JP2004243703A - Platen gap adjuster and recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a platen gap adjuster and a recorder capable of avoiding such a case that a sheet is rubbed and contaminated immediately after jamming or printing while preventing an ink ribbon from touching the sheet when a platen gap is adjusted. <P>SOLUTION: The recording head 18 of the recorder is provided, on the upstream side in the sheet carrying direction (shown by an arrow X) of the impacting area 18AR of a recording wire in the recording head 18, with a protrusion 30 abutting against a platen 21 or a sheet when the recording head 18 moves to the platen 21 side. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a platen gap adjustment device that adjusts a platen gap between a recording head and a platen, and a recording device including the device.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there has been known a dot impact printer in which a recording wire is ejected from a recording head, and the ejected recording wire is brought into contact with a sheet via an ink ribbon to record an image such as a character.
[0003]
In this type of dot impact printer, the recording head is moved and brought into contact with a platen or a sheet, and the distance to the platen surface or the distance to the sheet surface is measured based on the amount of movement of the recording head at that time. Some include a platen gap adjustment mechanism that adjusts a platen gap between a recording head and a platen in accordance with the difference in the distance (for example, see Patent Document 1).
[0004]
[Patent Document 1]
JP-A-10-52963 [0005]
[Problems to be solved by the invention]
By the way, in a dot impact printer equipped with a platen gap adjusting mechanism as described above, when the recording head is brought into contact with the sheet, it is necessary to prevent the ink ribbon from contacting the sheet and the sheet from being stained. There is a method in which a ribbon mask is provided which has an opening for exposing only an ink ribbon in a region facing a region where a recording wire of a recording head is to be ejected (hereinafter referred to as a recording region), and masks an ink ribbon in other regions. Have been.
[0006]
However, since the ribbon mask is formed of a thin plate, there is a problem that if the end of the sheet is floating, the sheet is caught in the opening and breaks the sheet to cause a paper jam.
[0007]
When a ribbon mask is not used, the sheet guide provided on the recording head side is disposed on the platen side of the recording head, thereby avoiding the ink ribbon disposed in front of the recording head from abutting on the sheet. In addition, the sheet is prevented from being stained when the platen gap is adjusted.
[0008]
However, since the distance between the sheet guide and the sheet is reduced, the sheet immediately after printing may be rubbed by the sheet guide, and there is a problem that printing stains occur.
[0009]
Therefore, an object of the present invention is to solve the above-described problems of the conventional technology, and to prevent the ink ribbon from contacting the sheet at the time of adjusting the platen gap, and rub the sheet immediately after printing with a paper jam. It is an object of the present invention to provide a platen gap adjusting device capable of avoiding such a case and a recording device having the platen gap adjusting mechanism.
[0010]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention according to claim 1 moves a recording head, contacts the recording head with a platen or a sheet, and determines a distance to a platen surface by a moving amount of the recording head at that time. Alternatively, in a platen gap adjusting device that measures a distance to a sheet surface and adjusts a platen gap between a recording head and a platen according to a difference between the measured distances, a recording ejected from the recording head on the recording head side. A projection is provided on the upstream side of the wire ejection area in the sheet conveyance direction when the recording head is moved to the platen side so as to come into contact with the platen or the sheet.
[0011]
Further, according to a second aspect of the present invention, in the configuration according to the first aspect, an ink ribbon is disposed between the recording head and the platen, and the protrusion is more than the ink ribbon. It is characterized in that it protrudes toward the platen and is provided upstream of the ink ribbon in the sheet conveying direction.
[0012]
According to a third aspect of the present invention, in the configuration of the first or second aspect, a sheet guide for guiding a sheet conveyed between the recording head and the platen is provided on the recording head side. The projection is projected to the platen side from a platen facing surface of the sheet guide.
[0013]
According to a fourth aspect of the present invention, in the configuration according to any one of the first to third aspects, the protrusion is formed integrally with a frame of the recording head.
[0014]
According to a fifth aspect of the present invention, in a recording apparatus for recording an image on a sheet conveyed between a recording head and a platen, the recording head is moved to apply the recording head to the platen or the sheet. The distance to the platen surface or the distance to the sheet surface is measured based on the amount of movement of the recording head at that time, and the platen gap between the recording head and the platen is adjusted according to the difference between the measured distances. A platen gap adjusting means that adjusts the position of the platen when the recording head is moved to the platen side in the sheet conveying direction more upstream than the ejection area of the recording wire ejected from the recording head. Alternatively, a projection is provided to abut the sheet.
[0015]
According to a sixth aspect of the present invention, in the configuration according to the fifth aspect, an ink ribbon is disposed between the recording head and the platen, and the protrusion is more than the ink ribbon. It is characterized in that it protrudes toward the platen and is provided upstream of the ink ribbon in the sheet conveying direction.
[0016]
According to a seventh aspect of the present invention, in the configuration of the fifth or sixth aspect, a sheet guide for guiding a sheet conveyed between the recording head and the platen is provided on the recording head side. The projection is projected to the platen side from a platen facing surface of the sheet guide.
[0017]
According to an eighth aspect of the present invention, in the configuration according to any one of the fifth to seventh aspects, the protrusion is formed integrally with a frame of the recording head.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0019]
FIG. 1 is a perspective view showing a state in which an outer cover of a dot impact printer 10 according to an embodiment of the recording apparatus of the present invention is removed, and FIG. 2 is a side sectional view of the printer 10.
[0020]
The printer 10 records dots by hitting a large number of recording wires included in the recording head 18 onto a sheet via an ink ribbon, thereby recording an image including characters. As described above, since the image is recorded by hitting the recording wire, the printer 10 can be used not only for a single sheet such as a cut sheet, a continuous sheet, a postcard, and a cut film, but also for a cut sheet, a continuous copy sheet, It is also possible to record images on copy paper such as.
[0021]
This dot impact printer 10 includes a printer main body 11, a push tractor unit 12, a discharge unit 13, and a paper feeding device 34 (simply shown in FIG. 2).
[0022]
The push tractor unit 12 feeds a continuous sheet (continuous paper, continuous copy paper, etc.) among the sheets usable for the printer 10 to the sheet transport mechanism 23. That is, the push tractor unit 12 conveys the continuous sheet in the direction of the arrow α by the action of the pin 27 of the tractor belt 26 by rotation of the tractor belt 26, and sends it out to the sheet guide 22.
[0023]
Further, the paper feeding device 34 feeds the cut sheets (cut sheets, cut sheet copy paper, etc.) cut to a predetermined length one by one to the sheet conveying mechanism unit 23. That is, the sheet feeding device 34 sends out the cut sheets one by one (or one by one) in the direction of the arrow β to the sheet guide 22.
[0024]
The discharge unit 13 converts the sheet (continuous sheet or cut sheet) fed from the push tractor unit 12 and the sheet feeding device 34 and conveyed between the sheet guide 22 and the platen 21 by rotation of a discharge roller 29. Pull out in the direction of arrow γ.
[0025]
In the printer 10, a bottom sheet supply port 32 is formed below the platen 21, and the continuous sheet can be conveyed between the recording head 18 and the platen 21 from the bottom sheet supply port 32.
[0026]
Next, the printer body 11 will be described.
[0027]
As shown in FIGS. 1 and 2, the printer main body 11 has a base frame 14, a sheet guide frame 15, a left side frame 16 and a right side frame 17, and a print head 18 and a carriage 19 provided on these frames. The mechanism unit 20 is supported by a sheet transport mechanism unit 23 including a platen 21, a sheet guide 22, and a pinch roller 25 (see FIG. 2).
[0028]
The carriage 19 is slidably inserted into a carriage guide shaft 24 rotatably bridged between the left side frame 16 and the right side frame 17, and is rotated by a carriage driving motor (not shown) to rotate the timing belt. Reciprocating in the main scanning direction (the direction of arrow A or the direction of arrow B shown in FIG. 1) which coincides with the axial direction of the carriage guide shaft 24 via 31 (see FIG. 2).
[0029]
The recording head 18 is mounted on a carriage 19, moves in the main scanning direction together with the carriage 19, and rotatably supports a number of recording wires (not shown) between the left side frame 16 and the right side frame 17. Into the platen 21. An ink ribbon 39 from an ink ribbon cassette 38 (indicated by a two-dot chain line in FIGS. 1 and 2) is wound between the recording head 18 and the platen 21, thereby being ejected from the recording head 18. The recording wire contacts the sheet conveyed to the platen 21 via the ink ribbon 39, causes the ink of the ink ribbon 39 to adhere to the sheet, and records an image including characters.
[0030]
FIG. 3 is a side view showing the recording head 18 together with peripheral components, FIG. 4 is a perspective view of FIG. 3, and FIG. 5 is a perspective view of the recording head 18. As shown in FIGS. 3 and 4, the recording head 18 protrudes toward the platen 21 below the ejection area 18AR where the recording head 18 projects the recording wire 18W (see FIG. 4) and approaches the platen 21. The contact projection 30 is provided. More specifically, as shown in FIG. 5, the contact projection 30 is formed integrally with a head nose 18A which is a frame on the platen 21 side of the recording head 18, and as shown in FIG. The distance between the contact projection 30 and the platen 21 is provided on the upstream side of the ink ribbon 39 in the sheet conveyance direction (the direction of the arrow X), and the distance between the surface 18AR1 of the ejection area 18AR and the platen 21 (And the distance between the ink ribbon 39 and the platen 21). The contact projection 30 is formed with a gentle slope on the upstream side in the sheet conveying direction (the direction of the arrow X) in order to prevent the sheet conveyed in the direction of the arrow X from being caught. In FIG. 3, reference numeral 35 denotes an auxiliary plate that functions as a plate spring for pressing the sheet against the platen 21.
[0031]
As shown in FIGS. 3 and 4, a sheet guide 40 fixed to the carriage 19 is disposed on the front side (the platen 21 side) of the recording head 18.
[0032]
As shown in FIGS. 3 and 4, the sheet guide 40 guides the sheet conveyed between the recording head 18 and the platen 21 along the platen surface. Is formed in a bent shape so as to guide the sheet toward the platen 21 side. The sheet guide 40 is provided with an opening 41 at a position corresponding to the ejection area 18AR of the recording head 18 so that the recording wire 18W ejected from the recording head 18 can pass through the ink ribbon 39 via the ink ribbon 39. The seat can be abutted.
[0033]
Further, as shown in FIG. 3, in the present embodiment, the platen facing surface 42 of the sheet guide 40 is disposed behind the surface 18AR1 of the ejection area 18AR of the recording head 18, whereby the recording head 18 Even when the distance between the platen 21 is small, a sufficient distance between the sheet guide 40 and the platen 21 can be ensured.
[0034]
Further, in the printer 10, a sheet thickness of the supplied sheet (cut sheet or continuous sheet) is measured, and a platen gap between the recording head 18 and the platen 21 is adjusted according to the sheet thickness. A mechanism 100 is provided. Here, FIG. 6 is a diagram showing the platen gap adjustment mechanism 100 together with peripheral components.
[0035]
In the platen gap adjustment mechanism 100, a gear 105 fixed to the carriage guide shaft 43 is rotated via a reduction gear 104 by rotation of a motor pinion 103 provided on a rotation shaft of the platen gap adjustment motor 101. An eccentric shaft 107 is fixed to the carriage guide shaft 43, and the carriage 19 is inserted through the eccentric shaft 107. As a result, when the eccentric shaft 107 is rotated by the forward or reverse rotation of the platen gap adjusting motor 101, the carriage 19 is moved by an amount corresponding to the amount of eccentricity of the eccentric shaft 107 on the side of the platen 21 in the arrow δ direction in the drawing or on the opposite side. Side, and the distance (platen gap) between the recording head 18 and the platen 21 is changed. Here, in the present embodiment, since the recording head 18 is provided with the contact protrusion 30, when the recording head 18 is moved to the platen 21 side, the contact protrusion 30 is moved to the platen 21 or the platen 21. It comes into contact with the seat.
[0036]
The reference position detector 108 is a microswitch that is turned on when the recording head 18 is at the reference position, which is the maximum retreat position where a sheet having the maximum thickness can be loaded. Thus, the range of movement of the carriage 19 is restricted from the position where the contact protrusion 30 of the recording head 18 contacts the platen 21 to the above-described reference position.
[0037]
The rotary encoder 102 includes a slit plate 110 fixed to the rotation shaft of the motor 101 for adjusting the platen gap, and a light emitting and receiving device 111 in which a light emitting diode and a photodiode are arranged to face each other with the slit plate 110 interposed therebetween. You. Thus, when the motor 101 for adjusting the platen gap rotates, the rotary encoder 102 intermittently interrupts the optical path from the light emitting diode to the photodiode by the slit plate 110, and outputs a pulse signal.
[0038]
The platen gap adjustment mechanism 100 is controlled by the control board unit 95. In other words, the control board unit 95 drives the platen gap adjusting motor 101 to move the recording head 18 from the reference position to the position where the contact protrusion 30 contacts the platen 21, and the pulse from the rotary encoder 102 at this time. The pulse number of the signal is counted, and then the sheet is conveyed between the recording head 18 and the platen 21, and the platen gap adjusting motor 101 is driven to move the recording head 18 from the reference position so that the contact projection 30 is moved. It moves to a position where it contacts the platen 21 and counts the number of pulses of the pulse signal from the rotary encoder 102 at this time. Next, the control board unit 95 calculates the sheet thickness from the difference between these two count values, and adjusts the platen gap by driving the platen gap adjusting motor 101 based on the sheet thickness. Note that this platen gap adjustment processing is performed for each cut sheet, and for a continuous sheet once or at intervals.
[0039]
As described above, in the printer 10 of the present embodiment, the contact projection 30 is provided on the recording head 18, and when the recording head 18 is moved to the platen 21 by the platen gap adjustment mechanism 100, the contact projection 30 is provided. By making the projection 30 contact the platen 21 or the sheet, it is possible to prevent the ink ribbon 39 from contacting the sheet when adjusting the platen gap.
[0040]
Further, the printer 10 of the present embodiment does not need to use a ribbon mask in order to prevent the ink ribbon 39 from contacting the sheet at the contact protrusion 30. The platen facing surface 42 of the sheet guide 40 can be retracted from the surface 18AR1 of the ejection area 18AR of the recording head 18 (see FIG. 3). For this reason, it is possible to avoid a case where the sheet is caught by the ribbon mask and causes a paper jam. Also, in a conventional printer that does not use a ribbon mask, the sheet guide is arranged on the platen side of the recording head in order to avoid the ink ribbon from contacting the sheet. However, as described above, the printer 10 according to the present embodiment can sufficiently secure the space between the sheet guide 40 and the platen 21, so that the sheet guide 40 rubs the sheet immediately after printing to make it dirty. Can be avoided.
[0041]
Further, in the printer 10 of the present embodiment, since the contact protrusion 30 is provided on the upstream side in the sheet conveyance direction with respect to the ejection area 18AR of the recording head 18, the contact protrusion 30 is provided immediately after printing. In addition, the abutting projection 30 can regulate the sheet entry path so that the end of the sheet does not contact the ink ribbon 39.
[0042]
Furthermore, in the printer 10 of the present embodiment, the contact projection 30 is formed integrally with the frame (head nose 18A) of the recording head 18, so that the contact projection 30 is retrofitted. The work of assembling the recording head 18 can be simplified.
[0043]
The invention of the present application is not limited to the embodiment described above, and can be implemented in various modes. Therefore, a modified example will be described below.
[0044]
In the above-described embodiment, the case where the contact protrusion 30 is provided on the frame of the recording head 18 has been described. However, the contact protrusion 30 may be provided on the sheet guide 40 or the carriage 19. In short, the contact protrusion 30 may be provided on the recording head 18 side. In the case where the contact protrusion is provided on the sheet guide, for example, as shown in a perspective view in FIG. 7 and a side view in FIG. 8, the contact protrusion 30A is provided upstream of the ejection area 18AR of the recording head 18 in the sheet conveyance direction. It may be provided on the left and right of the opening 41 of the sheet guide 40 within the range provided on the side.
[0045]
In the above-described embodiment, the case where the present invention is applied to a printer that does not use a ribbon mask has been described. However, a printer that uses a ribbon mask is not excluded. When the present invention is applied to a printer using a ribbon mask, the contact projection 30 may be provided on the ribbon mask. Even if a ribbon mask is used, the advancing path of the sheet can be regulated by the contact projection 30, so that it is possible to prevent the sheet from being caught by the ribbon mask and causing a paper jam.
[0046]
【The invention's effect】
As described above, according to the present invention, it is possible to prevent the ink ribbon from coming into contact with the sheet at the time of adjusting the platen gap, and it is possible to avoid a paper jam or a case where the sheet immediately after printing is rubbed and soiled.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a dot impact printer according to an embodiment of the present invention with an outer cover removed.
FIG. 2 is a side sectional view of the printer.
FIG. 3 is a side view showing a recording head of the printer together with peripheral components.
FIG. 4 is a perspective view showing a recording head of the printer together with peripheral components.
FIG. 5 is a perspective view of a recording head of the printer.
FIG. 6 is a diagram showing a platen gap adjusting mechanism of the printer together with peripheral components.
FIG. 7 is a perspective view showing a recording head according to a modification together with peripheral components.
FIG. 8 is a side view showing a recording head according to a modification together with peripheral components.
[Explanation of symbols]
Reference Signs List 10 Dot impact printer 11 Printer main body 18 Recording head 18A Head nose 19 Carriage 21 Platen 35 Auxiliary plate 38 Ink ribbon cassette 39 Ink ribbon 40 Sheet guide 95 Control board unit 100 Platen gap adjustment mechanism

Claims (8)

Move the recording head to bring the recording head into contact with the platen or sheet, and measure the distance to the platen surface or the distance to the sheet surface based on the amount of movement of the recording head at that time. In a platen gap adjustment device that adjusts the platen gap between the recording head and the platen in accordance with
On the recording head side, a projection that comes into contact with the platen or the sheet when the recording head is moved to the platen side is provided on the upstream side in the sheet conveyance direction from the ejection area of the recording wire ejected from the recording head. A platen gap adjusting device. An ink ribbon is arranged between the recording head and the platen,
The platen gap adjusting device according to claim 1, wherein the protrusion protrudes toward the platen from the ink ribbon, and is provided upstream of the ink ribbon in a sheet conveying direction. On the recording head side, a sheet guide for guiding a sheet conveyed between the recording head and the platen is provided,
The platen gap adjusting device according to claim 1, wherein the protrusion protrudes toward the platen from a platen facing surface of the sheet guide. 4. The platen gap adjusting device according to claim 1, wherein the projection is formed integrally with a frame of the recording head. In a recording apparatus that records an image on a sheet conveyed between a recording head and a platen,
By moving the recording head, the recording head is brought into contact with the platen or sheet, and the distance to the platen surface or the distance to the sheet surface is measured based on the amount of movement of the recording head at that time. Platen gap adjusting means for adjusting a platen gap between the recording head and the platen according to the difference,
On the recording head side, a projection that comes into contact with the platen or the sheet when the recording head is moved to the platen side is provided on the upstream side in the sheet conveyance direction from the ejection area of the recording wire ejected from the recording head. A recording device, characterized in that: An ink ribbon is arranged between the recording head and the platen,
6. The recording apparatus according to claim 5, wherein the protrusion protrudes toward the platen from the ink ribbon, and is provided upstream of the ink ribbon in a sheet conveying direction. On the recording head side, a sheet guide for guiding a sheet conveyed between the recording head and the platen is provided,
The recording apparatus according to claim 5, wherein the protrusion protrudes toward the platen with respect to a platen facing surface of the sheet guide. The recording apparatus according to claim 5, wherein the protrusion is formed integrally with a frame of the recording head.

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