JP2015214064A - Transport device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a transport device capable of starting transport processing in a short time by reducing standby time to adjust temperatures for thermal drying processing even when the kind of a sheet or the content of an image is changed; and a printing apparatus.SOLUTION: Transport of a sheet is started at timing t1 at which standby time until starting the transport is minimized under conditions that the sheet is smoothly transported at a predetermined speed, in a state in which a target temperature is achieved in each of a plurality of effective regions disposed along a transport passage.

Description

  The present invention relates to a conveying apparatus that performs a thermal drying process on a conveyed sheet.

  In an inkjet printing apparatus that uses solvent-based ink typified by solvent ink or the like, a thermal drying process may be performed on a print sheet using a plurality of heaters. The temperature suitable for the thermal drying process varies depending on the type of sheet and the amount of ink applied, but it takes time to realize the suitable temperature with a heater. Therefore, every time the type of sheet or the content of the image changes, time is consumed for temperature adjustment, and print throughput may be reduced.

  Patent Document 1 discloses a technique for adjusting the temperature of a fixing device by using a time for rendering image data in an electrophotographic copying machine that performs thermal fixing after applying a color material, although it is not an inkjet printer. Yes.

JP 2011-207224 A

  In an ink jet type raster printer, a printing operation is generally started using processed data before rendering of the entire page is completed. Therefore, even if the temperature adjustment of the heater is started together with rendering as in Patent Document 1, the printed sheet reaches the heat drying section before the heater is adjusted to an appropriate temperature, and an appropriate heat drying process is performed. There is a risk that it cannot be applied.

  The present invention has been made to solve the above problems. Therefore, the purpose is to suppress the waiting time for adjusting the temperature of the thermal drying process and to start the transport process in a short time even if the type of sheet or the content of the image changes. It is to provide a transport device.

  To this end, the present invention provides a plurality of heaters arranged along a path along which a sheet is conveyed, an acquisition unit that acquires a required time from the current time until the target temperature is reached for each of the plurality of heaters, And determining means for determining a timing at which sheet conveyance is started so that the sheet is conveyed without stagnation based on the acquisition by the acquisition means.

  According to the present invention, since the start timing for conveying a sheet to a path having a plurality of heaters is optimally determined, the sheet can be conveyed with a short standby time. A printing apparatus to which this is applied improves the total print throughput.

Sectional view of printing apparatus usable in the present invention Block diagram for explaining the configuration of control in the printing apparatus Flow chart for explaining heater drive control Flow chart for explaining heater drive control The figure explaining the temperature control of a heater and the conveyance control of a sheet | seat with elapsed time The figure which shows the conveyance state of the image area | region of a preceding job The figure explaining temperature control and conveyance control about two jobs with elapsed time Flowchart showing determination processing when operation of the apparatus is interrupted

(First embodiment)
FIG. 1 is a schematic diagram of an internal configuration of a printing apparatus 200 that can be applied as a conveying apparatus of the present invention. The sheet S held in a roll shape by the holding unit 106 is pulled out in accordance with an input of a print job, and is supplied to the conveyance path. The conveyance path includes a platen 100 that supports the sheet S from below and guides the path, and a plurality of conveyance rollers 105 that contact the sheet S on the platen 100 and move in the conveyance direction.

  A preheater 104, dry heaters 102 and 103, and a cure heater 101 are arranged in the middle of the transport path, and a print head 107 that discharges ink according to print data is provided between the preheater 104 and the dry heater 102. Has been. Each of the heaters 101 to 104 may have a form using a heat transfer wire or may be a form such as a halogen heater. Further, a fan for blowing the heat of the heater may be provided, and these four heaters may have different forms.

  The preheater 104 is a heater for preliminarily heating the sheet S before ink is applied by the print head 107. An effective area 111 that is a part of the sheet conveyance path indicates a range to which the heating effect of the preheater 104 extends. The dry heaters 102 and 103 are heaters for heating the sheet S from the front and back surfaces and evaporating ink applied by the print head 107. The effective area 112 indicates a range in which the heating effect of the dry heaters 102 and 103 is reached. The cure heater 101 is a heater for heating the sheet S after the ink is evaporated by the dry heaters 102 and 103 to promote image fixing. The effective area 113 indicates a range where the heating effect of the cure heater 101 reaches. Thus, each heater has its own role, and a suitable temperature (target temperature) for that role is determined independently. Each of the effective areas 111 to 113 is provided with a temperature sensor for detecting the temperature of the area, so that the power of these heaters can be adjusted and ON / OFF can be switched based on the detected temperature. It has become.

  FIG. 2 is a block diagram for explaining a control configuration in the printing apparatus 200. When a desired image is to be printed, the host computer 290 combines the print condition information for printing the image with the image data to be printed, and transmits it to the printing apparatus as a print job. Here, the print condition information is information for designating the type of sheet to be printed, the print quality, and the like, and the controller 210 determines an appropriate print mode from the information, and the printer engine via the I / F 220 and 139. 250.

  The CPU 230 of the printer engine 250 sets the first to third target temperatures corresponding to the individual heaters 101 to 104 based on the received print mode. However, such a print mode and target temperature may be set by the user using the display device 241. Further, such target temperature may be specified in the information received by the printer engine 250.

  On the other hand, the CPU 230 uses the detection values of the temperature sensors 108 to 110 associated with the heaters 101 to 104 provided in the apparatus and the detection values of the temperature sensor 235 and the humidity sensor 236 provided in the printing apparatus. get. And after considering that the degree of temperature rise of each heater also depends on the temperature and humidity of the environment, based on the target temperature and the detected temperature and humidity of each sensor, for each of the heaters 101 to 104, Set driving conditions such as ON / OFF switching and power. The memory 238 stores a table in which the required time until the target temperature is realized is associated with the set driving condition for each of the heaters 101 to 104. Under such a configuration, the CPU 230 of the printer engine drives the heaters 101 to 104 at appropriate timings based on the set driving conditions.

  On the other hand, in parallel with such drive control, the CPU 212 of the controller 210 executes image processing of image data. The CPU 212 stores image data included in the received print job in the RAM 218 via the memory controller 219 and also stores the same information in the HDD 240 via the HDD interface 214. The stored image data is subjected to predetermined image processing by the image processing unit 213 and converted into print data that can be printed by the print head 107. Thereafter, the generated print data is transferred to the printer engine 250 via the interface 220, and a printing operation is executed. Specifically, the print head 107 performs an ejection operation according to the print data, and the conveyance motor 237 rotates the conveyance roller 105 and conveys the sheet S in synchronization with this. Such image processing by the image processing unit 213, transfer processing to the printer engine 250, and printing operation by the printer engine 250 are executed for each predetermined unit by pipeline processing on the image data stored in the HDD 240. .

  FIG. 3 is a flowchart for explaining heater drive control executed by the CPU 230. Here, a case will be described in which the print operation is not performed immediately before and a print job is received at a timing when all the heaters 101 to 104 are in a standby state.

  When this process is started, the CPU 230 first starts temperature control of the preheater 104 located on the most upstream side of the transport path in step S301. In subsequent step S302, temperature control of the dry heaters 102 and 103 is started. In step S303, the temperature control of the cure heater 101 located on the most downstream side of the transport path is started. Specific steps of each temperature control will be described later.

  In step S304, the CPU 230 acquires a required time Tp from the current time until the preheater 104 achieves the target temperature based on the detected temperature of the temperature sensor 108 and the target temperature of the preheater 104. Such a required time Tp may be calculated using various parameters, or a table in which the required time Tp for the detected temperature and the target temperature is stored in advance in the memory 238 and obtained by reading from this table. You may do it.

  In step S <b> 305, the required time Tp acquired in step S <b> 304 is compared with the conveyance time Tp <b> 0 from when the printing operation starts until the leading edge of the sheet reaches the effective area 111 of the preheater 104. The conveyance time Tp0 is a fixed value corresponding to the conveyance speed and conveyance distance of the sheet, and can be stored in the memory 238 in advance. If Tp> Tp0, it is determined that the printing operation (conveying operation) cannot be started yet, and the process returns to step S304. On the other hand, if Tp ≦ Tp0, that is, if the conveyance time Tp0 until the sheet reaches the effective area 111 is equal to or longer than the required time Tp, the process proceeds to step S306.

  In step S306, based on the temperature detected by the temperature sensor 109 and the target temperature of the dry heaters 102 and 103, the CPU 230 obtains the required time Td from the current time until the dry heaters 102 and 103 reach the target temperature. Such a required time Td may be calculated using various parameters, or a table in which the required time Td for the detected temperature and the target temperature is stored in the memory 238 in advance, and is obtained by reading from this table. You may do it.

  In step S307, the required time Td acquired in step S304 is compared with the conveyance time Td0 from the start of the printing operation until the leading edge of the sheet reaches the effective area 112 of the dry heaters 102 and 103. Similarly to the transport time Tp0, the transport time Td0 is a fixed value corresponding to the transport speed and transport distance of the sheet, and can be stored in the memory 238 in advance. If Td> Td0, it is determined that the printing operation (conveyance operation) cannot be started yet, and the process returns to step S304. On the other hand, if Td ≦ Td0, that is, if the conveyance time Td0 until the sheet reaches the effective area 112 is longer than the required time Td, the process proceeds to step S308.

  In step S <b> 308, the CPU 230 acquires a required time Tc from the current time until the cure heater 101 reaches the target temperature, based on the temperature detected by the temperature sensor 110 and the target temperature of the cure heater 101. Such a required time Tc may be calculated using various parameters, or a table in which the required time Tc for the detected temperature and the target temperature is stored in advance in the memory 238 and obtained by reading from this table. You may do it.

  In step S309, the required time Tc acquired in step S308 is compared with the conveyance time Tc0 from the start of the printing operation until the leading edge of the sheet reaches the effective area 113 of the cure heater 101. Similarly to the conveyance time Tp0 and the conveyance time Td0, the conveyance time Tc0 is a fixed value corresponding to the conveyance speed and conveyance distance of the sheet, and can be stored in the memory 238 in advance. If Tc> Tc0, it is determined that the printing operation (conveying operation) cannot be started yet, and the process returns to step S304. On the other hand, if Tc ≦ Tc0, that is, if the conveyance time Tc0 until the sheet reaches the effective area 113 is longer than the required time, the process proceeds to step S310.

  In step S310, a printing operation (conveying operation) is started. That is, the sheet S is pulled out from the holding unit 106 and conveyed on the conveyance path at a predetermined speed. During the conveyance, the effective area 111 is heated to a target temperature by the preheater 104, and then an image according to the print data is printed by the print head 107. Further, in the effective region 112, heating at a target temperature is performed by the dry heaters 102 and 103, and in the effective region 113, heating according to the target temperature is performed by the cure heater 101.

  If a print job is canceled during the execution of the above process, the CPU 230 stops the process and returns the printing apparatus to a standby state or a state before the print job is input. This process is completed.

  FIGS. 4A to 4C are flowcharts for explaining the drive control process executed by the CPU 230 for each of the heaters 101 to 104. 4A is a flowchart showing the drive control of the pre-heater 104, FIG. 4B is a flowchart showing the drive control process of the dry heaters 102 and 103, and FIG. 4C is the drive control of the cure heater 101. It is a flowchart which shows this process. These three flowcharts are started in steps S301, S302, and S302 in FIG. 3, and then processed in parallel with the flowcharts. Since both flowcharts have the same contents, here, the drive control of the pre-heater 104 will be described as an example with reference to FIG. However, since the target temperature is determined independently in each of the effective regions 111 to 113, the target temperature may not be the same value.

  When this process is started, the CPU 230 starts drive control based on the set target temperature and the current temperature detected by the temperature sensor 108 in step S321. Specifically, when the target temperature is higher than the detected temperature, it is necessary to increase the temperature of the effective region 111, so the preheater 104 is turned on. On the other hand, when the target temperature is lower than the detected temperature, the preheater 104 is turned OFF because the temperature of the effective region 111 needs to be lowered. At this time, as a method of lowering the temperature, natural heat radiation with the preheater 104 turned off may be used, but a method of cooling more positively by separately providing a cooling device may be adopted.

  In subsequent step S322, CPU 230 obtains the current temperature from temperature sensor 108, and determines whether or not the target temperature has been reached. If it is determined that the target temperature has not yet been reached, the process returns to step S321, and steps S321 and S322 are repeated until the target temperature is reached. If it is determined that the target temperature has been reached, the process proceeds to step S323.

  In step S323, the CPU 230 ends the drive control of the preheater 104 started in step S321. This process is completed.

  FIG. 5 is a diagram for explaining the temperature control and sheet conveyance control for the heaters 101 to 104 executed by the CPU 230 together with the elapsed time. In the figure, the upper part shows the temperature control for each heater, and the lower part shows the conveyance control until each effective area is reached. The horizontal axis represents time, t0 represents the timing at which a print job is input to the printing apparatus, and t1 represents the timing at which the printing operation (conveyance operation) starts. Furthermore, t2 to t4 indicate the timing at which the leading edge of the sheet reaches each of the effective areas 111 to 113.

  When a print job is input, the CPU 230 starts temperature control (upper stage) for the heaters 101 to 104 in steps S301 to S303 in FIG. Here, the time until the preheater 104 achieves the target temperature is expressed as tp, the time until the dry heaters 102 and 103 realize the target temperature is expressed as td, and the time until the cure heater 101 realizes the target temperature is expressed as tc. Yes. Since the heating method and the target temperature are different for each heater 101 to 104, the time to reach the target temperature is also different for each heater. In the figure, the dry heaters 102 and 103 are the fastest and the cure heaters are the slowest and reach their target temperatures (td <tp <tc).

  Referring to FIG. 3 again, in steps S304 to S309, the CPU 230 determines the time required for each heater to reach the target temperature from the current time until the leading edge of the sheet reaches the effective area of each heater. It has been confirmed that For all the heaters, the process proceeds to step S310 at the timing when the above confirmation is obtained, and the printing operation, that is, the conveyance of the sheet is started.

  In the case of FIG. 5, the confirmation is most delayed in the case of the preheater 104. That is, when Tp ≦ Tp0 is confirmed in step S305, the CPU 230 proceeds to step S310. At this timing, Td ≦ Td0 is sufficiently satisfied in step S307 and Tc ≦ Tc0 is sufficiently satisfied in step S309. As a result, referring to FIG. 5, the timing at which the leading edge of the sheet reaches the effective area 111 coincides with the timing at which the effective area 111 reaches the target temperature at t2 by starting the conveyance operation at timing t1 when Tp = Tp0. To do. Therefore, it is not necessary to wait for the target temperature to be realized at this timing t2, and the sheet conveyance can be continued. Thereafter, at the timing t3 when the leading edge of the sheet reaches the effective area 112, the temperature control of the effective area 112 has already been completed, and the sheet conveyance can be continued. Further, at the timing t4 when the leading edge of the sheet reaches the effective area 113, the temperature control of the effective area 113 has already been completed, and the sheet conveyance can be continued.

  As described above, according to the present embodiment, the time required from the present time until the target temperature is reached for each of the plurality of heaters is acquired, and based on the acquisition, the sheets of the plurality of heaters can be obtained without predetermined stagnation. The timing for starting sheet conveyance is determined so as to be conveyed. At this time, for each of the plurality of effective areas, the timing is determined so that the conveyance time from the start of sheet conveyance to the arrival of each effective area does not fall below the required time. Accordingly, it is possible to perform a suitable printing operation without delaying the conveyance operation after the conveyance operation is started, while minimizing the standby time before the printing operation is started. Since the start timing for conveying the sheet to the path having a plurality of heaters is optimally determined, the standby time is short and the total print throughput is improved.

  In the above description, the continuous sheet held in a roll shape is described as being subjected to print processing and conveyance processing. However, the sheet may be a cut sheet. Further, although the target temperature for each effective area has been described with the content determined by the print mode, the target temperature may be adjusted according to the amount of ink applied to the sheet. In this case, the image processing unit 213 of the controller 210 may estimate the ink application amount for each page based on the input image data, and a target temperature corresponding to this may be set for each page.

(Second Embodiment)
In the first embodiment, a case has been described in which a print job is received at a timing when the printing apparatus is in a standby state (cold start). In contrast, in the present embodiment, a case where a print job is received at a timing when the three heaters are warmed to some extent, such as when the print job is continuously input, will be described (warm start).

  FIG. 6 is a diagram illustrating a conveyance state of an image area of a preceding job in the printing apparatus described with reference to FIG. The figure shows a state immediately after the image area (bold line portion) of the preceding job has passed through the effective area 111 of the preheater 104. At such timing, the CPU 230 can start the temperature control of the preheater 104 according to the next job. That is, the target temperature is updated to the target temperature of the next job.

  FIG. 7 is a diagram for explaining temperature control and sheet conveyance control for the heaters 101 to 104 executed by the CPU 230 together with elapsed time when two print jobs are continuously input. As in FIG. 5, the horizontal axis indicates time, and t0 indicates the timing at which two continuous print jobs (hereinafter referred to as the first job and the second job) are input to the printing apparatus. Further, t2 to t4 indicate timings at which the image area of the sheet corresponding to the first job reaches the effective areas 111 to 113, and t2 ′ to t4 ′ indicate timings at which the image area leaves the effective areas 111 to 113. Show. Here, a period during which the image area of the first job passes through the effective areas 111 to 113, that is, a period during which the heat treatment is actually performed is indicated by a band. Since the image area having a certain width moves in order through the effective areas 111 to 113, the three heat treatment periods overlap each other on the time axis.

  The conveyance state as shown in FIG. 6 is realized at the timing t2 ′. Therefore, the CPU 230 starts temperature control for the second job input subsequently with respect to the preheater 104 from this time point. However, at this time, the image area of the first job still exists in the effective area 112 and the effective area 113, and the temperature control for the dry heaters 102 and 103 and the cure heater 101 cannot be started. Therefore, the CPU 230 starts the temperature control for the dry heaters 102 and 103 from the timing t3 ′ when the image area of the first job has passed through the effective area 112. Further, temperature control for the cure heater 101 is started at timing t4 ′ when the image area of the first job has passed through the effective area 113. As described above, when a plurality of print jobs are continuously input, the CPU 230 starts temperature control of all heaters simultaneously (t0) for the first job. On the other hand, for the succeeding job, the temperature control of each heater is started at the timing when the image area of the preceding job leaves the effective area.

  In this embodiment, by performing such temperature control, the confirmation time in steps S304 to S309 in FIG. 3 can be advanced. As a result, it is possible to shorten the printing time for the second job input subsequently.

  If only the first job is canceled while the processing for the first job input in advance is being executed, the second job is switched to the first job from that timing. The process for the second job may be performed in the described process. In the case where the time difference between the input of the first job and the input of the second job is large and the second job is not input at the timing t2 ′, the CPU 230 consumes power during the standby time if the preheater 104 is turned off. Can be suppressed.

(Third embodiment)
In the present embodiment, a case will be described in which a plurality of jobs are continuously input and the job being processed cannot be continued. When the operation of the apparatus cannot be continued for some reason instead of inputting a cancel command, a job whose processing has been interrupted and a plurality of continuous jobs are held in an unprocessed state. In this case, there is a situation in which the time required to process all the jobs varies depending on which of the held jobs is processed in advance at the timing when the apparatus is restored. For example, when the target temperature of the heater set for the interrupted first job is higher than the target temperature set for the subsequent second job, the heater temperature at the timing when the apparatus is restored is higher than the target temperature of the first job. May be close to the target temperature of the second job. In this case, it is possible to reduce the overall required time by processing the second job first and then processing the first job rather than processing the first job in advance. In the present embodiment, a method for determining the processing order in such a situation will be described.

  FIGS. 8A and 8B are flowcharts for explaining a determination process executed by the CPU 230 at a timing when the operation of the apparatus is interrupted and the apparatus is subsequently restored. When this process is started, first, the CPU 230 confirms the command in step S701, and whether the target temperature of the interrupted first job is set automatically or whether it is set manually by the user. Judging. If it is determined that it has been manually set, the process advances to step S702.

  In step S702, the CPU 230 confirms the priority setting. If priority is set for the first job, the process advances to step S704 to set three target temperatures for the first job, and the processing described with reference to FIG. 3 is started. In other words, in any of the effective areas 111 to 113, the first transport operation after the apparatus is restored is performed with the shortest waiting time such that the target temperature of each effective area is realized when the image area of the first job arrives. Start.

  If priority is set for the second job subsequent to the first job, the process proceeds to step S705 to set three target temperatures for the second job, and the processing described in FIG. 3 is started. That is, for any of the effective areas 111 to 113, the first transport operation after the apparatus is restored is performed with the shortest waiting time such that the target temperature of each effective area is realized when the image area of the second job arrives. Start.

  On the other hand, if it is determined in step S701 that the target temperature of the first job is automatically set, the process proceeds to step S703, and the processing order is reset.

  FIG. 8B is a flowchart for explaining the process of resetting the processing order, which is executed in step S703. When this process is started, the CPU 230 first checks the current temperatures of the effective regions 111 to 113 using the temperature sensors 108 to 109 in step S731. Then, the processing order is set based on which of the three target temperatures of the first job and the three target temperatures of the second job is realized in a short time. For example, when the current temperature is detected in the effective areas 111 to 113 and it is determined that the current temperature is closer to the target temperature of the first job than the target temperature of the second job in two or more areas, processing is performed in advance. A first job is set as the job. In step S732, three target temperatures are set for the first job, and the process described with reference to FIG. 3 is started.

  On the other hand, if it is determined that the current temperature is closer to the target temperature of the second job than the target temperature of the first job in two or more areas, the second job is set as a job to be processed in advance. In step S733, three target temperatures are set for the second job, and the process described with reference to FIG. 3 is started. This process is complete | finished above.

  In the embodiment described above, the conveyance apparatus including three effective areas has been described. However, the number of effective areas, that is, the types of heaters is not limited to three. For example, even if the cure heater 101 and the effective area 113 described in the above embodiment are not present, the effect of the present invention can be exhibited if the other two heaters and the effective area exist. Even when four or more heaters and an effective area are provided, the conveying operation can be performed in the shortest standby time in which the target temperature of the effective area is realized at the timing when the sheet arrives in any effective area. If started, the same effect as described above can be obtained.

  In the above description, the printing apparatus having the print head between the effective area 111 and the effective area 112 has been described as an example. However, the transport apparatus of the present invention is not limited to such a printing apparatus. . If the sheet conveyed for some purpose is configured to require heat treatment at a target temperature in each of the plurality of regions, the present invention functions effectively.

S sheet
101 Cure heater 102, 103 Dry heater
104 Preheater 111-113 Effective area
210 Printer controller
230 CPU
250 Printer engine

Claims (7)

A plurality of heaters arranged along a path along which the sheet is conveyed;
For each of the plurality of heaters, an acquisition means for acquiring a required time from the current time until the target temperature is reached;
And a determining unit that determines a timing at which sheet conveyance is started so that the sheet is conveyed without a delay through the plurality of heater regions based on the acquisition by the acquisition unit. A plurality of temperature sensors for detecting the temperature of each of the effective areas of the plurality of heaters;
The acquisition means acquires the required time for each of the plurality of effective regions from the detection results of the plurality of temperature sensors and the plurality of target temperatures,
The determination unit determines the timing for each of the plurality of effective areas so that the conveyance time from the start of sheet conveyance to the arrival of each effective area does not fall below the required time. The transport apparatus according to claim 1. The path is provided with printing means for printing an image by applying ink to the conveyed sheet,
Among the plurality of effective areas, an effective area located upstream of the printing unit is an area for preheating the sheet before ink is applied by the printing unit, and is downstream of the printing unit. The transport apparatus according to claim 1, wherein the effective area located in is an area for promoting evaporation of ink to which ink has been applied by the printing unit.   A plurality of sheets are conveyed on the path corresponding to the plurality of input jobs, and the acquisition unit sets a target temperature for each of the plurality of effective areas for each of the plurality of jobs. The transport apparatus according to any one of claims 1 to 3, wherein the transport apparatus is characterized in that   The acquisition unit is configured so that, even when there is an effective area in the middle of performing the heat treatment corresponding to the previously input job among the plurality of effective areas, The transport apparatus according to claim 4, wherein a target temperature for a subsequent job is set for the effective area.   5. The acquisition unit according to claim 4, wherein each of the plurality of effective areas is updated to a target temperature for a job input subsequently at a timing when the job for the sheet being processed is cancelled. The conveying apparatus as described in.   The acquisition means sets or subsequently inputs a target temperature for the interrupted job for each of the plurality of effective areas at a timing when the heating process for the sheet being processed is interrupted and further restored. 5. The conveying apparatus according to claim 4, wherein whether to set a target temperature for a job is determined based on a current temperature of each of the plurality of effective areas.

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