Data carrier apparatus, data carrier drive apparatus, data communication system, image forming apparatus and replacement unit for the same

A system includes a data carrier drive apparatus and a data carrier apparatus. The data carrier apparatus includes a unit to output transmission data during a first state and adjustment data during a second state, and a current changer configured to change a current value of a current flowing from the data carrier drive apparatus to the data carrier apparatus according to data values of the transmission data and the adjustment data. The data carrier drive apparatus includes a detector to detect a detection value corresponding to the current value of the current, a determiner to determine the data value of the transmission data by comparing the detection value with a threshold value during the first state, and an updater to update the threshold value based on the detection value during the second state.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a data communication technique between a data carrier apparatus and a data carrier drive apparatus.

Description of the Related Art

US 2006/0098691 A1 discloses a data communication system including a data carrier drive apparatus and a data carrier apparatus. According to US 2006/0098691 A1, the data carrier drive apparatus transmits data to the data carrier apparatus by changing a duty ratio of a pulse signal. Further, the data carrier apparatus transmits data to the data carrier drive apparatus by turning a constant current source on and off.

In a configuration disclosed in US 2006/0098691 A1, the current value when the data carrier apparatus turns on the constant current source, and the current value when the data carrier apparatus turns off the constant current source may change due to a temperature change during operation of the data communication system. Further, variations may occur in the current value when the constant current source is turned on and the current value when the constant current source is turned off due to variations in elements and circuits of individual data carrier apparatuses. The data carrier drive apparatus is required to accurately discriminate data from the data carrier apparatus regardless of the variations in the current value for individual data carrier apparatuses and changes in the current value during operation.

SUMMARY OF THE INVENTION

According to an aspect of the present disclosure, a data communication system includes a data carrier drive apparatus and a data carrier apparatus. The data carrier apparatus includes: an output unit configured to output transmission data to be transmitted to the data carrier drive apparatus during a first state and output adjustment data to be transmitted to the data carrier drive apparatus during a second state; and a current changer configured to change a current value of an inter-apparatus current flowing from the data carrier drive apparatus to the data carrier apparatus according to data values of the transmission data and the adjustment data. The data carrier drive apparatus includes: a detector configured to detect a detection value corresponding to the current value of the inter-apparatus current; a determiner configured to determine the data value of the transmission data by comparing the detection value detected by the detector with a threshold value during the first state; and an updater configured to update the threshold value based on the detection value detected by the detector during the second state.

DESCRIPTION OF THE EMBODIMENTS

First Embodiment

FIG.1is a configuration diagram of a data communication system100according to the present embodiment. The data communication system100includes a data carrier drive apparatus102and a data carrier apparatus101. The data carrier drive apparatus102has a terminal A and a terminal B, and the data carrier apparatus101has a contact A and a contact B. Here, as illustrated inFIG.1, the terminal A and the contact A are connected by a communication line, the terminal B and the contact B are connected by a communication line, and the data carrier apparatus101and the data carrier drive apparatus102transmit and receive data through these two communication lines. Further, the data carrier drive apparatus102supplies operating power for the data carrier apparatus101to the data carrier apparatus101through the two communication lines.

For example, the data communication system100according to the present embodiment can be applied to an image forming apparatus. Specifically, the data carrier drive apparatus102is provided in a main body of the image forming apparatus, and the data carrier apparatus101is provided in a replacement unit for the image forming apparatus. Then, when the replacement unit is attached to the image forming apparatus, the image forming apparatus is configured so that the data carrier drive apparatus102and the data carrier apparatus101are connected by the two communication lines. Further, the data carrier apparatus101is provided with a memory (not shown) in which information regarding the replacement unit is stored. Thus, the image forming apparatus can acquire information about the replacement unit stored in the memory by using the data communication system100. Note that the information stored in the memory can be, for example, information regarding authentication of the replacement unit or information regarding control parameters in image formation control performed using the replacement unit.

As illustrated inFIG.2, the data communication system100according to the present embodiment transmits and receives data while transitioning between four states of a standby state, a transmission state, an adjustment state, and a reply state, which are communication states. Note that the transition order is the order illustrated inFIG.2. The transmission state is a state in which the data carrier drive apparatus102transmits command data (transmission data) to the data carrier apparatus101. For example, the data carrier drive apparatus102can use command data to instruct the data carrier apparatus101to read the data stored in the memory (not shown) of the data carrier apparatus101. When the data carrier drive apparatus102completes transmission of the command data, it transits to the adjustment state.

The adjustment state is a state in which the data carrier apparatus101analyzes the command data received in the transmission state, performs processing according to the command data, and acquires or generates reply data (transmission data) to be returned to the data carrier drive apparatus102in the subsequent reply state. Note that the data carrier apparatus101transmits adjustment data (threshold determination data) to the data carrier drive apparatus102in the adjustment state. The adjustment data is data for enabling the data carrier drive apparatus102to correctly demodulate the data transmitted (returned) by the data carrier apparatus101to the data carrier drive apparatus102in the reply state following the adjustment state. In the reply state, the data carrier apparatus101transmits the reply data to the data carrier drive apparatus102. For example, when the command received in the transmission state is to read data in the memory, the reply data includes values of the data stored in the memory. When the data carrier apparatus101completes the transmission of the reply data, it transits to the standby state. The standby state is a state in which data is not transmitted or received until the data carrier drive apparatus102transmits the next piece of command data to the data carrier apparatus101.

First, the data carrier drive apparatus102shown inFIG.1will be described. A first power supply107of the data carrier drive apparatus102outputs a voltage value V1to a demodulator106. Further, a second power supply108outputs a voltage value V2to a voltage converter112. Note that the voltage value V2is smaller than the voltage value V1. A processing unit or processor103creates command data, adjusts a threshold value that is based on the adjustment data received from the data carrier apparatus101, performs processing that is based on the reply data received from the data carrier apparatus101, and the like. Further, the processing unit103also manages the communication state.

A modulator105generates a clock pulse signal according to the command data generated by the processing unit103. Specifically, a duty ratio setting unit114stores values indicating two duty ratios of a duty ratio A and a duty ratio B. In the present embodiment, it is assumed that a value indicating the duty ratio A having a duty ratio smaller than 50% and a value indicating the duty ratio B having a duty ratio larger than 50% are stored. The duty ratio setting unit114selects the duty ratio A or the duty ratio B according to a data value of the command data, and notifies a generator113of the selected duty ratio. The generator113generates a clock pulse signal according to the duty ratio from the duty ratio setting unit114and outputs it to the voltage converter112. That is, the pulse of the clock pulse signal output by the generator113is one of the two pulses of the duty ratio A and the duty ratio B. Note that, in this example, it is assumed that the pulse of the duty ratio A indicates a bit value “0” and the pulse of the duty ratio B indicates a bit value “1”.

The voltage converter112outputs the voltage value V2output by the second power supply108to the terminal B while the input clock pulse signal is at a low level, and outputs 0V (GND) to the terminal B while the clock pulse signal is at a high level. Therefore, when the clock pulse signal input to the voltage converter112is as illustrated inFIG.3, a waveform of a voltage Vb output by the voltage converter112to the terminal B is also as illustrated inFIG.3.

The demodulator106demodulates the reply data transmitted by the data carrier apparatus101and outputs a demodulated signal to the processing unit103.FIG.4illustrates a detailed configuration of the demodulator106. A converter110has a current detection resistor Ri, and the current detection resistor Ri converts an inter-apparatus current Ia (hereinafter, simply referred to as a current Ia) flowing from the first power supply107to the data carrier apparatus101into a voltage Va. Although details will be described below, the data carrier apparatus101changes the value of the current Ia according to the data value transmitted to the data carrier drive apparatus102. In this example, when the data value transmitted to the data carrier drive apparatus102is “1”, the value of the current Ia is increased as compared with the case where the data value is “0”. The voltage Va is also a voltage of the contact A (terminal A) of the data carrier apparatus101. Here, the voltage Va=V1−IH×Ri when Ia=IH (corresponding to the data value “1”) is expressed as a voltage value Vy below, and the voltage Va=V1−IL×Ri when Ia=IL (corresponding to the data value “0”)<IH is expressed as a voltage value Vx below. For example, when the current Ia changes as illustrated inFIG.3, the voltage Va also changes as illustrated inFIG.3. This voltage Va is input to an AD port of the processing unit103and a comparator of a determiner109.

A threshold setting unit111has a variable resistor130including, for example, a digital potentiometer, and divides a voltage V1output from the first power supply107based on a control signal input from the processing unit103, to generate a threshold voltage Vth. The threshold voltage Vth from the threshold setting unit111and the voltage Va from the converter110are input to the comparator of the determiner109. Here, the threshold voltage Vth is set to a value that is larger than the voltage value Vy that the voltage Va can take and smaller than the voltage value Vx. The comparator of the determiner109compares the threshold voltage Vth with the voltage Va, and outputs a comparison result as a demodulated signal to the processing unit103. In this example, the comparator is to output the demodulated signal at the high level while the voltage Va is larger than the threshold voltage Vth, and output the demodulated signal at the low level while the voltage Va is smaller than the threshold voltage Vth. The processing unit103determines the data value of the reply data based on the demodulated signal. Note that, in this example, as described above, when the data value of the reply data is “1”, the voltage Va is the voltage value Vy, and when the data value of the reply data is “0”, the voltage Va is the voltage value Vx>the voltage value Vy. Therefore, when the data value of the reply data is “1”, the demodulated signal is at the low level, and when the data value of the reply data is “0”, the demodulated signal is at the high level. Therefore, the processing unit103determines that the data value of the reply data is “1” when the demodulated signal is at the low level, and determines that the data value of the reply data is “0” when the demodulated signal is at the high level.

As described above, the data carrier apparatus101transmits the adjustment data during the adjustment state. Further, the processing unit103detects the voltage Va that changes according to the adjustment data during the adjustment state, and determines a value of the threshold voltage Vth based on the detected value. Then, the processing unit103transmits the control signal to the variable resistor130in order to update the threshold voltage Vth to the determined value. Note that a method of determining the threshold voltage Vth will be described below. Then, during the reply state, the determiner109makes a comparison with the voltage Va using the value of the threshold voltage Vth determined during the previous adjustment state. In this way, the threshold value (threshold voltage Vth) used for data demodulation in the reply state is adjusted based on the adjustment data transmitted by the data carrier apparatus101to the data carrier drive apparatus102during the immediately preceding adjustment state.

When the voltage (voltage Vb) of the terminal B and the voltage (voltage Va) of the terminal A change as illustrated inFIG.3, a pulse voltage Vab between the terminal A and the terminal B also changes as illustrated inFIG.3. The pulse voltage Vab is also a voltage between the contact A and the contact B of the data carrier apparatus101. That is, when the voltage (voltage Vb) of the terminal B and the voltage (voltage Va) of the terminal A change as illustrated inFIG.3, the pulse voltage Vab illustrated inFIG.3is applied to the data carrier apparatus101.

Next, each block of the data carrier apparatus101will be described. A power supply generator118generates a voltage Vp used by the data carrier apparatus101by smoothing the pulse voltage Vab applied from the data carrier drive apparatus102. The voltage Vp is supplied to each part of the data carrier apparatus101. A signal converter124converts the pulse voltage Vab into a value that can be used in the data carrier apparatus101. In the present embodiment, the signal converter124converts the pulse voltage Vab into the voltage Vp when the pulse voltage Vab is at the high level (voltage value Vx or voltage value Vy), and converts the pulse voltage Vab into a reference voltage lower than the voltage Vp when the pulse voltage Vab is at the low level (voltage value (Vx−V2)). In the present embodiment, the reference voltage is set to 0V. The signal converter124outputs the converted signal to a demodulator122as a received pulse signal and outputs the converted signal to a processing unit123as a synchronization signal. An internal clock generator116generates an internal clock having a frequency sufficiently higher than that of the pulse voltage Vab and outputs the internal clock to the demodulator122and the processing unit123.

The demodulator122determines the duty ratio of the received pulse signal in the transmission state, determines (demodulates) the data value of the command data based on this determined result, and outputs the determined data value to the processing unit123. For example, when the received pulse signal illustrated inFIG.5is input to the demodulator122, the demodulator122counts a high level period and a low level period within one pulse period of the received pulse signal at a falling edge of the internal clock. Then, the demodulator122determines that the data value of the command data is “1” (duty ratio B) if the high level period is longer than the low level period, and if not, determines that the data value of the command data is “0” (duty ratio A).

The processing unit123manages the communication state. The processing unit123receives command data from the data carrier drive apparatus102during the transmission state, and generates reply data during the adjustment state. Then, the processing unit123outputs a reply signal corresponding to the reply data to a switching unit117during the reply state. Further, the processing unit123outputs an adjustment signal corresponding to the adjustment data to the switching unit117during the adjustment state. Further, the processing unit123monitors the transmission of the command data by the data carrier drive apparatus102during the standby state. In the present embodiment, signals output by the processing unit123are referred to as a reply signal and an adjustment signal in order to distinguish them from the reply data and the adjustment data transmitted to the data carrier drive apparatus102. However, the reply signal output by the processing unit123can be called reply data (transmission data), and the adjustment signal can also be called adjustment data.

The switching unit117transmits the reply data and the adjustment data to the data carrier drive apparatus102by controlling the current Ia flowing from the data carrier drive apparatus102to the data carrier apparatus101based on the reply signal and the adjustment signal. In this way, the switching unit117functions as a current changer that changes the current Ia according to the data value of the data transmitted to the data carrier drive apparatus102. In this example, when the data values of the reply data and the adjustment data are “0”, the reply signal and the adjustment signal are set to the low level. On the other hand, when the data values of the reply data and the adjustment data are “1”, the reply signal and the adjustment signal are set to the high level for a predetermined period.FIG.6is a configuration diagram of the switching unit117. A switch126includes a switch element such as an FET, and is turned on/off according to the reply signal and the adjustment signal output from the processing unit123. In this example, it is assumed that the switch126is in an ON state while the reply signal and the adjustment signal are at the high level, and the switch126is in an OFF state while the reply signal and the adjustment signal are at the low level. While the switch126is in the ON state, a current of a current value Id flows from a current source125to the switching unit117. On the other hand, while the switch126is in the OFF state, no current flows through the switching unit117. For example, when the reply signal or the adjustment signal changes as illustrated inFIG.7, the current flowing through the switching unit117also changes as illustrated inFIG.7. Here, when the total current value of the currents flowing through functional blocks other than the switching unit117of the data carrier apparatus101is Ic, the current Ia also changes as illustrated inFIG.7. Therefore, the voltage Va also changes as illustrated inFIG.7. Here, a voltage value Vc=V1−Ri×Ic, and a voltage value Vcd=V1−Ri×(Ic+Id). Note that the voltage value Vc corresponds to the voltage value Vx inFIG.3, and the voltage value Vcd corresponds to the voltage value Vy inFIG.3.

FIG.8illustrates time change of each signal in the reply state. The modulator105of the data carrier drive apparatus102continues to output the clock pulse signal of the duty ratio B (corresponding to the data value “1”) during a state different from the transmission state. This is to maintain synchronization between the data carrier drive apparatus102and the data carrier apparatus101. Since a waveform of the synchronization signal output by the signal converter124to the processing unit123is the same as the clock pulse signal, it is as illustrated inFIG.8. However, the high level and low level voltage values of the synchronization signal are different from the clock pulse signal. For example, as illustrated inFIG.8, it is assumed that the reply data is “00110101”. As described above, the processing unit123sets the reply signal at the low level when the data value of the reply data is “0”. On the other hand, when the data value is “1”, the processing unit123generates a reply signal that is at the high level while the synchronization signal is at the high level and that is at the low level while the synchronization signal is at the low level. Therefore, the reply signal output by the processing unit123is as illustrated inFIG.8.

As described above, since the switch126of the switching unit117is in the ON state while the reply signal is at the high level, and the switch126of the switching unit117is in the OFF state while the reply signal is at the low level, the current Ia and the voltage Va change as illustrated inFIG.8. As described above, since the threshold voltage Vth is set to be between the voltage value Vx=Vc and the voltage value Vy=Vcd, the demodulated signal output by the determiner109is as illustrated inFIG.8. The processing unit103detects the level of the demodulated signal at a timing slightly before the falling edge of the clock pulse signal (a timing indicated by an arrow inFIG.8), and determines that the data value is “0” if the level is the high level, and determines that the data value is “1” if the level is the low level. In this example, when the reply data is “1”, the pulse waveform of the reply signal is the same as the pulse waveform of the synchronization signal, but it can also be configured to keep the reply signal at the high level for a period of 1 bit when the reply data is “1”.

Subsequently, a process of determining the threshold voltage Vth performed during the adjustment state will be described. Note that, in the following, it is assumed that a period of the adjustment state is 8 cycles in the pulse cycle of the clock pulse signal. During the adjustment state, the modulator105of the data carrier drive apparatus102outputs the clock pulse signal illustrated inFIG.9, and thus the signal converter124outputs the synchronization signal illustrated inFIG.9to the processing unit123. The processing unit123sets the data value of the adjustment data to “0” in the first half period of the adjustment state, and sets the data value of the adjustment data to “1” in the second half period. Therefore, the processing unit123outputs the adjustment signal illustrated inFIG.9. Accordingly, the current Ia and the voltage Va also change as illustrated inFIG.9.

The processing unit103of the data carrier drive apparatus102acquires the voltage Va from the converter110. Then, the processing unit103determines the voltage value of the voltage Va at the same timing (a timing indicated by an arrow inFIG.9) as when the reply data is determined. In this example, “0” is transmitted four times (4 bits) and “1” is transmitted four times as the data value of the adjustment data. Therefore, the processing unit103detects the voltage value of the voltage Va when the data value is “0” and the voltage value of the voltage Va when the data value is “1” four times, respectively. The processing unit103obtains an average value Ac of the voltage values of the voltage Va when the data value is “0” and an average value Acd of the voltage values of the voltage Va when the data value is “1”, and determines the threshold voltage Vth as a value smaller than the average value Ac and larger than the average value Acd. For example, the processing unit103can determine the threshold voltage Vth as an average value (intermediate value) of the average value Ac and the average value Acd.

In the present embodiment, the period of the adjustment state is set to 8 cycles of the clock pulse signal, the data value of the adjustment data is set to “0” in its first half period, and the data value of the adjustment data is set to “1” in the second half period. However, a period in which the data value of the adjustment data is set to “0” and a period in which the data value of the adjustment data is set to “1” are arbitrary. Further, the period in which the data value of the adjustment data is set to “0” and the period in which the data value of the adjustment data is set to “1” may differ from each other. Further, one of the data values “0” and “1” is continuously transmitted at the beginning of the adjustment state, and the other data value is continuously transmitted in the remaining period, but the present invention is not limited to such data pattern. That is, the data pattern of the adjustment data in the present embodiment is “00001111”. However, if the data pattern of the adjustment data is known between the data carrier apparatus101and the data carrier drive apparatus102, any data pattern can be used as the adjustment data.

As described above, the data carrier drive apparatus102adjusts the threshold value based on the known adjustment data transmitted by the data carrier apparatus101during the adjustment state. With this configuration, the data carrier drive apparatus102can accurately demodulate the reply data regardless of variations in the current Ia due to individual differences of the data carrier apparatus101and changes in the current Ia due to a temperature change. In the present embodiment, the threshold value is adjusted each time the adjustment state is entered, but the threshold value may also be adjusted each time the number of times the adjustment state is entered reaches a predetermined value.

Second Embodiment

Next, a second embodiment will be described focusing on differences from a first embodiment.FIG.10is a configuration diagram of a data communication system200according to the present embodiment. Note that, of components of the data communication system200, the same components as those described in the first embodiment (FIG.1) are denoted by the same reference numerals, and a description thereof will be basically omitted. In the present embodiment, a switching unit217is provided in place of the switching unit117of the first embodiment (FIG.1).

FIG.11is a configuration diagram of the switching unit217. The switches226and228are switch elements such as bipolar transistors. The switch226is turned on/off according to the reply signal from the processing unit123. Note that the switch226is turned on when the reply signal is at the high level, and the current of the current value Id flows through the switch226and a resistor225. On the other hand, the switch226is turned off when the reply signal is at the low level, and no current flows through a series connection configuration portion of the switch226and the resistor225. Similarly, the switch228is turned on/off according to the adjustment signal from the processing unit123. The switch228is turned on when the adjustment signal is at the high level, and a current of a current value Ie flows through the switch228and a resistor227. On the other hand, the switch228is turned off when the adjustment signal is at the low level, and no current flows through a series connection configuration portion of the switch228and the resistor227. Note that the reply signal is set to the low level during the adjustment state, and the adjustment signal is set to the low level during the reply state.

Therefore, during the reply state, if the reply data is “1” (the reply signal is at the high level), the current value Id flows through the switching unit217, and if the reply data is “0” (the reply signal is at the low level), no current flows through the switching unit217. That is, an operation during the reply state is the same as that of the first embodiment. On the other hand, during the adjustment state, if the adjustment data is “1” (the adjustment signal is at the high level), the current value Ie flows through the switching unit217, and if the adjustment data is “0” (the adjustment signal is at the low level), no current flows through the switching unit217. Here, in the present embodiment, resistance values of the resistor225and the resistor227are set so that the current value Ie is half the current value Id.

FIG.12illustrates a time change of each signal in the adjustment state. In the first embodiment, the adjustment data has at least one data value “0” and at least one data value “1”. In the present embodiment, the adjustment data is a continuous pattern of the data value “1”. Therefore, during switching states, the current Ia is a current value (Ic+Ie) while the synchronization signal is at the high level, and is a current value Ic while the synchronization signal is at the low level. Similar to the first embodiment, the processing unit103of the data carrier apparatus acquires the voltage value of the voltage Va at the timing before the falling edge of the clock pulse signal. That is, the processing unit103acquires a voltage value Vce of the voltage Va when the current value of the current Ia is Ic+Ie. Here, Vce is Vce=V1−Ri×(Ic+Ie)=V1−Ri×(Ic+Id/2). The voltage value Vce is an intermediate value between the voltage value Vc and the voltage value Vcd in the reply state. Therefore, the processing unit103determines an average value of the voltage value Vce acquired at each timing as the value of the threshold voltage Vth, and outputs the control signal to the threshold setting unit111so as to be the determined threshold voltage Vth.

As described above, the data carrier drive apparatus102adjusts the threshold value based on the known adjustment data transmitted by the data carrier apparatus101during the adjustment state. With this configuration, the data carrier drive apparatus102can accurately demodulate the reply data regardless of variations in the current Ia due to individual differences of the data carrier apparatus101and changes in the current Ia due to temperature changes. In the present embodiment, the threshold value is adjusted each time the adjustment state is entered, but the threshold value may be adjusted each time the number of times the adjustment state is entered reaches the predetermined value. Further, in the present embodiment, the current value Ie is set to half the current value Id, but the current value Ie only has to be larger than 0 and smaller than the current value Id. Further, in the present embodiment, the adjustment data is the continuous pattern of the data value “1”. However, the data pattern of the adjustment data only has to include at least one data value “1”. The data carrier drive apparatus102determines the threshold value based on the voltage value of the voltage Va when the data value is “1”.

Other Embodiments

This application claims the benefit of Japanese Patent Application No. 2020-022668, filed Feb. 13, 2020, which is hereby incorporated by reference herein in its entirety.