CA2032060C - Self-regulating tape head - Google Patents
Self-regulating tape headInfo
- Publication number
- CA2032060C CA2032060C CA002032060A CA2032060A CA2032060C CA 2032060 C CA2032060 C CA 2032060C CA 002032060 A CA002032060 A CA 002032060A CA 2032060 A CA2032060 A CA 2032060A CA 2032060 C CA2032060 C CA 2032060C
- Authority
- CA
- Canada
- Prior art keywords
- tape
- region
- transducer
- island
- wear
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/10—Structure or manufacture of housings or shields for heads
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B15/00—Driving, starting or stopping record carriers of filamentary or web form; Driving both such record carriers and heads; Guiding such record carriers or containers therefor; Control thereof; Control of operating function
- G11B15/60—Guiding record carrier
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B15/00—Driving, starting or stopping record carriers of filamentary or web form; Driving both such record carriers and heads; Guiding such record carriers or containers therefor; Control thereof; Control of operating function
- G11B15/60—Guiding record carrier
- G11B15/62—Maintaining desired spacing between record carrier and head
Abstract
A tape head assembly for use in conjunction with a magnetic recording tape has a support structure, an island affixed to the support structure, and a transducer located on the island. The island has at least two sections of differing widths parallel to the direction of tape operation. The transducer is located in the wider section. The island is susceptible to wear as the magnetic recording tape streams across the island, such that the height profile of the island in a direction perpendicular to the direction of a tape operation varies over time. The island experiences substantially uniform wear at a substantially nonuniform height profile, and substantially nonuniform wear at a substantially uniform height profile.
Description
Self-Regulating Tape Head Background of the Invention This invention generally relates to magnetic tape head assemblies for use in conjunction with magnetic recording tape.
Magnetic tape head assemblies typically contain one or more raised strips or "islands" over which the magnetic recording tape passes. Embedded in each island is a transducer, which may be an encoding element for writing information onto the tape, or a decoding element for reading information off of the tape. An encoding element produces a magnetic field in the vicinity of a small gap in the encoding element, which causes information to be stored on the magnetic recording tape as the tape streams over the island in contact with the island. Likewise, a decoding element detects a magnetic field near the surface of the tape as the tape streams over the island in contact with the island. Yet, there is typically some microscopic separation between the transducer and the recording tape that reduces the magnetic field strength detected by the tape or the decoding element. The reduction in the detected magnetic field strength is known as "spacing loss."
The magnetic field strength detected by the tape or the decoding element is proportional to e kd/~ , where d is the head-to-tape separation, ~ is the recording wavelength, and k .
- lA -is a constant. The detected magnetic field strength decreases exponentially both with respect to separation between the tape and the island and with respect to recording density (which is inversely related to the recording wavelength ~). Thus, while a limited amount of head-to-tape separation might be acceptable at low recording densities of 10 - 20 KFCI, at the higher densities (40 - 60 KFCI) of new, smaller transducers the head-to-tape separation must not exceed a few micro-inches.
When a uniform tension T is applied to a recording tape as the tape passes at a wrap angle ~ around an island having a uniform height I~ and a uniform width Iw, the tape exerts a pressure P against the island that is uniform along an axis down the center of the length of the island. The pressure P is essentially proportional to the tension T and ` the wrap angle ~ and inversely proportional to the island width Iw. The pressure P of the tape against the island can be increased by increasing T or ~, or by decreasing Iw, thereby reducing any microscopic separation between the tape and the encoding element, and hence reducing spacing loss.
This increased pressure tends to cause the island to wear down more rapidly, however, resulting in a shortened head life. Moreover, the increased pressure may result in depressions in the island that also contribute to spacing loss, thus making spacing loss unavoidable.
Summary of the Invention The invention provides a tape head assembly for use in encoding or decoding a magnetic recording tape that passes over the assembly. The tape head assembly includes a transducer support that has a wear surface over which the tape passes and against which the tape exerts pressure. A
transducer is located in the support to encode or decode the tape passing over the wear surface. The wear surface has a first, wider region in proximity to the transducer, and a second, narrower region aligned with the first region along an axis. The first region has a greater extent transverse to the axis than the second region.
Initially, the wear surface is at a uniform height along its length. The pressure (force per unit area) of the tape on the wider region is less than the pressure of the tape on the narrower region. Consequently, the friction force per unit area in the wider region is less than the friction force per unit area in the narrower region. Thus the narrower region tends to wear more rapidly than the wider section, until the wider region approaches a raised height relative to the narrower region. As the wider region becomes raised, the pressure of the tape on the wider region increases relative to the initial pressure on the wider region when the wear surface is at a uniform height.
Eventually, the pressure across the entire wear surface becomes uniform, and consequently the wear across the wear surface becomes uniform. The wear surface continues to maintain a nonuniform height profile as it wears down uniformly in a self-adjusting manner.
Because the wider region containing the transducer becomes raised relative to the narrower region, spacing between the transducer and the magnetic recording tape is reduced, and the spacing tends to vary less with respect to changes in tension of the magnetic recording tape. When the wider region containing the transducer is raised relative to the narrower region, the raised wider region ensures that any small surface irregularities in the narrower region do not lift the tape away from the transducer.
The invention in its broad form resides in a tape head assembly, having a tape facing surface, for use in encoding or decoding a magnetic recording tape passing thereover comprising, a transducer support having a raised surface, and against which said tape exerts pressure, said raised surface being constructed to be ~, , .
~03206~
sufficiently close to said tape to constitute a wear surface, a transducer mounted in said support to encode or decode said tape passing over said surface, said wear surface being divided along an axis into a first region and a second region, said first region being in proximity to said transducer, said first region having a greater extent transverse to said axis than said second region, so as to present to said tape a wear surface portion that is wider than that presented by said second region, thereby permitting the maintenance of said wear surface closer to said tape in said first region than in said second region.
In preferred embodiments, the wear surface is provided by an island located on the transducer support. The island has three regions. A wide region containing the transducer is located between two narrower regions. The transducer is an encoding element for encoding information onto the magnetic recording tape, or a decoding element for reading information off of the magnetic recording tape. As the nonuniform height profile at which the island experiences substantially uniform wear, spacing between the , .,, ~,~
2Q~2060 transducer and the magnetic recording tape is low enough to permit recording by the transducer onto the magnetic recording tape at densities of at least 40 KFCI.
According to another aspect, the invention provides a method of using a tape head asæembly, having a tape facing surface, in conjunction with a magnetic recording tape, comprising the steps of providing a transducer support having a raised surface, relative to said tape facing surface, constructed to be sufficiently close to said tape to constitute a wear surface, said wear surface being divided along an axis into a first region and a second region, said first region being in proximity to a transducer, said first region having a greater extent transverse to said axis than said second region, said first region having a raised height relative to said second region, and running a tape over said wear surface in a manner such that said tape exerts pressure on said wear surface, while transferring information between said transducer and said tape, said pressure of said tape on said wear surface causing said first and second regions to tend to wear down at substantially the same rate, to thereby maintain said raised height of said first region relative to said second region, and hence to reduce separation between said tape and said transducer and thereby reduce spacing loss.
According to yet another aspect, the invention provides a method of using a tape head assembly, having a tape facing surface, in conjunction with a magnetic recording tape, comprising the steps of running tape over a raised surface, relative to said tape facing surface, surface of a transducer support in a manner such that said tape exerts pressure on said raised surface, said raised surface being constructed to be sufficiently close to said tape to constitute a wear surface, said wear surface being divided along an axis into a first region and a second region, said first region being in proximity to a transducer, said first region having a greater extent transverse to said axis than said second region, said pressure of said tape on said wear surface causing said second region to tend to wear down faster than said first region, until said first region approaches a raised height relative to said second region, at which raised height said first and second regions tend to wear down at substantially the same rate, thereby maintaining said raised height of said first region relative to said second region, and continuing to run a tape over said wear surface while transferring information between said transducer and said tape, said raised height of said first region serving to reduce separation between said tape and said transducer and thereby serving to reduce spacing loss.
Brief DescriPtion of the Drawinq A more detailed understanding of the invention may be had from the following description of a preferred embodiment, given by way of example only and to be understood in conjunction with the accompanying drawing wherein:
Figure 1 is a drawing of a tape head assembly according to one embodiment of the invention.
Figure 2 is a drawing of a portion of an island on a tape head assembly according to one embodiment of the invention.
Figure 3 is a graph showing island height as a function 4a of position along the length of the island, when the island is in its initial condition.
Figure 4 is a graph showing pressure of a tape on the island as a function of position along the length of the island, when the island is in its initial condition.
Figure 5 is a graph showing island height as a function of position along the length of the island, at several points in time after a tape has begun to wear on the island.
Figure 6 is a graph showing pressure of a tape on the island as a function of position along the length of the island, at several points in time after the tape has begun to wear on the island.
Detailed DescriPtion of the Preferred Embodiments Referring to Figure 1, one embodiment of the invention includes a tape head assembly 10 with a transducer support structure 12 and a pair of islands 14 over which a magnetic recording tape 16 passes at tension Tp in the direction indicated by the arrow in Figure 1. Each island 14 provides a wear surface over which the tape 16 passes, and contains a pair of transducers 18, which may be magnetic 4b -encoding elements or decoding elements. Each encoding element forms a magnetic field in the vicinity of a narrow gap in the surface of the island 14. Each decoding element detects a magnetic field near the surface of the magnetic tape 16.
Figure 2 shows an enlarged view of a portion of an island. The island has a height IH, a width IWl in a first region surrounding a transducer, and a more narrow width IW2 in a second region located away from the region surrounding the transducer. The wider region and the narrower region are aligned along axis 20. The wider region of the island need not have the rectangular protrusions as shown, but may instead have protrusions that are trapezoidal or rounded, or of various other shapes. As a practical matter, any sharp corners, which are undesirable, are quickly rounded off when tape 16 is run over the island. The wider region of the island 14 extends in the direction of axis 20 beyond the ends of transducer 18.
As the tape runs across an island of uniform height but nonuniform width, the island will experience a pressure p that is nonuniform along the length of the island. So long as the height of the island remains uniform, the nonuniform pressure p will tend to be higher in the narrower regions of the island than in the wider regions of the island. Figures 3 and 4 illustrate, respectively, the height IH and the pressure p on the island of Fig. 1, along an axis down the center of its length L. The island is in its initial condition, at time t=0, before any wear has occured. The island has two transducers, located at points Xl and x2 along the island's length. The width of the island is greater in the vicinity of points Xl and X2 than at other locations along the island~s length. As shown in Figure 3, the island height IH is uniform across the length of the island at time t~O. As shown in Figure 4, at time tzO the pressure p is reduced over the wider regions of the island containing the transducers relative to the more narrow regions of the island.
Since the pressure intensity (force per unit area) of the tape on the island is porportional to the frictional force per unit area on the island, the wider regions of the island initially experience less friction than the narrower regions.
Thus, at time t=O the island begins to wear nonuniformly, with the regions under the most pressure experiencing the most friction, and hence experiencing the most wear. The wider regions tends to wear less because they initially experience less pressure, and hence experience less friction.
The reduced pressure over the transducer would appear to be undesirable, because as the pressure p decreases, separation between the tape and the island tends to increase, leading to "spacing loss" between the transducer and the tape. The pressure intensity does not remain nonuniform for long, however, After a short initial break-in period, the system quickly stabilizes from the configurations shown in Figures 3 and 4 to the configurations shown in Figures 5 and 6.
Figure 5 shows the island height IH at times t1, t2, and t3 as tape is passed over the island. Due to the initial non-uniform wear on the island during the break-in period as described above, at time t1 the regions surrounding the transducers have become raised with respect to the rest of the island. The raising, after break-in of the wider regions of the island tends to lead to increased pressure intensity of the tape on the raised regions. Thus the pressure intensity p of the tape on the island, which was initially reduced over the wider regions of the island as compared to the narrower regions of the island, as shown in Figure 4, quickly stabilizes to become approximately uniform along the length of the island. The uniform pressure at times t1, t2, and t3 is shown in Figure 6. Once the pressure has become uniform, the island begins to wear down uniformly, as indicated by ~IH/~t. As shown in Figure 5, the raised regions remain raised with respect to the rest of the island. Thus, the island e~xperiences nonuniform wear at a substantially uniform height profile and substantially uniform wear at a nonuniform height profile.
The process of wear is self-adjusting for the life of the head. If the raised regions become to high or too low the rate of wear on the raised regions will accordingly increase or decrease. Thus, if at time t4 the raised region in the vicinity of x1 has become too high, as shown in Figure 5, the pressure p at time t4 increases in the vicinity of X1, relative to the pressure over the rest of the island, as shown in Figure 6. The increased pressure in the vicinity of x1 causes the rate of wear of the raised region surrounding X1 to increase, so that at time t5 the height profile of the island has returned to its desired configuration as shown in Figure 5.
when the height profile has returned to its desired configuration, the pressure p once again becomes substantially 2û32~GO
-uniform along the length of the island as shown in Figure 6.
Because the regions surrounding the transducers are raised, separation between the transducers and the tape is reduced compared to the separation between the narrow regions of the island and the tape, thereby minimizing spacing-loss.
The raising of the regions of the island 2032060 ~ -surrounding the transducers ensures that any small surface irregularities in the narrow regions of the island do not lift the tape away from the transducers. The reduction in transducer-to-tape separation ensures that the tape will adequately detect the small magnetic fields created by high-density (40-60 KFCI) encoding elements, and that high-density decoding elements will adequately detect the small magnetic fields near the surface of the tape. Yet, since the reduction in transducer-to-tape separation is achieved by virtue of the geometry of the island, rather than by increasing overall pressure on the island, the overall rate of wear of t~e island is no greater than the overall rate of wear of a similar island of uniform width. Moreover, in the event of any sudden reduction in the tension of the recording tape, the raised portions of the island will tend to remain in substantial contact with the tape after the tape has begun to separate from the other parts of the island. The reduced transducer-to-tape spacing of the invention also allows the tape head assembly to be utilized with lower density transducers at reduced tens ion on the recording tape, and hence reduced pressure of the tape on the island, thereby minimizing wear on the island and lengthening the life of the head.
Other embodiments are within the following claims.
Magnetic tape head assemblies typically contain one or more raised strips or "islands" over which the magnetic recording tape passes. Embedded in each island is a transducer, which may be an encoding element for writing information onto the tape, or a decoding element for reading information off of the tape. An encoding element produces a magnetic field in the vicinity of a small gap in the encoding element, which causes information to be stored on the magnetic recording tape as the tape streams over the island in contact with the island. Likewise, a decoding element detects a magnetic field near the surface of the tape as the tape streams over the island in contact with the island. Yet, there is typically some microscopic separation between the transducer and the recording tape that reduces the magnetic field strength detected by the tape or the decoding element. The reduction in the detected magnetic field strength is known as "spacing loss."
The magnetic field strength detected by the tape or the decoding element is proportional to e kd/~ , where d is the head-to-tape separation, ~ is the recording wavelength, and k .
- lA -is a constant. The detected magnetic field strength decreases exponentially both with respect to separation between the tape and the island and with respect to recording density (which is inversely related to the recording wavelength ~). Thus, while a limited amount of head-to-tape separation might be acceptable at low recording densities of 10 - 20 KFCI, at the higher densities (40 - 60 KFCI) of new, smaller transducers the head-to-tape separation must not exceed a few micro-inches.
When a uniform tension T is applied to a recording tape as the tape passes at a wrap angle ~ around an island having a uniform height I~ and a uniform width Iw, the tape exerts a pressure P against the island that is uniform along an axis down the center of the length of the island. The pressure P is essentially proportional to the tension T and ` the wrap angle ~ and inversely proportional to the island width Iw. The pressure P of the tape against the island can be increased by increasing T or ~, or by decreasing Iw, thereby reducing any microscopic separation between the tape and the encoding element, and hence reducing spacing loss.
This increased pressure tends to cause the island to wear down more rapidly, however, resulting in a shortened head life. Moreover, the increased pressure may result in depressions in the island that also contribute to spacing loss, thus making spacing loss unavoidable.
Summary of the Invention The invention provides a tape head assembly for use in encoding or decoding a magnetic recording tape that passes over the assembly. The tape head assembly includes a transducer support that has a wear surface over which the tape passes and against which the tape exerts pressure. A
transducer is located in the support to encode or decode the tape passing over the wear surface. The wear surface has a first, wider region in proximity to the transducer, and a second, narrower region aligned with the first region along an axis. The first region has a greater extent transverse to the axis than the second region.
Initially, the wear surface is at a uniform height along its length. The pressure (force per unit area) of the tape on the wider region is less than the pressure of the tape on the narrower region. Consequently, the friction force per unit area in the wider region is less than the friction force per unit area in the narrower region. Thus the narrower region tends to wear more rapidly than the wider section, until the wider region approaches a raised height relative to the narrower region. As the wider region becomes raised, the pressure of the tape on the wider region increases relative to the initial pressure on the wider region when the wear surface is at a uniform height.
Eventually, the pressure across the entire wear surface becomes uniform, and consequently the wear across the wear surface becomes uniform. The wear surface continues to maintain a nonuniform height profile as it wears down uniformly in a self-adjusting manner.
Because the wider region containing the transducer becomes raised relative to the narrower region, spacing between the transducer and the magnetic recording tape is reduced, and the spacing tends to vary less with respect to changes in tension of the magnetic recording tape. When the wider region containing the transducer is raised relative to the narrower region, the raised wider region ensures that any small surface irregularities in the narrower region do not lift the tape away from the transducer.
The invention in its broad form resides in a tape head assembly, having a tape facing surface, for use in encoding or decoding a magnetic recording tape passing thereover comprising, a transducer support having a raised surface, and against which said tape exerts pressure, said raised surface being constructed to be ~, , .
~03206~
sufficiently close to said tape to constitute a wear surface, a transducer mounted in said support to encode or decode said tape passing over said surface, said wear surface being divided along an axis into a first region and a second region, said first region being in proximity to said transducer, said first region having a greater extent transverse to said axis than said second region, so as to present to said tape a wear surface portion that is wider than that presented by said second region, thereby permitting the maintenance of said wear surface closer to said tape in said first region than in said second region.
In preferred embodiments, the wear surface is provided by an island located on the transducer support. The island has three regions. A wide region containing the transducer is located between two narrower regions. The transducer is an encoding element for encoding information onto the magnetic recording tape, or a decoding element for reading information off of the magnetic recording tape. As the nonuniform height profile at which the island experiences substantially uniform wear, spacing between the , .,, ~,~
2Q~2060 transducer and the magnetic recording tape is low enough to permit recording by the transducer onto the magnetic recording tape at densities of at least 40 KFCI.
According to another aspect, the invention provides a method of using a tape head asæembly, having a tape facing surface, in conjunction with a magnetic recording tape, comprising the steps of providing a transducer support having a raised surface, relative to said tape facing surface, constructed to be sufficiently close to said tape to constitute a wear surface, said wear surface being divided along an axis into a first region and a second region, said first region being in proximity to a transducer, said first region having a greater extent transverse to said axis than said second region, said first region having a raised height relative to said second region, and running a tape over said wear surface in a manner such that said tape exerts pressure on said wear surface, while transferring information between said transducer and said tape, said pressure of said tape on said wear surface causing said first and second regions to tend to wear down at substantially the same rate, to thereby maintain said raised height of said first region relative to said second region, and hence to reduce separation between said tape and said transducer and thereby reduce spacing loss.
According to yet another aspect, the invention provides a method of using a tape head assembly, having a tape facing surface, in conjunction with a magnetic recording tape, comprising the steps of running tape over a raised surface, relative to said tape facing surface, surface of a transducer support in a manner such that said tape exerts pressure on said raised surface, said raised surface being constructed to be sufficiently close to said tape to constitute a wear surface, said wear surface being divided along an axis into a first region and a second region, said first region being in proximity to a transducer, said first region having a greater extent transverse to said axis than said second region, said pressure of said tape on said wear surface causing said second region to tend to wear down faster than said first region, until said first region approaches a raised height relative to said second region, at which raised height said first and second regions tend to wear down at substantially the same rate, thereby maintaining said raised height of said first region relative to said second region, and continuing to run a tape over said wear surface while transferring information between said transducer and said tape, said raised height of said first region serving to reduce separation between said tape and said transducer and thereby serving to reduce spacing loss.
Brief DescriPtion of the Drawinq A more detailed understanding of the invention may be had from the following description of a preferred embodiment, given by way of example only and to be understood in conjunction with the accompanying drawing wherein:
Figure 1 is a drawing of a tape head assembly according to one embodiment of the invention.
Figure 2 is a drawing of a portion of an island on a tape head assembly according to one embodiment of the invention.
Figure 3 is a graph showing island height as a function 4a of position along the length of the island, when the island is in its initial condition.
Figure 4 is a graph showing pressure of a tape on the island as a function of position along the length of the island, when the island is in its initial condition.
Figure 5 is a graph showing island height as a function of position along the length of the island, at several points in time after a tape has begun to wear on the island.
Figure 6 is a graph showing pressure of a tape on the island as a function of position along the length of the island, at several points in time after the tape has begun to wear on the island.
Detailed DescriPtion of the Preferred Embodiments Referring to Figure 1, one embodiment of the invention includes a tape head assembly 10 with a transducer support structure 12 and a pair of islands 14 over which a magnetic recording tape 16 passes at tension Tp in the direction indicated by the arrow in Figure 1. Each island 14 provides a wear surface over which the tape 16 passes, and contains a pair of transducers 18, which may be magnetic 4b -encoding elements or decoding elements. Each encoding element forms a magnetic field in the vicinity of a narrow gap in the surface of the island 14. Each decoding element detects a magnetic field near the surface of the magnetic tape 16.
Figure 2 shows an enlarged view of a portion of an island. The island has a height IH, a width IWl in a first region surrounding a transducer, and a more narrow width IW2 in a second region located away from the region surrounding the transducer. The wider region and the narrower region are aligned along axis 20. The wider region of the island need not have the rectangular protrusions as shown, but may instead have protrusions that are trapezoidal or rounded, or of various other shapes. As a practical matter, any sharp corners, which are undesirable, are quickly rounded off when tape 16 is run over the island. The wider region of the island 14 extends in the direction of axis 20 beyond the ends of transducer 18.
As the tape runs across an island of uniform height but nonuniform width, the island will experience a pressure p that is nonuniform along the length of the island. So long as the height of the island remains uniform, the nonuniform pressure p will tend to be higher in the narrower regions of the island than in the wider regions of the island. Figures 3 and 4 illustrate, respectively, the height IH and the pressure p on the island of Fig. 1, along an axis down the center of its length L. The island is in its initial condition, at time t=0, before any wear has occured. The island has two transducers, located at points Xl and x2 along the island's length. The width of the island is greater in the vicinity of points Xl and X2 than at other locations along the island~s length. As shown in Figure 3, the island height IH is uniform across the length of the island at time t~O. As shown in Figure 4, at time tzO the pressure p is reduced over the wider regions of the island containing the transducers relative to the more narrow regions of the island.
Since the pressure intensity (force per unit area) of the tape on the island is porportional to the frictional force per unit area on the island, the wider regions of the island initially experience less friction than the narrower regions.
Thus, at time t=O the island begins to wear nonuniformly, with the regions under the most pressure experiencing the most friction, and hence experiencing the most wear. The wider regions tends to wear less because they initially experience less pressure, and hence experience less friction.
The reduced pressure over the transducer would appear to be undesirable, because as the pressure p decreases, separation between the tape and the island tends to increase, leading to "spacing loss" between the transducer and the tape. The pressure intensity does not remain nonuniform for long, however, After a short initial break-in period, the system quickly stabilizes from the configurations shown in Figures 3 and 4 to the configurations shown in Figures 5 and 6.
Figure 5 shows the island height IH at times t1, t2, and t3 as tape is passed over the island. Due to the initial non-uniform wear on the island during the break-in period as described above, at time t1 the regions surrounding the transducers have become raised with respect to the rest of the island. The raising, after break-in of the wider regions of the island tends to lead to increased pressure intensity of the tape on the raised regions. Thus the pressure intensity p of the tape on the island, which was initially reduced over the wider regions of the island as compared to the narrower regions of the island, as shown in Figure 4, quickly stabilizes to become approximately uniform along the length of the island. The uniform pressure at times t1, t2, and t3 is shown in Figure 6. Once the pressure has become uniform, the island begins to wear down uniformly, as indicated by ~IH/~t. As shown in Figure 5, the raised regions remain raised with respect to the rest of the island. Thus, the island e~xperiences nonuniform wear at a substantially uniform height profile and substantially uniform wear at a nonuniform height profile.
The process of wear is self-adjusting for the life of the head. If the raised regions become to high or too low the rate of wear on the raised regions will accordingly increase or decrease. Thus, if at time t4 the raised region in the vicinity of x1 has become too high, as shown in Figure 5, the pressure p at time t4 increases in the vicinity of X1, relative to the pressure over the rest of the island, as shown in Figure 6. The increased pressure in the vicinity of x1 causes the rate of wear of the raised region surrounding X1 to increase, so that at time t5 the height profile of the island has returned to its desired configuration as shown in Figure 5.
when the height profile has returned to its desired configuration, the pressure p once again becomes substantially 2û32~GO
-uniform along the length of the island as shown in Figure 6.
Because the regions surrounding the transducers are raised, separation between the transducers and the tape is reduced compared to the separation between the narrow regions of the island and the tape, thereby minimizing spacing-loss.
The raising of the regions of the island 2032060 ~ -surrounding the transducers ensures that any small surface irregularities in the narrow regions of the island do not lift the tape away from the transducers. The reduction in transducer-to-tape separation ensures that the tape will adequately detect the small magnetic fields created by high-density (40-60 KFCI) encoding elements, and that high-density decoding elements will adequately detect the small magnetic fields near the surface of the tape. Yet, since the reduction in transducer-to-tape separation is achieved by virtue of the geometry of the island, rather than by increasing overall pressure on the island, the overall rate of wear of t~e island is no greater than the overall rate of wear of a similar island of uniform width. Moreover, in the event of any sudden reduction in the tension of the recording tape, the raised portions of the island will tend to remain in substantial contact with the tape after the tape has begun to separate from the other parts of the island. The reduced transducer-to-tape spacing of the invention also allows the tape head assembly to be utilized with lower density transducers at reduced tens ion on the recording tape, and hence reduced pressure of the tape on the island, thereby minimizing wear on the island and lengthening the life of the head.
Other embodiments are within the following claims.
Claims (15)
1. A tape head assembly, having a tape facing surface, for use in encoding or decoding a magnetic recording tape passing thereover comprising, a transducer support having a raised surface, and against which said tape exerts pressure, said raised surface being constructed to be sufficiently close to said tape to constitute a wear surface, a transducer mounted in said support to encode or decode said tape passing over said surface, said wear surface being divided along an axis into a first region and a second region, said first region being in proximity to said transducer, said first region having a greater extent transverse to said axis than said second region, so as to present to said tape a wear surface portion that is wider than that presented by said second region, thereby permitting the maintenance of said wear surface closer to said tape in said first region than in said second region.
2. The tape head assembly of claim 1, wherein a portion of said first region lies between said transducer and said second region along the direction of said axis.
3. The tape head assembly of claim 2, wherein said second region has first and second portions spaced along said axis and said first region extends between said portions of said second region.
4. The tape head assembly of claim 3, wherein said raised surface is an island providing said wear surface, said island extending along said axis and having a wide region separating two narrow regions, said transducer being in said wide region.
5. A tape head assembly of claim 1, wherein said regions are of material of the same wearability, so that any differential wear rate is due essentially to differential tape pressure.
6. The tape head assembly of claim 1 in a condition wherein said regions are of uniform height, so that in initial use said second region will wear faster than said first region, to bring said first region closer to said tape.
7. The tape head assembly of claim 1 in a condition wherein said first region is closer to said tape than said second region.
8. The tape head assembly of claim 1 wherein said first region extends transverse to said axis sufficiently beyond the extent of said second region to permit transfer of information between said transducer and said tape at a density of at least 40 KFCI.
9. A tape head assembly, having a tape facing surface, for use in encoding or decoding a magnetic recording tape passing thereover comprising, a transducer support having an island that provides a raised surface, and against which said tape exerts pressure, said raised surface being constructed to be sufficiently close to said tape to constitute a wear surface, and a transducer mounted in said island to encode or decode said tape passing over said wear surface, said island extending along an axis, and having a wide region separating two narrow regions, thereby permitting maintenance of said wear surface closer to said tape in said wide region than in said narrow regions, said transducer being located in said wide region, said regions being of material of the same wearability, so that any differential wear rate is due essentially to differential tape pressure.
10. A tape head assembly, having a tape facing surface, for use in encoding or decoding a magnetic recording tape passing thereover comprising a transducer support having an island that provides a raised surface, and against which said tape exerts pressure, said raised surface being constructed to be sufficiently close to said tape to constitute a wear surface, and a transducer mounted in said island to encode or decode said tape passing over said wear surface, said island extending along an axis, and having a wide region separating two narrow regions, thereby permitting maintenance of said wear surface closer to said tape in said wide region than in said narrow regions, said transducer being located in said wide region, a portion of said wide region lying between said transducer and each of said narrow regions along the direction of said axis, said wide region extending transverse to said axis sufficiently beyond the extent of said narrow regions to permit transfer of information between said transducer and said
11 tape at a density of at least 40 KFCI, said regions being of material of the same wearability, so that any differential wear rate is due essentially to differential tape pressure.
11. A method of using a tape head assembly, having a tape facing surface, in conjunction with a magnetic recording tape, comprising the steps of providing a transducer support having a raised surface, relative to said tape facing surface, constructed to be sufficiently close to said tape to constitute a wear surface, said wear surface being divided along an axis into a first region and a second region, said first region being in proximity to a transducer, said first region having a greater extent transverse to said axis than said second region, said first region having a raised height relative to said second region, and running a tape over said wear surface in a manner such that said tape exerts pressure on said wear surface, while transferring information between said transducer and said tape, said pressure of said tape on said wear surface causing said first and second regions to tend to wear down at substantially the same rate, to thereby maintain said raised height of said first region relative to said second region, and hence to reduce separation between said tape and said transducer and thereby reduce spacing loss.
11. A method of using a tape head assembly, having a tape facing surface, in conjunction with a magnetic recording tape, comprising the steps of providing a transducer support having a raised surface, relative to said tape facing surface, constructed to be sufficiently close to said tape to constitute a wear surface, said wear surface being divided along an axis into a first region and a second region, said first region being in proximity to a transducer, said first region having a greater extent transverse to said axis than said second region, said first region having a raised height relative to said second region, and running a tape over said wear surface in a manner such that said tape exerts pressure on said wear surface, while transferring information between said transducer and said tape, said pressure of said tape on said wear surface causing said first and second regions to tend to wear down at substantially the same rate, to thereby maintain said raised height of said first region relative to said second region, and hence to reduce separation between said tape and said transducer and thereby reduce spacing loss.
12. A method of using a tape head assembly, having a tape facing surface, in conjunction with a magnetic recording tape, comprising the steps of running tape over a raised surface, relative to said tape facing surface, surface of a transducer support in a manner such that said tape exerts pressure on said raised surface, said raised surface being constructed to be sufficiently close to said tape to constitute a wear surface, said wear surface being divided along an axis into a first region and a second region, said first region being in proximity to a transducer, said first region having a greater extent transverse to said axis than said second region, said pressure of said tape on said wear surface causing said second region to tend to wear down faster than said first region, until said first region approaches a raised height relative to said second region, at which raised height said first and second regions tend to wear down at substantially the same rate, thereby maintaining said raised height of said first region relative to said second region, and continuing to run a tape over said wear surface while transferring information between said transducer and said tape, said raised height of said first region serving to reduce separation between said tape and said transducer and thereby serving to reduce spacing loss.
13. The method of claim 11 or 12, wherein the step of transferring information between said transducer and said tape comprises encoding information onto the recording tape by means of the transducer.
14. The method of claim 11 or 12, wherein the step of transferring information between said transducer and said tape comprises decoding information from said recording tape by means of said transducer.
15. The method of claim 11 or 12, wherein said information on said recording tape has a density of at least 40 KFCI.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US07/462,562 | 1990-01-09 | ||
US07/462,562 US5055959A (en) | 1990-01-09 | 1990-01-09 | Tape head with low spacing loss produced by narrow and wide wear regions |
Publications (1)
Publication Number | Publication Date |
---|---|
CA2032060C true CA2032060C (en) | 1995-04-25 |
Family
ID=23836885
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CA002032060A Expired - Fee Related CA2032060C (en) | 1990-01-09 | 1990-12-12 | Self-regulating tape head |
Country Status (5)
Country | Link |
---|---|
US (1) | US5055959A (en) |
EP (1) | EP0437147B1 (en) |
JP (1) | JP2593964B2 (en) |
CA (1) | CA2032060C (en) |
DE (1) | DE69029931T2 (en) |
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US5307227A (en) * | 1991-08-06 | 1994-04-26 | Sharp Kabushiki Kaisha | Magnetic recording/reproducing apparatus capable of high-density recording on a magnetic tape guided at high speed |
US5426551A (en) * | 1993-07-19 | 1995-06-20 | Quantum Corp. | Magnetic contact head having a composite wear surface |
JPH09503606A (en) * | 1993-07-19 | 1997-04-08 | クウォンタム・コーポレイション | Magnetic head with self-regulating wear area |
US5615069A (en) * | 1995-06-07 | 1997-03-25 | Seagate Technology, Inc. | Thin-film transducer design for undershoot reduction |
JPH11510297A (en) * | 1995-07-26 | 1999-09-07 | クウォンタム・コーポレイション | Method and apparatus for a multi-channel head assembly |
US5774306A (en) * | 1996-11-12 | 1998-06-30 | Seagate Technology, Inc. | Multi-channel, high speed, tape head contour |
US5973872A (en) * | 1997-01-23 | 1999-10-26 | Quantum Corporation | Method and apparatus for a low cost multi-channel tape recording head |
US6236537B1 (en) * | 1997-10-28 | 2001-05-22 | Hewlett-Packard Co. | Wear resistant magnetic write head |
US5969912A (en) * | 1997-12-10 | 1999-10-19 | Cope; James Robert | Bidirectional magnetic read/write recording head surface contour with plurality of Bernoulli Pocket cavities for generating very low media-to-head separations |
US6288870B1 (en) | 1998-01-13 | 2001-09-11 | Quantum Corporation | Self-aligned metal film core multi-channel recording head for tape drives |
US6064529A (en) * | 1998-07-02 | 2000-05-16 | Optiteck, Inc. | Spherical aberration correction using flying lens and method |
US6639753B1 (en) | 2000-09-01 | 2003-10-28 | Hewlett-Packard Development Company, L.P. | Method of forming a head assembly, a head assembly, and a linear tape drive |
US6937435B2 (en) * | 2003-05-16 | 2005-08-30 | Quantum Corporation | Tape head with thin support surface and method of manufacture |
US7085095B2 (en) * | 2003-10-20 | 2006-08-01 | Quantum Corporation | Electromagnetic void-sensing probes and position control systems |
US7102845B2 (en) * | 2003-10-20 | 2006-09-05 | Quantum Corporation | Servo methods and systems using existing data structures and medium edge position |
US7139152B2 (en) * | 2003-10-20 | 2006-11-21 | Quantum Corporation | Servo methods and systems using existing data structures and optical masks |
US7149050B2 (en) * | 2003-10-20 | 2006-12-12 | Quantum Corporation | Diffractive position sensors and control systems |
US7136255B2 (en) * | 2003-10-20 | 2006-11-14 | Quantum Corporation | Servo methods and systems using masked medium edge position sensors |
US7116514B2 (en) * | 2003-10-20 | 2006-10-03 | Quantum Corporation | Methods and systems for magnetic recording |
US7154691B2 (en) * | 2003-12-18 | 2006-12-26 | Quantum Corporation | Multi-format thinfilm head and associated methods |
US7184233B2 (en) * | 2004-06-04 | 2007-02-27 | Quantum Corporation | Dual source tracking servo systems and associated methods |
US7256963B2 (en) * | 2004-09-16 | 2007-08-14 | Quantum Corporation | Magnetic head with adaptive data island and mini-outrigger and methods of manufacture |
US7271983B2 (en) * | 2004-09-16 | 2007-09-18 | Quantum Corporation | Magnetic head with mini-outriggers and method of manufacture |
US20060103968A1 (en) * | 2004-11-12 | 2006-05-18 | Jurneke Joe K | Dynamic skew compensation systems and associated methods |
US7369362B2 (en) * | 2005-03-16 | 2008-05-06 | Quantum Corporation | Tape cleaning apparatus |
US7499235B2 (en) * | 2005-03-18 | 2009-03-03 | Quantum Corporation | Auto-servo tape system and associated recording head |
US20070183091A1 (en) * | 2006-02-03 | 2007-08-09 | Saliba George A | Read/write head having varying wear regions and methods of manufacture |
US7826169B2 (en) * | 2007-04-25 | 2010-11-02 | Quantum Corporation | Servo error detection and compensation utilizing virtual data tracking servo methods |
US8964319B1 (en) | 2014-03-05 | 2015-02-24 | International Business Machines Corporation | Tape media kiss-contact read verification |
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JPS55117728A (en) * | 1979-03-06 | 1980-09-10 | Victor Co Of Japan Ltd | Magnetic head |
US4300179A (en) * | 1979-09-04 | 1981-11-10 | Minnesota Mining And Manufacturing Co. | Composite magnetic head with multitrack support structure |
JPS57189325A (en) * | 1981-05-18 | 1982-11-20 | Toshiba Corp | Composite magnetic head |
JPH0622042B2 (en) * | 1983-11-10 | 1994-03-23 | 株式会社日立製作所 | Magnetic head |
JPS60131604A (en) * | 1983-12-20 | 1985-07-13 | Victor Co Of Japan Ltd | Magnetic recording and reproducing element |
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JPS62259208A (en) * | 1986-05-06 | 1987-11-11 | Nippon Hoso Kyokai <Nhk> | Magnetic head |
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JPS63231707A (en) * | 1987-03-19 | 1988-09-27 | Hitachi Ltd | Magnetic head |
US4839959A (en) * | 1987-10-22 | 1989-06-20 | Odetics, Inc. | Method of forming a magnetic head |
JPH01158607A (en) * | 1987-12-15 | 1989-06-21 | Hitachi Ltd | Magnetic head |
US4853814A (en) * | 1987-12-28 | 1989-08-01 | Eastman Kodak Company | Magnetic head with constant area wear profile |
JPH03502743A (en) * | 1987-12-28 | 1991-06-20 | イーストマン・コダック・カンパニー | Shaped head assembly used in cassette-loading recorders |
DE3850494T2 (en) * | 1987-12-28 | 1995-01-26 | Eastman Kodak Co | MAGNETIC HEAD WITH CONSTANT SUPPORT ZONE WEAR PROFILE. |
US4949208A (en) * | 1988-04-13 | 1990-08-14 | Eastman Kodak Company | Multihead magnetic head assembly having a single piece faceplate of magnetic ferrite |
-
1990
- 1990-01-09 US US07/462,562 patent/US5055959A/en not_active Expired - Lifetime
- 1990-12-12 CA CA002032060A patent/CA2032060C/en not_active Expired - Fee Related
- 1990-12-27 EP EP90403787A patent/EP0437147B1/en not_active Expired - Lifetime
- 1990-12-27 DE DE69029931T patent/DE69029931T2/en not_active Expired - Fee Related
-
1991
- 1991-01-08 JP JP3000427A patent/JP2593964B2/en not_active Expired - Fee Related
Also Published As
Publication number | Publication date |
---|---|
EP0437147A3 (en) | 1992-08-05 |
US5055959A (en) | 1991-10-08 |
DE69029931T2 (en) | 1997-09-04 |
EP0437147B1 (en) | 1997-02-12 |
JP2593964B2 (en) | 1997-03-26 |
EP0437147A2 (en) | 1991-07-17 |
JPH04162205A (en) | 1992-06-05 |
DE69029931D1 (en) | 1997-03-27 |
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EEER | Examination request | ||
MKLA | Lapsed |