Patent Application
20210162777
Printing images or text on printable media in a printer includes various media processing activities, including pick-up, delivery to a print engine, printing, and conditioning of sheets of printable media. Conditioning involves heating and pressing the sheets through or past a heated pressure roller (HPR) to remove liquid (for printers using liquid ink), to remove wrinkles or curvature, or to reform or flatten fibers in the sheets.
Various examples are described below referring to the following figures:
In the figures, certain features and components disclosed herein may be shown exaggerated in scale or in somewhat schematic form, and some details of certain elements may not be shown in the interest of clarity and conciseness. In some of the figures, in order to improve clarity and conciseness, a component or an aspect of a component may be omitted.
In the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . ” Also, the term “couple” or “couples” is intended to be broad enough to encompass both indirect and direct connections. Thus, if a first device couples to a second device, that connection may be through a direct connection or through an indirect connection via other devices, components, and connections. In addition, as used herein, the terms “axial” and “axially” generally refer to positions along or parallel to a central or longitudinal axis (e.g., a central axis of a body or a port). As used herein, including in the claims, the word “or” is used in an inclusive manner. For example, “A or B” means any of the following: “A” alone, “B” alone, or both “A” and “B.”
In various examples, a media printing system includes a media conditioner coupled to a printer apparatus, which may also be called a print engine. The print engine is capable of forming an image on a sheet of printable media by a technology such as inkjet, laser, or digital offset, as examples. The media conditioner is positioned to receive sequentially sheets of printed media from the printing device after images are formed on the sheets. The images may include text, figures, or photographic images and may be black, monochrome, or multi-color, as examples. In various examples, conditioning the media includes heating the media, removing an ink solvent, melting an ink, or improving the flatness of the media. In various examples, the media printing system may also be called a printer, an all-in-one printer, or a photocopier. The media conditioner includes a conveying component to conductively heat and move a sheet of printable media and a first heating element and a second heating element to heat the conveying component. The conveying component may be a roller or a belt, as examples. In an example, the first conveying component is a belt, and the media conditioner includes a first heating element to heat an inner portion of the width of the belt, a first temperature sensor positioned to measure the inner portion, a second heating element to heat the outer portion of the width of the belt, which includes the two sides of the belt, a second temperature sensor positioned to measure the outer portion, and a controller to provide separate power levels to the heating elements based on measurements from the temperature sensors While active, the controller is to maintain the belt at a temperature set-point.
During operation, the controller is to make a determination based on recently measured values of operating temperatures from the first and second sensors, in view of set-point values or other anticipated values. A large difference between the measured and the anticipated temperatures or temperature differences may indicate a hardware or firmware issue needs attention. The determination may occur during various stages of operation, such as a heat-up, a cool-down, or steady state.
In addition, the controller may include functionality to compare the power levels of the heaters, or another set of parameters associated with the power levels, to evaluate the performance of the media conditioner, which may be helpful, for example, while the first and second sensors provide results that are or that appear acceptable. For example, the controller may calculate a running average of the power level that is provided to the first heating element over a time period and to calculate a running average of the separate power level that is provided to the second heating element over the same time period. The controller is to calculate an arithmetic difference between these two power levels and to compare that difference against a predetermined threshold value for the power levels. The controller is to perform a task if the difference is greater than the threshold value. The task may include, as examples, refusing to accept printable media, shutting-down, or sending a notification. In some examples, arithmetic differences are calculated for each reading of the two power levels, and the multiple values of these power level differences are then averaged and evaluated against the threshold value. In a scenario in which both temperature sensors are fully functional, but a temperature sensor is misaligned, a comparison of readings from the temperature sensors might not reveal the misalignment. In some examples, evaluating the relative power levels of the heaters, as described, could indicate that a heating issue may merit attention. Examples of media conditioners for media printing systems and techniques of evaluating them are described below.
The example of
Referring now to
Belt 120 and roller 130 contact and press against each other along a nip region 136 to receive and convey the media. Nip region 136 extends along the shared width of belt 120 and roller 130. During operation, rotational movement of the roller 130 drives the belt 120 to rotate, with or without media, in between the roller 130 and the belt 120. First and second temperature sensors 163, 164 are non-contacting thermistors located outside and below belt 120. Other examples may include another form of non-contact temperature sensor or may include a contact temperature sensor located in an appropriate position.
Some examples of a media conditioner 110 include temperature sensors to monitor the temperatures at locations along the width of the second conveying component, for example roller 130. Some examples of a media conditioner may include a conveying component, such as a belt 120 or a roller 130, that is conductively heated.
Referring now to the bottom view of
Still referring to
The central, active portion 145 of inner heating element 142 is sized and positioned to heat the belt's inner portion 123 along the belt's inner surface 121A, and the first temperature sensor 163 is positioned to measure temperature on the outer surface 121B of inner portion 123. The outer, active portion 156 of heating element 152 of lamp 150 is sized and positioned to heat the belt's outer portion 124 along the belt's inner surface 121A, and the second temperature sensor 164 is positioned to measure temperature on the outer surface 121B of outer portion 124. In some examples, inner portion 123 and the first heating element 142 extend along 60% of the belt's width 122, and outer portion 124 and second heating element 152 extend along 40% of the belt's width. A size ratio of 60:40 thus may exist for the inner and outer portions 123, 124 and between the effective heating lengths of lamps 140, 150. In some examples, the ratio is greater than 60:40, and in some examples the ratio is less than 60:40. In some examples, the ratio is greater than or equal to 50:50 and less than or equal to 90:10. Other ratios are possible.
As shown in
Storage 174 is a computer-readable storage medium storing, for example, machine executable code to be executed by processor 172. In various examples, machine executable code may also be called machine readable instructions or computer executable code. The machine executable code stored in storage 174 includes code 175A, code 175B, and code 175C. When executed by controller 170, code 175A governs the normal heating operations of lamps 140, 150, code 175B governs a power level evaluation for lamps 140, 150, and code 175C governs a temperature level evaluation for sensors 163, 164. Code 175A, when executed by controller 170, includes instructions to cause controller 170 (e.g., its processor 172) to provide a first power level to first lamp 140 and its heating element 142 and to provide a second power level to the second lamp 150 and its heating element 152, and to cause the first and second heating elements 142, 152 to generate heat to heat the belt 120. In addition, code 175A includes instructions to cause controller 170 to monitor signals or data from sensors 163, 164 to modulate the power supplied to heating elements 142, 152 and maintain a uniform temperature or a selected temperature distribution across the width of belt 120, based on a targeted temperature set-point or set-points. The first and second power levels are variable. During operation, controller 170 is to provide separate first and second power level signals and may vary the signals to vary the first and second power levels provided to heating elements 142, 152, respectively. In an example, the power level signals are pulse-width-modulated (PWM) signals. Whether controller 170 uses a PWM signal, another analog power level signal, or a digital power level signal, the signals may vary incrementally or smoothly from zero to 100%. The value of 100% power refers to the maximum power that the heating element can accept or the maximum power that the system can provide, whichever is lower. Broadly, the term “power level” will refer to the electrical power available to a heating element or used by a heating element, or it will refer to the power level signal for controlling the electrical power to a heating element. Although electrical couplings 180 are simply shown as a direct connection between controller 170 and heating lamps 140, 150, in various examples, electrical couplings 180 connect the controller 170 to a power supply that feeds heating lamps 140, 150.
Referring again to
The following discussion will describe an example of a temperature sensor performance evaluation for belt 120 in media conditioner 110 as may be implemented by controller 170 executing code 175C. Expression 1, shown here, presents a failing condition for temperature measurements from sensors 163, 164 during the operation of media conditioner 110:
(T1−T2)−ΔTref<−Ttolerance
Or
(T1−T2)−ΔTref>Ttolerance
In Expression 1, T1 is a temperature of the belt inner portion 123, as may be measured by sensor 163 during operation. The parameter T2 is a temperature of the belt outer portion 124, as may be measured by sensor 164 during operation.
The value ΔTref is a reference value describing an anticipated difference in temperatures for belt inner portion 123 and outer portion 124. This reference temperature difference will be discussed below. The value Ttolerance is a tolerance or threshold value.
If a result of Expression 1 is true, then the difference between temperatures T1 and T2 is too large, which is a failing condition for the operation of media conditioner 110. Detecting whether or not media conditioner 110 has reached a failing condition is a goal of code 175C. Controller 170 is to produce the result indicator as a result of the failing condition being determined from Expression 1.
If instead a result of the following expression, Expression 2, is true, then a “passing condition” has been determined for media conditioner 110. A passing condition indicates that the temperatures for belt inner portion 123 and outer portion 124 are acceptably balanced or have an acceptable difference and indicates that power levels provided to heating elements 142, 152 are likely to be set properly. A passing condition may be expressed as:
−Ttolerance≤(T1−T2)−ΔTref≤Ttolerance 2
A passing condition is achieved when a comparison between the temperature difference (T1−T2) during operation and the reference temperature difference, ΔTref, returns a value that is equal to or less than the threshold value, Ttolerance. For Expressions 1 or 2 the comparison is a subtraction, but in some examples, the comparison may use a ratio between the temperature difference (T1−T2) and the reference temperature difference. A passing condition may be determined by Expression 2 producing a true result or by Expression 1 producing a false result. For convenience, the temperature difference (T1−T2) may be called a first temperature difference, the reference temperature difference (ΔTref) may be called a second temperature difference, and the subtraction of these values ((T1−T2)−ΔTref) may called a third temperature difference.
In various examples, as a result of a passing condition, controller 170 is to produce no result indicator equivalent to the result indicator for the true result of Expression 1, or controller 170 is to cancel a result indicator that was activated based on Expression 1. For example, in a first time period (e.g., time period Δt0) the controller may use Expression 1 or 2 and make a determination that activates the result indicator. During a subsequent time period (e.g., time period Δt1), the controller is to evaluate updated values of the first, second, and third temperature differences and is to make an updated determination. If the magnitude of the updated value of the third temperature difference is less than or equal to the magnitude of the threshold value, the controller is to make a determination that a passing condition exists. As a result, the controller may cease to produce the result indicator.
Considering the parameters of Expression 1 and Expression 2 in more detail, the temperatures T1 or T2 may be measured by temperature sensors 163, 164, respectively. Temperatures T1 or T2 reflect the current operating condition of lamps 140, 150 and may be called present or real-time temperature values, and the expression (T1−T2) may be called a real-time temperature difference. The real-time values T1 and T2 may be evaluated as single values (for example, single values at a given time t0) or as averages of a plurality of temperature values, such as running averages calculated over a moving time period, as examples. As used herein, including the claims, an operating condition of media conditioner 110, its belt 120, or its roller 130 may refer to a condition when media is being processed or when the equipment is in a standby or waiting mode, with heating elements 142, 152 active but waiting to process a piece of media, as examples. Thus, in various examples, an operating condition may be a processing condition or a stand-by condition.
The threshold value, Ttolerance, may be a constant value as shown in this example:
T
tolerance=10 C 3
In other examples, the threshold value is a constant value selected from the range: 5 C to 15 C. In still other examples, the threshold value is a constant value less than 5 C or greater than 15 C. In some examples, the threshold value is within the range zero to 20 C. The threshold value, Ttolerance, may be determined based on limits of accuracy or on thermodynamic or heat transfer parameters related to belt 120, roller 130, heating lamps 140, 150, another component, or the media (e.g., thickness, material properties, etc.), as examples. The threshold value may be based on the feed rate of the media. Although units of degrees Celsius are shown, any unit for temperature may be used. In some examples, voltage, current, or resistance values from a temperature sensor are used without converting the data to a unit that is specifically associated with temperature.
The difference in temperatures for a reference operating condition, ΔTref, may be evaluated as:
ΔTref=(T1ref−T2ref) 4
In Expression 4, the parameter T1ref is a temperature of the belt inner portion 123, and the parameter T2ref is a temperature of the belt outer portion 124 for the reference condition. The first and second reference temperatures may be single values or may be averages of multiple data points collected during an earlier time period, for example. The reference temperature difference ΔTref of Expression 4 is based on a reference condition, which may be a design condition related to a specified heating rate of the heat lamps 140, 150, may be an operational period when the media conditioner 110 is known or perceived to be operating properly, or may be a desired condition or setting based on operational attributes (e.g., media size, density, or thickness or image size or density), as examples. The reference condition may be steady state, a heat-up ramp, or a cool-down ramp.
The evaluation of Expression 1 can also be written as:
|(T1−T2)−ΔTref|>Ttolerance 5
Expression 5 provides a true result when an absolute value taken after subtracting the reference temperature difference, ΔTref, from the real-time temperature difference, (T1−T2), is greater than the threshold value, Ttolerance. A true result from Expression 5 indicates a failing condition for media conditioner 110.
Referring to
In some examples, controller 170 includes wired circuits that accomplish some aspects of the functionality described for codes 175A, 175B, 175C. Controller 170 may be implemented within a single housing or may be distributed in multiple housings or circuits through the extent of media conditioner 110 or printing system 100.
In an example, method 300 includes the use of Expression 1 (above). In this example, forming the first comparison of Block 302 includes determining a first temperature difference, e.g., (T1−T2), the real-time temperature difference between the first and second measured temperatures. Forming the second comparison of Block 302 includes determining a second temperature difference, which may be the reference temperature difference, ΔTref, evaluated from first and second reference temperatures, T1ref and T2ref, as shown in Expression 4, above. Forming the third comparison of Block 306 includes determining a third temperature difference between the first temperature difference and the second temperature difference. For example, in Expression 1, the third temperature difference is (T1−T2)−ΔTref. At Block 308, the result indicator is to be generated or produced when the third temperature difference of Block 306 is greater than the threshold value, e.g., Ttolerance, or less than the negative of the threshold value, which would be a “true” result from Expression 1, representing a failing condition for media conditioner 110. This outcome may also be described by stating that the result indicator is to be produced if the magnitude of the third temperature difference is greater than the magnitude of the threshold value. Thus, in this example, method 300 evaluates a comparison that includes the first temperature difference, the second temperature difference, and a threshold value and is to produce a result indicator based on the comparison. The method may further include ceasing to produce or negating the result indicator in response to the magnitude of the third difference becoming equal to or dropping below the magnitude of the threshold value in a subsequent time period.
The third comparison of Block 306 may also be evaluated using Expression 5, which also involves a first, a second, and a third temperature difference. Then, At Block 308, the result indicator may be generated or produced when the absolute value of a subtraction of the second temperature difference from the first temperature difference is greater than a threshold value.
In some examples, method 300 includes the use of Expression 2 to perform corresponding activities and to achieve the accomplishments described herein. Some implementations of method 300 may incorporate other functionalities disclosed herein. Various examples of method 300 may be implemented in media conditioner 110, and some examples, the functionality of method 300 is included in code 175C (
The above discussion is meant to be illustrative of the principles and various examples of the present disclosure. Numerous variations and modifications will become apparent to those skilled in the art. It is intended that the following claims be interpreted to embrace all such variations and modifications.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2018/042156 | 7/13/2018 | WO | 00 |
