Patent ID: 12219106

DESCRIPTION OF THE EMBODIMENTS

Exemplary embodiments for implementing the present disclosure will be described in detail below with reference to the attached drawings. However, components described in the following exemplary embodiments can be appropriately modified in dimension, material, shape, and relative position with configurations and various conditions of an apparatus to which the present disclosure is applied, and are not intended to limit the scope of the present disclosure.

[Configuration of Image Forming Apparatus]

FIG.1is the overall view of an image forming system100according to the present exemplary embodiment. The image forming system100is a system in which a printer101, an image reading apparatus102, and a stacking apparatus103are connected. The image forming system100includes an operation unit21for users to perform various inputs to the image forming system100.

The printer101, which is an image forming apparatus, is a full color printer using an electrophotographic process with four colors. The printer101forms a toner image on a recording material based on an image signal input to a control unit301from an information terminal such as a personal computer (PC) or an external apparatus300such as an image reader. The recording material is a recording medium (hereinafter, referred to as a sheet P) on which a toner image can be formed, and plain paper, thick paper, super-thick paper, an overhead projector (OHP) sheet, coated paper, label paper, and other types of paper can be used as the recording material.

The printer101includes four image forming mechanism units101aas image forming units that each form a toner image in the corresponding color among yellow (Y), magenta (M), cyan (C), and black (Bk). The image forming mechanism units101aform toner images using the conventionally known electrophotographic process. These four image forming mechanism units101aare arranged in parallel from left to right inFIG.1.

A laser scanner unit3, which is an exposure apparatus, is arranged above each image forming mechanism unit101a, and an intermediate transfer belt50is arranged below the image forming mechanism units101a. The intermediate transfer belt50is stretched around a driving roller51, a tension roller52, and an inner secondary transfer roller53, and is driven in the direction of an arrow inFIG.1.

Each of the image forming mechanism units101ahas a similar electrophotographic process configuration and differs only in the color of toner (developer) to be used. Each image forming mechanism unit101aincludes a photosensitive drum1as an image bearing member, a charger2, a development unit4, a primary transfer roller6, and a drum cleaner7. InFIG.1, the reference numerals of the image forming mechanism units101aother than the image forming mechanism unit101afor black (Bk) are omitted to avoid complication of the drawing.

The toner image in each color is primarily transferred from the photosensitive drum1of the image forming mechanism unit101ato the intermediate transfer belt50to be superimposed one by one. This process forms an unfixed full-color toner image with the four color toners of Y, M, C, and Bk superimposed on the intermediate transfer belt50.

The printer101includes a cassette24in which the sheet P is stored. The sheet P fed from the cassette24passes through a conveyance path13and is conveyed into a secondary transfer nip portion15, which is a pressure contact portion between the intermediate transfer belt50and a secondary transfer roller14, at a predetermined control timing. Then, the superimposed four-color toner image on the intermediate transfer belt50is secondarily transferred onto the sheet P. Then, the residual toner remaining on the intermediate transfer belt50after the secondary transfer to the sheet P is removed from the surface of the intermediate transfer belt50by a belt cleaner19.

Then, the sheet P with the toner image transferred thereon is conveyed into a fixing device16and is subjected to fixing processing of heating and pressing. After passing through the fixing device16, the sheet P is discharged from the printer101by a discharging roller pair17and is conveyed to the image reading apparatus102. In duplex printing, the sheet P with an image formed on one surface passes through a reverse conveyance path57and is conveyed again to the secondary transfer nip portion15.

Each image forming unit of the printer101according to the present exemplary embodiment has a configuration using the electrophotographic process, but may have a configuration using another image forming system such as an ink-jet system.

[Configuration of Image Reading Apparatus]

FIG.2is a cross-sectional view of the image reading apparatus102. The image reading apparatus102reads an image on a sheet formed by the printer101. The image reading apparatus102includes a conveyance path123along which the sheet conveyed from the printer101is conveyed. The conveyance path123is a nearly horizontal conveyance path formed by an upper conveyance guide121and a lower conveyance guide122. Inlet conveyance rollers111and112as first conveyance rollers and outlet conveyance rollers119and120as second conveyance rollers are arranged on the conveyance path123. The inlet conveyance rollers111and112are rollers that receive the sheet discharged from the printer101upstream of the image reading apparatus102. The outlet conveyance rollers119and120are rollers that discharge the sheet to the stacking apparatus103downstream of the image reading apparatus102.

A first reading unit113and a second reading unit116are arranged in an image reading unit147of the image reading apparatus102. The first reading unit113reads an image on the lower surface (a first surface) of the sheet, and the second reading unit116reads an image on the upper surface (a second surface) of the sheet. This configuration allows the image reading apparatus102to read the images on both surfaces of the sheet. The second reading unit116is at a position downstream of the first reading unit113in the conveyance direction of the conveyance path123, and the reading position (a second reading position) of the second reading unit116is downstream of the reading position (a first reading position) of the first reading unit113. The first reading unit113and the second reading unit116are, for example, contact image sensors (CIS) or charge coupled device (CCD) cameras.

The images read by the first reading unit113and the second reading unit116are transmitted as signals to an external PC305. The external PC305compares the images read by the first reading unit113and the second reading unit116with the corresponding image data registered in advance and detects an image defect such as dirt on the sheet. This manner allows the external PC305, which is a determination unit, to determine whether the sheet on which the image is formed by the printer101is normal.

According to the present exemplary embodiment, the external PC305is provided outside the image reading apparatus102, but may be provided integrally with the image reading apparatus102or the printer101.

A glass114, which is a first transparent member and forms a part of the conveyance path123, is incorporated in the lower conveyance guide122. The glass114faces the lower surface of the sheet being conveyed. The image on the lower surface of the sheet conveyed along the conveyance path123is read by the first reading unit113through the glass114.

A backing roller115is arranged at a position opposed to the glass114of the conveyance path123. The backing roller115is an example of a first opposing roller according to the present exemplary embodiment. The backing roller115is arranged at the reading position of the first reading unit113in the conveyance direction. The backing roller115is supported by the upper conveyance guide121. The backing roller115can be rotationally driven by a driving gear351connected to a driving motor350, which is a first motor (refer toFIG.4described below). The driving gear351transmits driving force from the driving motor350to the backing roller115. The pair of driving motor350and the driving gear351are an example of a driving unit according to the present exemplary embodiment.

A glass117, which is a second transparent member and forms a part of the conveyance path123, is incorporated in the upper conveyance guide121. The glass117faces the upper surface of the sheet being conveyed. The image on the upper surface of the sheet conveyed along the conveyance path123is read by the second reading unit116through the glass117.

A backing roller118is arranged at a position opposed to the glass117of the conveyance path123. The backing roller118is an example of a second opposing roller according to the present exemplary embodiment. The backing roller118is arranged at the reading position of the second reading unit116in the conveyance direction. The backing roller118is supported by the lower conveyance guide122. The backing roller118can be rotationally driven by a second motor, which is not illustrated, in the same manner as the backing roller115. The pressure with which the backing rollers115and118press the sheet is smaller than the nip pressure between the outlet conveyance rollers119and120.

The sheet of which the images are read by the first reading unit113and the second reading unit116is conveyed from the image reading apparatus102to the stacking apparatus103by the outlet conveyance rollers119and120. A control apparatus302, which is a control unit, controls the driving of each roller in the image reading apparatus102, and controls the first reading unit113, and the second reading unit116. Each roller, the first reading unit113, the second reading unit116, and the control apparatus302described above are housed inside a housing136of the image reading apparatus102.

[Configuration of Stacking Apparatus]

FIG.3is a cross-sectional view of the stacking apparatus103. Sheets conveyed from the image reading apparatus102to the stacking apparatus103are stacked in a first stacking unit158or a second stacking unit165. A flapper155switches between conveyance paths153and154to and along which the sheet is to be conveyed.

If the sheet is discharged to the first stacking unit158, the sheet is conveyed along the conveyance path153by conveyance rollers151and152and conveyance rollers156and157. If the sheet is discharged to the second stacking unit165, the sheet is guided to the conveyance path154by the flapper155and is conveyed by conveyance rollers159and160, conveyance rollers161and162, and conveyance rollers163and164. A control unit303controls the driving of each conveyance roller and the flapper155.

As described above, the image forming system100can inspect the image read by the image reading apparatus102. The control unit303controls each conveyance roller and the flapper155to discharge the sheet determined to be normal by the external PC305to the first stacking unit158and to discharge the sheet determined to be abnormal by the external PC305to the second stacking unit165.

[Description of Image Reading Unit]

FIG.4is a side view of the first reading unit113and the backing roller115with a sheet201having a thickness t of less than 0.4 millimeter [mm] conveyed therein. An example of the sheet201having a thickness t of less than 0.4 [mm] is plain paper generally used for printing.

As illustrated inFIG.4, abutting units131that abut on the glass114are arranged at both ends of the backing roller115in the width direction of the backing roller115(perpendicular to the conveyance direction). The backing roller115is movable in a direction separating from the glass114(upward inFIG.4) and is urged toward the glass114by springs135, which are an urging member. At this time, the abutting units131, which are a gap forming unit, abut on the glass114, forming a gap133between the glass114and the backing roller115.

According to the present exemplary embodiment, the gap133is approximately 0.4 [mm], and the backing roller115prevents the sheet201being conveyed from floating above the glass114by 0.4 [mm] or more. Since the thickness of the sheet201is less than 0.4 [mm], the sheet201does not lift the backing roller115. Thus, when the sheet201is being conveyed, the abutting unit131remains abutting on the glass114. The second reading unit116downstream is also configured with a mechanism similar to the first reading unit113and the backing roller115, except that it is disposed upside down.

FIG.5is a side view of the first reading unit113and the backing roller115with a sheet (super-thick paper)202having a thickness t of 0.4 [mm] or more conveyed therein.

As illustrated inFIG.5, the thickness of the sheet202is greater than the original gap133, so that the sheet202lifts the backing roller115against the urging force of the springs135, and the abutting units131are lifted up from the glass114. At this time, the lower surface of the sheet202is in close contact with the glass114, so that the first reading unit113can correctly read the image on the sheet202.

If the gap133is set wider, it is not possible to regulate floating of the sheet201having a thickness t of less than 0.4 [mm] in the depth direction (a direction perpendicular to the surface of the glass114), which may result in a reading failure. According to the present exemplary embodiment, the gap133is set at 0.4 [mm], which is a range in which the first reading unit113and the second reading unit116can read the image correctly. If the sheet202having a thickness t of 0.4 [mm] or more, the backing roller115is pushed and lifted by the sheet being conveyed, causing the gap133to be changed. Thus, the image reading apparatus102can read images on sheets of various thicknesses. According to the present exemplary embodiment, the gap133is 0.4 [mm], but the gap between the glass114and the backing roller115is not limited to this value and is desirable to be set appropriately based on the performance of the reading units.

FIG.6is an enlarged view of the backing roller115with the sheet201(a second sheet) having a thickness t of less than 0.4 [mm] conveyed therein. The sheet201is conveyed at a movement speed (a conveyance speed) Vs. The outlet conveyance rollers119and120are provided at positions at which the outlet conveyance rollers119and120are in contact with the sheet while the second reading unit116reads the image on the sheet. Thus, the conveyance speed Vs is almost the same as the circumferential speed of the outlet conveyance rollers119and120located downstream of the first reading unit113. Then, while the outlet conveyance rollers119and120convey the sheet, the trailing edge of the sheet passes over the reading position of the first reading unit113(between the glass114and the backing roller115). According to the present exemplary embodiment, a circumferential speed is the speed of the outer surface of a roller in rotation.

The backing roller115rotates at a circumferential speed Vb. According to the present exemplary embodiment, the control apparatus302controls the driving motor350in such a manner that the circumferential speed Vb of the backing roller115is faster than the conveyance speed Vs. In other words, the circumferential speed Vb of the backing roller115is set to a value faster than the circumferential speed of the outlet conveyance rollers119and120. When the sheet201is conveyed, the backing roller115does not move in the direction separating from the glass114.

As illustrated inFIG.6, the backing roller115is driven to rotate at the circumferential speed Vb, and when the sheet201having a thickness t of less than 0.4 [mm] is conveyed, there is a gap between the backing roller115and the sheet201. Thus, the sheet conveyance force applied to the sheet201by the backing roller115is extremely small. Thus, the speed difference between the conveyance speed Vs and the circumferential speed Vb of the backing roller115has almost no effect on the image reading of the sheet201.

FIG.7is an enlarged view of the backing roller115with the sheet202(a first sheet) having a thickness t of 0.4 [mm] or more conveyed therein. As illustrated inFIG.7, when the sheet202is conveyed, the backing roller115is pushed by the sheet202and is moved in the direction separating from the glass114. At this time, the backing roller115is in contact with the sheet202. However, the pressure with which the backing roller115presses the sheet is set smaller than the nip pressure between the outlet conveyance rollers119and120, so that the speed difference between the conveyance speed Vs and the circumferential speed Vb of the backing roller115has almost no effect on the image reading of the sheet202. The sheet202having a thickness t of 0.4 [mm] or more has higher rigidity than the sheet201having a thickness t of less than 0.4 [mm] and is hard to deform, and the backing roller115slips on the sheet202. This reduces the effect on the image reading of the sheet202due to the speed difference between the conveyance speed Vs and the circumferential speed Vb of the backing roller115. The pressure with which the backing roller115presses the sheet is determined by the springs135.

FIG.8is an enlarged view of the backing roller115when the trailing edge of the sheet202having a thickness t of 0.4 [mm] or more exits the backing roller115. As illustrated inFIG.8, when the trailing edge of the sheet202exits the backing roller115, the trailing edge of the sheet202is advancing by an angle θ from immediately under the rotation center of the backing roller115in the conveyance direction. At this time, the component in the conveyance direction of the circumferential speed Vb of the backing roller115at a point where the sheet202is in contact with the backing roller115is expressed as Vb×cos(θ).

Supposing the circumferential speed Vb of the backing roller115is set to the same speed as the conveyance speed Vs (Vb=Vs), the component Vb×cos(θ) is smaller than the conveyance speed Vs (Vb×cos(θ)<Vs). As a result, the sheet is pulled by the outlet conveyance rollers119and120and the backing roller115, so that a shock that occurs when the sheet202is released from the pull out of contact with the backing roller115could lead to an image defect in the second reading unit116.

On the other hand, according to the present exemplary embodiment, the circumferential speed Vb of the backing roller115is set to the value faster than the conveyance speed Vs. More specifically, the circumferential speed Vb of the backing roller115is set to a value satisfying Vs<Vb×cos(θ). Thus, the sheet is not pulled by the outlet conveyance rollers119and120and the backing roller115. In other words, the shock is prevented, which prevents the image defect in the second reading unit116downstream from occurring.

According to the present exemplary embodiment, as an example, the conveyance speed Vs is 100 [mm/S], the circumferential speed Vb of the backing roller115is 103 [mm/S], and the outer diameter of the backing roller115is 20 [mm]. If the thickness t of the sheet202is 0.5 [mm], the angle θ is about 8.1°, and the component Vb×cos(θ)=101.97 [mm/S]. In other words, the circumferential speed Vb of the backing roller115has a value satisfying Vs<Vb×cos(θ).

[Description of Disturbance in Image Scaling Ratio]

FIGS.9A to9Dare graphs indicating image scaling ratios in the sub scanning direction of image reading when the second reading unit116downstream reads an image on a sheet (super-thick paper) having a thickness t of about 0.5 [mm]. InFIGS.9A to9D, the vertical axes and the horizontal axes of the graphs respectively indicate image scaling ratios and sheet conveyance distances, respectively. The image scaling ratios are ratios of enlargement and reduction of a read image at a predetermined pitch in the conveyance direction. It is desirable that the image scaling ratio is stable near 0%. InFIGS.9A to9D, ratios of the circumferential speed Vb of the backing roller115to the conveyance speed Vs are respectively different.FIG.9Ais a graph when the circumferential speed Vb of the backing roller115is 97% of (3% slower than) the conveyance speed Vs.FIG.9Bis a graph when the circumferential speed Vb of the backing roller115is 100% of (the same speed as) the conveyance speed Vs.FIG.9Cis a graph when the circumferential speed Vb of the backing roller115is 103% of (3% faster than) the conveyance speed Vs.

FIG.9Dis a graph when the circumferential speed Vb of the backing roller115is 106% of (6% faster than) the conveyance speed Vs. In other words,FIGS.9A and9Bare the graphs when the circumferential speed Vb of the backing roller115is set to the circumferential speed of the outlet conveyance rollers119and120or less. Meanwhile,FIGS.9C and9Dare the graphs when the circumferential speed Vb of the backing roller115is set to values greater than the circumferential speed of the outlet conveyance rollers119and120.

InFIGS.9A to9D, the timing when the trailing edge of the sheet exits from the backing roller115corresponds to a value near 400 on the horizontal axis. At the timing when the trailing edge of the sheet exits from the backing roller115, the image scaling ratio of the read image of the second reading unit116can be disturbed as the speed of the sheet temporarily changes.

As illustrated inFIG.9A, when the circumferential speed Vb of the backing roller115is 97% of (3% slower than) the conveyance speed Vs, the image scaling ratio is greatly disturbed, causing a reading failure to occur. As illustrated inFIG.9B, even when the circumferential speed Vb of the backing roller115is 100% of (the same speed as) the conveyance speed Vs, the image scaling ratio is slightly disturbed. As illustrated inFIG.9C, when the circumferential speed Vb of the backing roller115is 103% of (3% faster than) the conveyance speed Vs, the disturbance on the image scaling ratio is small, and positive and negative waveforms cancel each other out. As illustrated inFIG.9D, when the circumferential speed Vb of the backing roller115is 106% of (6% faster than) the conveyance speed Vs, the image scaling ratio is slightly disturbed.

As described above, the circumferential speed Vb of the backing roller115is set to a value greater than the circumferential speed of the outlet conveyance rollers119and120, so that the image scaling ratio is stabilized, reducing reading failures. Further, it is desirable that the circumferential speed Vb of the backing roller115is 101% or more and 104% or less of the circumferential speed of the outlet conveyance rollers119and120.

[Description of Flowchart]

As illustrated inFIG.8, when the thickness t of the sheet is greater than the gap133, the backing roller115is pushed and lifted up by the sheet. Thus, when the thickness t of a sheet is a predetermined thickness or more, the circumferential speed Vb of the backing roller115may be set to a value greater than the circumferential speed of the outlet conveyance rollers119and120.

FIG.10is a flowchart illustrating a reading operation corresponding to a paper type performed by the control apparatus302. In the image reading apparatus102, the circumferential speed Vb of the backing roller115can be set to a value greater than the circumferential speed of the outlet conveyance rollers119and120regardless of the paper type, but when the frequency of opportunities of conveying super-thick paper is small, the circumferential speed Vb of the backing roller115can be changed based on the paper type.

The control apparatus302starts processing in the flowchart illustrated inFIG.10when a sheet is conveyed from the printer101to the image reading apparatus102. As illustrated inFIG.10, in step S101, the control apparatus302acquires information about the sheet to be conveyed. At this time, the control apparatus302functions as an acquisition unit and refers to the information about the sheet input by a user using the operation unit21. The information about the sheet input by the user using the operation unit21is stored in the control unit301.

Next, in step S102, the control apparatus302determines whether the thickness t of the sheet is a predetermined thickness or greater based on the information about the sheet acquired in step S101. According to the present exemplary embodiment, the predetermined thickness is set to 0.4 [mm], but may be appropriately changed based on the width of the gap133.

If the thickness t of the sheet is the predetermined thickness or greater (YES in step S102), in step S103, the control apparatus302performs a high-speed backing roller mode. The high-speed backing roller mode is a mode for controlling the driving motor350so that the circumferential speed Vb of the backing roller115is greater than the circumferential speed of the outlet conveyance rollers119and120. More specifically, in the high-speed backing roller mode, the control apparatus302sets the circumferential speed Vb of the backing roller115between 101% and 104%, inclusive, of the circumferential speed of the outlet conveyance rollers119and120. The circumferential speed Vb of the backing roller115at this time is defined as a first circumferential speed.

On the other hand, if the thickness t of the sheet is not the predetermined thickness or more (NO in step S102), in step S104, the control apparatus302performs a normal-speed backing roller mode. The normal-speed backing roller mode is a mode for controlling the driving motor350so that the circumferential speed Vb of the backing roller115is equivalent to the circumferential speed of the outlet conveyance rollers119and120. The circumferential speed Vb of the backing roller115at this time is defined as a second circumferential speed. The second circumferential speed is slower than the first circumferential speed.

Then, in step S105, the control apparatus302performs image reading with the first reading unit113and the second reading unit116while conveying the sheet in the high-speed backing roller mode or the normal-speed backing roller mode. After the image reading is completed, the control apparatus302terminates the processing in the flowchart.

By the above-described processing in the flowchart, the control apparatus302performs the high-speed backing roller mode if the thickness of the sheet is a first thickness greater than or equal to the predetermined thickness, and performs the normal-speed backing roller mode if the thickness of the sheet is a second thickness less than the predetermined thickness.

In the processing in the flowchart inFIG.10, the control apparatus302switches between the high-speed backing roller mode and the normal-speed backing roller mode based on the thickness t of the sheet. However, the control apparatus302can switch between the high-speed backing roller mode and the normal-speed backing roller mode based on the basis weight of the sheet. Specifically, the control apparatus302performs the high-speed backing roller mode if the basis weight of the sheet is a first basis weight greater than or equal to a predetermined basis weight, and performs the normal-speed backing roller mode if the basis weight of the sheet is a second basis weight less than the predetermined basis weight.

The control apparatus302can switch between the high-speed backing roller mode and the normal-speed backing roller mode based on whether the print job specifies duplex printing. Specifically, the control apparatus302performs the high-speed backing roller mode if the print job specifies duplex printing, and performs the normal-speed backing roller mode if the print job specifies simplex printing.

The above-described control enables the control apparatus302to set the circumferential speed Vb of the backing roller115to an appropriate value corresponding to the type of the sheet to be conveyed.

The image reading apparatus102may include another conveyance roller pair between the first reading position and the second reading position in the conveyance direction. In this case, it is desirable that the circumferential speed Vb of the backing roller115is faster than the circumferential speed of the other conveyance roller pair.

The image forming system100according to the present exemplary embodiment is a system in which the printer101, the image reading apparatus102, and the stacking apparatus103are connected, but the configuration of the image forming system100is not limited to this one. The image forming system100may include another apparatus not illustrated. For example, an inserter for inserting sheets may be arranged between the printer101and the image reading apparatus102. In this case, all apparatuses including the printer101arranged upstream of the image reading apparatus102are collectively referred to as an image forming apparatus. Further, for example, a cutting apparatus for cutting sheets may be arranged between the image reading apparatus102and the stacking apparatus103. In this case, all apparatuses including the stacking apparatus103arranged downstream of the image reading apparatus102are collectively referred to as a discharge apparatus.

According to the present exemplary embodiment, the circumferential speed of the backing roller118can be the same as the conveyance speed. In other words, when the circumferential speeds of the backing roller115and the backing roller118are compared, the circumferential speed of the backing roller115may be set faster than the circumferential speed of the backing roller118. In this case, the power consumption can be reduced as compared with a case where the backing roller118is rotated at high speed.

As described above, the image reading apparatus102according to the present exemplary embodiment sets the circumferential speed Vb of the backing roller115to be greater than the circumferential speed of the outlet conveyance rollers119and120. This reduces a shock that will occur when a sheet is released from the pull between rollers, reducing an image defect in the second reading unit116downstream.

Embodiments of the present disclosure can also be realized by a computer of a system or apparatus that reads out and executes computer executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be referred to more fully as a ‘non-transitory computer-readable storage medium’) to perform the functions of one or more of the above-described Embodiments and/or that includes one or more circuits (e.g., application specific integrated circuit (ASIC)) for performing the functions of one or more of the above-described Embodiments, and by a method performed by the computer of the system or apparatus by, for example, reading out and executing the computer executable instructions from the storage medium to perform the functions of one or more of the above-described Embodiments and/or controlling the one or more circuits to perform the functions of one or more of the above-described Embodiments. The computer may include one or more processors (e.g., central processing unit (CPU), micro processing unit (MPU)) and may include a network of separate computers or separate processors to read out and execute the computer executable instructions. The computer executable instructions may be provided to the computer, for example, from a network or the storage medium. The storage medium may include, for example, one or more of a hard disk, a random-access memory (RAM), a read-only memory (ROM), a storage of distributed computing systems, an optical disk (such as a compact disc (CD), digital versatile disc (DVD), or Blu-ray Disc™ (BD)), a flash memory device, a memory card, and the like.

While the present disclosure has been described with reference to exemplary embodiments, it is to be understood that the disclosure is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.