JP2006150698A - Thermal printing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To constitute a thermal printing device which can record a desired high grade image by solving the problem resulting from foreign matter adhered to the recording surface of a heat-sensitive recording paper. <P>SOLUTION: A cleaning section equipped with a cleaning roller 4 having tackiness on the surface is provided on the upstream side of an image deleting section which deletes an image on the paper by pressing a heat roller 3 to the recorded surface of the heat-sensitive recording paper which is carried on a paper carrying path, and an image recording section which press-bonds a thermal head 1 to the recording surface of the paper, and at the same time, records the image by heating by the thermal head 1. Then, the paper is made to pass through a space between the cleaning roller 4 and a platen roller 12 facing the cleaning roller 4. Thus, foreign matter such as dust and dirt on the recording surface of the paper are removed by the cleaning roller 4. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a thermal printing apparatus that performs image recording control on a sheet using a thermal recording material.

Many proposals have been made for thermal printers that record images by bringing a thermal head into contact with a thermal recording material. Also, a certain type of thermal printer, for example, a so-called rewritable printing apparatus that performs image recording using a color-forming reversible thermosensitive recording material (for example, see Patent Document 1) using a leuco dye and a reversible developer. In addition to performing image recording with a thermal head, the image can be erased using a heat roller (see, for example, Patent Document 2).
JP 2004-106308 A JP 2002-331697 A

  However, in a thermal printing apparatus in which an image is recorded by a thermal head using a thermal recording sheet that records an image by such a thermal action, the thermal head contacts the sheet and the heat of the thermal head is transferred to the sheet. Since heat is transferred directly to the heat-sensitive recording surface, if foreign matter such as dust adheres to the recording surface of the paper, heat transfer to the recording surface of the paper will not be normal, and normal images will be recorded. There was a problem that it was not performed (because of poor printing).

  In particular, in the so-called rewritable printing apparatus, the reversible thermosensitive recording paper is repeatedly used several hundred times, so that the recording surface is contaminated with dust and oil with the use, and the above-mentioned problem becomes remarkable. . In addition, such a rewritable printing apparatus requires an image erasing process in which an image on the paper is erased by heating the reversible thermosensitive recording paper and then gradually cooling it. In this image erasing process, a heat roller heated to a predetermined temperature is pressed against the recording surface of the paper and heat is directly transferred to the recording surface of the paper. At this time, foreign matter such as dust is present on the recording surface of the paper. If adhered, normal heat transfer is not performed only on that portion, and an image erasing defect (image remains unerased) occurs. As a result, there is a problem that a high-quality formed image cannot be obtained.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a thermal printing apparatus capable of solving the above-described problems and recording a desired high-quality image.

  (1) A thermal printing apparatus according to the present invention includes a sheet conveyance path for conveying a thermal recording sheet for recording an image by a thermal action, and a thermal head for the recording surface of the thermal recording sheet conveyed on the sheet conveyance path. And an image recording unit for recording an image by heating a thermal head, and a cleaning roller having an adhesive surface on the surface and rotating while contacting the recording surface of the thermal recording sheet during conveyance of the sheet The cleaning unit is arranged upstream of the image recording unit.

  (2) The heat-sensitive recording paper is a reversible heat-sensitive recording paper that enables recording and erasing of an image by a thermal action, and a heat roller with respect to the recording surface of the heat-sensitive recording paper conveyed on the paper conveyance path And an image erasing unit for erasing an image on the paper by gradual cooling after the heating, and the cleaning unit is provided on the paper conveying path. It is characterized by being arranged on the upstream side.

  (1) During conveyance of the paper in the paper conveyance path, the cleaning roller comes into contact with the recording surface and rotates, so that foreign matters such as dust and oil adhering to the recording surface of the thermal recording paper are adhered to the surface of the cleaning roller. Adsorbed and removed by action. Therefore, the recording surface is conveyed to the image recording unit with a clean state, and high-quality image formation is possible.

  (2) Since the cleaning unit is provided on the upstream side of the image erasing unit, foreign matters such as dust and oil adhering to the recording surface of the reversible thermosensitive recording paper are removed. Since the image is erased by appropriately transferring the heat of the roller to the recording surface of the paper, image erasure failure can be prevented, and high-quality image formation can be performed in the image recording unit.

  FIG. 2 is a top view showing an internal configuration of the printing apparatus 100 according to the embodiment of the present invention. FIG. 1 is a cross-sectional view taken along line AA in FIG. On the right side of the printing apparatus 100 in FIGS. 1 and 2, an elevating table 14 on which a large amount of paper is placed, and a separate paper feed tray 16 are provided. The sheet placed on the lifting table 14 is brought into contact with the pickup roller 9 at the left end of the uppermost sheet in the drawing when the lifting table 14 is raised. A clutch 19 is provided on the drive shaft of the pickup roller 9, and the pickup roller 9 rotates rightward in FIG. Thus, the paper is conveyed in the left direction in the figure. Since the paper feed roller 6 rotates in the right direction in the figure, the fed paper is conveyed as it is in the left direction.

  A clutch is provided on the drive shaft of the registration roller 21, and the leading end (left end in FIG. 1) of the fed paper comes into contact with the registration roller 21 when the clutch is off. Thereafter, when the clutch is turned on, the registration roller 21 rotates in the left direction and the sheet is conveyed in the left direction in the drawing.

  Similarly, the leading end (left end in the figure) of the uppermost sheet of the sheets placed on the sheet feeding tray 16 contacts the pickup roller 8. A clutch 18 is provided on the drive shaft of the pickup roller 8, and when the clutch 18 is in an on state, the pickup roller 8 rotates in the right direction in FIG. 1, and the sheet is conveyed in the left direction in the drawing. Since the paper feed roller 7 rotates in the right direction in the figure, the fed paper is conveyed in the left direction. A clutch is provided on the drive shaft of the registration roller 20, and the leading edge of the fed paper comes into contact with the registration roller 20 when the clutch is off. Thereafter, when the clutch is turned on, the registration roller 20 rotates in the left direction, and the sheet is conveyed in the left direction in the drawing.

  On the paper transport path, an R / W unit 5 that reads and writes a non-contact IC tag is disposed between the transport roller 13 and the transport roller 22. A clutch 15 is provided on the drive shaft of the transport roller 13, and when the R / W unit 5 reaches a position where the R / W unit 5 can read and write with respect to the non-contact IC tag built in the paper being transported, the clutch of the transport roller 13 By turning off 15, the paper is stopped in that state. When the sheet is stopped, the R / W unit 5 reads / writes data from / to the non-contact IC tag. Thereafter, the sheet is conveyed by turning on the clutch 15 of the conveying roller 13. The transport roller 22 transports the paper forward (leftward in the figure).

  A cleaning roller 4 and a platen roller 12 as a driving roller facing the cleaning roller 4 are arranged in front of the conveying roller 22 to constitute a cleaning unit. When the sheet passes between the cleaning roller 4 and the platen roller 12, the cleaning roller 4 removes dust adhering to the upper surface (recording surface) of the sheet.

  A heat roller 3 and a platen roller 11 which is a driving roller facing the heat roller 3 are arranged in front of the cleaning roller 4 to constitute an image erasing unit. When the paper passes between the heat roller 3 and the platen roller 11, the paper is raised to a predetermined temperature.

  In front of the heat roller 3, cooling fans 2 and 2 for blowing air to the front and back surfaces of the paper are arranged above and below the paper transport path to constitute a cooling unit. The upper and lower cooling fans 2 and 2 gradually lower the temperature of the paper conveyed between them. This erases the image recorded on the paper.

  Further downstream of the cooling unit by the cooling fans 2 and 2, a platen roller 10 that sandwiches the paper between the thermal head 1 and the thermal head 1 is arranged to constitute an image recording unit. When the leading edge of the paper reaches the lower part of the thermal head 1, the thermal head 1 descends, contacts the recording surface of the paper, and records an image by driving the thermal head as the paper is transported.

  Conveying rollers 24 and 25 and a normal paper discharge unit 40 are provided further downstream from the position of the thermal head 1, and the image-recorded paper is conveyed and discharged to the normal paper discharge unit 40.

  Further, an abnormal paper discharge unit 50 is provided between the conveying roller 22 and the platen roller 12 to drop the abnormal paper downward by the flapper and discharge it.

FIG. 3 is a diagram showing a configuration in the vicinity of the cleaning unit provided with the cleaning roller 4. FIG. 4 is an exploded perspective view of a part thereof.
The cleaning roller 4 is a nitrile (NBR) -based synthetic rubber-based roller or a silicone rubber-based roller, and has increased surface adhesiveness. For example, as the synthetic rubber roller, a roller having a hardness of 15 ° to 30 ° (according to a rubber hardness test of JIS-K-6253) and an adhesive strength of 30 to 180 hpa is used. Alternatively, a silicone rubber roller having a hardness of 3 ° to 7 ° and an adhesive strength smaller than that of the synthetic rubber roller is used.

  The cleaning roller 4 is pivotally supported by a cleaning roller unit 29 as shown in FIG. The pressing unit 36 includes a compression coil spring 28 that presses the cleaning roller unit 29 downward. The pressing unit 36 is fixed by engaging an engaging member 35 with the printing apparatus main body. Thereby, the pressing unit 36 presses the cleaning roller unit 29 against the lower platen roller 12 with a constant pressure.

  As the cleaning roller 4 is used, dust and oil adhere to the surface, and the adhesive force decreases. The cleaning roller unit 29 is removed from the printing apparatus main body and washed with water or alcohol when the adhesive force falls below a predetermined value or when used for a predetermined time. The nitrile (NBR) -based synthetic rubber-based or silicone rubber-based cleaning roller can be used repeatedly because the adhesive strength is restored by this cleaning.

  A heat roller 3 and a platen roller 11 are arranged on the downstream side (left side in FIG. 3) of the cleaning roller 4 on the conveyance path. A cleaning felt mounting tool 30 is detachably disposed in the vicinity of the mounting position of the heat roller 3. A cleaning felt 27 is bonded to the cleaning felt mounting tool 30. With the cleaning felt attachment 30 attached, the cleaning felt 27 abuts against the heat roller 3 in the entire width direction with a predetermined pressure. Thereby, when the heat roller 3 rotates together with the platen roller 11 as the driving roller, the surface of the heat roller 3 is cleaned by the cleaning felt 27.

  Therefore, when the paper from which dust and oil on the recording surface have been removed by passing between the cleaning roller 4 and the platen roller 12 passes between the heat roller 3 and the platen roller 11, Thus, the heat of the heat roller 3 is evenly transmitted, and the recording surface of the paper rises uniformly to a predetermined temperature. Further, since the surface of the heat roller 3 is also kept clean by the action of the cleaning felt 27, the recording surface of the paper is kept clean even after the paper passes through the heat roller 3.

FIG. 5 is a block diagram of the control unit of the printing apparatus 100. The control circuit 70 performs the following controls.
A drive signal is output to the motor 17 of the lifting table 14 via the drive unit 75.
A driving signal is output to the clutches 18 and 19 of the pickup roller via driving units 77 and 78, respectively.
A drive signal is output via the drive unit 76 to the flapper 52 that drops and discharges abnormal paper in the direction of the abnormal paper discharge unit 50.
A drive signal is output via the drive unit 74 to the clutch 15 of the R / W unit.
The R / W unit 5 reads / writes data from / to the non-contact IC tag built in the paper.
Control of the heater of the heat roller 3 is performed via the drive unit 73.
A drive signal is output to the thermal head elevating motor 26 via the drive unit 72.
A drive signal is output to the thermal head 1 via the drive unit 71.
Read the operation content of the operation unit 79 such as a key switch.
The detection signals of various sensors 80 such as a sensor for detecting the presence or absence of paper at a plurality of positions on the paper conveyance path and a sensor for detecting the temperature of the heat roller 3 are read.
Data is input / output to / from the host computer 101 via the interface 90.
Next, the processing procedure of the control circuit 70 shown in FIG. 5 will be described with reference to FIG.
FIG. 6 is a flowchart showing a series of flows under the control of the control circuit 70 from when a sheet is fed to when it is discharged. First, one of the clutches 18 or 19 of the pickup roller 8 or 9 is turned on to feed the paper and start conveying (S1). If it is detected that the sheet has reached the R / W unit 5 according to the reading result of the sensor for detecting the position of the sheet on the sheet conveyance path, the clutch 15 of the conveyance roller 13 of the R / W unit 5 is turned off ( S2 → S3).

  In this state, the non-contact IC tag in the sheet is close to the R / W unit 5, and the R / W unit 5 reads data from the non-contact IC tag (S4).

  The state (read status) of whether or not the data has been correctly read from the non-contact IC tag is checked (S5). If normal, the data is written in the non-contact IC tag or from the host computer 101. In response to the instruction, bitmap data to be recorded on the paper is generated (S6).

  Then, the sheet is conveyed again by turning on the clutch 15 (S7). As a result, the sheet passes between the cleaning roller 4 and the platen roller 12, and the recording surface of the sheet is cleaned (S8).

  Thereafter, the sheet passes through the heat roller 3 so that the recording surface of the sheet is heated to a predetermined temperature (predetermined temperature of approximately 150 ° C. to 200 ° C.), and the previously recorded image is erased by subsequent cooling. (S9). In addition, by driving the cooling fan 2, heat storage of the paper transport path and the paper is suppressed, and the recording surface of the paper is kept in a predetermined temperature range at the time of image recording by the subsequent thermal head.

Subsequently, when the leading edge of the paper reaches immediately before the head position of the thermal head 1, the thermal head lifting motor 26 is driven to bring the head portion of the thermal head 1 into contact with the paper, and then the thermal head 1 is driven to newly A simple image is recorded (S10).
Further, the sheet is conveyed as it is and discharged to the normal sheet discharge unit 40 (S11).

  If the data cannot be read from the non-contact IC tag, or the read data is abnormal, the flapper 52 is started up and the clutch 15 of the R / W unit is turned on to feed the paper to the abnormal paper discharge unit 50. It discharges (S5-> S12-> S13-> S14).

It is a figure which shows the structure inside the printing apparatus which concerns on embodiment of this invention, and is sectional drawing of the AA part of FIG. FIG. 2 is a top view illustrating an internal configuration of the printing apparatus. FIG. 3 is a diagram illustrating a configuration near a cleaning unit of the printing apparatus. It is a partial exploded perspective view of the cleaning part. FIG. 3 is a block diagram illustrating a configuration of a control unit of the printing apparatus. It is a flowchart which shows the process sequence of the control part.

Explanation of symbols

1-thermal head 2-cooling fan 3-heat roller 4-cleaning roller 5-R / W unit (non-contact IC tag read / write unit)
6,7-Feeding roller 8,9-Pickup roller 10,11,12-Platen roller 13-Conveying roller 14-Elevating table 15-Clutch 16-Feeding tray 18, 19-Clutch 20, 21-Registration roller 22 ~ 25-Conveying roller 27-Cleaning felt 28-Spring 29-Cleaning roller unit 30-Cleaning felt attachment 35-engaging member 36-pressing unit 40-normal paper discharging unit 50-abnormal paper discharging unit 100-printing device 101-host Computer

Claims (2)

A paper transport path for transporting thermal recording paper for recording images by thermal action;
In a thermal printing apparatus comprising: an image recording unit that presses a thermal head against a recording surface of the thermal recording sheet that has been conveyed on the sheet conveying path and records an image by heating the thermal head;
A thermal unit characterized in that a cleaning unit having a cleaning roller having an adhesive surface on the surface and rotating on and in contact with the recording surface of the thermal recording sheet during the conveyance of the sheet is disposed upstream of the image recording unit. Printing device. The thermal recording paper is a reversible thermal recording paper that enables recording and erasing of images by a thermal action,
An image erasing unit that heats a recording surface of the thermosensitive recording paper conveyed on the paper conveying path by pressing a heat roller against the recording surface, and erases an image on the paper by gradual cooling after the heating. The thermal printing apparatus according to claim 1, further provided on the upstream side, and the cleaning unit disposed upstream of the image erasing unit on the paper conveyance path.

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