Patent Description:
In the related art, for example, an inkjet printer that discharges liquid to form an image on a recording medium includes a liquid supply device including a channel through which liquid is fed and a movable portion that is movable to feed liquid.

In addition, for the purpose of discharging air bubbles and foreign matter in a channel, a configuration has been proposed in which ink is forcibly supplied and circulated in an ink channel between an ink tank and an inkjet head, and supply control is performed such that the supply amount of ink in a first period at a certain timing from the start of circulation is less than the supply amount of ink in a second period after the first period (see, for example, <CIT>).

However, in an apparatus described in <CIT>, when a component such as a channel deteriorates over time, the amount of liquid fed per unit time decreases, which may cause a shortage of the supply amount of liquid.

<CIT> discloses: In an image forming apparatus, a first detection part and a second detection part, each for detecting a position of a displacement member that changes its position according to a remaining amount of liquid in a sub-tank, are provided to a carriage carrying the sub-tank and a recording head, and a body of the image forming apparatus, respectively. A first position is a position of the displacement member detected by the first detection part such that the remaining amount of liquid in the sub-tank is smaller than that at a second position detected by the second detection part. The liquid is supplied to the sub-tank of a differential supply amount, corresponding to a displacement amount of the displacement member between a position detected by the first detection part and a position detected by the second detection part, after the first detection part detects the displacement member.

An object of the present disclosure is to provide a liquid supply device that can prevent a shortage of a liquid supply amount.

According to an embodiment of the present disclosure, there is provided a liquid supply device that includes a channel, a movable portion, and a controller. Liquid is to be fed through the channel. The movable portion moves to feed the liquid. The controller controls the movable portion. The controller controls at least one of a moving speed and a moving time of the movable portion in accordance with a liquid feed amount of the liquid fed through the channel such that the liquid feed amount increases.

According to an embodiment of the present disclosure, there is provided a liquid supply method to be performed by a liquid supply device that includes a channel through which liquid is fed and a movable portion to move to feed the liquid. The method includes controlling the movable portion. The controlling includes controlling at least one of a moving speed and a moving time of the movable portion in accordance with a liquid feed amount of the liquid fed through the channel such that the liquid feed amount increases.

According to the present disclosure, a liquid supply device can be provided that prevents a shortage of a liquid supply amount.

The aforementioned and other aspects, features, and advantages of the present disclosure would be better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:.

However, the disclosure of this patent specification is not intended to be limited to the specific terminology so selected and it is to be understood that each specific element includes all technical equivalents that operate in a similar manner and achieve similar results.

Although the embodiments are described with technical limitations with reference to the attached drawings, such description is not intended to limit the scope of the disclosure and all of the components or elements described in the embodiments of this disclosure are not necessarily indispensable.

Below, embodiments of the present disclosure are described in detail with reference to the accompanying drawings. In the drawings, like reference signs denote like elements, and overlapping description may be omitted where appropriate.

Note that the embodiments described below are examples of a liquid supply device and a liquid discharge apparatus for embodying the technical idea of the present disclosure, and the present disclosure is not limited to the embodiments described below. For example, the dimension, material, and shape of components and the relative positions of the arranged components are given by way of example in the following description, and the scope of the present disclosure is not limited thereto unless particularly specified. The size, positional relation, and the like of components illustrated in the drawings may be exaggerated for clarity of description.

A liquid supply device according to an embodiment includes a channel through which liquid is fed, a movable portion that is movable to feed the liquid, and a controller that controls the movable portion. The liquid supply device is, for example, an ink supply device that supplies ink to a discharge head that discharges ink as an example of liquid in a liquid-discharge-type image forming apparatus such as an inkjet printer.

When such a liquid supply device is used for a long period of time, a component such as an ink tube deteriorates over time. As a result, the amount of liquid fed per unit time by the liquid supply device decreases, and the amount of liquid supplied by the liquid supply device may become insufficient.

In the present embodiment, at least one of the moving speed and the moving time of the movable portion is controlled so that the liquid feed amount increases in accordance with the liquid feed amount of the liquid fed through the channel, thereby making it possible to prevent the shortage of the liquid supply amount by the liquid supply device.

Hereinafter, an embodiment will be described using an example of a liquid-discharge-type image forming apparatus that includes a liquid supply device and a liquid discharge device to discharge liquid supplied by the liquid supply device, and forms an image on a recording medium using the liquid discharged by the liquid discharge device. Note that image formation, recording, printing, printing, and printing in the terms of the embodiments are synonymous.

Further, the term "liquid" includes any liquid having a viscosity or a surface tension that can be discharged from a liquid discharge device. The "liquid" is not limited to a particular liquid and may be any liquid having a viscosity or a surface tension to be discharged from a liquid discharge device. However, preferably, the viscosity of the liquid is not greater than <NUM> mPa s under ordinary temperature and ordinary pressure or by heating or cooling. Examples of the liquid include a solution, a suspension, or an emulsion that contains, for example, a solvent, such as water or an organic solvent, a colorant, such as dye or pigment, a functional material, such as a polymerizable compound, a resin, or a surfactant, a biocompatible material, such as deoxyribonucleic acid (DNA), amino acid, protein, or calcium, or an edible material, such as a natural colorant. The above-described examples may be used for inkjet inks, for example.

The liquid discharge device is a functional component that discharges and jets liquid from nozzles. Examples of an energy source for generating energy to discharge liquid include a piezoelectric actuator (a laminated piezoelectric element or a thin-film piezoelectric element), a thermal actuator that employs a thermoelectric conversion element, such as a thermal resistor, and an electrostatic actuator including a diaphragm and opposed electrodes.

<FIG> is a schematic diagram illustrating a configuration of an image forming apparatus <NUM> according to a first embodiment. In <FIG>, the image forming apparatus <NUM> includes a sheet feeding unit <NUM>, an image forming unit <NUM>, a drying unit <NUM>, and a sheet ejection unit <NUM>. In the image forming apparatus <NUM>, the image forming unit <NUM> forms an image on a sheet P with ink. Here, the sheet P is an example of a recording medium as a sheet material fed from the sheet feeding unit <NUM>. Ink is an example of liquid for image formation. After the ink adhering to the sheet P is dried in the drying unit <NUM>, the sheet P is ejected from the sheet ejection unit <NUM>.

As illustrated in <FIG>, the sheet feeding unit <NUM> includes a sheet feeding tray <NUM> on which a plurality of sheets P are stacked, a feeding device <NUM> that separates and feeds the sheets P one by one from the sheet feeding tray <NUM>, and a registration roller pair <NUM> that feeds the sheets P to the image forming unit <NUM>. The feeding device <NUM> may be any feeding device such as a device using a roller(s) and a device using air suction. After the leading edge of the sheet P fed from the sheet feeding tray <NUM> by the feeding device <NUM> reaches the registration roller pair <NUM>, the registration roller pair <NUM> is driven at a predetermined timing to feed the sheet to the image forming unit <NUM>. In the present embodiment, the configuration of the sheet feeding unit <NUM> is not limited to any particular configuration as long as the sheet feeding unit <NUM> can feed the sheet P to the image forming unit <NUM>.

The sheet feeding unit <NUM> includes an operation unit <NUM> that receives, for example, an operation for starting the image forming apparatus <NUM>, an operation for starting or stopping image formation by the image forming apparatus <NUM>, and operations for various settings of the image forming apparatus <NUM>. However, the installation position of the operation unit <NUM> is not limited to the sheet feeding unit <NUM> and may be installed at any position.

As illustrated in <FIG>, the image forming unit <NUM> includes a receiving cylinder <NUM>, a sheet carrying drum <NUM>, an ink discharge unit <NUM>, and a delivery cylinder <NUM>. The receiving cylinder <NUM> receives the fed sheet P. The sheet carrying drum <NUM> carries the sheet P conveyed by the receiving cylinder <NUM> on its outer peripheral surface. The ink discharge unit <NUM> discharges ink toward the sheet P carried by the sheet carrying drum <NUM>. The delivery cylinder <NUM> delivers the sheet P carried by the sheet carrying drum <NUM> to the drying unit <NUM>. The image forming unit <NUM> includes an ink supply device <NUM>.

The leading end of the sheet P conveyed from the sheet feeding unit <NUM> to the image forming unit <NUM> is gripped by a sheet gripper disposed on the surface of the receiving cylinder <NUM>. The sheet P is conveyed along with the movement of the surface of the receiving cylinder <NUM>. The sheet P conveyed by the receiving cylinder <NUM> is delivered to the sheet carrying drum <NUM> at a position facing the sheet carrying drum <NUM>.

A sheet gripper is also disposed on the surface of the sheet carrying drum <NUM>, and the leading end of the sheet is gripped by the sheet gripper. Multiple suction holes are dispersedly formed on the surface of the sheet carrying drum <NUM>. A suction device <NUM> generates a suction air flow toward the inside of the sheet carrying drum <NUM> in each suction hole. The leading end of the sheet P transferred from the receiving cylinder <NUM> to the sheet carrying drum <NUM> is gripped by the sheet gripper. The sheet P is sucked onto the surface of the sheet carrying drum <NUM> by the suction air flow and is conveyed along with the movement of the surface of the sheet carrying drum <NUM>.

The ink supply device <NUM> is an example of a liquid supply device that supplies ink to the ink discharge unit <NUM>. The ink supply device <NUM> includes a supply controller <NUM>. The supply controller <NUM> is an example of a control device that controls a movable portion included in the ink supply device <NUM>. The supply controller <NUM> controls the movable portion to control the supply of ink by the ink supply device <NUM>.

The ink discharge unit <NUM> is an example of a liquid discharge device that discharges ink of four colors of C (cyan), M (magenta), Y (yellow), and K (black) to form an image and includes individual liquid discharge heads 364C, <NUM>, 364Y, and <NUM> for each ink. The configuration of the liquid discharge heads 364C, <NUM>, 364Y, and <NUM> is not limited to any particular configuration and may be any configuration that can discharge. In some embodiments, the liquid discharge device may include a liquid discharge head that discharges special ink such as white, gold, and silver or a liquid discharge head that discharges a surface coating liquid that does not form an image.

Discharge operations of the liquid discharge heads 364C, <NUM>, 364Y, and <NUM> of the ink discharge unit <NUM> are controlled by drive signals corresponding to image information. When the sheet P carried on the sheet carrying drum <NUM> passes through a region facing the ink discharge unit <NUM>, color inks are discharged from the liquid discharge heads 364C, <NUM>, 364Y, and <NUM> to form an image corresponding to the image information. In the present embodiment, the configuration of the image forming unit <NUM> is not limited to any particular configuration as long as an image is formed by applying liquid onto the sheet P. In the following description, the liquid discharge heads 364C, <NUM>, 364Y, and <NUM> may be collectively referred to as the ink discharge unit <NUM> unless particularly distinguished from each other.

As illustrated in <FIG>, the drying unit <NUM> includes a drying mechanism <NUM> and a conveying mechanism <NUM>. The drying mechanism <NUM> dries ink adhering to the sheet P in the image forming unit <NUM>. The conveying mechanism <NUM> conveys a sheet P conveyed from the image forming unit <NUM>. The sheet P conveyed from the image forming unit <NUM> is received by the conveyance mechanism <NUM>, then conveyed so as to pass through the drying mechanism <NUM>, and delivered to the sheet ejection unit <NUM>. When the sheet P passes through the drying mechanism <NUM>, ink on the sheet P is subjected to a drying process. Accordingly, liquid components such as moisture in the ink are evaporated, the ink is fixed on the sheet P, and curling of the sheet P is prevented.

The sheet ejection unit <NUM> includes a sheet ejection tray <NUM> on which a plurality of sheets P are stacked. The sheet P conveyed from the drying unit <NUM> is sequentially stacked and held on the sheet ejection tray <NUM>. In the present embodiment, the configuration of the sheet ejection unit <NUM> is not limited to any particular configuration and may be any configuration that can eject the sheet P.

As described above, the image forming apparatus <NUM> according to the present embodiment includes the sheet feeding unit <NUM>, the image forming unit <NUM>, the drying unit <NUM>, and the sheet ejection unit <NUM>. However, other functional units may be added as appropriate. For example, a pre-processing unit that performs pre-processing of image formation may be added between the sheet feeding unit <NUM> and the image forming unit <NUM>. Alternatively, a post-processing unit that performs post-processing of image formation may be added between the drying unit <NUM> and the sheet ejection unit <NUM>.

An example of the pre-processing device performs a processing liquid applying operation to apply processing liquid onto the sheet P so as to reduce bleeding by reacting with ink. However, the content of the pre-processing operation is not limited particularly. Examples of the post-processing unit include a sheet reversing-and-conveying process for reversing a sheet on which an image has been formed by the image forming unit <NUM> and sending the sheet to the image forming unit <NUM> again to form images on both sides of the sheet, a process for binding a plurality of sheets on which images have been formed, a correction mechanism that corrects sheet deformation, and a cooling mechanism that cools the sheet.

<FIG> is a diagram illustrating an example of an ink supply path in the image forming apparatus <NUM>. The ink supply path refers to a path through which ink is fed and supplied between an ink cartridge and a discharge head in the image forming unit <NUM>.

As illustrated in <FIG>, the image forming unit <NUM> includes an ink cartridge <NUM>, a flow-velocity measuring device <NUM>, an ink supply device <NUM>, an ink discharge unit <NUM>, a suction pump <NUM>, and a waste liquid tank <NUM>. The ink cartridge <NUM> further includes a supply opening-and-closing solenoid <NUM> and an ink-end detection sensor <NUM>. The ink discharge unit <NUM> includes a head tank <NUM>, a remaining-amount detection feeler <NUM>, a remaining-amount detection sensor <NUM>, and a suction cap <NUM>.

The ink cartridge <NUM> is an example of a storage unit that stores ink. The ink cartridge <NUM> is replaceably installed. When ink in the ink cartridge <NUM> is in an empty state (an ink end state) or a state close to empty (a near end state), the ink cartridge <NUM> is replaced with a new ink cartridge <NUM> that is in a state of being full of ink. The ink stored in the ink cartridge <NUM> is sent and supplied to a head tank <NUM> as an example of an in-head storage unit by the ink supply device <NUM> under the control of the supply controller <NUM>.

The flow-velocity measuring device <NUM> is disposed between the head tank <NUM> and the ink-end detection sensor <NUM> and measures the flow velocity of the ink supplied from the ink supply device <NUM> to the ink discharge unit <NUM> that is a supply destination. The flow-velocity measuring device may be either a device capable of measuring the flow velocity from the outside of the path or a device capable of measuring the flow velocity inside the path.

The head tank <NUM> includes the remaining-amount detection feeler <NUM> and the remaining-amount detection sensor <NUM>, which can be used to detect the amount of ink (amount of liquid) in the head tank <NUM>. The head tank <NUM> has a function of forming a predetermined negative pressure in order to normally discharge ink by the ink discharge unit <NUM>.

A plurality of nozzle holes are disposed in a portion of the ink discharge unit <NUM> that faces the sheet. The ink discharge unit <NUM> discharges ink in the head tank <NUM> as ink droplets from the nozzle orifices under the control of the supply controller <NUM>. Ink droplets discharged by the ink discharge unit <NUM> land on the sheet P and adhere to the sheet, thereby forming an image on the sheet.

When the ink in the head tank <NUM> increases in viscosity or contains bubbles, the ink discharge unit <NUM> may not appropriately discharge ink. For this reason, maintenance of the ink discharge unit <NUM> is performed. When maintenance is performed, the suction cap <NUM> is attached to the portion where the nozzle orifices of the ink discharge unit <NUM> are disposed, and the ink in the head tank <NUM> is sucked out through the nozzle holes by the suction pump <NUM>. Thus, for example, the ink containing air bubbles and the thickened ink are removed, and the ink in the ink discharge unit <NUM> is replaced with fresh ink. The sucked ink is sent to the waste liquid tank <NUM> as waste liquid.

The opening-and-closing solenoid <NUM> and the ink-end detection sensor <NUM> are disposed between the ink cartridge <NUM> and the ink supply device <NUM>. The opening-and-closing solenoid <NUM> opens and closes a solenoid under the control of the supply controller <NUM> to switch between supply and supply-stop of ink from the ink cartridge <NUM>. The ink-end detection sensor <NUM> detects that the ink cartridge <NUM> is empty of ink, and outputs the detection result to the supply controller <NUM>.

The ink cartridge <NUM> has an integrated-circuit (IC) chip in which information such as ink type, color, date of manufacture, ink remaining amount, and ink end state is stored. For example, the ink cartridge <NUM> is attached to the image forming unit <NUM> in an ink full state when the ink cartridge <NUM> is new. When ink is discharged from the ink cartridge <NUM> in image formation and the ink cartridge <NUM> reaches an ink end state in ink is empty, the ink cartridge <NUM> is replaced with a new one. The cumulative number of replacement times of the ink cartridge <NUM> is managed by the supply controller <NUM>.

The amount of ink discharged by the ink discharge unit <NUM> can be managed by the supply controller <NUM> based on the counted cumulative number of discharges of ink droplets.

<FIG> is a diagram illustrating another example of an ink supply path in the image forming apparatus <NUM>. The ink supply path illustrated in <FIG> further includes a circulation path <NUM> for circulating ink in addition to the ink supply path illustrated in <FIG>.

For example, depending on the type of ink such as white ink, ink components such as pigment may settle in the ink supply path. The circulation path <NUM> circulates the ink in the ink supply path at predetermined time intervals in order to prevent such sedimentation of the ink components.

The circulation path <NUM> includes an on-off valve <NUM>. Opening and closing of the on-off valve <NUM> are controlled by the supply controller <NUM> in order to control liquid feeding of ink in the circulation path <NUM>.

The ink is circulated in the circulation path <NUM> between the ink supply device <NUM> and the head tank <NUM>. The supply controller <NUM> drives the ink supply device <NUM> in a state where the opening-and-closing solenoid <NUM> is closed and the on-off valve <NUM> is opened, thereby circulating ink between the channel downstream from the ink supply device <NUM> and the head tank <NUM>.

In a type of ink such as white ink in which sedimentation of ink components is likely to occur and circulation of ink is necessary, the ink supply device <NUM> is driven at predetermined intervals and the driving frequency increases. Accordingly, for example, an ink tube included in the ink supply device <NUM> is likely to deteriorate. The deterioration of the ink tube may cause a decrease in the liquid feed amount.

On the other hand, in a type of ink in which sedimentation of ink components is less likely to occur, circulation of ink is not so necessary. Since the ease of sedimentation of the ink component can be distinguished by the type of ink, the supply controller <NUM> preferably controls whether to use the circulation path <NUM> based on the type of ink.

The remaining-amount detection feeler <NUM> and the remaining-amount detection sensor <NUM> in the head tank <NUM> detect the remaining amount of ink in the head tank <NUM>. <FIG> are diagrams illustrating the configurations and operations of the remaining-amount detection feeler <NUM> and the remaining-amount detection sensor <NUM>. <FIG> illustrates a case where an ink cartridge is full of ink. <FIG> illustrates a case where the ink cartridge is depleted of ink.

As illustrated in <FIG>, a flexible head tank film 31a is disposed on a part of the head tank <NUM>. When the ink in the head tank <NUM> increases, the head tank film 31a expands as illustrated in <FIG>. When the ink in the head tank <NUM> decreases, the head tank film 31a contracts as illustrated in <FIG>.

The remaining-amount detection feeler <NUM> is pressed against the head tank film 31a. The remaining-amount detection feeler <NUM> is, for example, a light plastic piece formed in a band shape and has a fixed end on a fulcrum 32a and a free end on the remaining-amount detection sensor <NUM>.

The remaining-amount detection sensor <NUM> includes an upper-limit sensor 33a and a lower-limit sensor 33b. Each of the upper-limit sensor 33a and the lower-limit sensor 33b is an optical sensor having a light emitter and a light receiver and outputs a detection signal indicating that the remaining-amount detection feeler <NUM> is interposed between the light emitter and the light receiver.

The free end of the remaining-amount detection feeler <NUM> moves in accordance with expansion and contraction of the head tank film 31a. The state in which the head tank <NUM> is full of ink is detected based on a detection signal output when the free end of the remaining-amount detection feeler <NUM> is interposed between the light emitter and the light receiver in the upper-limit sensor 33a. On the other hand, the state in which ink in the head tank <NUM> is empty is detected based on a detection signal output when the free end of the remaining-amount detection feeler <NUM> is interposed between the light emitter and the light receiver in the lower-limit sensor 33b.

<FIG> is a diagram illustrating an example of a configuration of the ink supply device <NUM>. As illustrated in <FIG>, the ink supply device <NUM> includes an ink tube <NUM>, a ring <NUM>, an eccentric cam <NUM>, a stepping motor <NUM>, and a supply controller <NUM>. In the present embodiment, the ink supply device <NUM> employs a tube pump system.

The ink tube <NUM> is an example of a channel through which ink is fed. The material of the ink tube <NUM> may be, for example, a thermoplastic elastomer.

The ring <NUM> is an annular member rotatable about a predetermined rotation axis and is disposed such that an outer peripheral portion of the ring <NUM> is in contact with the ink tube <NUM>. The ring <NUM> is an example of a movable portion that rotates to feed ink, and is an example of a rotating body. Rotation is an example of mobility of the movable portion.

The eccentric cam <NUM> is coupled to the ring <NUM> such that the central axis of the eccentric cam <NUM> substantially coincides with the central axis of the ring <NUM>. The eccentric cam <NUM> is attached to the rotary shaft of the stepping motor <NUM> so that the central axis of the eccentric cam <NUM> is eccentric to the rotation axis of the stepping motor <NUM>.

When the stepping motor <NUM> is driven to rotate, the eccentric cam <NUM> rotates to rotate the ring <NUM>. Since the center axis of the eccentric cam <NUM> is eccentric with respect to the rotation axis of the stepping motor <NUM>, the ring <NUM> eccentrically rotates, and a region in which the ink tube <NUM> is pressed by the ring <NUM> moves with the rotation. Accordingly, the ink in the ink tube <NUM> is volumetrically moved, thus allowing the ink to be fed.

The ink supply device <NUM> can increase the amount of liquid to be fed by increasing the rotation speed or time of the ring <NUM>. The rotation speed is an example of a moving speed, and the rotation time is an example of a moving time.

Each of the ring <NUM> and the eccentric cam <NUM> may be made of, for example, a resin material.

The stepping motor <NUM> is a driving device that rotates the ring <NUM> via the eccentric cam <NUM>. The stepping motor <NUM> is electrically connected to the supply controller <NUM> and driven under the control of the supply controller <NUM>. However, the driving unit is not limited to the stepping motor, and may be, for example, a direct current (DC) motor.

<FIG> is a block diagram illustrating an example of a hardware configuration of the supply controller <NUM>. As illustrated in <FIG>, the supply controller <NUM> is implemented by a computer and includes a central processing unit (CPU) <NUM>, a read only memory (ROM) <NUM>, a random access memory (RAM) <NUM>, a hard disk drive (HDD) <NUM>, and an external device connection interface (I/F) <NUM>.

The CPU <NUM> executes control processing including various types of computing processing. The ROM <NUM> stores programs used to drive the CPU <NUM>, such as an initial program loader (IPL). The RAM <NUM> is used as a working area for the CPU <NUM>. The HDD <NUM> stores various types of data such as programs.

The external device connection I/F <NUM> is an interface for connecting various external devices. The external devices in this case are, for example, devices such as the ink discharge unit <NUM>, the ink-end detection sensor <NUM>, and the remaining-amount detection sensor <NUM>.

<FIG> is a block diagram illustrating an example of a functional configuration of the supply controller <NUM>. As illustrated in <FIG>, the supply controller <NUM> includes an information acquisition unit <NUM>, a rotation control unit <NUM>, and a reset unit <NUM>. The information acquisition unit <NUM> includes a cumulative-rotation-count information acquisition unit <NUM>, a cumulative-supply-time information acquisition unit <NUM>, a cumulative-replacement-count information acquisition unit <NUM>, a flow-velocity information acquisition unit <NUM>, a cumulative-discharge-amount information acquisition unit <NUM>, an ink-type information acquisition unit <NUM>, a selection-value reception unit <NUM>, and a liquid-feed-time information acquisition unit <NUM>. These functions are implemented by the CPU <NUM> in <FIG> executing a program stored in, for example, the ROM <NUM> or the HDD <NUM>.

The cumulative-rotation-count information acquisition unit <NUM> acquires cumulative-rotation-count information, i.e., information on the cumulative number of rotations of the ring <NUM>. For example, the cumulative-rotation-count information acquisition unit <NUM> can acquire the cumulative-rotation-count information of the ring <NUM> based on the information on rotation of the stepping motor <NUM>.

The cumulative-supply-time information acquisition unit <NUM> acquires cumulative supply time information, i.e., information on cumulative supply time during which the ink supply device <NUM> has supplied ink to the ink discharge unit <NUM>. For example, the cumulative-supply-time information acquisition unit <NUM> can acquire the cumulative supply time information by counting the number of clocks of the CPU <NUM> and measuring the elapsed time while the ink supply device <NUM> is supplying ink.

The cumulative-replacement-count information acquisition unit <NUM> acquires cumulative replacement count information, i.e., information on the cumulative number of times of replacement of the ink cartridge <NUM>. For example, the cumulative-replacement-count information acquisition unit <NUM> can detect that the ink cartridge <NUM> has been replaced by referring to the IC chip of the ink cartridge <NUM>, and can acquire the cumulative replacement count information by counting the number of detected replacements.

The flow-velocity information acquisition unit <NUM> acquires flow velocity information, i.e., information on the flow velocity of ink supplied from the ink supply device <NUM> to the ink discharge unit <NUM>. For example, the flow-velocity information acquisition unit <NUM> can acquire the flow velocity information of ink by inputting a measurement value of the ink flow velocity from the flow-velocity measuring device <NUM>.

The cumulative-discharge-amount information acquisition unit <NUM> acquires cumulative discharge amount information from the ink discharge unit <NUM>. For example, the cumulative-discharge-amount information acquisition unit <NUM> can acquire the cumulative discharge amount information by counting the number of times of discharge of ink by the ink discharge unit <NUM> and multiplying the cumulative count number by the amount of ink per discharge.

The ink-type information acquisition unit <NUM> acquires ink type information, i.e., information on the type of ink supplied by the ink supply device <NUM>. For example, the ink-type information acquisition unit <NUM> can acquire the ink type information supplied by the ink supply device <NUM> by referring to the IC chip of the ink cartridge <NUM>.

The selection-value reception unit <NUM> receives a selection value of at least one of the rotation speed and the rotation time of the ring <NUM> selected by the operator of the ink supply device <NUM>. For example, the selection-value reception unit <NUM> can receive a selection value input by an operator of the ink supply device <NUM> using the operation unit <NUM>. The operator refers to a person who operates the ink supply device <NUM>. Examples of the operator include a user of the ink supply device <NUM>, a user of the image forming apparatus <NUM>, a service person of the ink supply device <NUM>, and a service person of the image forming apparatus <NUM>.

The liquid-feed-time information acquisition unit <NUM> acquires liquid-feed-time information until the amount of ink stored in the head tank <NUM> reaches a full state from the lower limit value by liquid feeding from the ink supply device <NUM>. For example, the liquid-feed-time information acquisition unit <NUM> can acquire the liquid-feed-time information by measuring the period of time from the time when the detection signal indicating the lower limit is output to the time when the detection signal indicating the upper limit is output in the remaining-amount detection sensor <NUM>.

The rotation control unit <NUM> controls at least one of the rotation speed and the rotation time of the ring <NUM> such that the liquid feed amount increases gradually or stepwisely in accordance with the liquid feed amount of the ink fed through the ink tube <NUM>.

For example, the rotation control unit <NUM> can control at least one of the rotation speed and the rotation time of the ring <NUM> by controlling the driving of the stepping motor <NUM>, based on each piece of information acquired by the information acquisition unit <NUM> according to the liquid feed amount of ink, such that the liquid feed amount increases gradually or stepwisely.

When the ink supply device <NUM> is replaced, the reset unit <NUM> returns at least one of the rotation speed and the rotation time of the ring <NUM> to the initial state. For example, when information indicating that the ink supply device <NUM> has been replaced is acquired based on an operation performed by the operator using the operation unit <NUM>, the reset unit <NUM> can reset at least one of the rotation speed and the rotation time of the ring <NUM> controlled so as to increase the liquid feed amount in accordance with the liquid feed amount of the ink and return the ring <NUM> to the initial state.

Next, with reference to <FIG>, a description is given of a control result of the liquid feed amount by the ink supply device. <FIG> is a diagram illustrating a control result of the liquid feed amount by an ink supply device 2X according to a comparative example. <FIG> are diagrams illustrating first to fifth examples of the control result of the liquid feed amount by the ink supply device <NUM> according to the present embodiment.

In <FIG>, <FIG>, and <FIG> to <FIG>, the horizontal axis indicates the cumulative supply time of ink by the ink supply device in units of level. The first vertical axis on the left side indicates the amount of feed liquid in units of milliliters per second (ml / s), and the second vertical axis on the right side indicates the rotation speed of the ring in units of level. In <FIG>, the horizontal axis indicates the cumulative supply time of ink by the ink supply device in units of level, the first vertical axis on the left side indicates the amount of feed liquid per operation of the ink supply device in units of milliliters (ml), and the second vertical axis on the right side indicates the rotation time of the ring in units of second (sec).

As the level of the cumulative supply time, the lifetime (i.e., mechanical durability period) required for the ink supply device is set to level <NUM>. For example, the lifetime required for the ink supply device is five years, and the level "<NUM>" of the cumulative supply time corresponds to one year.

Further, in <FIG>, the solid line graph indicates the liquid feed amount, the one dot chain line graph indicates the minimum necessary liquid feed amount, and the two dot chain line graph indicates the upper-limit liquid feed amount. The broken line graphs in <FIG>, <FIG> and <FIG> to <FIG> indicate the rotation speed of the ring, and the broken line graph in <FIG> indicates the rotation time of the ring. The minimum necessary liquid feed amount is, for example, <NUM> / s.

As illustrated in <FIG>, in the ink supply device 2X according to the comparative example, the liquid feed amount decreases as the cumulative supply time is longer, and the liquid feed amount falls below the line of the minimum necessary liquid feed amount at a time point of approximately level <NUM>.

When ink is supplied for a long period of time, the ink tube is repeatedly compressed by the ring, so that the ink tube deteriorates and the restoring force of returning to the cylindrical shape is gradually lost. Accordingly, the volume of ink in the ink tube may not be moved, and the amount of ink supplied by the ink supply device may decrease.

If the liquid feed amount is less than the minimum necessary liquid feed amount, the ink amount may be insufficient when an image having a large area ratio is formed on the sheet P by the ink discharge unit <NUM>. Accordingly, for example, blurring may occur in the formed image.

In the control result of the ink supply device <NUM> according to the present embodiment illustrated in <FIG>, the liquid feed amount decreases as the cumulative supply time increases. However, the liquid feed amount increases by increasing the rotation speed of the ring <NUM> by one each time the level of the cumulative supply time increases by one. In other words, the rotation speed of the ring <NUM> is increased in a stepwise manner such that the amount of ink fed through the ink tube <NUM> increases in accordance with the amount of ink fed. In <FIG>, the rotation time of the ring <NUM> is increased stepwise such that the amount of ink fed through the ink tube <NUM> is increased in accordance with the amount of ink fed.

As a result of the control illustrated in <FIG> and <FIG>, the minimum necessary liquid feed amount is ensured over the entire lifetime required for the ink supply device <NUM>. From the viewpoint of ease of control, it is preferable to make the rotation time of the ring <NUM> constant when controlling the rotation speed of the ring <NUM>, and to make the rotation speed of the ring <NUM> constant when controlling the rotation time of the ring <NUM>. However, embodiments of the present disclosure are not limited to such control, and at least one of the rotation speed and the rotation time of the ring <NUM> may be controlled. Hereinafter, a case where the rotation speed of the ring <NUM> is controlled will be exemplified, but the same applies to a case where the rotation time is controlled.

<FIG> illustrates a control result in the case where the rotation speed of the ring <NUM> is increased only once within the lifetime required for the ink supply device <NUM>. When the number of times of increase of the rotation speed of the ring <NUM> is set to be only once, the control can be further simplified, thus allowing the man-hour and cost of development of the supply controller <NUM> to be reduced. However, the number of times of change for increasing the rotation speed of the ring <NUM> is not limited to one, and may be any number as long as the number is one or more within the lifetime required for the ink supply device <NUM>.

In a case where the rotation time of the ring <NUM> in the ink supply device <NUM> is changed in at least two stages, it is preferable that the rotation time in the change in the subsequent stage is longer than the rotation time in the change in the previous stage among the two or more stages. Thus, the liquid feed amount can be increased in the case where the cumulative supply time is longer, thus allowing the necessary liquid feed amount to be ensured more reliably.

<FIG> illustrates a control result in a case where the ink supply device <NUM> fails and is replaced with a new ink supply device <NUM> within a lifetime required for the ink supply device <NUM>. A time point K illustrated in <FIG> represents a time point when the ink supply device <NUM> is replaced with a new one.

If the liquid feed amount is increased every time the level of the cumulative supply time increases by one as illustrated in <FIG> after the ink supply device <NUM> is replaced with a new one, there is a concern that the liquid feed amount may increase too much. For this reason, when the ink supply device <NUM> is replaced, the reset unit <NUM> in the ink supply device <NUM> returns at least one of the rotation speed and the rotation time of the ring <NUM> to the initial state at the time point K. Such a configuration can prevent the liquid feed amount from increasing too much.

<FIG> illustrates a case where the rotation speed of the ring <NUM> is exponentially increased in accordance with the cumulative supply time. Since the deterioration of the ink tube <NUM> progresses as the cumulative supply time is longer, the decrease in the liquid feed amount can be made smaller by exponentially increasing the speed than by increasing the speed by a fixed amount at predetermined time intervals.

In <FIG>, the control results in which the supply controller <NUM> automatically increases the rotation speed of the ring <NUM> or extends the rotation time are illustrated. In addition, the rotation speed or the rotation time may be manually changed by the selection-value reception unit <NUM> receiving a selection value by an operator.

For example, in the control result of <FIG> described above, the example has been described in which the level of the rotation speed of the ring <NUM> is increased by <NUM> every time the level of the cumulative supply time increases by one. Alternatively, this increase may be performed manually. For example, the level of the rotation speed of the ring <NUM> may be increased as illustrated in Example <NUM> or Example <NUM> below. Example <NUM>: Every time the level of the cumulative supply time increases by <NUM>, the level of the rotation speed of the ring <NUM> is increased by <NUM>. Example <NUM>: Every time the level of the cumulative supply time increases by <NUM>, the level of the rotation speed of the ring <NUM> is increased by <NUM>.

The level of the rotation time of the ring <NUM> in the control result of <FIG> may also be manually increased.

As described above, the ink supply device <NUM> serving as the liquid supply device according to the present embodiment includes the ink tube <NUM> (an example of the channel) to which ink (an example of liquid) is fed, the ring <NUM> (an example of the movable portion) that rotates (moves) to feed the ink, and the supply controller <NUM> (an example of the controller) that controls the ring <NUM>. The supply controller <NUM> controls at least one of the rotation speed (moving speed) and the rotation time (moving time) of the ring <NUM> such that the liquid feed amount increases in accordance with the liquid feed amount of the ink fed in the ink tube <NUM>.

Accordingly, even in a case where the ink supply device <NUM> is used for a long period of time and the channel such as the ink tube deteriorates over time, increasing the liquid supply amount of the ink can prevent the shortage of the ink supply amount by the ink supply device <NUM>. In addition, the necessity of changing the material of the ink tube <NUM> to a material that does not easily deteriorate or replacing the deteriorated ink supply device <NUM> can be obviated, thus preventing an increase in development process and cost.

In the present embodiment, the supply controller <NUM> controls at least one of the rotation speed and the rotation time of the ring <NUM> in a stepwise manner in accordance with the liquid feed amount so that the liquid feed amount increases. Accordingly, at least one of the rotation speed and the rotation time of the ring <NUM> is not constantly controlled, thus preventing the shortage of the ink supply amount by the ink supply device <NUM> while simplifying the control.

In addition, in the present embodiment, at least one of the rotation speed and the rotation time of the ring <NUM> is controlled based on at least one of the cumulative number of rotations of the ring <NUM>, the cumulative supply time of ink by the ink supply device <NUM>, the number of times of replacement of the ink cartridge <NUM>, and the cumulative discharge amount by the ink discharge unit <NUM>. These pieces of information can be acquired by counting by software. Thus, the shortage of the ink supply amount by the ink supply device <NUM> can be prevented based on the acquired information without increasing the component cost.

In the present embodiment, at least one of the rotation speed and the rotation time of the ring <NUM> is controlled based on the flow velocity of the ink supplied from the ink supply device <NUM> to the ink discharge unit <NUM>. The control is based on the flow velocity of the ink directly related to the liquid feeding amount, thus reliably detecting a decrease in the liquid feeding amount and preventing the shortage of the ink supply amount by the ink supply device <NUM>.

In the present embodiment, a selection value of at least one of the rotation speed and the rotation time selected by the operator of the ink supply device <NUM> is received, and at least one of the rotation speed and the rotation time of the ring <NUM> is controlled based on the received selection value. At least one of the rotation speed and the rotation time can be manually selected by the operator. Accordingly, even when the liquid feed amount by the ink supply device <NUM> is less than the minimum necessary liquid feed amount, the liquid feed amount can be reliably changed to be equal to or more than the minimum necessary liquid feed amount.

In the present embodiment, wen the ink supply device <NUM> is replaced, at least one of the rotation speed and the rotation time of the ring <NUM> is returned to the initial state. Such a configuration can prevent the liquid feed amount from being excessive even when the ink supply device <NUM> is replaced with a new one due to a failure.

Further, in the present embodiment, at least one of the rotation speed and the rotation time of the ring <NUM> is controlled based on the type of ink discharged by the ink discharge unit <NUM>. Depending on the type of ink, a sufficient liquid feed amount can be obtained without changing the rotation speed or the rotation time of the ring <NUM>. Accordingly, the control can be simplified without performing unnecessarily complicated control.

In the present embodiment, the ink discharge unit <NUM> includes the head tank <NUM> that stores ink therein, and controls at least one of the rotation speed and the rotation time of the ring <NUM> based on the liquid feed time until the ink amount stored in the head tank <NUM> reaches a full state from the lower limit value by the liquid feeding from the ink supply device <NUM>. Such liquid-feed-time information can be acquired by counting by software, thus preventing the shortage of the ink supply amount by the ink supply device <NUM> based on the acquired information without increasing the component cost.

In the above-described first embodiment, the ink supply device <NUM> of the tube pump type is described. In some embodiments, the ink supply device may use another type such as a diaphragm type or a piston pump type.

<FIG> are diagrams illustrating an example of a diaphragm-pump-type ink supply device 2a according to a second embodiment. <FIG> is a diagram illustrating ink suction. <FIG> is a diagram illustrating ink discharge. As illustrated in <FIG>, the ink supply device 2a includes a diaphragm <NUM>, a pump shaft <NUM>, check valves 26a and 26b, an inlet <NUM>, and an outlet <NUM>.

The diaphragm <NUM> repeats expansion and contraction in accordance with reciprocating translation of the pump shaft <NUM> using, for example, a motor as a driving source. As illustrated in <FIG>, when the diaphragm <NUM> expands, the volume in the ink supply device 2a increases, the check valve 26a closes, and the check valve 26b opens, so that ink is sucked into the ink supply device 2a through the inlet <NUM>.

As illustrated in <FIG>, when the diaphragm <NUM> contracts, the volume in the ink supply device 2a decreases, the check valve 26a opens, and the check valve 26b closes, so that ink is sent out to the outside of the ink supply device 2a through the outlet <NUM>.

The diaphragm <NUM> corresponds to an example of the movable portion and an example of a translation body. A path from the inlet <NUM> to the outlet <NUM> corresponds to an example of the channel.

The ink supply device 2a can send ink from the inlet <NUM> side to the outlet <NUM> side by repeating the operation described above. Although a rubber material or the like can be applied as the material of the diaphragm <NUM>, the liquid feed amount decreases due to deterioration over time of the rubber constituting the diaphragm <NUM>. In this case, at least one of the translation speed and the translation time at which the expansion and contraction of the diaphragm <NUM> are performed is controlled so that the liquid supply amount increases according to the liquid supply amount of the ink. Thus, an effect similar to that of the first embodiment can be obtained.

<FIG> is a diagram illustrating an example of a configuration of a piston-pump type ink supply device 2b according to a third embodiment. As illustrated in <FIG>, the ink supply device 2b includes a cylinder <NUM>, a piston <NUM>, a connecting rod <NUM>, a crankshaft <NUM>, a drive shaft <NUM>, a ball 76a, a ball 76b, an inlet <NUM>, and an outlet <NUM>.

The piston <NUM> is connected to the crankshaft <NUM> via the connecting rod <NUM>. When the crankshaft <NUM> is rotated by the rotation of the drive shaft <NUM>, the piston <NUM> reciprocates between a bottom dead center 72a and a top dead center 72b in the cylinder <NUM>.

When the piston <NUM> reaches the bottom dead center 72a, the ball 76a opens and the ball 76b closes, so that ink is sucked into the ink supply device 2b through the inlet <NUM>. When the piston <NUM> moves to the top dead center 72b, the ball 76a closes and the ball 76b opens, so that ink is sent out to the outside of the ink supply device 2b through the outlet <NUM>.

The piston <NUM> corresponds to an example of the movable portion and an example of the translation body, and a path from the inlet <NUM> to the outlet <NUM> corresponds to an example of the channel.

The ink supply device 2b can send ink from the inlet <NUM> side to the outlet <NUM> side by repeating the operation described above. A sealing material such as rubber is used in a contact portion between the cylinder <NUM> and the piston <NUM>, and the liquid feed amount decreases due to deterioration over time caused by wearing of the sealing material. In this case, at least one of the translation speed and the translation time of the piston <NUM> is obtained so that the liquid feed amount increases in accordance with the liquid feed amount of the ink. Thus, an effect similar to those of the first embodiment can be obtained.

Although some embodiments have been described above, embodiments of the present invention are not limited to the above-described embodiments specifically disclosed, and various modifications and changes can be made without departing from the scope of the claims.

The numbers such as ordinal numbers and numerical values that indicates quantity are all given by way of example to describe the technologies to implement the embodiments of the present disclosure, and no limitation is indicated to the numbers given in the above description. In addition, the above-describe connections among the components are examples for specifically describing the technology of the present invention, and connections for implementing functions of the present invention are not limited to the above-described examples.

Embodiments also include a liquid supply method. For example, a liquid supply method according to an embodiment of the present disclosure is a liquid supply method using a liquid supply device having a channel through which liquid is fed and a movable portion that is movable to feed the liquid, and includes a control step of controlling the movable portion. With such a liquid supply method, an effect similar to that of the above-described liquid supply device can be obtained.

Claim 1:
A liquid supply device (<NUM>, 2a, 2b), comprising:
a channel (<NUM>) through which liquid is to be fed;
a movable portion (<NUM>) configured to move to feed the liquid; and
a controller (<NUM>) configured to control the movable portion,
wherein the controller (<NUM>) is configured to control at least one of a moving speed and a moving time of the movable portion (<NUM>) in accordance with a liquid feed amount of the liquid fed through the channel (<NUM>) such that the liquid feed amount increases,
characterized in that
the movable portion (<NUM>) is a rotating body and the controller (<NUM>) is configured to control at least one of a rotation speed and a rotation time of the rotating body based on a cumulative number of rotations of the rotating body, or in that
the controller (<NUM>) is configured to control the at least one of the moving speed and the moving time based on at least one of a cumulative supply time of the liquid by the liquid supply device.