side shaft core and a braking means for applying a braking force to a driven side shaft core are provided on the main body side of the apparatus, and a driving means for applying a braking force to a driven side shaft core of the ink sheet cartridge is provided. A friction member is provided, and the friction member applies a braking force to the driven shaft.

[Function] According to the drive mechanism of the above-mentioned aspect, when printing is started with the cartridge loaded in the apparatus main body as described above, the driving force of the driving means provided on the apparatus main body side is applied to the ink. The torque is transmitted to the sheet cartridge via a friction member, and the ink sheet winding side axis of the ink sheet cartridge is rotated while maintaining a constant torque to apply a predetermined tension to the ink sheet. Additionally, when the ink sheet is wound up and the feed-out shaft rotates, the braking means provided in the main body of the device generates frictional torque on this shaft that attempts to prevent rotation, and the ink sheet is kept under a predetermined pack tension. will be granted.

According to the drive mechanism of the above-mentioned aspect, when printing is started with the cartridge loaded in the apparatus main body as described above, the driving force of the drive means provided on the apparatus main body side is applied to the ink sheet cartridge. The ink sheet winding side axis of the ink sheet cartridge is rotated while maintaining a constant torque to apply a predetermined tension to the ink sheet. Furthermore, when the ink sheet is wound up and the feed-out shaft rotates, the braking means provided in the main body of the apparatus tries to prevent the rotation of the 20-axis center via the friction member provided on the cartridge side. Frictional torque is generated and a predetermined pack tension is applied to the ink sheet.

[Example] Hereinafter, an ink sheet drive mechanism related to the implementation of the present invention will be described.
This will be explained together with an image forming apparatus equipped with this. FIG. 1A is an external view of an image forming apparatus to which an embodiment of the ink sheet drive mechanism of the image forming apparatus according to the present invention is applied.
1a is an operation panel, 1b is a front door, 200 is a paper feed cassette unit, and 300 is a paper feed cassette unit.
indicate the paper output trays, respectively. FIG. 1B shows a state in which the front door 1b is opened and the paper feed cassette section unit 200 and the paper discharge tray 300 are taken out.

FIG. 2 is a diagram showing a schematic configuration of an image forming apparatus according to the present invention, in which reference numeral 2 is a platen roller;
The pinch roller is biased in the direction of the platen roller 2 by a spring (not shown), the reference numerals 5, 6, 7, and 8 are paper guides, and the numeral 9 detects the advancing position of the fed recording sheet and starts printing. Reference numeral 10 is an ink sheet sensor for positioning the ink sheet, reference numeral 11 is a paper ejection roller, reference numeral 50 is a paper ejection pinch section unit provided so as to be able to approach and separate from the paper ejection roller, reference numeral 1 is
00 is an ink sheet cartridge configured to wind up a known ink sheet 103 made up of a plurality of ink parts of different colors arranged at equal intervals from one winding core (shaft core) to the other winding core (shaft core); Reference numeral 150 is a head unit that holds a Marsal head that forms an image by selectively generating heat on a recording sheet via an ink sheet. Reference numeral 151 is provided in the head unit 150 and serves to guide the ink sheet 103 along the platen roller. Pinch roller, code 1
Reference numeral 59 denotes a thermal head rotatable around the central axis 152; reference numeral 180 denotes a head drive shaft for raising and lowering the head unit 150 in accordance with the print sequence;
Reference numeral 50 indicates a paper feed drive unit that feeds the recording sheets in the paper feed cassette unit 200 one by one and sends them to the print unit. This unit 250 includes the paper feed roller 2
51 and the forward roller 25 located downstream of this.
2 and a reverse roller 253. Further, in the figure, reference numeral 300 is a paper output tray for storing recording sheets sent out from the print unit after the printer is finished, and reference numeral 301 is a paper output tray for storing recording sheets in the paper feed cassette unit 200 when feeding paper. The tongues are shown for lifting and bringing the topmost recording sheet into contact with the paper feed roller 251 for paper feeding.

Next, the general operation of the image forming apparatus will be explained using FIG. 2. The recording sheet placed on the paper feed cassette unit 200 is lifted by a tongue 301 that moves up and down in conjunction with the movement of the head unit 150, and the topmost recording sheet placed on the paper feed roller 251 Contact. In this state, the paper feed roller 251 rotates to feed paper, and only the uppermost recording sheet sandwiched between the forward roller 252 and the reverse roller 253 is selectively fed. The fed recording sheet passes through a pair of paper guides 7.
8, platen roller 2 and pinch roller 3.4
When the leading edge of the recording sheet is caught between the platen roller 2 and the downstream pinch roller 4 by a few millimeters, the recording sheet stops. Here, the ink sheet is slightly wound up, the head of the ink sheet is located, and the head unit 150 rises and presses the recording sheet on the platen roller 2 through the ink sheet. In this state, the platen roller 2 rotates and the recording sheet is sent downstream to start printing the first color. After printing the first color, head unit 1
50 is lowered, the platen roller 2 rotates in reverse, and the recording sheet is sent upstream and returned to the print start position. At this time, the cue for the next color on the ink sheet is simultaneously performed. By repeating this printing operation for three colors, a color image is formed on the recording sheet. After printing is completed, the head unit 150 is lowered and the ink sheet is slightly wound to take up any slack in the ink sheet. The recording sheet passes between a pair of paper guides 5 and 6, and then passes through a paper ejection roller 11.
At this point, the paper ejection bin unit 50 presses the recording sheet against the paper ejection roller 11 to sandwich it, and as the paper ejection roller 11 rotates, the paper ejection tray 300
The recording sheet is ejected.

The drive device according to the first embodiment of the present invention will be described below as a third embodiment.
This will be explained with reference to FIGS. 8 to 3E.

The ink sheet cartridge 100 shown in FIGS. 3A to 3C has a housing 99 made of synthetic resin. Inside the housing 99, ink sheet winding-side cores (driving-side cores) are arranged at a predetermined distance from each other. 101 and an ink sheet delivery side winding core (driven side axis) 102 are arranged in parallel.

These winding cores 101 and 102 have a cylindrical shape, and are located on both sides of the housing 99! The ink sheet 103 is rotatably supported between the two cores, and as a result of the rotation of both cores, the ink sheet 103 wound around the ink sheet feed-out core is moved to the ink sheet take-up core 10.
It can be wound up into two. The pivot of the winding core is such that a pin protruding from one end face of the winding core is inserted into a hole formed in one wall of the housing, and the other end of the winding core is inserted into a hole formed in one wall of the housing. This is achieved by being rotatably supported on this wall in a more exposed manner. Thin disc-shaped friction pads 101g and 102a, which are friction members, are attached to the exposed other end surfaces of both cores 101 and 102, respectively. These friction pads are made of a material having a large friction coefficient, such as rubber. In addition, in these figures, the code 100
a, IQO, and b indicate positioning holes for positioning the ink sheet cartridge when it is loaded into the main body of the image forming apparatus.

The main body of the image forming apparatus is provided with a drive mechanism as shown in FIG. 3D. This drive mechanism includes a drive frame 110 and a rear frame 111 that are located parallel to each other and are fixed to the main body of the device. This drive frame 110
the first stud 11 toward the rear frame 111.
2 are erected. The upper part of this stud 112 is inserted into a hole formed in the base end surface of the first slider 113 and extending along the axis. As a result, the slider 113 is supported by the stud 112 so as to be slidable in the axial direction and rotatable about the axis. A tip end surface (sliding surface) 113d of this slider 113 can be frictionally engaged with the friction pad 101a. In addition, an input shaft gear portion 11 is coaxially disposed at the base of the slider 113.
3b is formed. This gear portion 113b is meshed with an idler gear 114 rotatably supported by the drive frame 110. This idler gear 114
is connected to an ink sheet take-up motor 115, which is a drive source and is fixed to the drive frame 110. Thus, by driving this motor 115, the slider 11
3 is an idler gear 114 and an input shaft gear section 113
rotated via b. A slider 1 is provided between the base end surface of the slider 113 and the drive frame 110.
13 in the direction of the rear frame 111, and a pressing spring 116 is interposed to cause the distal end surface 113d of the slider 113 to protrude from an opening formed in the rear frame 111. Although not shown, a stopper is provided between the stud 112 and the slider 113 to restrict the slider to a predetermined movement position so that the slider does not jump out from the stud due to the pressure spring 116.

A second stud 117 is erected on the drive frame 110 toward the rear frame 111 and in parallel with the first stud 112 at a predetermined distance.

The upper part of this stud 117 is connected to the second slider 118.
It is inserted into a hole formed on the proximal end surface of the tube and extending along the axis.

This second slider 118 is prevented from rotating relative to the second stud 117 by a method such as keying. As a result, this slider 118 is attached to the stud 117.
axially slidably but non-rotatably supported. The tip surface (sliding surface) 11 of this slider 118
8d can be frictionally engaged with the friction pad 102a. Moreover, this slider 118 and the drive frame 11
0, the slider 118 is connected to the rear frame 111.
The tip surface 118 of the slider 118 is always biased in the direction of
A pressing spring 119 is interposed to cause the rear frame 111 to protrude from a hole formed in the rear frame 111. Tip surfaces 113 of a pair of sliders 113 and 118 provided in this drive mechanism
d and 118d are located on substantially the same plane, and the distance between them is set to be equal to the distance between the pair of friction pads 101a and 102a provided on the cartridge 100.

In the main body of the device having the drive mechanism configured as above,
When loading the cartridge 100, as shown in FIG. 3E, the housing 99 of the cartridge 100 is inserted into the cartridge (not shown) so that the friction pads 101a, 102g and the front end surfaces of the sliders 113, 118 are in contact with each other, respectively. Fix it to the holding part. At this time, the slider 11 is caused by both friction pads 101a and 102a that are in contact with each other.
3.118 slides slightly against the biasing forces of springs 116 and 119, and as a result, frictional engagement occurs due to the biasing forces of springs 116 and 119. When the ink sheet take-up motor 115 is driven in this state, its driving torque is transmitted to the first slider 113 via the idler gear 114, and due to the urging force of the pressing spring 116, the drive torque is transmitted to the first slider 113 via the friction pad 101a of the cartridge 100. Then, the ink sheet winding-side winding core 101 is rotated to apply a predetermined tension to the ink sheet, and the ink sheet feeding-side winding core 102 is rotated to wind up the ink sheet. At this time, the second slider 118 located on the ink sheet feeding side
is urged by a pressing spring 119, and this sliding surface 118d
is pressing the friction pad 102a of the cartridge 100, or because the slider 118 cannot rotate, slipping occurs between the sliding surface 118d and the friction pad 102a, and the rotation of the ink sheet delivery side winding core 102 prevents the ink sheet from rotating. This is possible while applying a predetermined pack tension.

As described above, in the drive mechanism of this embodiment, it is only necessary to load the ink sheet cartridge so that its friction butt comes into contact with the sliding surface of the drive mechanism, making the operation easy.

When the ink sheet is transported, a predetermined back tension is applied to the ink sheet so that the ink sheet does not become loose. Further, these structures are extremely simple and require only a small number of parts.

Next, other embodiments will be sequentially described with reference to the corresponding drawings. In these embodiments, members that are substantially the same as those in the first embodiment are denoted by the same reference numerals, and explanations thereof will be omitted.

In the second embodiment, the ink sheet cartridge 10
0, as shown in FIG. 4A, between one wall of the I\Using 99 and one end surface of the winding core 101, 102, there is a slide provided on the other end of the winding core. Moving surface 101d
, 102d is provided with a pressing spring 100C. Further, the winding cores 101 and 102 are rotatably supported by the nozzing 99, and unlike the previous embodiment, they are supported so as to be slidable in the axial direction. As a result, the winding core is elastically supported by the pressing spring 100C, and the sliding surface 101d.

102d is the friction pad 1 on the drive mechanism side shown in FIG. 4B.
13a, 118a, the pressing spring]00c
is adapted to push the friction pad with a predetermined urging force, for example, 30 gf. As shown in FIG. 4B, the drive mechanism does not include a pressure spring on either the take-up side or the delivery side. That is, the slider 113 provided with the friction pad 113a on the winding side is supported by the stud 112 so as not to be able to move in the axial direction. On the other hand, the friction 41 on the sending side
Hat 118a is directly fixed to rear frame 111.

In such a drive mechanism, as in the above embodiment,
With the cartridge as a drive mechanism, each sliding surface 101d
, 102d and friction pads 113a and 118a, and by driving the motor 115, the ink sheet can be wound up with pack tension applied. In this embodiment, the pressing spring 100C provided on the cartridge side not only achieves the frictional engagement between the friction pads but also controls the thrust of the winding core inside the cartridge.

In the third embodiment, the ink sheet cartridge 10
As shown in FIG. 5A, the winding core 101 on the winding side of the winding cores 101 and 102 rotatably supported by the housing 99 is provided with a pressing spring 100C that biases the winding core 101, as shown in FIG. 5A.
Further, the winding core 102 on the feeding side is not provided with a pressing spring.

A friction pad 1 is provided on one end surface of the winding core 102 on the feeding side.
02g is installed. A cross-shaped engagement groove 101C is formed on one end surface of the winding core 101 on the winding side. As shown in FIG. 5B, the drive mechanism has a configuration similar to that of the first embodiment on the sending side. - A torque limiter 134 is provided on the 10,000-winding side. The torque limiter 134 houses a pair of friction pads that come into contact with each other to generate friction torque, and a pressure spring that biases the friction pads in a direction in which they come into contact with each other, and is rotatably supported on the stud 112. It has a rotating body 135. This rotating body 1
An input gear portion 135a is coaxially formed on the outer periphery of the input gear 35. This gear portion 135a is meshed with an idler gear 114 rotated by a motor 115. A cross-shaped output shaft hook 136 that can be engaged with the engagement groove 101c formed in the winding core 101 is provided on the distal end surface of the rotating body 135. In the torque limiter having such a configuration, drive torque is inputted from the input gear section 135a via the idler gear 114 by the winding motor 115, and the torque is applied to a pair of friction pads that are brought into contact with each other by the urging force of a pressing spring. Output shaft hook 13 through
6. The output shaft hook 136 rotates the ink sheet take-up side winding core 101 engaged with it.

In the fourth embodiment, the ink sheet cartridge 10
As shown in FIG. 6A, pressure springs 100C are provided to bias winding cores 101 and 102 rotatably supported by the housing 99, respectively. One end surface of the winding core 102 on the feeding side is a sliding surface 102b. A cross-shaped engagement groove 1010 is formed in one end surface of the winding core 101 on the winding side. The drive mechanism, as shown in FIG. 6B,
The delivery side portion has the same structure as the second embodiment. - A torque limiter 134 is provided on the 10,000-winding side.

In the third and fourth embodiments described above, the connection between the winding core and the slider through the friction knot, which is the technical idea of the present invention, is achieved only on the feeding side, and the connection between the winding core and the slider through the friction knot is achieved on the winding side, and the connection is achieved by engagement on the winding side. The connection between the winding core and the slider has been achieved. As described above, even if the friction pad (friction member) of the present invention is provided only on the delivery side, there is a practical effect.

[Effect] With the above configuration, it is possible to apply a predetermined tension to the ink sheet without requiring any complicated mechanism on either the ink sheet cartridge side or the image forming apparatus side. It is possible to provide an image forming apparatus having an ink sheet drive mechanism with fewer problems and failures, since the friction member is pressed and separated by the operations of loading and pulling out the ink sheet cartridge.

[Brief explanation of the drawing]

1A and 1B are perspective views showing an image forming apparatus using the ink sheet drive mechanism of the present invention in different states, FIG. 2 is a sectional view of the image forming apparatus, and FIGS. 3A to 3E. 3A is a top view of the ink sheet cartridge, FIG. 3B is a partially cutaway front view of the same, and FIG. 3C is for explaining the drive mechanism of the first embodiment.
FIG. 3D is a side view of the drive mechanism, FIG. 3E is a side view showing the cartridge loaded in the drive mechanism, and FIGS. 4A and 4B are the drive mechanism of the second embodiment. 4A is a partially cutaway front view of the ink sheet cartridge, FIG. 4B is a side view of the drive mechanism, and FIGS. 5A and 5B are views of the third embodiment. This is for explaining the drive mechanism, and FIG. 5A is a partially cutaway front view of the ink sheet cartridge;
FIG. 5B is a side view of the drive mechanism, FIGS. 6A and 6B are for explaining the drive mechanism of the fourth embodiment, and FIG. 6A is a partially cutaway view of the ink sheet cartridge. The front view and FIG. 6B are side views of the drive mechanism. 100... Ink ribbon cassette, 101... Winding side winding core, 102... Sending side winding core, 101a, 102a... Friction pad (friction member)
, 113.118...Slider, 115...Motor. Applicant's agent Patent attorney Atsushi Tsuboi 18' Sotobahanru 200 years old ~ Nohito, Toban P unit 300: flF #VFn4 IIS1A Ward 118 Ward 99 l\tsu/n7 No. 38 Figure 11.3C Figure 3D Section f115 @3E Figure 101d, 102d: ↑Fu★force surface 100c: QL/ F1,7 *5A section JR5B figure 1fI6 8th section JfS68m

Claims (1)

[Scope of Claims] An ink cartridge having an ink sheet stretched between one or two shaft cores, and an ink cartridge that is tightly attached to the ink sheet while winding the ink sheet from one shaft core to the other shaft core. The image recording apparatus is used in an image recording apparatus having a printing means for recording on a recording sheet, and the apparatus main body is provided with a driving means for driving a driving side shaft and a braking means for applying a braking force to a driven side shaft. An ink sheet drive mechanism for an image forming apparatus, characterized in that a friction member is provided on a driven member of the drive side axis of an ink sheet cartridge, and the drive side axis is driven via the friction member. 2. The ink sheet drive mechanism for an image forming apparatus according to claim 1, further comprising means provided on the ink cartridge side for pressing the drive side axis against a drive means provided on the apparatus main body side. 3. An ink cartridge having an ink sheet stretched between two shaft cores, and recording on a recording sheet that is brought into close contact with the ink sheet while winding the ink sheet from one shaft core to the other shaft core. The apparatus is used in an image recording apparatus having a printing means for printing, and a driving means for driving a driving side shaft core and a braking means for applying a braking force to a driven side shaft core are provided on the main body side of the apparatus, and the driven side of the ink sheet cartridge is An ink sheet drive mechanism for an image forming apparatus, characterized in that a friction member is provided on the shaft core, and the friction member applies a braking force to the driven shaft core. 4. The ink sheet drive mechanism for an image forming apparatus according to claim 3, further comprising means provided on the ink sheet cartridge side for pressing the driven shaft against a braking means provided on the apparatus main body side.