Image forming apparatus

Abstract

To provide an image forming apparatus capable of confirming the trouble of a heating element during printing operation.SOLUTION: An image forming apparatus according to an embodiment includes a conveyance motor, a thermal head, a head drive unit, a check circuit, and a processor. The conveyance motor conveys the print medium to a print position. The thermal head includes a plurality of heating elements arranged in a printing line orthogonal to a conveying direction of the printing medium at a printing position. The head drive unit causes each heating element to generate heat according to image data for each print line of the print image. The check circuit checks a malfunction for each heating element. The processor is configured or programmed to execute the check for the operation fault using the check circuit for the heating element determined to require the check for the operation fault by the priority setting for each image region in the print image.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] FIELD An embodiment of the present invention relates to an image forming apparatus. [Background technology]

[0002] One type of image forming device found in the workplace is a thermal transfer printer (thermal printer). A thermal printer transfers ink onto a medium by applying heat to an ink ribbon placed on the medium. A thermal printer has a thermal head with multiple heating elements arranged in a printing line.

[0003] A thermal printer prints an image on a medium by controlling the heat generation of each heating element according to image data while transporting the ink ribbon and the medium together to a printing position. Each heating element in the thermal head is connected to a drive circuit or the like, and generates heat according to the amount of heat provided by the circuit.

[0004] Thermal printers sometimes check for broken wires in each heating element to determine whether each heating element is in a state where it can print normally. A broken wire check for each heating element in a thermal head cannot be performed while any of the group of heating elements arranged on a print line is currently printing. Conventional thermal printers perform a broken wire check for each heating element while the printing operation is stopped, which results in the problem of a long time required between the printing operation and the broken wire check. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-214456 Summary of the Invention [Problem to be solved by the invention]

[0006] The problem to be solved by the embodiments of the present invention is to provide an image forming apparatus that can check for defects in heating elements during printing operations. [Means for solving the problem]

[0007] An image forming apparatus according to an embodiment includes a transport motor, a thermal head, a head drive unit, a check circuit, and a processor. The transport motor transports the print medium to the printing position. The thermal head includes multiple heating elements arranged in a print line perpendicular to the print medium transport direction at the printing position. The head drive unit causes each heating element to generate heat in accordance with image data for each print line of the print image. The check circuit checks for malfunctions for each heating element. The processor uses the check circuit to check for malfunctions for heating elements that are determined to require a malfunction check based on priority settings for each image area in the print image. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a block diagram showing an example of the configuration of a label printer as an image forming apparatus according to an embodiment. [Figure 2] FIG. 2 is a diagram showing an example of a print image that is printed on a label material as a print medium by a label printer as an image forming apparatus according to an embodiment. [Figure 3] FIG. 3 is a diagram showing an example in which the label printer according to the embodiment prints print images on a plurality of label materials arranged on a label sheet. [Figure 4] FIG. 4 is a diagram showing a first example of the configuration of a group of heat generating elements provided in a thermal head used in a label printer as an image forming apparatus according to an embodiment. [Figure 5] FIG. 5 is a diagram showing a second example of the configuration of the heat generating element group provided in the thermal head used in the label printer as the image forming apparatus according to the embodiment. [Figure 6] FIG. 6 is a flowchart for explaining a printing operation including a disconnection check by a label printer as an image forming apparatus according to an embodiment. [Figure 7] FIG. 7 is a flowchart for explaining an example of an operation for checking for disconnection in a label printer as an image forming apparatus according to an embodiment. [Figure 8] FIG. 8 is a flowchart illustrating an example of an operation of a disconnection error process in a label printer as an image forming apparatus according to an embodiment. [Figure 9] FIG. 9 is a diagram showing an example of a print defect mark that is printed on the label material when a label printer serving as an image forming apparatus according to an embodiment detects a break in a heating element. [Figure 10] FIG. 10 is a diagram showing an example of an error notification screen displayed on the display unit when a label printer serving as an image forming apparatus according to an embodiment detects a break in a heating element. [Figure 11] FIG. 11 is a diagram showing an example of a mark that is additionally printed when a label printer serving as an image forming apparatus according to an embodiment detects a break in a heating element. DETAILED DESCRIPTION OF THE INVENTION

[0009] A label printer as an image forming apparatus according to an embodiment will be described below with reference to the drawings. However, the scale of each part in the drawings used to describe the following embodiment may be changed as appropriate. Also, the drawings used to describe the following embodiment may omit some components to make the description easier to understand.

[0010] First, the configuration of a label printer 1 as an image forming apparatus according to the embodiment will be described. FIG. 1 is a block diagram showing an example of the configuration of a label printer 1 as an image forming apparatus according to an embodiment. The label printer 1 is placed in a workplace. In the configuration example shown in Figure 1, the label printer 1 includes a processor 11, a ROM (Read Only Memory) 12, a RAM (Random Access Memory) 13, a data memory 14, a communication unit 15, a display unit 16, an operation unit 17, and a printing mechanism 18. The printing mechanism 18 also includes a sensor group 21, a head driving unit 22, a thermal head 23, a wire break check circuit 25, a motor driving unit 26, a feed motor 27, a ribbon driving unit 28, and a ribbon motor 29.

[0011] Processor 11 is connected via a bus line to ROM 12, RAM 13, data memory 14, communication unit 15, display unit 16, operation unit 17, sensor group 21, head drive unit 22, disconnection check circuit 25, motor drive unit 26, ribbon drive unit 28, etc. The bus line includes an address bus, a data bus, control signal lines, etc. Processor 11 is connected via the bus line to each unit directly or via a signal input / output circuit, and is configured to transmit data signals exchanged between them.

[0012] The processor 11 is a hardware processor that performs overall control of the label printer 1. The processor 11 controls each section of the label printer 1 in accordance with an operating system or a control program. The processor 11 is, for example, a CPU (Central Processing Unit). The processor 11 may also include an MPU (Micro Processing Unit), SoC (System on a Chip), DSP (Digital Signal Processor), GPU (Graphics Processing Unit), ASIC (Application Specific Integrated Circuit), PLD (Programmable Logic Device), FPGA (Field-Programmable Gate Array), or the like.

[0013] The ROM 12 is a non-volatile memory that stores programs executed by the processor 11 and various data. The RAM 13 is a volatile memory that temporarily stores data. For example, the RAM 13 operates as a development memory that temporarily stores programs and data when the processor 11 executes a program.

[0014] The data memory 14 corresponds to an auxiliary storage section. The data memory 14 is a rewritable non-volatile memory. The data memory 14 is configured, for example, by an EEPROM (registered trademark) (Electric Erasable Programmable Read-Only Memory), an HDD (Hard Disc Drive), or an SSD (Solid State Drive). The data memory 14 stores data used by the processor 11 when performing various processes, data created by the processes in the processor 11, etc.

[0015] The communication unit 15 is a communication interface for communicating with an external host computer, a user terminal, etc. For example, the communication unit 15 is connected to a host computer for communication and receives print data for label printing and print commands supplied from the host computer.

[0016] The display unit 16 is composed of a display device that displays information. The display unit 16 is provided in a position where the display screen can be viewed by an operator of the label printer 1. The display unit 16 displays operation guides for the label printer 1, information indicating the status of the label printer 1, and the like.

[0017] The operation unit 17 is configured with an input device for an operator to input operation instructions. The input device serving as the operation unit 17 is, for example, various input buttons or a touch panel. The display unit 16 and the operation unit 17 may also be configured with a display device equipped with a touch panel.

[0018] The printing mechanism 18 prints an image on a label medium by using a thermal head 23 to heat an ink ribbon. A sensor group 21 including various sensors is arranged in the printing mechanism 18. The sensor group 21 includes, for example, a sensor that detects the medium being transported, a sensor that detects the ink ribbon, and other sensors. The processor 11 controls each part of the printing mechanism 18 based on the detection results of each sensor in the sensor group 21.

[0019] The head drive unit 22 is connected to the thermal head 23. The head drive unit 22 drives the thermal head 23. The thermal head 23 is provided at a predetermined printing position. The thermal head 23 has a plurality of heating elements (elements) 24 arranged in a printing line at the printing position in a direction perpendicular to the medium transport direction. The thermal head 23 is arranged so that the plurality of heating elements 24 come into contact with the ink ribbon that is transported overlapping the label at the printing position. The thermal head 23 prints on the label paper by having each heating element 24 apply heat to the ink ribbon that is transported overlapping the label paper at the printing line.

[0020] The head driver 22 heats each heating element 24 that makes up the thermal head 23 based on the print image. For example, the head driver 22 controls the heat generation state of each heating element 24 in the thermal head 23 in accordance with image data for each print line in the print image of each page to be printed on the medium. The heating elements 24 that generate heat at a predetermined printing position heat the ink ribbon pressed against the medium (label material). This causes ink corresponding to the image data to be transferred to the medium for each print line.

[0021] The open circuit check circuit 25 is connected to each heating element 24 in the thermal head 23. The open circuit check circuit 25 is also connected to the head drive unit 22 and the processor 11. The open circuit check circuit 25 checks for open circuits (malfunctions or defects) in each heating element 24 that constitutes the thermal head 23 and is driven by the head drive unit 22. For example, the open circuit check circuit 25 reads the resistance value of each heating element 24 and compares the read resistance value with a predetermined threshold value (predetermined resistance value) to check for open circuits in each heating element 24.

[0022] The motor drive unit 26 is connected to the transport motor 27. The motor drive unit 26 drives the transport motor 27 in response to instructions from the processor 11. The transport motor 27 rotates a transport roller to transport the medium on which an image is to be printed along a predetermined transport path. In this embodiment, the label printer 1 prints an image on label material as the print medium on which the image is to be printed. For example, the transport motor 27 transports label paper in which multiple label materials are arranged on a long, strip-shaped backing. The label paper is made by attaching multiple rectangular label materials at equal intervals to one surface of the long, strip-shaped backing, with a predetermined gap (for example, about 1 to 3 mm) between them. The label paper is formed into a roll and set at a predetermined position.

[0023] The ribbon drive unit 28 is connected to the ribbon motor 29. The ribbon drive unit 28 drives the ribbon motor 29 in response to instructions from the processor 11. The ribbon motor 29 transports the ink ribbon so that it overlaps the label paper at the printing position. The ribbon motor 29 is a motor that rotates the take-up roller. The ribbon motor 29 may also include a motor that rotates the feed roller and a motor that rotates the take-up roller. The ribbon motor 29 transports the ink ribbon by rotating the take-up roller or both the feed roller and the take-up roller.

[0024] For example, the feed roller winds up a long, unused ink ribbon into a roll. The take-up roller takes up the used ink ribbon that has passed the printing position into a roll. The ink ribbon is transported between the feed roller and the take-up roller, passing through the printing position and overlapping with the label paper. The ribbon drive unit 28 controls the ribbon motor 29 so that the ink ribbon is transported in the same direction and at the same speed as the label paper at the printing position.

[0025] Next, a description will be given of a print image that is printed on a label material as a print medium by the printing mechanism 18 of the label printer 1 according to the embodiment. FIG. 2 is a diagram showing an example of a print image that the label printer 1 according to the embodiment prints on a label material 31 as a print medium. The print image that the label printer 1 prints on the label material 31 is configured in a predetermined print format. As shown in the example of Figure 2, the print image is configured in a print format that has multiple image areas. For example, the label printer 1 obtains the print image for each page to be printed on the label material 31 from the host computer 2. In this case, the host computer 2 selects the print format of the print image specified by the operator. The host computer 2 generates the print image for each page by setting the image for each page (barcode, 2D code, character, symbol) in each image area of ​​the selected print format.

[0026] The print quality required for a printed image may differ depending on the image area of ​​the print format. For example, if there is missing printing on a 2D code or barcode, the information may not be accurately recognized. For this reason, high print quality is often required for the image area where the 2D code or barcode is printed. Furthermore, images that are visible to humans, such as letters or marks, are likely to be visible to humans even if some of the printing is missing. For this reason, image areas where images that are visible to humans, such as letters or marks, are printed often require print quality that is sufficient for humans to see. Furthermore, even if there is missing printing on images such as ruled lines, this often does not affect the functionality of the label as a printed product printed on label material. For this reason, image areas where images such as ruled lines are printed often do not require high print quality.

[0027] In this embodiment, a priority setting is assigned to each image area of ​​the print image according to the print quality required for each image area of ​​the print format. For example, a high priority setting is assigned to an image area where a two-dimensional code or barcode is printed, which does not tolerate missing characters. An image area where images to be visually inspected by humans, such as characters or marks, is printed is assigned a priority setting that allows missing characters to be printed. An image area where images such as ruled lines are printed is assigned a priority setting that does not require checking for missing characters.

[0028] On the other hand, in the label printer 1, one cause of missing print is defective heating of the heating elements 24 in the thermal head 23. Malfunctioning of each heating element 24 in the thermal head 23 can be detected by a wire break check using the wire break check circuit 25. The wire break check is an operation that checks for malfunction of each individual heating element 24 in the thermal head 23. The wire break check can be configured to check each heating element 24 in a specific range (a specific section of the print line), making it possible to check for missing print within a specific image area.

[0029] The label printer 1 acquires information indicating the priority setting for disconnection checks for each image area in the print image along with the print image. The label printer 1 determines whether or not to check for disconnections and the content of the checks based on the priority setting for each image area. The priority setting for each image area in the print image is set before the label printer 1 executes printing.

[0030] For example, when the host computer 2 requests printing from the label printer 1, it supplies the print image along with information indicating the priority setting for each image area. The label printer 1 may also store the priority setting for each image area for each print format. In this case, the label printer 1 may specify the priority setting for each image area in the print image according to the specified print format.

[0031] As a specific example, the printed image illustrated in FIG. 2 has a plurality of image areas 41-43, 51-56, and 61-62. Here, the description will be given assuming that the priority setting for each image area is set to either "High," "Low," or "None (no disconnection check required)."

[0032] Image areas 41 and 42 indicate the print area of ​​the barcode, and image area 43 indicates the print area of ​​the two-dimensional code. If there are any missing characters in these image areas 41-43, the information indicated by the code may not be accurately recognized. For this reason, the priority setting for image areas 41-43 may be set to "high."

[0033] Image areas 51-56 are areas where characters and symbols that are visible to humans are printed. Images printed in these image areas 51-56 are likely to be visible to humans even if some of the printing is missing. For this reason, it is considered that the priority setting for image areas 51-56 is set to "low."

[0034] Image areas 61-62 are areas where ruled lines and the like are printed. Even if there are missing print characters in the images printed in these image areas 61-62, there will be no problem in the function of the label as a printed image. For this reason, it is conceivable that the priority setting for image areas 61-62 is set to "none" (no open circuit check required). Image areas with a priority setting of "none" are set to not require open circuit check.

[0035] Next, a description will be given of non-printed areas in a printed image that allow for disconnection checks during printing processing. FIG. 3 is a diagram showing an example in which print images are printed on a plurality of label materials 31 (31A, 31B) of label paper 32 by the label printer 1. In FIG. 3, label paper 32 has multiple label materials 31A, 31B arranged at predetermined intervals on a long backing sheet. In printing mechanism 18, label paper 32 having multiple label materials 31A, 31B arranged side by side is transported in the direction of arrow a (transport direction) shown in FIG.

[0036] The multiple heating elements (element group) that make up the thermal head 23 are aligned at predetermined printing positions in a direction perpendicular to the conveyance direction a of the label paper 32. In other words, the element group of the thermal head 23 prints (prints) an image on the label material 31A being conveyed in the conveyance direction a, line by line (printing line) in a direction perpendicular to the conveyance direction a.

[0037] The print image printed by the label printer 1 on the label material 31 includes areas (non-printed areas) where there are continuous print lines with no pixels to be printed, as shown in Figure 3. The open circuit check can be performed when there are no heating elements in the group of heating elements in the thermal head 23 that are generating heat for printing. In other words, even while the label paper 32 is being transported, the open circuit check can be performed in the non-printed area where all of the heating elements in the group of heating elements in the thermal head 23 are not printing.

[0038] For example, if we look at image area 43 on label material 31A in the print image shown in Figure 3, we can see that after image area 43 is printed, there is an unprinted area 71. Furthermore, in the conveying direction a, the section from the printing end position on label material 31A to the printing start position on label material 31B is an unprinted area 72. A wire break check for image area 43 can be performed during the period when unprinted area 71 passes the printing position and during the period when unprinted area 72 passes the printing position.

[0039] Furthermore, the image in image area 43 is printed by the group of heating elements 24 arranged in section 70 on a printing line perpendicular to transport direction a. In other words, if only image area 43 is the subject of a disconnection check, the disconnection check only needs to be performed on each heating element 24 arranged in section 70. In other words, the disconnection check for image area 43 only needs to be performed on heating elements 24 arranged in section 70 during the period when non-printed area 71 and non-printed area 72 pass the printing position.

[0040] Next, the configuration of the group of heating elements 24 of the thermal head 23 that is the target of the disconnection check in the label printer 1 according to this embodiment will be described. FIG. 4 is a diagram showing a first example of the configuration of the heat generating element group 24 provided in the thermal head 23 used in the label printer 1 according to the embodiment. 4, the thermal head 23 includes a group of heating elements (group of elements) 24 arranged in a line on a printing line at the printing position. The group of elements 24 is connected to one power source 81.

[0041] In the first configuration example, the element groups 24 are connected to a single power source 81, so a check for disconnection cannot be performed unless the entire print line is not printing. In other words, when the element groups 24 arranged on the entire print line are connected to a single power source 81, a check for disconnection can be performed while the entire print line is not printing.

[0042] FIG. 5 is a diagram showing a second configuration example of the heat generating element group 24 (241, 242) in the thermal head 23 used in the label printer 1 according to the embodiment. In the second configuration example shown in FIG. 5, the thermal head 23 includes a first element group 241 and a second element group 242. The first element group 241 is arranged halfway from one end of the print line (left half). The second element group 242 is arranged halfway from the other end of the print line (right half). In other words, the first element group 241 and the second element group 242 are arranged so as to line up across the entire print line. The first element group 241 is connected to a first power source 811. The second element group 242 is connected to a second power source 812 that can operate independently of the first power source 811.

[0043] Because the first element group 241 and the second element group 242 in the thermal head 23 of the second configuration example are connected to separate power supplies, a check for disconnection can be performed on each. That is, a check for disconnection on the first element group 241 can be performed while the left half of the print line is unprinted, regardless of whether the right half of the print line is printed. Similarly, a check for disconnection on the second element group 242 can be performed while the right half of the print line is unprinted, regardless of whether the left half of the print line is printed. If the entire print line is unprinted, a check for disconnection can be performed on both the first element group 241 and the second element group 242.

[0044] The thermal head 23 is not limited to the configuration illustrated in Fig. 5, and may have a configuration including multiple element groups and power supplies. The disconnection check for each element group connected to a separate power supply can be performed during a period when no printing is performed in the area corresponding to the element group being checked for disconnection.

[0045] Next, a printing operation including a wire break check according to the priority setting for each image area in the printed image by the label printer 1 will be described. FIG. 6 is a flowchart for explaining the printing operation of the label printer 1, including the check for broken wires according to the priority setting for each image area. First, when executing printing, the processor 11 of the label printer 1 acquires print data (ACT11). For example, the processor 11 of the label printer 1 acquires print data along with a print request from the host computer 2. The print data includes a print image and information indicating the priority setting for each image area in the print image. The processor 11 expands the print image included in the print data into image data for each print line and stores the image data in a memory such as the RAM 13.

[0046] The processor 11 transports the label material 31 as a printing medium to a print start position in order to print the print image for each page on the label material 31 (ACT12). For example, the processor 11 transports the label material 31 placed on the label paper to the print start position by driving the transport motor 27 using the motor drive unit 26 to transport the label paper 32.

[0047] When the label material 31 reaches the print start position, the processor 11 prints (prints) each print line while transporting the label material 31 at a predetermined transport speed (ACT13). For example, the processor 11 controls the heat generation of each heating element 24 according to the image data of the print line using the head drive unit 22 at a timing according to the transport speed. As a result, an image according to the image data is printed for each print line at the printing position on the label material 31 transported in the transport direction.

[0048] When the processor 11 prints the image data of the print line, it stores information indicating the heating elements (used elements) 24 that generated heat in the RAM 13 or the data memory 14 (ACT14). For example, the processor 11 provides a table in the RAM 13 or the data memory 14 indicating whether or not each heating element 24 was used, and stores information indicating the heating elements (used elements) that were used.

[0049] Each time printing of a print line is completed, processor 11 determines whether it is possible to perform a disconnection check in the unprinted area in the print image (ACT15). Processor 11 sets the period during which the unprinted area in the print image passes the print position (print line) as the period during which the disconnection check is possible. For example, processor 11 calculates the period during which the unprinted area passes the print position based on the print data, the transport speed, etc. Processor 11 then sets in advance the period during which the disconnection check is possible based on the calculated period during which the unprinted area passes the print position.

[0050] If processor 11 determines that a disconnection check can be performed in an unprinted area in the print image (ACT15, YES), it performs the disconnection check (ACT16). The disconnection check in ACT16 is a process that is performed during the period when an unprinted area present in the print image of the page passes the printing position. Processor 11 sets the group of heating elements that will perform the disconnection check based on the priority setting of each image area in the print image. The group of heating elements that will perform the disconnection check are the group of heating elements that are arranged in the section where the image of the image area for which the disconnection check is to be performed is printed. Processor 11 performs a disconnection check, which will be explained in detail later, for each heating element for which a disconnection check is to be performed.

[0051] The open circuit check in ACT 16 is a process that is executed during the period when the non-printed area in the print image passes the printing position. When the period during which the non-printed area passes the printing position ends (when printing is resumed), if the open circuit check is not complete, processor 11 controls to interrupt the open circuit check and proceed to ACT 17. When interrupting the open circuit check, processor 11 stores information in RAM 13 or data memory 14 that indicates the heating elements for which the open circuit check has been completed.

[0052] If it is not a period in which a disconnection check can be performed (ACT15, NO), processor 11 determines whether printing of the print image for that page has been completed (ACT17). In addition, if processor 11 completes the disconnection check in ACT16 or interrupts the disconnection check, processor 11 also determines whether printing of the print image for that page has been completed. If printing of the print image for that page has not been completed (ACT17, NO), processor 11 returns to ACT13 and executes printing of the next print line in the print image for that page.

[0053] When the printing of the print image for the page is completed (the final print line of the page is printed) (ACT17, YES), the processor 11 determines whether the disconnection check is incomplete (ACT18). When the disconnection check is completed (ACT18, NO), the processor 11 determines whether printing of all pages is completed (ACT22). When printing of all pages is not completed (ACT22, NO), the processor 11 returns to ACT12 and executes printing of the print image for the next page. When printing of all pages is completed (ACT22, YES), the processor 11 ends the series of printing operations.

[0054] If the disconnection check is not complete (ACT18, YES), processor 11 determines whether to stop the transport of the label material (printing operation) to perform the disconnection check (ACT 19). Processor 11 determines whether to stop the printing operation depending on whether the disconnection check can be completed in the non-printing area from the printing end position of the print image on the current page to the printing start position of the next page.

[0055] For example, processor 11 estimates the time required to perform the disconnection check after printing a page (disconnection check time after printing a page) based on the number of heating elements that will perform the disconnection check, the implementation status of the disconnection check, etc. Processor 11 determines whether the disconnection check can be completed without stopping the printing operation based on the disconnection check time after printing a page, the label material conveyance speed, the size of the non-printed area (length in the conveyance direction), etc.

[0056] However, depending on the printing speed (transport) and other factors, even if the non-printed area is large enough, it may not be possible to complete the disconnection check in the time it takes for printing of the next page to begin. In such cases, a limit is placed on the non-printed area (overlap area) from the leading edge of the next page to the printing start position of that page, which is included in the non-printed area where the disconnection check can be performed. In this case, processor 11 determines whether the disconnection check can be completed based on the non-printed area at the trailing edge of the page and the limited overlap area of ​​the next page.

[0057] When processor 11 determines to stop the transport of label material as a print medium (printing operation) (ACT19, YES), it stops transport of label material by transport motor 27 (ACT20). Processor 11 stops the printing operation so that the label material on which the print image of the next page is to be printed is stopped at a position where printing of the next page can be smoothly resumed. For example, processor 11 stops the printing operation by stopping the label material on which the print image of the next page is to be printed at the print start position of the next page.

[0058] When the processor 11 stops the printing operation, it controls the label material for the next page to stop at a predetermined position and also checks for a break (ACT 21). In this case, the next page is to be printed (ACT 22, NO), so once the break check is complete, the processor 11 proceeds to ACT 12 and resumes printing on the label material for the next page.

[0059] If processor 11 determines not to stop the printing operation (label paper transport) (ACT19, NO), it performs a wire break check while continuing the printing operation (ACT21). In this case, if the next page is to be printed (ACT22, NO), processor 11 proceeds to ACT12 after completing the wire break check, moves the label material for the next page to the print start position, and prints the next page. Here, processor 11 may backfeed the label paper as necessary to move the label material for the next page to the print start position before starting printing of the next page.

[0060] Furthermore, when the disconnection check in ACT21 is completed, if there is no print image for the next page (ACT22, YES), the processor 11 ends the series of printing operations.

[0061] As described above, the label printer according to the embodiment determines whether or not a check for disconnections is necessary based on the priority setting for each image area in the printed image. The label printer performs a check for disconnections using the disconnection check circuit for heating elements that are determined to require a check for disconnections based on the priority setting for each image area.

[0062] This allows the label printer according to the embodiment to check for disconnections only for those heating elements that require such a check, thereby reducing the time required for the disconnection check that is performed in parallel with the printing operation, and enabling the entire printing operation, including the disconnection check, to be completed in a short amount of time.

[0063] Furthermore, the label printer according to the embodiment performs a wire break check using the wire break check circuit while the unprinted area in the print image of each page passes the printing position. This allows the label printer according to the embodiment to perform a wire break check during printing without having to stop printing operations such as transporting the print medium. As a result, the label printer according to the embodiment can speed up the entire printing operation, including the wire break check.

[0064] Furthermore, when printing multiple pages of print images continuously, the label printer according to the embodiment performs a wire break check in the period from the end of printing one page to the start of printing the next page. This allows the label printer according to the embodiment to perform a wire break check by shortening the pause in the printing operation even if there are few unprinted areas in the print image. As a result, the label printer according to the embodiment can speed up the entire printing operation, including the wire break check.

[0065] Next, the operation of checking for disconnection in the label printer 1 as the image forming apparatus according to the embodiment will be described. FIG. 7 is a flowchart for explaining an example of the operation of checking for disconnection in the label printer 1 according to this embodiment. When starting a check for disconnection, processor 11 performs initialization for executing the check for disconnection (ACT31). Processor 11 sets the group of heating elements 24 of thermal head 23 so that power for the check for disconnection is supplied. Processor 11 also sets a variable n, which is used to specify the heating elements 24 for which the check for disconnection is actually performed, to an initial value. In the example shown in FIG. 3, processor 11 sets section 70 as the target of the check for disconnection, and sets the initial value of variable n so that the heating elements 24 located at positions corresponding to section 70 are specified in order.

[0066] The processor 11 also performs initialization and discharges the voltage in the circuits of the head driving unit 22 and the thermal head 23 (ACT32). After discharging the voltage in the circuits, the processor 11 turns on the open circuit check circuit 25 (ACT33) and sets the nth heating element (element n) as the target for open circuit check (ACT34).

[0067] After selecting element n, processor 11 determines whether element n has executed (used) printing (ACT 35). For example, processor 11 stores information indicating each element used during printing in a memory such as RAM 13 as part of the processing in ACT 14. Processor 11 determines whether element n has been used based on the information stored in memory in ACT 14.

[0068] If element n is unused (ACT35, NO), the processor 11 skips (omits) the disconnection check for element n and proceeds to ACT40. If element n is in use (ACT35, YES), processor 11 determines whether a disconnection check for element n is necessary based on the priority setting for the image area (ACT36). For example, processor 11 determines whether element n is an element located at a position corresponding to an image area that requires a disconnection check in the priority setting.

[0069] If element n is not located in a position corresponding to an image area that requires a disconnection check, processor 11 determines that a disconnection check is unnecessary. If a disconnection check for element n is unnecessary (ACT36, NO), processor 11 skips (omits) the disconnection check for element n and proceeds to ACT40.

[0070] The processor 11 determines that an open circuit check is necessary if the element n is located at a position corresponding to an image area that requires an open circuit check. When the processor 11 determines that an open circuit check is necessary for the element n (ACT36, YES), it turns on the element n (ACT37) and reads the resistance value using the open circuit check circuit 25 (ACT38).

[0071] The open circuit check circuit 25 outputs a signal indicating whether or not the resistance value when the element n is turned on is a value indicating an open circuit (malfunction) to the processor 11. The processor 11 determines whether or not there is an open circuit (malfunction) in the element n based on the output from the open circuit check circuit 25 (ACT 39).

[0072] When processor 11 determines that there is no break in element n (ACT39, YES), it determines whether n is the final element (ACT40). Processor 11 determines whether the nth element is the last element for which a break check is to be performed. If variable n is the final element (ACT40, YES), processor 11 ends the break check.

[0073] If the variable n is not the final one (ACT40, NO), the processor 11 increments the variable n (n=n+1), returns to ACT34, and performs a disconnection check on the next element.

[0074] However, the processor 11 monitors whether the period during which the check for disconnection is possible is still in progress while the check for disconnection is being performed. If the period during which the check for disconnection is possible ends while the check for disconnection is being performed, the processor 11 suspends the check for disconnection, returns to ACT 17, and resumes printing.

[0075] Furthermore, when the processor 11 detects a disconnection (malfunction) of element n (ACT39, NO), it sets information (an error flag) indicating the element n in which the disconnection was detected (ACT42). For example, the processor 11 stores an error flag indicating the disconnection of element n in a memory such as the RAM 13 or the data memory 14. After setting the error flag in the memory, the processor 11 executes a disconnection error process according to the priority setting of the image area corresponding to the element n in which the disconnection was detected (ACT43).

[0076] Next, the operation of the label printer 1 according to the embodiment for handling a disconnection error will be described. FIG. 8 is a flowchart illustrating an example of the operation of the label printer 1 according to the embodiment in handling a disconnection error. The processor 11 executes an error process (disconnection error process) according to the priority setting of the image area corresponding to the element in which the disconnection was detected. The details of the disconnection error process are stored in advance in the data memory 14 as setting information corresponding to the priority setting.

[0077] Here, the priority setting for each image area includes a priority level in addition to whether or not to check for disconnection. In the following explanation, the priority setting for each image area is set to either "None," "High," or "Low." Heating elements with a priority setting of "No Check for Disconnection" for all image areas that include pixels to be printed will not be checked for disconnection. In other words, a disconnection check is performed on heating elements that print pixels included in image areas with a priority setting of "High" or "Low."

[0078] When processor 11 detects a break in the break check, it identifies the priority of the heating element in which the break was detected (ACT 50). Here, the priority of each heating element is set to the highest priority setting for the image area that includes the group of pixels to be printed. In other words, processor 11 determines whether the priority of the heating element in which the break was detected is "high" or "low."

[0079] For example, if there is an image area with a "high" priority setting in the image area containing pixels printed by the heating element, the priority of that heating element will be set to "high." If there is no image area with a "high" priority setting in the image area containing pixels printed by the heating element and there is an image area with a "low" priority setting in the image area, the priority of that heating element will be set to "low."

[0080] When the processor 11 determines that the priority of the heating element in which the disconnection was detected is "high" (ACT51, YES), it executes the error processing corresponding to the heating element with "high" priority. The data memory 14 stores setting information indicating the content of the error processing (high priority error processing) when the priority of the heating element in which the disconnection was detected is "high".

[0081] For example, high priority error processing may be set to the timing at which the printing operation of the print image is stopped, the content of the print defect mark (described later), etc. Here, the timing at which the printing operation is stopped as high priority error processing is set to either "immediately" or "at the end of page printing." In this case, the processor 11 determines whether the high priority error processing is to stop the printing operation of the print image immediately or at the end of page printing (ACT 52).

[0082] When the processor 11 determines that the printing operation should be stopped immediately (ACT52, YES), it immediately stops the printing operation of the print image being executed (ACT53). The processor 11 stops the transport of the label paper on which the label material is placed as the printing medium, and stops the driving of the thermal head 23 by the head driving unit 22.

[0083] When the processor 11 immediately stops the printing operation, it prints information (a print defect mark) indicating that there is a print defect in the image printed on the label material (a break in the heating element has been detected) (ACT54). For example, after immediately stopping the printing operation, the processor 11 causes the conveyance motor 27 to backfeed the label material on which printing has stopped. The processor 11 moves the label material by backfeeding to the print start position or the print defect mark start position.

[0084] When the label material moves to the print start position or the print defect mark print start position, processor 11 again transports the label material in the specified transport direction at the specified print speed. While transporting the label material in the specified transport direction, processor 11 controls the heat generation of each heating element of thermal head 23 to print a print defect mark on the label material.

[0085] FIG. 9 is a diagram showing an example of a print defect mark 91 that is printed on the label material when a break (malfunction) is detected in a high priority heating element. The print defect mark 91 indicates that the label was printed using a heating element that was detected to be disconnected (malfunctioning) in an image area with a high priority setting. The print defect mark 91 printed on the label makes it clear that the label cannot be used (there is missing printing) because the print defect mark 91 is printed over the printed image.

[0086] The print defect mark 91 shown in Fig. 9 is a diagonal line printed across the entire label material on which the print image is printed. However, the print defect mark 91 is not limited to the one shown in Fig. 9, and may be any mark that indicates that an image area with a high priority setting has been printed with a malfunctioning element. For example, the print defect mark may be a variety of marks, or may be a character string such as "VOID" set by the user that is printed on the label material.

[0087] Furthermore, when processor 11 detects a break in the heating element, it notifies an error that a break in the heating element has been detected (ACT 55). For example, processor 11 displays an error notification screen on display unit 16, which displays information indicating the position of the heating element in which the break has been detected.

[0088] FIG. 10 is a diagram showing an example of an error notification screen that is displayed on the display unit 16 when a break in a heating element is detected by the break check. 10, the display unit 16 displays, as an error notification screen, information indicating the heating element in the thermal head 23 in which a break (malfunction) has been detected by the break check. In the display example shown in Fig. 10, text information indicating the position of the heating element in which the break was detected and a solid line indicating the position in the printed image are displayed. This allows the operator to clearly identify the heating element in which the break was detected.

[0089] Furthermore, the processor 11 may notify the host computer 2 via the communication unit 15 that a break in a heating element has been detected. For example, when the processor 11 stops a printing operation, it may notify the host computer 2 that the printing operation has been stopped because a break in a heating element has been detected. This allows the host computer 2 to recognize from the notification from the label printer 1 that printing has been stopped due to the detection of a break in a heating element.

[0090] Furthermore, when the processor 11 determines that the printing operation will not be stopped immediately but will be stopped when the page printing is completed (ACT52, NO), it performs a stop setting to stop the printing operation when the page printing is completed (ACT56). When the stop setting is performed when the page printing is completed, the processor 11 continues the printing operation of the print image of the page, and stops the printing operation when the printing of the print image of the page is completed.

[0091] The stop setting may not only stop the printing operation when page printing is completed, but also print a print defect mark 91 on the label material as shown in Fig. 9. When the stop setting includes printing a print defect mark, the processor 11 stops the printing operation when page printing is completed, and then executes processing to print a print defect mark on the label material.

[0092] Furthermore, even if processor 11 determines that the printing operation should be stopped at the end of page printing, it also issues an error notification indicating the heating element in which a break has been detected (ACT 55). For example, processor 11 displays an error notification screen on display unit 16 as shown in Fig. 10 described above. Furthermore, processor 11 may display an error notification screen on display unit 16 that includes not only information indicating the heating element in which a break has been detected, but also a notice that the printing operation will be stopped at the end of page printing.

[0093] When the processor 11 is set to stop printing at the end of page printing as described above, it can continue printing the print image of that page while reporting an error. In this case, after the printing operation of the print image of that page is completed, the processor 11 executes the operation based on the stop setting as described above. This allows the processor to stop printing at the end of printing of that page while reporting an error, even if the priority of the heating element in which a break was detected is high.

[0094] Furthermore, if the priority of the heating element in which a break has been detected is "low" (ACT51, NO), the processor 11 executes error processing corresponding to the "low" priority (low priority error processing). The data memory 14 stores setting information indicating the content of the error processing for the low priority heating element in which a break has been detected. Here, the low priority error processing is set to print additional information indicating that there is a break in the print image (missing print) without stopping the printing operation. In this case, the processor 11 sets the additional printing of information indicating that there is a heating element in which a break has been detected while continuing the printing operation based on the setting information (ACT57).

[0095] FIG. 11 is a diagram showing an example of information to be additionally printed when a break in a heating element corresponding to an image area with a low priority setting is detected. In the example shown in FIG. 11, a position mark 92 and a print-omitted mark 93 are additionally printed on top of the print image as a low-priority error process.

[0096] The position mark 92 is a mark that indicates the printing position of the heating element (low priority heating element) where a break has been detected. A label with the position mark 92 printed on it can clearly indicate that the printing at the position indicated by the position mark 92 may be missing.

[0097] Additionally, print missing mark 93 indicates that the print image was printed using a thermal head that includes the heating element in which a break was detected. Because print is missing in the heating element in which a break was detected, print missing mark 93 is a mark that indicates that there is a print missing. A label with print missing mark 93 printed on it can clearly indicate that there may be an area in the printed image where print is missing.

[0098] 11, the position mark 92 and the print-omitted mark 93 are printed in an area subsequent to the printing end line of the print image of the page. This allows the marks 92 and 93 to be additionally printed after printing of the print image of the page has finished. In other words, even if additional printing of the marks 92 and 93 is set during the printing operation of the print image, the marks 92 and 93 can be additionally printed without stopping the printing operation.

[0099] The additionally printed information may be any information indicating that it was printed by the thermal head 23 that includes the heating element in which the disconnection was detected, and is not limited to the example shown in Fig. 11. For example, the additionally printed information may be only either the position mark 92 or the print-missing mark 93, or it may be another mark, or it may be a character string, etc.

[0100] Furthermore, even when additional printing is set, the processor 11 issues an error notification indicating the heating element in which a break has been detected (ACT55). For example, the processor 11 displays an error notification screen such as that shown in Fig. 10 on the display unit 16. Furthermore, the processor 11 may display on the display unit 16 not only information indicating the heating element in which a break has been detected, but also a message indicating that the printing operation of the print image will continue.

[0101] When the additional printing setting is performed as described above, the processor 11 returns to ACT 40 after reporting an error and continues the printing operation of the print image. As a result, if the priority of the heating element in which the disconnection was detected is low, the processor 11 can continue the printing operation while reporting an error and perform additional printing on the label.

[0102] As described above, the label printer according to the embodiment performs an open circuit check on heating elements that are determined to require an open circuit check based on the priority setting for each image area. When the label printer according to the embodiment detects an open circuit in a heating element during the open circuit check, it performs error processing according to the priority setting for the image area printed by the heating element for which the open circuit was detected. This allows the label printer according to the embodiment to perform error processing according to the print quality required for the image area printed by the heating element for which the open circuit was detected.

[0103] Furthermore, the label printer according to the embodiment stops printing and notifies an error if the priority setting for the image area corresponding to the heating element in which a break has been detected is high, and continues printing while notifying an error if the priority setting for the image area corresponding to the heating element in which a break has been detected is low.

[0104] As a result, the label printer according to the embodiment can stop printing and report an error if a break is detected in a heating element that has printed an image area that requires high print quality. Furthermore, the label printer according to the embodiment can report an error without stopping printing if a break is detected in a heating element that has printed an image area where low quality is acceptable.

[0105] Furthermore, in the above embodiment, the ROM 12 or data memory 14 of the label printer 1 stores a program for the processor 11 to execute the above-described processing or control. An individually assigned program may be written to the data memory 14, which is a writable storage device provided in the label printer 1, in response to an operation by an administrator or the like. The program may also be stored and assigned on a removable, non-transitory, tangible computer-readable storage medium, or may be assigned via communication via a network. The non-transitory, tangible computer-readable storage medium may be any medium capable of storing program data, such as an optical disk or memory card, and readable by the device.

[0106] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0107] 1...label printer, 2...host computer, 11...processor, 12...ROM, 13...RAM, 14...data memory, 15...communication unit, 16...display unit, 17...operation unit, 18...printing mechanism, 21...sensor group, 22...head drive unit, 23...thermal head, 24...heating element (element), 25...disconnection check circuit (check circuit), 26...motor drive unit, 27...conveyor motor, 28...ribbon drive unit, 29...ribbon motor

Claims

1. a transport motor that transports the print medium to a printing position; a thermal head including a plurality of heating elements arranged in a print line perpendicular to the transport direction of the print medium at the printing position; a head driving unit that drives each heating element to generate heat in accordance with image data for each printing line of a print image; A check circuit that checks for malfunctions of each heating element; a processor that uses the check circuit to check for malfunctions of heating elements that are determined to need to be checked for malfunctions based on priority settings for each image area in the print image; An image forming apparatus comprising:

2. the processor executes a check for malfunction using the check circuit during a period when a non-printed area in the print image passes through the print position; The image forming apparatus according to claim 1 .

3. When printing a plurality of pages of print images continuously, the processor executes a check for malfunctions using the check circuit during a period from the end of printing of a print image of a certain page to the start of printing of a print image of a next page. The image forming apparatus according to claim 1 .

4. When the check circuit detects a malfunction of a heating element, the processor executes an error process according to the priority level of the image area corresponding to the heating element in which the malfunction is detected. The image forming apparatus according to claim 1 .

5. The processor stops the printing operation and notifies the error when the priority setting of the image area corresponding to the heating element for which the check circuit has detected a malfunction is high, and notifies the error while continuing the printing operation when the priority setting of the image area corresponding to the heating element for which the check circuit has detected a malfunction is low. The image forming apparatus according to claim 4 .

Images