JP2007182001A - Recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recorder for enhancing durability of a recording head. <P>SOLUTION: In addition to a temperature of the entire recording head, a distribution of the number of recording pixels by the nozzle is predicted during some arbitrary period or a temperature rise in the vicinity of a nozzle is predicted by the total number of pixels. When a predetermined temperature is exceeded, print speed is slowed down or printing is interrupted. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ink jet recording head, and more particularly to a recording apparatus such as a line printer having a high recording speed.

  In an inkjet printer equipped with a line head, in order to prevent a reduction in the life of the recording head, conventionally, an ink discharge is dispersed by shifting an image for each predetermined page so that a load is not concentrated on a specific nozzle. There is something. (For example, Patent Document 1)

JP 07-047714 A

  However, since the image position on the recording medium is shifted in the horizontal direction in the method of Patent Document 1, even a slight shift may be a problem depending on the image contents. In addition, a slight shift amount cannot be sufficiently shifted, and a heat stress may be generated by heating a certain heating element in a continuous burst. As a result, there is a possibility that the heat generating element may be damaged, and there is a concern that the durability of the nozzle is lowered even if the heating element is not damaged.

  In particular, since a recording apparatus equipped with a line head is used for high-frequency continuous printing that is frequently used, means for improving the durability of the recording head is important.

  In addition, in the ink jet system in which the ink in the nozzle portion is heated by the heat generating element, the maximum temperature reached in the heat generating element itself or in the vicinity of the heat generating element is also a major factor that determines the durability.

As means for solving the above problems, a recording apparatus according to the present invention includes an image memory for storing image data,
A recording head that discharges ink by heating nozzles based on the image data;
In a recording apparatus having recording head temperature detecting means for detecting the temperature of the recording head,
Nozzle temperature instruction memory for instructing the temperature in the vicinity of the nozzle, preset means for setting the nozzle temperature instruction memory based on a detection result by the recording head temperature detection means,
Image memory searching means for searching the image memory;
Based on the search result by the image memory search means,
Memory update means for updating the nozzle temperature instruction memory;
It is characterized by having.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the relative arrangement, numerical formulas, numerical values, and the like of the constituent elements described are not intended to limit the scope of the present invention only to those unless otherwise specified.

  FIG. 1 is a perspective view of a state in which a recording apparatus 101 embodying the present invention and a host PC 100 are connected by a printer cable 102. For example, a USB, a network, or the like is used as an interface. As the recording medium, a continuous roll paper 104 is fed from the roll paper holder 103 toward the recording apparatus 101 main body.

  The operation panel (operation panel) 105 includes a display for displaying the status of the recording apparatus 101, a power ON / OFF key, and the like.

  FIG. 2 is a perspective view schematically illustrating a recording unit of the recording apparatus 101 embodying the present invention.

  The recording unit includes four recording heads K1 to K4 (201 to 204) that discharge ink of the same color (for example, black), and these images are recorded at a position shown in the figure during a recording operation.

A recording medium (hereinafter, also referred to as a sheet) is fed in a direction toward the recording head by a plurality of labels 205 temporarily attached onto a mount of roll paper 104 wound in a roll shape, and then conveyed at a constant speed by a conveyance motor 208 to a feed roller 210. Then, an image is recorded when passing under the recording heads 201 to 204, and the recorded label 206 is continuously discharged. When the leading end of the label 206 is detected by a paper leading end detection sensor 212, each recording head 201-204 records each assigned raster in synchronization with the output of the rotary encoder 211 coupled to the motor shaft of the transport motor 208.
The sheet 213 on the downstream side in the transport direction is also used for detecting a paper jam by a paper leading edge detection sensor.

  FIG. 3 is an electrical block diagram of the recording apparatus 101 embodying the present invention.

  The recording data on the paper is created by the host PC 100 and transferred to the interface controller 301 of the recording apparatus 101.

  The memory controller 306 once writes the received data in the image buffer 307 at a high speed according to an instruction from the CPU 302.

  After receiving a predetermined amount of recording data, the CPU 302 starts recording operation preparation.

  First, the head U / D motor 314 and the capping motor 315 are operated with each other via the I / O (312) and the drive unit 313, and the recording head 201 that has been capped during standby by a cap mechanism (not shown) until then. -204 are moved to the recording position. At this time, the recording heads 201 to 204 move forward and backward, and a cap mechanism (not shown) moves forward and backward in a direction parallel to the paper transport direction.

  Subsequently, the paper feed motor 316 is driven via the I / O (312) and the drive unit 313, and the roll paper 104 is fed out to the recording apparatus main body side.

  Subsequently, when the CPU 302 writes a designated value of the conveyance speed including the conveyance direction in a register (not shown) in the servo logic circuit 310, the conveyance motor 208 is also activated via the drive unit 311. When the conveyance is started, two phase signals having different phases synchronized with the conveyance are outputted from the rotary encoder 211 described above.

  After that, the output of the rotary encoder 211 is fed back to the servo logic circuit 310, and constant speed control is performed in the feedback loop of the drive unit 311 to the transport motor 208 to the rotary encoder 211 to the servo logic circuit 310.

  The servo logic circuit 310 converts the output of the rotary encoder 211 into a transport position pulse and outputs it as a cut-out signal for each of the recording heads 201 to 204 to perform raster recording.

  When the leading end of the label 205 is detected by the leading end detection sensor 212 on the upstream side in the transport direction, and the transport position pulse corresponding to the distance of each of the recording heads 201 to 204 is received from the leading end detection sensor 212, the image is read by the memory controller 306. Reading of the buffer 307 is started and the data is transferred to the recording head control circuit 309.

  As a supplement, the mounting portion of the recording heads 201 to 204 may have a spare mounting space.

  The processing of the CPU 302 depends on the control program written in the ROM 303, but the RAM 304 is also used as a working memory. The EEPROM 305 is a non-volatile memory that stores numerical values unique to the apparatus, including adjustment values for fine recording positions (registration) in the X and Y directions with respect to a reference recording head, for example, the recording head K1 (201).

  Output analog values of the temperature sensors 320 of the recording heads K1 to K4 including the leading edge detection sensors 212 and 213 of the paper and the temperature sensor 210 inside the recording apparatus can be read out almost in real time via the AD converter 218.

  The pump motor 317 pressurizes the inside of the recording heads 201 to 204 from an ink tank (not shown), and drives a pressure pump (not shown) used when recovering sound recording performance by forcibly discharging ink from the ejection nozzle.

  When the recording heads 201 to 204 are line heads, the temperature sensors 320 described above are provided at all nozzle locations and are difficult to read. Therefore, the recording heads are conventionally arranged at several points at both ends and the center of the entire recording head. Or an average value.

  A method for predicting the temperature rise value in the vicinity of the nozzle and the processing operation, which is a characteristic part of the present invention, will be described with reference to FIG.

  When the print command is received and the printing operation is started, the CPU 302 sequentially reads the output of the temperature sensor 320 of each recording head 201 to 204 (401), and writes the converted value corresponding to the corresponding nozzle temperature prediction register (402).

  FIG. 6 shows a conversion table of conversion values to be written in the nozzle temperature prediction register for the print head temperature at this time. The conversion table is stored in the ROM 303. Writing to the nozzle temperature prediction register is performed, for example, for 2 [Byte] for each nozzle as shown in FIG. 6, and the writing value increases rapidly as the temperature of the recording head increases. If the recording resolution of the recording head is 600 [dot / inch] and the maximum recording width is 4 [inch], a maximum of 2400 nozzle temperature prediction registers are provided for each recording head, and these are stored in the RAM 304 area. Secured.

  In addition, the nozzle temperature prediction register may have a practically sufficient effect even if the nozzle temperature prediction register is thinned every 4 nozzles or every 8 nozzles.

  Returning to FIG. 4 again, when a value corresponding to the initial temperature of each nozzle is written, the CPU 302 starts preparation for printing on the first page (403). First, paying attention to the leftmost image data in the recording medium conveyance direction, the temperature increase value (addition value) or temperature decrease that the corresponding nozzle will reach immediately after printing the corresponding page according to the distribution of the recording pixels in the corresponding page The value (subtraction value) is calculated (406) and reflected in the nozzle temperature prediction register (407). For the recording pixel distribution, the image memory 307 is searched. For example, a value of +8 is accumulated in the page if there is a recording pixel, and -2 if there is no recording pixel.

  If the reflected result is smaller than the initial value (408-Yes), the initial value is set (409).

It is preferable to change the distribution of the recording pixels by the search of the image memory 307, that is, the weighting of presence / absence of the recording pixels based on the printing speed. For example, printing speed 1000 [mm / sec] ⇒ With recording pixels: +16 Without: -1
Printing speed 500 [mm / sec] ⇒ With recording pixels: +8 None: -2
Printing speed 250 [mm / sec] ⇒ With recording pixels: +4 None: -3
Next, it is determined whether the register value after reflection is a predetermined value, for example, +70 [° C.] in the vicinity of the nozzle as a guide or more than BFFF _H. If so (410-Yes), then the Max. Value, for example, +85 [° C. ] As a guideline, it is determined whether or not it is greater than or equal to CFFF _{H. If} this value is also exceeded (415-Yes), printing is temporarily suspended (417). Otherwise (415-No), the printing speed is reduced from, for example, 1000 [mm / sec] to 500 [mm / sec] (416), and the processing is continued (411).

  If the reflected register value does not reach the predetermined value (410-No), it is determined whether the next processed object is the right margin of the image, and if it is not yet the right margin (411-No). Since the processing of the page has not been completed, the process proceeds to search for image data corresponding to the next nozzle (404). If the target for which the series of processes has been repeated is the right margin of the image (411-Yes), the temperature prediction of all nozzles related to the image has been completed, and the printing process for the page is executed (412).

  Subsequently, it is determined whether or not printing of the designated number of pages has been completed. If not (413-No), the process proceeds to the next page processing (414), and is repeated until the designated number of sheets is completed (413-Yes).

  It is possible to increase the printing speed to 1000 [mm / sec] again depending on the value of the temperature prediction register of each nozzle after entering the printing speed slowdown process (416), but the description is omitted here. To do.

  In the present invention, the process described with reference to FIG. 4 is further simplified, and details will be described with reference to FIG.

  When the printing command is received and the printing operation is started, the CPU 302 sequentially reads the output of the temperature sensor 320 of each recording head 201 to 204 (501), and writes the conversion value corresponding to the corresponding nozzle temperature prediction register (502).

  A conversion table of conversion values to be written to the nozzle temperature prediction register with respect to the print head temperature at this time is based on FIG. 6 which is the same as the embodiment. The conversion table is stored in the ROM 303. Writing to the nozzle temperature prediction register is performed, for example, for 2 [Byte] for each nozzle as shown in FIG. 6, and the writing value increases rapidly as the temperature of the recording head increases. If the recording resolution of the recording head is 600 [dot / inch] and the maximum recording width is 4 [inch], a maximum of 2400 nozzle temperature prediction registers are provided for each recording head, and these are stored in the RAM 304 area. Secured.

  In addition, the nozzle temperature prediction register may have a practically sufficient effect even if the nozzle temperature prediction register is thinned every 4 nozzles or every 8 nozzles.

  Returning to FIG. 5 again, when a value corresponding to the temperature immediately before printing the page is written, the CPU 302 starts preparation for printing on the first page (503). First, paying attention to the image data located at the leftmost in the recording medium conveyance direction, the temperature increase value (added value) that the corresponding nozzle will reach immediately after printing the corresponding page is added according to the number of recording pixels in the corresponding page (506). ).

  For the number of recording pixels, the image memory 307 is searched. For example, a value of +8 is accumulated in the page if there is a recording pixel, and 0 if there is no recording pixel.

  In the case of recording pixels, the weighting is preferably changed based on the printing speed. For example, the weight per recording pixel is set as follows.

Printing speed 1000 [mm / sec] ⇒ +16
Printing speed 500 [mm / sec] ⇒ +8
Printing speed 250 [mm / sec] ⇒ +4
Next, it is determined whether the addition result after reflection is BFFF _H or more with a predetermined value, for example, +70 [° C.] near the nozzle as a guide. If so (510-Yes), then the Max. Value, for example +85 [° C. ] Is used as a guideline to determine whether the value is greater than or equal to CFFF _{H. If} this value is also exceeded (515-Yes), printing is temporarily suspended (517).

  Otherwise (515-No), the printing speed is reduced from, for example, 1000 [mm / sec] to 500 [mm / sec] (516), and the processing is continued (511).

  If the addition result after reflection does not reach the predetermined value (510-No), it is determined whether the next processed target is the right margin of the image, and if not yet the right margin (511-No). Since the processing of the page has not been completed, the process proceeds to retrieval of image data corresponding to the next nozzle (504). If the target for which the series of processes has been repeated is the right margin of the image (511-Yes), the temperature prediction of all nozzles related to the image has been completed, and the printing process for the page is executed (512).

  Subsequently, it is determined whether or not printing of the designated number of pages is completed. If not (513-No), the process proceeds to the next page processing (514), and is repeated until the designated number of pages is completed (513-Yes).

Note that after entering the print speed slowdown process (516), the print speed can be increased again to 1000 [mm / sec] depending on the read temperature value of the recording head. Description is omitted.

  Needless to say, the recording operation is temporarily stopped even when the value of the recording head temperature sensor 320 exceeds the printable temperature during printing.

  The recording apparatus of the present invention can significantly improve the operation reliability of the recording apparatus when used in a line printer such as a high-speed and heavy-duty label printer or a large color printer.

FIG. 3 is a connection diagram between a recording apparatus according to the present invention and a host PC. It is a perspective view which shows the concept of the recording device recording part by this invention. 1 is an electrical block diagram of a recording apparatus according to the present invention. 3 is a flowchart illustrating processing according to the first embodiment. 10 is a flowchart illustrating processing according to the second embodiment. It is a write value conversion table for recording head temperature to nozzle temperature prediction register.

Explanation of symbols

100 Host computer (host PC)
101 Recording device

201 Recording head (K1)
202 Recording head (K2)
203 Recording head (K3)
204 Recording head (K4)
205 Label 208 Transport motor 211 Rotary encoder 212 Tip detection sensor

301 Interface controller 302 CPU
303 ROM
305 EEPROM
307 Image memory 309 Printhead control circuit 310 Servo logic circuit 320 Printhead temperature sensor

Claims (5)

An image memory for storing image data;
A recording head that discharges ink by heating nozzles based on the image data;
In a recording apparatus having recording head temperature detecting means for detecting the temperature of the recording head,
Nozzle temperature instruction memory for instructing the temperature in the vicinity of the nozzle, preset means for setting the nozzle temperature instruction memory based on a detection result by the recording head temperature detection means,
Image memory searching means for searching the image memory;
Based on the search result by the image memory search means,
Memory update means for updating the nozzle temperature instruction memory;
A recording apparatus comprising:   The recording apparatus according to claim 1, wherein the nozzle temperature instruction memory is provided for each nozzle.   The recording apparatus according to claim 1, wherein the nozzle temperature instruction memory includes only a specific nozzle.   4. The recording apparatus according to claim 1, wherein the printing speed is changed when the value of the nozzle temperature instruction memory exceeds a predetermined value. 5. The recording apparatus according to claim 1, wherein printing is interrupted when the value of the nozzle temperature instruction memory exceeds a predetermined value.

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