Patent Description:
Sublimation thermal transfer type printing apparatuses capable of printing an image shot by a digital still camera, a smartphone, or any other image shooting apparatus are known. Sublimation thermal transfer type printing is a printing method in which a heated thermal head is pressed against an ink ribbon to sublimate ink from solid to gas and apply the ink to a printing sheet. Recently, sublimation thermal transfer type printing apparatuses are demanded to have portability, and highly portable type small printing apparatuses with built-in batteries are popularly used. Many of such small-sized printing apparatuses with built-in batteries are each configured to charge the battery with power received from an external device through a general-purpose external connection interface (hereinafter, simply referred to as an interface or an I/F) such as USB.

Since a thermal head in such a sublimation thermal transfer type printing apparatus includes a large number of heating elements, it is demanded to supply regulated power to the thermal head. Further, a power supply source for such a sublimation thermal transfer type printing apparatus is demanded to have an ability to supply power to all the heating elements substantially simultaneously. However, such power supply increases the load on the power supply source.

Sublimation thermal transfer type printing apparatuses make high electrical loads as described above, and further demand stable power supply without instantaneous interruption. If such a sublimation thermal transfer type printing apparatus is to perform printing with power supplied from an I/F other than the specified power supply adapter, it may cause issues such as adverse effects on printing quality and abnormal heat generation in a terminal portion of the printing apparatus may occur. Therefore, there are few small sublimation thermal transfer type printing apparatuses for printing high-definition photographs, which can perform printing while being directly driven with external power received from an I/F to which various devices such as a USB are connected. Most printing apparatuses supplied with power from USB interfaces are each configured to perform printing while being driven with prescribed power from a built-in battery or a dedicated battery connected to itself.

For example, in response to receiving a print instruction from a user, the printing apparatus described in <CIT> checks the remaining battery level before the start of printing, and stops the printing execution when determining that the battery is in a low battery state such that printing on one sheet is not executable.

For another example, after starting charging, the printing apparatus described in <CIT> continues the charging until the remaining battery level becomes sufficient for printing on at least one sheet.

However, in response to receiving a print instruction from a user, the printing apparatus described in <CIT> is not allowed to start the printing operation under the condition that the remaining battery level is insufficient for printing on one sheet, even if the printing apparatus is externally supplied with power from the I/F. Such a printing apparatus thus has room for improvement. On the other hand, the printing apparatus described in <CIT> in the similar situation charges its battery until the remaining battery level becomes sufficient for printing on at least one sheet, which causes a long standby time while the printing apparatus is charging the battery. Such a printing apparatus thus also has room for improvement. <CIT> discloses a printer according to the preamble of claim <NUM>.

The present invention provides printing apparatuses, control methods thereof, and storage media, capable of starting reliable printing quickly even if the remaining battery level is insufficient for printing on one sheet when power is supplied from an external connection I/F and of shortening the standby time caused by battery charging.

Accordingly, a first aspect of the present invention provides a printing apparatus as specified in claims <NUM> to <NUM>.

Accordingly, a second aspect of the present invention provides a method for controlling a printing apparatus as specified in claim <NUM>, and a third aspect of the present invention provides a non-transitory computer-readable storage medium as specified in claim <NUM>.

According to the present invention, the printing apparatus is capable of starting reliable printing quickly even if the remaining battery level is insufficient for printing on one sheet when power is supplied from an external connection I/F and of shortening the standby time caused by battery charging.

The present invention will now be described in detail below with reference to the accompanying drawings showing embodiments thereof.

Hereinafter, a first embodiment will be described in detail with reference to <FIG>.

In the following description, "printing" refers to the entire series of processes or operations of a printing apparatus from when the printing apparatus performs image-printing on a printing medium based on a print instruction from a user to when the printing apparatus ejects the printing medium. Furthermore, "image-printing" refers to a process or operation of a printing apparatus in the printing, which forms an image on a printing medium (also referred to as a printing sheet or simply a "sheet") by thermally transferring a transfer material (ink or overcoat) applied to an ink sheet or in ribbon onto the printing medium.

<FIG> illustrate external perspective views of a printer <NUM> as a printing apparatus according to the present embodiment and an ink ribbon cassette <NUM> used in the printer <NUM>. Specifically, <FIG> illustrates a perspective view of the printer <NUM> as viewed from the top side, and <FIG> is a perspective view of the printer <NUM> as viewed from the bottom side.

The printer <NUM> is a printing apparatus configured to perform image-printing by thermally transferring inks of multiple colors applied to an ink ribbon onto a printing medium in a superimposed manner. As described later, the printer <NUM> includes a conveyance unit for conveying a printing medium, and an image-printing unit. The conveyance unit is configured to convey a printing medium to an image-printing start position (a position where image-printing is started on the printing medium), and the image-printing unit is configured to transfer at least one color of inks of multiple colors on an ink ribbon onto the printing medium.

The printer <NUM> includes a hollow housing in which the main body upper case <NUM>-<NUM> and the main body lower case <NUM>-<NUM> are assembled. The printer <NUM> further includes a sheet-ejection opening <NUM>-<NUM> formed as a gap (opening) between the main body upper case <NUM>-<NUM> and the main body lower case <NUM>-<NUM> on one of side surfaces thereof.

With this configuration, during printing, a sheet <NUM> as a printing medium (see <FIG>) is conveyed to transitorily protrude from the sheet-ejection opening <NUM>-<NUM> to the outside of the printer <NUM>, or the sheet <NUM> on which image-printing has been finished is ejected from the sheet-ejection opening <NUM>-<NUM>.

The printer <NUM> further includes, on its upper surface, an indicator <NUM> including an LED therein, and a power switch <NUM> located adjacent to the indicator <NUM>.

In the indicator <NUM>, a plurality of colors of LEDs blinking or lighting up are exposed through windows in an upper portion of the main body upper case <NUM>-<NUM>. The lighting up and blinking of the LEDs indicate a power state of the printer <NUM> and status information about a printing operation, an error, or the likes.

The power switch <NUM> is an operation button configured to switch on and off the power of the printer <NUM> by being pressed by a user.

The printer <NUM> further includes a cassette cover <NUM>-<NUM> supported in an openable and closable manner and a USB connector <NUM>, on another of the side surfaces thereof, which is different from the side surface on which the sheet-ejection opening <NUM>-<NUM> is formed. The printer <NUM> further includes a chassis <NUM> having a cassette mounting portion <NUM>-<NUM> inside thereof.

The cassette mounting portion <NUM>-<NUM> is accessible while the cassette cover <NUM>-<NUM> is open. That is, a user is allowed to mount the cassette <NUM> on the cassette mounting portion <NUM>-<NUM> by opening the cassette cover <NUM>-<NUM> and inserting the ink ribbon cassette <NUM> (hereinafter, simply referred to as a cassette <NUM>) into cassette mounting portion <NUM>-<NUM> in the direction of the arrow <NUM>.

The cassette <NUM> contains an ink ribbon <NUM> coated with sublimation ink and wound into a roll. The ink ribbon <NUM> is conveyed by a conveyance mechanism (conveyance unit) included in the printer <NUM>.

The USB connector <NUM> is an I/F (external connection interface), and is configured to electrically connect to an external power adapter or an external device via an USB cable, which is not illustrated, to supply power from the outside to the printer <NUM> and configured to communicate with an external device.

An openable and closable tray cover <NUM>-<NUM> is provided on the bottom surface of the printer <NUM>.

While the tray cover <NUM>-<NUM> is open, a user is allowed to load printing sheets <NUM> (<FIG>) into a sheet storage part <NUM> (<FIG>).

<FIG> illustrates a block diagram depicting a hardware configuration example of the printer <NUM>. In <FIG>, the components illustrated in <FIG> are denoted by the same reference numerals, and redundant description is omitted.

As illustrated in <FIG>, the printer <NUM> includes a main control unit <NUM>, an image processing unit <NUM>, a thermal head control unit <NUM>, a thermal head <NUM>, a head temperature sensor <NUM>, an environmental temperature sensor <NUM>, a head position sensor <NUM>, and a sheet detection sensor <NUM>. The printer <NUM> further includes an ink ribbon detection sensor <NUM>, a marker detection sensor <NUM>, a motor driver unit <NUM>, a head position drive motor <NUM>, a sheet conveyance motor <NUM>, a wireless communication unit <NUM>, an operation unit <NUM>, and a USB control unit <NUM>. The printer <NUM> further includes an indicator control unit <NUM>, a battery control unit <NUM>, a battery <NUM>, and a battery level detection unit <NUM>.

The main control unit <NUM> is configured to control operations of the printer <NUM>, and includes a CPU <NUM>, a flash ROM <NUM>, and an SDRAM <NUM>.

The CPU <NUM> is configured to perform system control of the printer <NUM> and computations. The flash ROM <NUM> stores system control programs for the printer <NUM>. Loading programs from the flash ROM <NUM>, the CPU <NUM> controls components of the printer <NUM>, based on the loaded programs. The SDRAM <NUM> transitorily stores image data and uses the image data for data processing work.

Functions and processes of the printer <NUM> described later are implemented by the CPU <NUM> loading programs stored in the flash ROM <NUM> and executing the programs.

The image processing unit <NUM> is configured to perform image processing on image data transmitted from a digital camera, a mobile terminal, or any other image shooting apparatus. The image processing unit <NUM> is configured to perform various image processing such as decompression processing on the compressed image data, resizing processing according to sheets <NUM> to be used, image correction processing, and the like, to generate print data for image-printing on the basis of the image data subjected to the image processing.

As another example, processes executed by the image processing unit <NUM> may be executed by the main control unit <NUM> instead of the image processing unit <NUM>, or may be executed by both the image processing unit <NUM> and the main control unit <NUM>.

The thermal head control unit <NUM> is configured to convert print data generated by the image processing unit <NUM> into an electrical signal and output the electrical signal to the thermal head <NUM>. The thermal head <NUM> is configured to convert the electric signal into thermal energy, and transfers dye (ink) on the ink ribbon <NUM> (<FIG>) onto a sheet <NUM>.

The head temperature sensor <NUM> is configured to measure the temperature of the thermal head <NUM> and output the measurement value to the main control unit <NUM>. The environmental temperature sensor <NUM> is configured to measure the environmental temperature in the printer <NUM> and output the measurement value to the main control unit <NUM>. The main control unit <NUM> is configured to correct a drive signal for the thermal head on the basis of outputs of the head temperature sensor <NUM> and the environmental temperature sensor <NUM>, or causes the thermal head <NUM> to stand by for driving.

The head position sensor <NUM> is configured to detect positions such as a pressing position and a retraction position of the thermal head <NUM>, and output a detection result to the main control unit <NUM>. The sheet detection sensor <NUM> is configured to detect the position of a sheet <NUM> and output the detection result to the main control unit <NUM>. The ink ribbon detection sensor <NUM> is configured to detect information about the ink ribbon <NUM> and output the detected information to the main control unit <NUM>. The marker detection sensor <NUM> is a reflective optical sensor, and includes a light emitting unit and a light receiving unit so that light emitted from the light emitting unit is reflected bay a reflector on a wall of the ink ribbon cassette <NUM>, and the reflected light is received by the light receiving unit. The marker detection sensor <NUM> is configured to detect a marker on the ink ribbon <NUM> when the reflected light is blocked by the marker, and output the detection result to the main control unit <NUM>.

The motor driver unit <NUM> is configured to control the head position drive motor <NUM> (second drive unit) and the sheet conveyance motor <NUM> (first drive unit). The head position drive motor <NUM> is a motor for driving the thermal head <NUM> to a pressing position at which image-printing is performed or a retracted position at which the thermal head <NUM> is retracted so that the cassette <NUM> can be replaced with another one or a sheet <NUM> can be conveyed. The sheet conveyance motor <NUM> is a motor for conveying a sheet <NUM>, and constitutes a conveyance unit of the printer <NUM>.

The main control unit <NUM> is configured to issue a command to the motor driver unit <NUM> according to sensor information from the above-described sensors (<NUM> to <NUM>) and information programmed in advance, and control the driving of the head position drive motor <NUM> and the sheet conveyance motor <NUM>. In the present embodiment, the sheet conveyance motor <NUM> may be configured to convey the ink ribbon <NUM>. To convey both a sheet <NUM> and the ink ribbon <NUM> together, the sheet conveyance motor <NUM> may rotate a conveyance roller <NUM> and a sheet feeding roller <NUM>, and further rotate a ribbon winding shaft (which is not illustrated) of the printer <NUM>, coupled to the winding shaft of the ink ribbon <NUM>. The transmission of the power of the sheet conveyance motor <NUM> may be switched so that only the conveyance roller <NUM> and the sheet feeding roller <NUM> can be rotated to convey a sheet <NUM>, or the ribbon winding shaft of the printer <NUM> can be driven to convey the ink ribbon without conveying a sheet <NUM>. Instead of conveying a sheet <NUM> and the ink ribbon <NUM> by one motor, a drive motor for a sheet <NUM> and the ink ribbon <NUM> may be separately provided as a conveyance unit of the printer <NUM>.

The wireless communication unit <NUM> is configured to control wireless communication with an external device such as a digital camera. The operation unit <NUM> is configured to receive a user's operation instruction through the power switch <NUM> or the like provided on the main body upper case <NUM>-<NUM>.

The USB control unit <NUM> is configured to judge information from an external device connected to the USB connector <NUM>, which is an I/F, to perform communication control, configured to control power transfer, and configured to control transmission of various kinds of data such as operation information and image data. The indicator control unit <NUM> is configured to control output of the indicator <NUM> such as lighting or blinking of the LEDs of the indicator <NUM>.

The battery control unit <NUM> is configured to acquire the remaining battery level of the battery <NUM> detected by the battery level detection unit <NUM>, and perform charge control of the battery <NUM> and power supply from the battery <NUM> to the components of the printer <NUM> on the basis of the acquired remaining battery level.

The battery <NUM> is built in the printer <NUM>. Note that the battery <NUM> only needs to be able to supply power to the printer <NUM> with high reliability, and may be, for example, located outside the printer <NUM> and connected to the printer <NUM>.

Next, a configuration of the ink ribbon <NUM> will be described with reference to <FIG>.

<FIG> illustrates a plan view depicting a configuration example of the ink ribbon <NUM>. The ink ribbon <NUM> has a configuration in which inks (dyes) of multiple colors are regularly arranged one by one in the conveyance direction on a base material thereof. Here, the ink ribbon <NUM> is for full-color printing, and dye-applied areas of respective colors of yellow (Y), magenta (M), and cyan (C) are arranged on the base material. Image printing is performed by thermally transferring dyes or inks of the respective colors onto a sheet <NUM> to be superimposed on one another and then a full-color image is formed on the sheet <NUM>. On the base material of the ink ribbon <NUM>, a colorless and transparent overcoat (OC) area for forming a protective layer on the surface of the sheet <NUM> on which the image has been formed is arranged next to the dye-applied areas.

Markers <NUM>-1Y, <NUM>-<NUM>, <NUM>-1C, and <NUM>-1OC are black belts printed on the base material for detecting the head positions of the dye-applied areas of the respective colors and the OC area, and are provided between these areas. The marker <NUM>-1Y indicating the head of the yellow (Y) dye-applied area is comprised of two printed black belts so as to be distinguished from the other markers <NUM>-<NUM>, <NUM>-1C, and <NUM>-1OC.

The ink ribbon <NUM> in the present embodiment uses a film having high heat resistance such as a polyethylene terephthalate film having a thickness of about <NUM> to <NUM> microns as a base material. In each of the dye-applied areas of colors of yellow (Y), magenta (M), and cyan (C), a sublimation ink prepared by mixing a dye, a binder, a plasticizer, a binder, and the like is applied to a thickness of about <NUM> to <NUM> on the film. In the colorless and transparent overcoat area, a styrene derivative, a styrene resin, a styrene copolymer resin, a binder and the like are applied to a thickness of about <NUM> to <NUM> on the film. In addition, a lubricant for reducing frictional resistance with the sliding portion and stabilizing traveling of the ink ribbon <NUM>, a polishing agent for polishing and cleaning the surface of the thermal head <NUM>, and the like are applied to a surface of the ink ribbon <NUM> opposite to a surface applied with the sublimation inks.

Next, a printing operation of the printer <NUM> will be described with reference to <FIG>.

<FIG> illustrate cross-sectional views depicting the operation of the printer <NUM>, and <FIG> is a flowchart of printing processing of the printer <NUM>. <FIG> illustrates the printer <NUM> in an image-printing standby state, <FIG> illustrates the printer <NUM> in a sheet feeding state, <FIG> illustrates the printer <NUM> in a state during image-printing operation, and <FIG> illustrates the printer <NUM> in a state after completion of image-printing and before sheet ejection. <FIG> illustrates the printer <NUM> in a state after the sheet ejection.

As illustrated in <FIG>, after the cassette <NUM> is set in the printer <NUM> by a user, sheets <NUM> are loaded in the sheet storage part <NUM>, and in response to the power switch <NUM> being pressed, the printer <NUM> enters the image-printing standby state as illustrated in <FIG>. The printer <NUM> includes a platen roller <NUM> and a thermal head <NUM>. The thermal head <NUM> is rotatably supported by the thermal head rotation shaft <NUM>, and is restricted to a position where a distance from the platen roller <NUM> is maximized so as not to interfere with the cassette <NUM> when the cassette <NUM> is inserted or removed. The platen roller <NUM> and the thermal head <NUM> constitute an image-printing unit of the printer <NUM>.

Next, when image data to be printed is specified in an external device like as a digital camera or a smartphone and a print instruction is given, the printer <NUM> receives information of the print instruction through the wireless communication unit <NUM>. With this reception, the main control unit <NUM> starts the printing processing illustrated in <FIG> (step S501).

When this processing starts, the main control unit <NUM> performs, before conveyance of a sheet <NUM> starts, a first determination to determine whether the remaining battery level of the battery <NUM> is equal to or more than a first threshold. That is, first, the main control unit <NUM> causes the battery level detection unit <NUM> to detect the remaining battery level of the battery <NUM> (hereinafter, referred to as a "first battery level check"). Thereafter, the main control unit <NUM> determines whether the remaining battery level detected in the first battery level check is equal to or more than a battery level that allows the printer <NUM> (for example, a conveyance unit and an image-printing unit) to complete image-printing on one sheet using all colors of Y, M, C, and OC (step S502). In other words, the main control unit <NUM> determines whether the remaining battery level of the battery <NUM> is equal to or more than the first threshold (first determination).

In consideration of variations in individual capacity and differences in state of the battery <NUM>, it is difficult to accurately detect the remaining battery level in the first battery level check only by measuring the open circuit voltage of the battery <NUM>. Therefore, in the first battery level check of the present embodiment, the battery level detection unit <NUM> checks how much the voltage drops when a pseudo load under a condition close to the actual load is applied, and detects the remaining battery level with high accuracy. Here, in a case where the remaining battery level sufficient for image-printing on one sheet is detected (YES in step S502), the battery control unit <NUM> notifies the main control unit <NUM> of the detection result and starts power supply from the battery <NUM> to the components of the printer <NUM> (step S503). At this time, even if the printer <NUM> is supplied with external power through the USB connector <NUM>, the battery <NUM> is not charged by the external power supply.

Upon receiving such a notification from the battery control unit <NUM>, the main control unit <NUM> drives and controls the head position drive motor <NUM> to rotate the thermal head <NUM> counterclockwise in <FIG> around the thermal head rotation shaft <NUM>. That is, as illustrated in <FIG>, the main control unit <NUM> moves the thermal head <NUM> to an intermediate position between the standby position in <FIG> and the printing position illustrated in <FIG> where the thermal head <NUM> nips with the platen roller <NUM> (step S504). As a result, position control of the thermal head <NUM> and the platen roller <NUM> is performed.

When the movement of the thermal head <NUM> to the intermediate position is completed, the main control unit <NUM> starts feeding a sheet <NUM> from the sheet storage part <NUM> (step S505). When the sheet feeding starts, the pressure plate <NUM> is biased toward the sheet feeding roller <NUM> by a biasing unit (which is not illustrated), and pushes-up sheets <NUM> stacked in the sheet storage part <NUM> to press the sheets <NUM> against the sheet feeding roller <NUM>.

The sheet feeding roller <NUM> is retracted to a position separated from the sheets <NUM> at the standby position in <FIG>. In the intermediate position illustrated in <FIG>, the sheet feeding roller <NUM> is pushed down to a position in contact with the sheets <NUM> by a driving force (which is not illustrated). At this time, the driving force of the sheet conveyance motor <NUM> is transmitted to the sheet feeding roller <NUM>, and the sheet feeding roller <NUM> rotates in the clockwise direction in <FIG>, and conveys a sheet <NUM> in pressure contact with the sheet feeding roller <NUM> toward the image-printing unit including the thermal head <NUM> and the platen roller <NUM>. At this time, sheets <NUM> abut on the separation bank portion <NUM> provided in the printer <NUM>. As a result, only one sheet at the top of the sheet s <NUM> in the sheet storage part <NUM> is conveyed.

Subsequently, when the conveyed sheet <NUM> is detected by the sheet detection sensor <NUM> and it is confirmed that there is no sheet feeding failure, the main control unit <NUM> pushes out the rotatably supported switching plate <NUM> upward and rotates it in the clockwise direction in <FIG>. As a result, the sheet <NUM> traveling in the left direction in <FIG> enters the nip between the conveyance roller <NUM> and the conveyance driven roller <NUM>. The conveyance roller <NUM> has a plurality of minute protrusions that pierce the back surface of the sheet <NUM> so as to accurately convey the sheet <NUM>. The conveyance roller <NUM> is driven by the sheet conveyance motor <NUM>. The sheet conveyance motor <NUM> is a stepping motor, and is configured to accurately control the feeding amount of a sheet <NUM>.

After the sheet <NUM> is conveyed into the nip between the conveyance roller <NUM> and the conveyance driven roller <NUM>, the main control unit <NUM> moves the sheet feeding roller <NUM> to the position of the standby state illustrated in <FIG> by power (which is not illustrated). This is to prevent other sheets in the sheet storage part <NUM> from being erroneously conveyed by the sheet feeding roller <NUM>.

Thereafter, the main control unit <NUM> continues the conveyance of the sheet <NUM> by rotating the conveyance roller <NUM> and the conveyance driven roller <NUM> by the sheet conveyance motor <NUM>. Thereafter, as a result of the rear end of the sheet <NUM> passing through the sheet detection sensor <NUM> and being conveyed by a predetermined amount, the sheet detection sensor <NUM> detects that the sheet <NUM> has passed through the front end of the switching plate <NUM>. In response to the detection, the main control unit <NUM> stops the conveyance of the sheet <NUM>.

Next, the main control unit <NUM> controls the sheet conveyance motor <NUM>. By this control, the conveyance roller <NUM> and the conveyance driven roller <NUM> convey the sheet <NUM> in the reverse direction, and stop the sheet <NUM> at the image-printing start position as illustrated in <FIG> (step S506). As a result, position control of the sheet <NUM> and the ink ribbon <NUM> is performed. At this time, the rear end of the sheet <NUM> passes through the upper side of the switching plate <NUM> and the lower side of the sheet feeding roller <NUM>, and is conveyed to a space between the guide wall <NUM> that partitions and holds the lower portion of the battery <NUM> and the sheet storage unit wall <NUM>.

When the sheet feeding is completed and the sheet <NUM> stops at the image-printing start position (when the image-printing preparation operation is completed), the main control unit <NUM> performs a cueing operation on the ink ribbon <NUM> (step S507). Here, the cueing is an operation of detecting the head (front) position of an area of the ink ribbon <NUM> to be used for the next image-printing and adjusting the detected head position to a predetermined position where the image-printing processing is started.

Hereinafter, the cueing of the ink ribbon <NUM> will be described. When a sheet <NUM> is conveyed to the position illustrated in <FIG> and the conveyance of the sheet <NUM> to the image-printing start position is completed, the ink ribbon <NUM> stored in the cassette <NUM> is rolled up. That is, the tip of the winding shaft <NUM> arranged in the cassette <NUM> is engaged with an engaging unit (which is not illustrated) provided in the printer <NUM>, and is rotated counterclockwise in <FIG> by power not illustrated, and the ink ribbon <NUM> wound around the supply shaft <NUM> is wound around the winding shaft <NUM>.

As illustrated in <FIG>, markers <NUM>-<NUM> Y to <NUM>-1OC are provided at the heads of the areas of the respective colors on the ink ribbon <NUM>, and in particular, the marker <NUM>-1Y at the head of yellow (Y) is comprised of two printed black belts. When the marker detection sensor <NUM> detects one of the markers on the ink ribbon <NUM>, the main control unit <NUM> stops the conveyance of the ink ribbon <NUM> to end the cueing operation.

When the cueing of the ink ribbon <NUM> is ended, the main control unit <NUM> determines whether or not the marker <NUM>-1Y comprised of the two printed black belts is normally detected (step S508). In the present embodiment, a case where the marker <NUM>-1Y is not normally detected is a case where the marker detection sensor <NUM> detects only a marker comprised of one black belt-like print, or a case where the marker detection sensor <NUM> cannot detect the marker <NUM>-1Y within a specified time. In such a case (NO in step S508), the main control unit <NUM> controls the indicator <NUM> to blink to indicate abnormality (error) in the cassette <NUM> (step S509).

Furthermore, the main control unit <NUM> notifies, through the wireless communication unit <NUM>, the external device that has transmitted the information of the print instruction to the printer <NUM> in step S501 that an abnormality has occurred in the ink ribbon <NUM> (step S510), and finishes the present processing.

On the other hand, in a case where the marker <NUM>-1Y is normally detected (YES in step S508) and the yellow (Y) cueing is completed, the processing proceeds to step S511.

In step S511, the main control unit <NUM> further rotates a holding unit that holds the thermal head <NUM> in the counterclockwise direction in <FIG> around the thermal head rotation shaft <NUM>. As a result, the thermal head <NUM> moves to an image-printing position where the ink ribbon <NUM> and the sheet <NUM> are sandwiched between the platen roller <NUM> and the thermal head <NUM>.

Thereafter, in step S512, the main control unit <NUM> performs image-printing of one single-color image of yellow (Y) on the sheet <NUM>. Specifically, when the movement of the thermal head <NUM> to the image-printing position is completed, the main control unit <NUM> conveys the sheet <NUM> and the ink ribbon <NUM> toward the sheet-ejection opening <NUM>-<NUM> with the sheet <NUM> and the ink ribbon <NUM> being pressed and sandwiched by the thermal head <NUM> and the platen roller <NUM> as illustrated in <FIG>. During the conveyance, the ink on the ink ribbon <NUM> is heated by the thermal head <NUM> and is transferred to the sheet <NUM>.

During the image-printing operation, the ink ribbon <NUM> and the sheet <NUM> are conveyed at the same speed. For this purpose, the ink-ribbon conveyance mechanism of the printer <NUM> includes a torque limiter mechanism (which is not illustrated) configured to slip when a load of a certain torque or more is applied.

When image-printing is performed by the heated thermal head <NUM>, the ink ribbon <NUM> and the sheet <NUM> are conveyed while maintaining a close contact state for a certain distance, and then conveyed in respective directions away from each other. That is, the sheet <NUM> is conveyed leftward in <FIG> by the conveyance roller <NUM>, and the ink ribbon <NUM> is conveyed toward the guide shaft <NUM> disposed in the cassette <NUM> while sliding on the peeling plate <NUM> integrated with in the thermal head <NUM>. The ink ribbon <NUM>, which has been stuck to the sheet <NUM> due to heat applied by the thermal head <NUM> for image-printing, is conveyed to the position of the peeling plate <NUM> and peeled off from the sheet <NUM>.

Thereafter, when the image-printing of a yellow image on the sheet <NUM> is completed (NO in step S513), the main control unit <NUM> rotates the holding unit for the thermal head <NUM> to retract the thermal head <NUM> to the intermediate position as illustrated in <FIG> (step S514). Thereafter, the main control unit <NUM> controls the sheet conveyance motor <NUM> to convey the sheet <NUM> in the direction opposite to the image-printing operation, stops the sheet <NUM> at the image-printing start position (<FIG>) (step S515), and returns to step S507.

Thereafter, similarly to the start of the yellow (Y) image-printing operation, the ink ribbon <NUM> is wound around the winding shaft <NUM>, and in response to normal detection of the marker <NUM>-<NUM>, the main control unit <NUM> controls the sheet conveyance motor <NUM> to convey the sheet <NUM> to the image-printing start position and then performs image-printing of one single-color image of magenta (M) on the sheet <NUM>. Similarly, cyan (C) image-printing and overcoat (OC) image-printing are performed in the same manner.

When a series of image-printing up to the overcoat image-printing is completed (YES in step S513), as illustrated in <FIG>, the main control unit <NUM> controls the head position drive motor <NUM> to move the thermal head <NUM> to the standby position so as to retreat from the sheet <NUM> (step S516). Next, the main control unit <NUM> controls the sheet conveyance motor <NUM> to further convey the sheet <NUM> in the direction to be ejected from the sheet-ejection opening <NUM>-<NUM>, and completes the sheet ejection when the rear end of the sheet <NUM> passes through the conveyance roller <NUM> (step S517). When the sheet ejection is completed, the printing is ended, and the present processing is finished (step S522).

Thus, the image-printing operation in which the inks are superimposed and transferred onto the sheet <NUM> in the order of yellow, magenta, cyan, and overcoat is completed. As described above, in the case where the remaining battery level of the battery <NUM> detected in the first battery level check in step S502 is more than the battery level that allows the printer <NUM> to perform image-printing on one sheet using all colors of inks (the remaining battery level is equal to or more than the first threshold), the main control unit <NUM> carries out the conveyance of the sheet <NUM> by power from the battery <NUM> and then performs the image-printing processing without performing the second battery level check. Further, in the case where the remaining battery level of the battery <NUM> detected in the first battery level check is equal to or more than the first threshold, the main control unit <NUM> carries out the conveyance of the sheet <NUM> by power from the battery <NUM> without charging the battery <NUM> with power from the USB connector <NUM> even if the printer <NUM> is supplied with power from the USB connector <NUM>.

On the other hand, in the case where, at the time of the first battery level check in step S502, the remaining battery level that allows the printer <NUM> to perform image-printing on one sheet has not been detected (the remaining battery level is less than the first threshold), the USB control unit <NUM> determines whether the USB connector <NUM> has external power supply (step S518). When there is no external power supply, that is, no power is supplied from the USB connector <NUM> to the printer <NUM> (NO in step S518), the main control unit <NUM> controls the indicator <NUM> to blink to indicate an error that printing is impossible (step S519).

Further, the main control unit <NUM> notifies, through the wireless communication unit <NUM>, the external device that has transmitted the information of the print instruction to the printer <NUM> in step S501 that printing is disabled due to insufficient battery level (step S520), and finishes the present processing.

On the other hand, when power is supplied from the outside to the printer <NUM> via the USB connector <NUM> (YES in step S518), the processing proceeds to step S600 in <FIG> to start the printing processing according to the first embodiment, which is to be executed when the remaining battery level is insufficient power is being supplied externally (step S521).

<FIG> is a flowchart of a printing processing according to the first embodiment, to be executed in step S521 of <FIG> in which the remaining battery level is insufficient while power is being supplied externally. That is, this processing is printing processing to be executed in a case where the first battery level check fails to detect the remaining battery level that allows the printer <NUM> to perform image-printing on one sheet (NO in step S502), but the printer <NUM> is supplied with power the outside (step S518).

First, when the present processing starts in step S600, the main control unit <NUM> controls the thermal head <NUM> to move to the intermediate position as illustrated in <FIG> (step S601), similarly to step S504 in <FIG>.

When the movement of the thermal head <NUM> to the intermediate position is completed, the main control unit <NUM> starts feeding a sheet <NUM> from the sheet storage part <NUM>, similarly to step S505 in <FIG> (step S602). Similarly to the above-described sheet feeding operation, when it is detected that the sheet <NUM> has passed through the leading end of the switching plate <NUM>, the main control unit <NUM> stops the conveyance of the sheet <NUM>.

Next, as in step S506 in <FIG>, the main control unit <NUM> carries out conveyance of the sheet <NUM> in the reverse direction, and stops the sheet <NUM> at the image-printing start position (predetermined position) as illustrated in <FIG> (step S603).

Thereafter, after the sheet feeding operation is completed and the sheet <NUM> is conveyed to the image-printing start position (when the image-printing preparation operation is completed), the main control unit <NUM> performs the cueing operation on the ink ribbon <NUM> as in step S507 in <FIG> (step S604). When the cueing operation on the ink ribbon <NUM> is ended, the main control unit <NUM> determines whether or not the marker <NUM>-1Y comprised of the two printed black belts is normally detected as in step S508 in <FIG> (step S605).

In a case where the marker <NUM>-1Y is not normally detected (NO in step S605), the main control unit <NUM> controls the indicator <NUM> to blink to indicate abnormality (error) in the cassette <NUM> as in step S509 in <FIG> (step S606). Further, as in step S510, the main control unit <NUM> notifies, through the wireless communication unit <NUM>, the external device that has transmitted the information of the print instruction to the printer <NUM> in step S501 that an abnormality has occurred in the ink ribbon <NUM> (step S607), and finishes the present processing.

On the other hand, in a case where the marker <NUM>-1Y is normally detected (YES in step S605) and the yellow (Y) cueing is completed, the processing (in <FIG>) proceeds to step S608.

In step S608, the main control unit <NUM> causes the battery level detection unit <NUM> to detect the remaining battery level of the battery <NUM> (hereinafter referred to as "second battery level check"). Thereafter, the main control unit <NUM> determines whether the remaining battery level detected in the second battery level check is equal to or more than a battery level that allows the printer <NUM> to perform image-printing of one single-color image on one sheet for each single color of Y, M, C, and OC (step S608). In other words, the main control unit <NUM> determines whether the remaining battery level of the battery <NUM> is equal to or more than the second threshold (second determination).

Also in the second battery level check, the remaining battery level may be checked by the battery level detection unit <NUM> by a load test using a pseudo load similarly to the first battery level check, but in the load test, there is power consumption due to test execution. Therefore, in the present embodiment, the battery level detection unit <NUM> stores, as data for use in the second battery level check, the remaining battery level detected in the first battery level check and the power consumption in operation of the printer <NUM> performed after the first battery level check (or the first determination). That is, in the second battery level check, the battery level detection unit <NUM> detects the remaining battery level by obtaining a calculation value given by subtracting power consumed by operation of the printer <NUM> performed after the first battery level check (or the first determination) from the remaining battery level in the first battery check. As described above, in the second battery level check, the remaining battery level is detected using the calculated value, so that the power consumption from the battery <NUM> can be suppressed.

Here, the second threshold value may be a predetermined value set for each color of Y, M, C, and OC, or may be a predetermined value common to colors of Y, M, C, and OC. For example, the power consumed by the printer <NUM> to perform image-printing of a black solid image is usually larger than the power consumed by the printer <NUM> to perform image-printing of one single-color image using each color of Y, M, C, and OC. Therefore, by setting the second threshold to four times the power consumed by the printer <NUM> to perform image-printing of a black solid image, it is possible to expect a sufficient remaining battery level regardless of an image to be subjected to image-printing. However, when the second threshold value is set with higher accuracy, it shortens the standby time in step S609, which will be described later. For this purpose, the amount of power consumed by the printer <NUM> to perform image-printing of one single-color image calculated for each color of Y, M, C, and OC of an image subjected to image-printing may be set to the second threshold value.

In a case where the remaining battery level detected in the second battery level check is equal to or more than the second threshold (YES in step S608), the main control unit <NUM> controls the battery control unit <NUM> to start the image-printing processing using power from the battery <NUM>, and proceeds to step S610. In the present embodiment, as a result, only the platen roller <NUM>, the thermal head <NUM>, the head position drive motor <NUM> (second drive unit), and the sheet conveyance motor <NUM> (first drive unit) are driven by power from the battery <NUM>. In addition, power supplied from the USB connector <NUM> is used to cover power required by the printer <NUM> other than the power for the platen roller <NUM>, the thermal head <NUM>, the head position drive motor <NUM>, and the sheet conveyance motor <NUM>.

In step S610, the main control unit <NUM> controls the thermal head <NUM> to move to the image-printing position similarly to step S511 in <FIG>. That is, the second battery level check in step S608 is performed while the platen roller <NUM> and the thermal head <NUM> are separated from each other.

Thereafter, in step S611, the main control unit <NUM> performs image-printing of one single-color image of yellow (Y) on the sheet <NUM> as in step S512 in <FIG>. Hereinafter, since steps S612 to S617 are similar to steps S513 to S517 in <FIG>, the description thereof will be omitted. That is, in <FIG>, the second battery level check is performed each time when image-printing of one single-color image is performed for one of the colors of Y, M, C, and OC by the processes from steps S604 to S614.

On the other hand, in a case where the remaining battery level detected in the second battery level check is less than the second threshold (NO in step S608), the processing proceeds to step S609.

In step S609, the main control unit <NUM> causes components of the printer <NUM> to stand by, causes the battery control unit <NUM> to start charging the battery <NUM>, and then returns to step S608. Thereafter, when the charging results in that the remaining battery level detected in the second battery level check in step S608 becomes equal to or more than the second threshold (YES in step S608), the processing proceeds to step S610.

According to the present embodiment, the main control unit <NUM> performs the first battery level check before the conveyance of a sheet <NUM> is started by the conveyance unit of the printer <NUM>. In the case where the remaining battery level is equal to or more than the first threshold as a result of the first battery level check, and is equal to or more than the battery level that allows the printer <NUM> to complete image-printing on one sheet using all the colors of Y, M, C, and OC, the main control unit <NUM> causes the conveyor to convey the sheet <NUM> by power from the battery <NUM>. At this time, even if power is supplied from the USB connector <NUM> to the printer <NUM>, it is preferable not to charge the battery <NUM> with power from the USB connector <NUM>. The main control unit <NUM> may cause the conveyance unit to convey the ink ribbon <NUM> using power from the battery <NUM> to perform cueing of the ink ribbon <NUM>. Thereafter, the main control unit <NUM> executes the image-printing processing without performing the second battery level check.

In the present embodiment, even in a case where the remaining battery level is less than the first threshold in the first battery level check, and the remaining battery level that allows the printer <NUM> to perform image-printing on one sheet using all the colors of Y, M, C, and OC is not detected, the main control unit <NUM> starts a printing operation including sheet feeding while the printer <NUM> is being supplied with power from the USB connector <NUM> (when there is external power supply). In addition, the main control unit <NUM> charges the battery <NUM> with power from the USB connector <NUM> at a predetermined timing. In the printing operation, the main control unit <NUM> may cause the conveyance unit to convey a sheet <NUM> using power from the battery <NUM>, and cause the conveyance unit to convey the ink ribbon using power from the battery <NUM> to perform the cueing of the ink ribbon <NUM>. After causing the conveyance unit to convey the sheet <NUM> to a predetermined position like the image-printing start position and perform the cueing of the ink ribbon <NUM> to complete the image-printing preparation operation, the main control unit <NUM> performs a second battery level check. In the case where the remaining battery level is equal to or more than the second threshold as a result of the second battery level check, and the detected remaining battery level is equal to or more than the battery level that allows the printer <NUM> to perform image-printing of one single-color image for one of the colors of Y, M, C, and OC (YES in step S608), image-printing of one single-color image of at least one color of Y, M, C, and OC is started. On the other hand, in the case where the above remaining battery level is not be detected as a result of the second battery level check, (NO in step S608), the main control unit <NUM> performs the minimum necessary charging on the battery <NUM> using power from the USB connector <NUM>. That is, the main control unit <NUM> performs the charging until the remaining battery level reaches a battery level that allows the printer <NUM> to perform image-printing of one single-color image each of the colors of Y, M, C, and OC. When the second battery level check is performed each time when image-printing of one single-color image is performed for one of the colors of Y, M, C, and OC, it allows the printer <NUM> to perform image-printing processing to transferring Y, M, C, and OC inks onto a sheet along while performing the minimum necessary charging of the battery <NUM>.

By controlling the printer <NUM> as described above, it is possible to shorten a standby time caused by charging of the battery <NUM> after a print instruction is issued from an external device to the printer <NUM>. That is, in the present embodiment, even when the remaining battery is insufficient to perform image-printing on one sheet by the printer <NUM> at the time of the first battery level check, the printer <NUM> starts the printing operation rather than prohibiting the start of printing. It enhances user convenience.

The second threshold value is not limited to the above value. For example, in a case where a use of power from the battery <NUM> in the image-printing processing has been specified such that the power from the battery <NUM> is used to cover all the power necessary for the processes of steps S610 to S617 (image-printing of one single-color image of at least one of the multiple colors), the second threshold may be set to a value that enables the specified use of the power from the battery <NUM>.

A second embodiment will be described. The present embodiment is different from the first embodiment only in the printing processing when the remaining battery level is insufficient while power is being supplied externally in step S521 in <FIG>. Therefore, the same configurations and steps as those in the first embodiment are denoted by the same reference numerals, and redundant description will be omitted.

<FIG> is a flowchart of a printing processing according to the second embodiment, to be executed in step S521 in <FIG> in which the remaining battery level is insufficient while power is being supplied externally. That is, this processing is a printing processing to be executed when the first battery level check fails to detect the remaining battery level that allows the printer <NUM> to perform image-printing on one sheet (NO in step S502), but power is externally supplied to the printer <NUM> via the USB connector <NUM> (step S518).

When the present processing starts in step S700, the main control unit <NUM> first uses the USB control unit <NUM> to determine whether or not the value of power externally supplied via the USB connector <NUM> is a specified value or more (step S701). The specified value is a power value at which the battery <NUM> can be charged and the residual power can be used to drive the main control unit <NUM>, motor driver unit <NUM>, and the various sensors to perform the image-printing preparation operation, which is to be carried out before the thermal head <NUM> is driven for image-printing.

In a case where the value of the power externally supplied is less than the specified value (NO in step S701), the main control unit <NUM> determines that the power externally supplied is insufficient to perform both the image-printing preparation operation and the charging of the battery <NUM>, and proceeds to step S600 in <FIG> (step S702). As a result, the printing processing according to the first embodiment, which is to be executed when the remaining battery level is insufficient while power is being supplied externally, starts.

On the other hand, in a case where the value of the power externally supplied is equal to or more than the specified value (YES in step S701), the processing proceeds to step S703.

In step S703, the main control unit <NUM> controls the battery control unit <NUM> to start charging the battery <NUM> using power externally supplied via the USB connector <NUM>. Next, unlike step S504 in <FIG>, the battery <NUM> is being charged, so the main control unit <NUM> uses the externally supplied power to drive the head position drive motor <NUM> to move the thermal head <NUM> to the intermediate position (step S704).

When the movement of the thermal head <NUM> to the intermediate position is completed, the main control unit <NUM> starts feeding a sheet <NUM> from the sheet storage part <NUM> as in step S505 in <FIG> (step S705). Similarly to the above-described sheet feeding operation, when it is detected that the sheet <NUM> has passed through the leading end of the switching plate <NUM>, the main control unit <NUM> stops the conveyance of the sheet <NUM>. It should be noted that, unlike step S505, the sheet feeding operation at this time uses not the power supplied from the battery <NUM> but the power externally supplied.

Next, the main control unit <NUM> conveys the sheet <NUM> in the reverse direction, and stops the sheet <NUM> at the image-printing start position as illustrated in <FIG>, similarly to step S506 in <FIG> (step S706).

When the sheet feeding operation is completed and the sheet <NUM> stops at the image-printing start position, the main control unit <NUM> performs the cueing operation on the ink ribbon <NUM> as in step S507 in <FIG> (step S707). When the cueing operation on the ink ribbon <NUM> is ended, the main control unit <NUM> determines whether or not the marker <NUM>-1Y comprised of the two printed black belts is normally detected as in step S508 in <FIG> (step S708).

In a case where the marker <NUM>-1Y is not normally detected (NO in step S708), the main control unit <NUM> controls the indicator <NUM> to blink to indicate abnormality (error) in the cassette <NUM> as in step S509 in <FIG> (step S709). Further, as in step S510, the main control unit <NUM> notifies, through the wireless communication unit <NUM>, the external device that has transmitted the information of the print instruction to the printer <NUM> in step S501 that an abnormality has occurred in the ink ribbon <NUM> (step S710), and finishes the present processing.

On the other hand, in a case where the marker <NUM>-1Y is normally detected (YES in step S708) and the yellow (Y) cueing is completed, the main control unit <NUM> stops charging of the battery <NUM> before performing the second battery level check (step S711), unlike the first embodiment.

Thereafter, similarly to step S608 in <FIG> of the first embodiment, the main control unit <NUM> performs the second battery level check and determines whether the detected remaining battery level is equal to or more than the second threshold (step S712). In the present embodiment, the battery level detection unit <NUM> stores, as data for use in the second battery level check, not only the remaining battery level detected in the first battery level check and the power consumption in operation of the printer <NUM> after the first battery level check, but also the time period of the charging performed in steps S703 to S711 as the data. That is, in the second battery level check, the battery level detection unit <NUM> detects the remaining battery level by obtaining a calculation value given by adding the power charged during the charging time to the remaining battery level detected in the first battery level check, and then subtracting power consumed by operation of the printer <NUM> performed after the first battery level check (or the first determination) from the added value. As described above, the remaining battery level is detected using the calculated value also in the second battery level check in the present embodiment, so that the power consumption from the battery <NUM> can be suppressed as much as possible.

In a case where the remaining battery level detected in the second battery level check is equal to or more than the second threshold (YES in step S712), the processing proceeds to step S714.

In step S714, the main control unit <NUM> controls the battery control unit <NUM> to start the printing operation with power supplied from the battery <NUM>, and the processing proceeds to step S715.

In step S715, the main control unit <NUM> controls the thermal head <NUM> to move to the image-printing position similarly to step S511 in <FIG>.

As described above, in the present embodiment, after performing the cueing of the ink ribbon <NUM>, the main control unit <NUM> performs the second battery level check before the thermal head is moved to the print start position, for the following reasons. If the second battery level check is performed after the thermal head <NUM> is moved to the image-printing position, the ink ribbon <NUM> and the sheet <NUM> will maintain pressure contact with each other for a while when battery charging starts due to insufficient remaining battery level. In such a case, if the thermal head <NUM> has residual heat, it may result in unintended dye transfer on a sheet <NUM>.

Returning to <FIG>, thereafter, in step S716, the main control unit <NUM> performs image-printing of one single-color image of yellow (Y) on the sheet <NUM>, similarly to step S512 in <FIG>. It should be noted that in the image-printing, at least the thermal head <NUM>, which is an image-printing unit, is always driven by power from the battery <NUM> in order to ensure sufficient image-printing quality. At this time, in order to suppress power consumption as much as possible, externally supplied power may be used as power for various sensors and system control. Further, power supplied externally may be used to drive the sheet conveyance motor <NUM>, the head position drive motor <NUM>, the motor driver unit <NUM>, and the like. Thereafter, when the image-printing of the yellow image on the sheet <NUM> is completed (NO in step S717), the processing proceeds to step S718.

On the other hand, in a case where the remaining battery level detected in the second battery level check is less than the second threshold (NO in step S712), the main control unit <NUM> causes components of the printer <NUM> to stand by, and causes the battery control unit <NUM> to start charging the battery <NUM> (step S713).

Thereafter, until the remaining battery level detected in the second battery level check becomes equal to or more than the second threshold (NO in step S712), the processing returns to step S713, and the battery <NUM> is charged.

In step S718, the main control unit <NUM> controls the battery control unit <NUM> to start charging the battery <NUM> again using power externally supplied via the USB connector <NUM>. Next, unlike step S514 in <FIG>, while the battery <NUM> is charged, the main control unit <NUM> drives the head position drive motor <NUM> using power externally supplied, to move the thermal head <NUM> to the intermediate position (step S719).

When the movement of the thermal head <NUM> is completed, the main control unit <NUM> controls the sheet conveyance motor <NUM> to convey the sheet <NUM> in a direction opposite to the image-printing operation, stops the sheet at the image-printing start position (step S720), and returns to step S707. Also the power required at this time is covered by not the power from the battery <NUM> but the power received from the outside. Thereafter, similarly to the yellow (Y) image-printing, magenta (M) image-printing, cyan (C) image-printing, and overcoat (OC) image-printing are performed in the same manner.

When a series of image-printing up to the overcoat image-printing is completed (YES in step S717), the main control unit <NUM> starts charging the battery <NUM> using power externally supplied, similarly to step S718 (step S721). Next, the head position drive motor <NUM> is driven with power externally supplied, to move the thermal head <NUM> to the standby position so as to be retracted from the sheet <NUM> (step S722).

Next, the main control unit <NUM> drives the sheet conveyance motor <NUM> using power externally supplied, to further convey the sheet <NUM> in the direction to be ejected from the sheet-ejection opening <NUM>-<NUM>, and ejects the sheet so that the rear end of the sheet <NUM> passes through the conveyance roller <NUM> (step S723). When the sheet ejection is completed, the printing and the charging of the battery <NUM> using power externally supplied are ended, and the present processing is finished (step S724).

In the present embodiment, as in steps S703, S718, and S721 in the flowchart of <FIG>, the main control unit <NUM> starts charging the battery <NUM> using power (external power) externally supplied from the USB connector <NUM> while the printer <NUM> is performing printing and image-printing is not being executed. That is, in a case where the remaining battery level of the battery <NUM> is less than the first threshold in the first battery level check and the image printing processing is performed while the printer <NUM> is supplied with power from the USB connector <NUM>, the main control unit <NUM> charges the battery <NUM> with the power from the USB connector <NUM> while the image printing processing is not performed. While such charging is performed on the battery <NUM>, the position movement of the thermal head <NUM>, the conveyance of the sheet <NUM>, and the like are executed using the external power. As a result, the power consumption of the battery <NUM> during the execution of printing can be suppressed, and the charging increases the remaining battery level. Furthermore, as a result, the remaining battery level detected in the second battery level check in step S712 becomes the sufficient remaining battery level that allows the printer <NUM> to perform image-printing of one single-color image on one sheet for each single color of Y, M, C, and OC in many cases, and even if the remaining battery level is sufficient, the time required for charging the battery <NUM> in step S713 can be reduced.

It should be noted that the remaining battery level detected in the second battery level check in step S712 is preferably calculated from the remaining battery level detected in the first battery level check, power consumed by operation of the printer <NUM> performed after the first battery level check, and time period of battery charging with power from the USB connector <NUM> while the image-printing processing is not performed.

Furthermore, during the printing illustrated in <FIG>, the main control unit <NUM> changes the thermal head <NUM> and the platen roller <NUM>, which can perform operations that affects the image-printing quality when using the power externally supplied, so as to use power supplied from the battery <NUM>, whose reliability is ensured. On the other hand, power supplied from the outside to the printer <NUM> via the USB connector <NUM> is used to cover the power required by the printer to perform the image-printing processing other than the power for the thermal head <NUM> and the platen roller <NUM>. As a result, it is possible to suppress the power consumption of the battery <NUM> while ensuring the reliability of the image-printing quality. It should be noted that, during the printing illustrated in <FIG>, if the power supplied from the battery <NUM> is also used for the main control unit <NUM>, the reliability of the image quality can be further secured.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the gist of the present invention. For example, the present invention is also applicable to an apparatus incorporating the printer <NUM>.

Note that, in the present embodiment, it is also possible to implement processing in which a program for implementing one or more functions is supplied to a computer of a system or an apparatus via a network or a storage medium, and a system control unit of the system or the apparatus reads and executes the program. A system control unit has one or more processors or circuits, and may include a network of multiple isolated system control units or multiple isolated processors or circuits to read out and execute executable instructions.

A processor or circuit may include a central processing unit (CPU), a micro processing unit (MPU), a graphics processing unit (GPU), an application specific integrated circuit (ASIC), and a field programmable gate array (FPGA). The processor or circuit may also include a digital signal processor (DSP), data flow processor (DFP), or neural processing unit (NPU).

The invention is defined in the claims.

Claim 1:
A printing apparatus (<NUM>) that performs image-printing by thermally transferring inks of multiple colors applied to an ink ribbon (<NUM>) onto a printing medium (<NUM>) in a superimposed manner, the printing apparatus (<NUM>) comprising:
an image-printing unit (<NUM>, <NUM>) configured to transfer at least one color of the inks of multiple colors applied to the ink ribbon (<NUM>) onto a printing medium (<NUM>);
an interface (<NUM>) configured to supply power from an outside to the printing apparatus (<NUM>);
a battery (<NUM>);
a conveyance unit (<NUM>, <NUM>, <NUM>) configured to convey a printing medium (<NUM>) to an image-printing start position, at which the image-printing unit (<NUM>, <NUM>) starts transferring at least one color of the inks of multiple colors onto the printing medium (<NUM>), using power from the battery (<NUM>) or the interface (<NUM>); and
a control unit (<NUM>) configured to
perform, before conveyance of a printing medium (<NUM>) is started by the conveyance unit (<NUM>, <NUM>, <NUM>), a first determination to determine whether a remaining battery level of the battery (<NUM>) is equal to or more than a first threshold, characterized in that,
in a case where the remaining battery level is equal to or more than the first threshold as a result of the first determination, cause the conveyance unit (<NUM>, <NUM>, <NUM>) to convey the printing medium (<NUM>) by power from the battery (<NUM>),
in a case where the remaining battery level is less than the first threshold as a result of the first determination and the printing apparatus (<NUM>) is supplied with power from the interface (<NUM>), charge the battery (<NUM>) with power from the interface (<NUM>), cause the conveyance unit (<NUM>, <NUM>, <NUM>) to convey the printing medium (<NUM>), and perform, after the printing medium (<NUM>) reaches a predetermined position, a second determination to determine whether a remaining battery level of the battery (<NUM>) is equal to or more than a second threshold, and
in a case where the remaining battery level is equal to or more than the second threshold as a result of the second determination, start image-printing processing to cause the image-printing unit (<NUM>, <NUM>) to transfer the inks of multiple colors onto the printing medium (<NUM>).